WO2006027711A2 - Prodrugs and codrugs containing bio- cleavable disulfide linkers - Google Patents

Prodrugs and codrugs containing bio- cleavable disulfide linkers Download PDF

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Publication number
WO2006027711A2
WO2006027711A2 PCT/IB2005/052797 IB2005052797W WO2006027711A2 WO 2006027711 A2 WO2006027711 A2 WO 2006027711A2 IB 2005052797 W IB2005052797 W IB 2005052797W WO 2006027711 A2 WO2006027711 A2 WO 2006027711A2
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Prior art keywords
drugs
mmol
prodrug
acid
group
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PCT/IB2005/052797
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French (fr)
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WO2006027711A3 (en
Inventor
Apparao Satyam
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Nicholas Piramal India Limited
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Publication date
Priority to CA002577490A priority Critical patent/CA2577490A1/en
Priority to EP05781464A priority patent/EP1789091B1/en
Priority to MX2007002210A priority patent/MX2007002210A/en
Priority to DE602005023185T priority patent/DE602005023185D1/en
Priority to BRPI0515218-6A priority patent/BRPI0515218A/en
Priority to JP2007529100A priority patent/JP5198063B2/en
Application filed by Nicholas Piramal India Limited filed Critical Nicholas Piramal India Limited
Priority to NZ552539A priority patent/NZ552539A/en
Priority to AU2005281359A priority patent/AU2005281359A1/en
Priority to AT05781464T priority patent/ATE478685T1/en
Publication of WO2006027711A2 publication Critical patent/WO2006027711A2/en
Priority to IL181504A priority patent/IL181504A0/en
Publication of WO2006027711A3 publication Critical patent/WO2006027711A3/en

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    • A—HUMAN NECESSITIES
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    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/56—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule
    • A61K47/61—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule the organic macromolecular compound being a polysaccharide or a derivative thereof
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    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D211/00—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings
    • C07D211/04—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D211/80—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having two double bonds between ring members or between ring members and non-ring members
    • C07D211/84—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having two double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen directly attached to ring carbon atoms
    • C07D211/90—Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen
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    • A61K31/21—Esters, e.g. nitroglycerine, selenocyanates
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    • A61K31/335—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin
    • A61K31/337—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having four-membered rings, e.g. taxol
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    • A61K47/55—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound the modifying agent being also a pharmacologically or therapeutically active agent, i.e. the entire conjugate being a codrug, i.e. a dimer, oligomer or polymer of pharmacologically or therapeutically active compounds
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    • A61K47/555—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound pre-targeting systems involving an organic compound, other than a peptide, protein or antibody, for targeting specific cells
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    • A61K47/56—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule
    • A61K47/59—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyureas or polyurethanes
    • A61K47/60—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyureas or polyurethanes the organic macromolecular compound being a polyoxyalkylene oligomer, polymer or dendrimer, e.g. PEG, PPG, PEO or polyglycerol
    • A—HUMAN NECESSITIES
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    • C07D233/91—Nitro radicals

Definitions

  • the present invention relates to compositions of prodrugs, including NO-releasing prodrugs, codrugs, double prodrugs and mutual prodrugs, containing bio-labile linkers and linkages, processes for their preparation and pharmaceutical compositions containing them and their use.
  • a prodrug is an active drug chemically transformed into a per se inactive derivative which by virtue of chemical or enzymatic attack is converted to the parent drug within the body before or after reaching the site of action.
  • the process of converting an active drug into inactive form is called drug latentiation.
  • Prodrugs can be carrier-linked- prodrugs and bioprecursors.
  • the carrier-linked prodrug results from a temporary linkage of the active molecule with a transport moiety.
  • Such prodrugs are less active or inactive compared to the parent active drug.
  • the transport moiety will be chosen for its non- toxicity and its ability to ensure the release of the active principle with efficient kinetics.
  • the bioprecursors result from a molecular modification of the active principle itself by generation of a new molecule that is capable of being a substrate to the metabolizing enzymes releasing the active principle as a metabolite.
  • Prodrugs are prepared to alter the drug pharmacokinetics, improve stability and solubility, decrease toxicity, increase specificity, and increase duration of the pharmacological effect of the drug.
  • By altering pharmacokinetics the drug bioavailability is increased by increasing absorption, distribution, biotransformation, and excretion of the drug.
  • Limited intestinal absorption, distribution, fast metabolism, and toxicity are some of the causes of failure of drug candidates during development. Avoidance of the foreseeable or proven pharmacokinetic defects thus assumes considerable significance in drug research. Accordingly, prodrugs play a significant role in drug research as well.
  • the linkage between the carrier and the drug is usually a covalent bond
  • the prodrug is inactive or less active than the active principle
  • the prodrug synthesis should not be expensive
  • the prodrug has to be reversible or bioreversible derivative of the drug
  • the carrier moiety must be non-toxic and inactive when released.
  • Prodrugs are usually prepared by: a) formation of ester, hemiesters, carbonate esters, nitrate esters, amides, hydroxamic acids, carbamates, imines, mannich bases, and enamines of the active drug, b) functionalizing the drug with azo, glycoside, peptide, and ether functional groups, c) use of polymers, salts, complexes, phosphoramides, acetals, hemiacetals, and ketal forms of the drug. For example, see Andrejus Korolkovas's, "Essentials of Medicinal Chemistry", pp. 97-118.
  • NO endothelium-derived nitric oxide
  • NO is produced from arginine by the catalytic action of nitric oxide synthase. See, for example, Nathan, C. et al., Cell 1994, 78, 915, and Marietta, M. A., Cell 1994, 78, 927.
  • NO is a free radical as well as a scavenger of free radicals. NO reacts quickly with ubiquitously generated reactive oxygen species (ROS) such as superoxide (O 2 " ) to generate a nefarious peroxynitrite (ONOO " ) molecule, which is implicated in many human diseases such as diabetes, heart disease, Alzheimer's disease and multiple sclerosis. In this setting, NO is often viewed as pathogenic. However, the chemistry of NO can also be a significant factor in lessening the injury mediated by reactive oxygen species (ROS) and reactive nitrogen oxide species (RNOS). There is a relationship between NO and oxidation, nitrosation and nitration reactions. A number of factors determine whether NO promotes, abates or interconnects these chemistries. See, for example, Espay, et al., A chemical perspective on the interplay between NO, reactive oxygen species, and reactive nitrogen oxide species, Ann N. Y. Acad. Sci. 2002, 962, 195.
  • ROS reactive oxygen species
  • NO is placed in a pivotal regulatory position. Insight into these pathophysiological processes and signaling are highly relevant to develop therapeutics.
  • NO deficiency has been implicated in the genesis and evolution of several disease states.
  • the production of superoxide is increased and level or location of NO synthesis is disrupted thereby causing cellular dysfunction as a result of vasoconstriction of blood vessels, which can lead to, if prolonged, cell damage or death.
  • Agents that act to maintain the normal balance between NO and superoxide in vascular endothelial cells may prove particularly useful in this regard. See, for example, Stokes, K., et al., Free Radic. Bio. Med., 2002, 33, 1026-1036.
  • Nutritional and pharmacological therapies that enhance the bioactivity or production of NO have been shown to improve endothelium-dependent vasodilation, reduce symptoms, and slow the progression of atherosclerosis.
  • Some of the strategies for NO modulation encompass anti-inflammatory, sexual dysfunction, and cardiovascular indications.
  • several commonly used cardiovascular drugs exert their beneficial action, at least in part, by modulating the NO pathway.
  • Pharmacological compounds that release NO have been useful tools for evaluating the pivotal role of NO in cardiovascular physiology and therapeutics.
  • NO-DONORS There are a wide variety of structurally dissimilar organic compounds that act as
  • NO donors and release NO in solution Some NO donors, such as isoamyl nitrite, nitroglycerine (GTN) and sodium nitroprusside, have been used in cardiovascular medicine long before their biochemical mechanism was understood.
  • GTN nitroglycerine
  • the common mode of action for these drugs is liberation of NO, which evokes relaxation of smooth muscle through activation of guanylate cyclase with subsequent formation of cGMP.
  • the relative importance of enzymatic versus non-enzymatic pathways for NO release, the identity of the actual NO-generating enzymes and the existence of competing metabolic events are additional important determinants of the different NO donor classes.
  • Pharmacological compounds that release NO constitute two broad classes of compounds: those that release NO or one of its redox congeners spontaneously and those that require enzymatic metabolism to generate NO. See, for example, Ignarro, L. J. et al., Nitric oxide donors and cardiovascular agents modulating the bioactivity of nitric oxide: an overview, Circ. Res. 2002, 90, 21-28.
  • Nitroglycerine/glycerine trinitrate (GTN) and compounds referred to as nitrovasodilators or NO donors are frequently used in the treatment of ischemic heart disease.
  • the common mode of action for these drugs is liberation of NO, which evokes relaxation of smooth muscle through activation of guanylate cyclase with subsequent formation of cGMP.
  • GTN glycerine/glycerine trinitrate
  • nitrate therapy particularly during acute myocardial infarction, has been the clinically significant drawback with GTN and some of the other available organic nitrates. This is a significant clinical problem and there exists a need for novel nitrate-based anti-anginal agents, which do not cause the problem of nitrate tolerance.
  • Nicox's patents include: Synthesis and evaluation of nitrooxy derivatives of NSAIDs (WO 9412463, WO 0230867, WO 0292072, WO 0313499 and WO 0384550), aspirin (WO 9716405, WO 0044705 and WO 0104082), paracetamol (WO 0112584 and WO 0230866), antiepileptic agents (WO 0300642 and WO 0300643), COX-2 inhibitors (WO 0400781 and WO 0400300), statins (WO 04105754), ACE inhibitors (WO 04110432 and WO 04106300), and of known drugs used for the treatment of disease conditions resulting from oxidative stress and endothelial dysfunction (WO 0061537).
  • nitrate esters were shown to possess not only superior or equal efficacy when compared to the original drug but also exhibit much-reduced side effects. In fact, because of their superior efficacy combined with reduced toxicity, a few of such nitrate ester-containing drug conjugates are successfully passing through various stages of clinical trials.
  • Nicox's nitrooxy derivatives of drugs which are in clinical trials include: NCX 4016 (Phase II, peripheral vascular diseases), NCX 701 (Phase II, Acute pain), HCT 1026 (Phase I, Alzheimer's disease), HCT 3012 (Phase II, Osteoarthritis), NCX 285 (IND, Osteoarthritis), NCX 1022 (Phase Ha completed, Dermatitis), NCX 1020 (Phase I, Asthma/COPD), NCX 1000 (Phase I, Portal hypertension), and NCX 1510 (Phase II, Allergic rhinitis).
  • NCX 4016 Phase II, peripheral vascular diseases
  • NCX 701 Phase II, Acute pain
  • HCT 1026 Phase I, Alzheimer's disease
  • HCT 3012 Phase II, Osteoarthritis
  • NCX 285 IND, Osteoarthritis
  • NCX 1022 Phase Ha completed, Dermatitis
  • NCX 1020 Phase I, Asthma/COP
  • WO 9842661 has shown superior vasorelaxant activity and no tolerance was observed to the cGMP-increasing effects of those compounds under the same experimental conditions used for the induction of in vivo tolerance.
  • WO 0149275 reports drug conjugates where an anti-inflammatory drug is covalently linked to the ⁇ et ⁇ -mercapto-nitrate via thioester bond. Biotransformation pathways proposed for NO release from GTN have largely been heme-dependent or sulfahydryl-dependent. See, for examples, Thatcher, G. R. J. et al., Chem.Soc. Rev. 1998, 27, 331 and reference cited therein, and Bennett, B M. et al., Trends Pharmacol, Sci.
  • a mutual prodrug is the association in a unique molecule of two drugs, usually synergistic, attached to each other, one drug being the carrier for the other and vice versa.
  • the embodiments of the invention also provide mutual prodrugs, which are prodrugs of two or three therapeutic agents currently used/potential for use in combination therapy utilizing novel bio-cleavable linkers, water-soluble prodrugs of insoluble/sparingly- soluble therapeutic agents using the same linker technology and water-soluble double and triple prodrugs of sparingly-soluble therapeutic agents or any of the prodrugs linked to NO-releasing agent using the same linker technology.
  • a and A 1 independently represent a bond, (CH 2 )a, 1,2-phenylene, 1,3-phenylene or 1,4- phenylene; d is 1-8;
  • D 1 represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of -OH, -SH, -NHR 1 , -CO 2 H, -CONHR 1 , - ⁇
  • D 2 independently represents D 1 , a peptide, protein, monoclonal antibody, vitamin, R 2 , R 3 , R 4 , NO, NO 2 , a linkable nitric oxide-releasing group comprising a NONOate, a group comprising one or more of water-solubilizing functional groups, or a polymer;
  • E independently represents CH 2 or a bond
  • L 1 and L 2 independently represent a bond, O, S, NR 1 , L, or a linkage selected from the group consisting of:
  • L is R 12 or a group with bonding in any direction, independently selected from the group consisting of:
  • X independently represents a bond, C, O, S, or NR 1 ;
  • Z independently represents a bond, or (CH 2 )J; wherein, j is 1-4;
  • R 1 independently represents a bond, H, (C 1 -Cs)alkyl, (Cs-Cu)SIyI, aralkyl or M 6+ ;
  • R 2 independently represents H, NH 2 , or NHAc;
  • R 3 independently represents H, CO 2 R 5 , CH 2 CO 2 R 5 ,
  • R 4 independently represents H, OH, 0-(Ci-C 8 )alkyl, 0M e+ , or a group selected from the group consisting of:
  • X 2 independently represents O, S, SO, SO 2 , or NR 5 ;
  • R 6 independently represents H, Na + , K + , any other pharmaceutically acceptable metal ion, (Ci-C 8 )alkyl, or (C 3 -C 8 )cycloalkyl,
  • R 7 independently represents at each occurrence same or different R 5 ;
  • R 9 independently represents H, (Ci-C 8 )alkyl or an amino acid; f is 0-6; g is 0-1; h is 1-2000; i is 1-4;
  • R 10 and R 11 independently represent H, (Ci-C 8 )alkyl, (C 3 -C 8 )cycloalkyl, or a group selected from the group consisting of:
  • R 11 represents H or (C 1 - C 8 )alkyl, and when R 11 is selected from the above group, R 10 represents H or (Ci- C 8 )alkyl;
  • R 12 independently represents a group selected from the group consisting of:
  • X 3 is independently O or NR 7 .
  • Another embodiment of the invention is a pharmaceutical composition
  • a pharmaceutical composition comprising one or more compounds of formula I or intermediates thereof and one more of pharmaceutically acceptable carriers, vehicles or diluents.
  • Further embodiments include methods of preparation and methods of use of prodrugs including NO-releasing prodrugs, double prodrugs and mutual prodrugs comprising the compounds of formula I.
  • the present invention characterizes compositions, methods of preparation and methods of use of prodrugs, NO-releasing prodrugs, mutual prodrugs, double prodrugs, and codrugs.
  • the compounds of the present invention are prodrugs or mutual prodrugs in which known therapeutic agents or potential therapeutic agents are linked covalently to novel biocleavable linkers.
  • the compounds of the present invention also include NO-releasing prodrugs in which a therapeutic agent is linked covalently to nitrooxy (nitrate ester) group via a novel bio-cleavable linker containing a strategically placed disulfide group at ⁇ -position to the nitrate ester.
  • the present invention also characterizes composition of NO-releasing prodrugs (i.e., nitrooxy ester or nitrate ester prodrugs), processes for their preparation, pharmaceutical composition containing them and their use.
  • amino-containing refers to drug/carrier molecule with NH functional groups such as amino (both primary and secondary), amide, urea, sulfonamide, carbamate, phosphoramadite, sulfamate, hydrazone, semicarbazone, thiosemicarbazone, hydrazide, carbazate and the like.
  • This also includes NH-containing heterocylic compounds such as imidazoles, benzimidazoles, pyrazoles, benzpyrazols, pyrrols, indoles, triazoles, tetrazoles, benzotriazoles, benzotetrazoles and their derivatives.
  • NH-containing heterocyclic compounds can be sub-structures of more complex drug/carrier molecules.
  • Amino group of the candidate drug can be primary or secondary (both acyclic and cyclic) which include amide-NH, sulfonamide-NH, carbamate-NH, sulfamate-NH, hydrazide-NH, hydrazone-NH, semicarbazone-NH, thiosemicarbazone- NH, urea-NH and also drugs containing indole, imidazole, benzimidazole, thiazole, oxozole, pyrrole, pyrazole, triazole, tetrazole, or similar NH-containing heterocylic sub ⁇ structures of a more complex drug molecule.
  • hydroxyl-containing refers to drug/carrier molecules with hydroxyl groups (primary, secondary and tertiary) including hydroxyl groups of hydroxamic acids and ketoximes derived from keto-containing molecules. Hydroxyl group of drugs can be of primary, secondary or tertiary nature.
  • sulfahydryl-containing refers to drug/carrier with free sulfahydryl (SH) group.
  • halo refers to fluoro, chloro, bromo, and iodo.
  • halide refers to fluoride, chloride, bromide, and iodide.
  • alkyl refers to acyclic alkyl chains.
  • C 1 -C 8 alkyl refers to methyl, ethyl, propyl, isopropyl, butyl, cyclobutyl, s-butyl, and t-butyl, ,pentyl, hexyl, heptyl, octyl, and the like.
  • cycloalkyl refers to cyclic alkyl chains, e.g., the term “C 3 -C 8 cycloalkyl” refers to cyclopropyl, cyclooctyl, cyclopentyl, cyclohexyl, cycloheptyl, , cyclooctyl and the like.
  • aryl refers to phenyl, naphthyl and the like.
  • aralkyl refers to benzyl, phenethyl and the like.
  • alkoxy refers to both acyclic and cyclic Ci-C 8 alkyloxy.
  • Ci-C 8 alkyloxy refers to methoxy, ethoxy, propoxy, isopropoxy, cyclopropoxy, butoxy, cyclobutoxy, s-butoxy, and t-butoxy, cyclopentyloxy, pentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, cycloheptyloxy, octyloxy, cyclooctyloxy and the like.
  • heterocyclic and heteroaryl refers to both saturated and unsaturated 5- and 6-membered rings (including benzo-fused) containing from 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. All of these rings may be substituted with up to three substituents independently selected from the group consisting of amino, halo, alkoxy, alkyl, cyano, nitro, hydroxyl, sulfahydryl, carboxyl and the like, Saturated rings include, for example, pyrrolidinyl, piperidinyl, piperazinyl, tetrahydrofiiryl, oxazolidinyl, dioxanyl, pyranyl, and the like.
  • Benzofused saturated rings include indolinyl, 1,2,3,4-tetrahydroquinolinyl, 1,2,3,4-tetrahydroisoquinolinyl and the like.
  • Unsaturated rings include furyl, thienyl, pyridinyl, pyrrolyl, N-methylpyrrolyl, oxazolyl, isoxazolyl, pyrazolyl, imidazolyl, tetrazolyl, triazolyl, oxadiazolyl, thiadiazolyl, thiazolyl, pyrimidinyl, pyrazinyl, pyridazinyl, and the like.
  • Benzofused unsaturated rings include isoquinolinyl, benzoxazolyl, benzthiazolyl, quinolinyl, benzofuranyl, thionaphthyl, indolyl and the like.
  • substituted alkyl refers to acylic and cyclic alkyl groups substituted with one or more of groups such as alkyl, aryl, hydroxy, alkoxy, cyano, carboxyl, sulfahydryl, alkylthio, amino, nitro, halo, carbonyl, carbamato, sulfamato, sulfonato, sulfato, and the like.
  • substituted aryl refers to aryl groups substituted (including fused) with one or more of groups such as alkyl, aryl, hydroxy, alkoxy, cyano, carboxyl, sulfahydryl, .alkylthio, amino, nitro, halo, carbonyl, carbamato, sulfamato, sulfonato, sulfato, and the like.
  • amino acid refers to molecules containing one or more amino and carboxyl groups.
  • alfa-amino acids D-, L- and DL- amino acids
  • alfa-amino acids include natural alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine.
  • beta-amino acids and known unnatural amino acids.
  • amino acid ester refers to an amino acid where the carboxyl group is substituted with a Ci-C 8 alkyl group. That is, the alkyl group when taken together with the carboxyl group forms a Ci -C 6 alkyl ester. It is appreciated that some amino acids (e.g., aspartic acid and glutamic acid) have two carboxyl groups these may form mono- and di-esters.
  • protecting group refers to an 'amino protecting group' or a 'hydroxyl protecting group' or a 'carboxyl protecting group' and the like.
  • amino protecting group refers to a group that selectively blocks or protects the amino functionality in presence of other functional groups on the molecule.
  • amino-protecting groups examples include the formyl group, the trityl group, the phthalimido group, the acetyl group, the trifluoroacetyl group, the chloroacetyl, bromoacetyl, and iodoacetyl groups, urethane-type blocking groups such as benzyloxycarbonyl ("CBZ”), 9-fluorenylmethoxycarbonyl ("FMOC”), tert- butoxycarbonyl (“BOC”), trichloroethylcarbonyl and the like. Additional examples of amino protecting groups are described by T. W.
  • Molecules with two or more amino groups may form mono-, di-, tri-, poly-, protected derivatives depending on the reaction conditions used.
  • hydroxyl protecting group refers to a group that selectively blocks or protects hydroxyl functionality in presence of other reactive functional groups on the molecule.
  • hydroxyl-protecting groups include, for example, ether groups including methyl and substituted methyl ether groups such as methyl ether, methoxymethyl ether, methylthiomethyl ether, tert-buylthiomethyl ether, triphenylmethyl, tetrahydropuranyl (THP), (phenyldimethylsilyl)methoxy-methyl ether, benzyloxymethyl ether, p-methoxybenzyloxy-methyl ether, and tert-butoxymethyl ether; substituted ethyl ether groups such as ethoxyethyl ether, l-(2-chloroethoxy)-ethyl ether, 2,2,2-trichloroethoxymethyl ether, and 2-(trimethylsilyl)ethyl ether; isopropyl ether groups;
  • hydroxyl protecting groups are described by T. W. Greene, "Protective Groups in Organic Synthesis", John Wiley and Sons, New York, N.Y., 1991. Molecules with two or more hydroxyl groups may form mono- and di-esters/ethers depending on the reaction condition.
  • carboxyl protecting group refers to a group that selectively blocks or protects carboxyl functionality in presence of other reactive functional groups on the molecule.
  • carboxyl-protecting groups include, for example (substituted) alkyl esters such methyl ester, ethyl ester, t-butyl ester, (substituted) benzyl ester, trichloroethyl ester, and the like. Additional examples of carboxylic acid protecting groups are described T. W. Greene, "Protective Groups in Organic Synthesis", John Wiley and Sons, New York, N.Y., 1991. Molecules with two or more carboxylic acid groups may form mono-, di-, tri-, tetra-, poly- protected derivatives depending upon the reaction conditions used.
  • carbonyl activating group refers to leaving group ("LG") of a carboxyl derivative that is easily replaced by an incoming nucleophile.
  • LG leaving group
  • Such “LG” groups include, but are not limited to, (substituted) alkoxy, aryloxy, nitrogen containing unsaturated heterocycles such as N-oxybenzotriazole, imidazolyl, o/p-nitrophenoxy, pentachloro- phenoxy, N-oxysuccinimide, N,N'-dicyclohexylisoure-O-yl, N-hydroxy-N- methoxyamino, and the like; acetates, formates, sulfonates such as methanesulfonate, ethanesulfonate, benzenesulfonate, or p-toluenesulfonate, and the like; and halides especially fluoride, chloride, bromide, or iodide.
  • carbonyl activating reagent refers to a reagent that converts the carbonyl of a carboxylic acid group into one that is more susceptible to nucleophilic attack and includes, but is not limited to, such reagents as those found in "The Peptides”, Gross and Meienhofer, Eds., Academic Press (1979), Ch. 2, and M. Bodanszky, "Principles of Peptide Synthesis", 2.sup.nd Ed., Springer- Verlag Berlin Heidelberg, 1993, hereafter referred to as "The Peptides” and “Peptide Synthesis” respectively.
  • Carbonyl group (i.e., aldehyde or keto group) of candidate drugs may be converted first to aldoxime, ketoxime, hydrazone, semicarbazone and the like, before coupling to the linker.
  • carbonyl activating reagents include thionyl bromide, thionyl chloride, oxalyl chloride, and the like; esters of alcohols such as nitrophenol, pentachlorophenol, and the like; and compounds such as l,l'-carbonyldiimidazole (CDI), benzotriazole, imidazole, N-hydroxysuccinimide, dicyclohexylcarbodiimide (DCC), EDC, phosgene or its equivalents, N, N-dimethylaminopyridine (DMAP) and the like.
  • CDI l,l'-carbonyldiimidazole
  • DCC dicyclohexylcarbodiimide
  • EDC phos
  • phosgene or its equivalents refer to phosgene or it equivalents such as diphosgene, triphosgene, CDI, DSC, BTBC, alkoxycarbonyl chlorides, o/p- nitrosubstituted phenoxycarbonyl chlorides, and the like.
  • pharmaceutical when used as an adjective means substantially non-toxic to living organisms.
  • salts refer to salts of the compounds of this invention, which are substantially non-toxic to living organisms. See, e.g., Berge, S. M. et al., "Pharmaceutical Salts", J. Pharm. Sci., 66:1, 1977.
  • Typical pharmaceutical salts include those salts prepared by reaction of the compounds of this invention with an inorganic or organic acid or base. Such salts are known as acid addition or base addition salts respectively.
  • These pharmaceutical salts frequently have enhanced solubility characteristics compared to the compound from which they are derived, and thus are often more amenable to formulation as liquids or emulsions.
  • Examples of pharmaceutically acceptable salts are those with inorganic bases such as sodium, potassium, calcium, magnesium, and hydroxides, and the like, or with organic bases such as lysine, arginine, triethylamine, dibenzylamine, piperidine, and the like.
  • suitable solvent refers to a solvent that is inert to the ongoing reaction and sufficiently solubilizes the reactants to effect the desired reaction.
  • suitable solvents include but are not limited to, dichloromethane, chloroform, 1,2- dichloroethane, diethyl ether, tert-butylmethyl ether, acetonitrile, ethyl acetate, 1,3- dimethyl-2-imidazolidinone, tetrahydrofuran, dimethylformamide, benzene, toluene, xylene, N-dimethylacetamide, N-methylpyrrolidine, chlorobenzene, dimethylsulfoxide, dimethoxyethane, water, methanol, ethanol, isopropanol, pyridine, nitromethane, mixtures thereof, and the like.
  • suitable base refers to a base, which acts as a proton trap for any protons, which may be produced as a byproduct of the desired reaction, or to a base, which provides a reversible deprotonation of an acidic proton from the substrate and is reactive enough to effect the desired reaction without significantly effecting any undesired reactions.
  • bases include, but are not limited to, carbonates, bicarbonates, and hydroxides (e.g., lithium, sodium, potassium, magnesium, calcium and the like), sodium/potassium/calcium hydride, sodium/potassium alkoxide (i.e., methoxide, ethoxide, tert-butoxide and the like), triethylamine, diisopropylethylamine, N- methylpyrrolidine, N-methylmorpholine, tetramethylguinidine, or aromatic nitrogen containing heterocycles such pyridine, 4-(dimethylamino)pyridine (DMAP), and the like.
  • carbonates bicarbonates, and hydroxides
  • sodium/potassium/calcium hydride sodium/potassium alkoxide (i.e., methoxide, ethoxide, tert-butoxide and the like)
  • sodium/potassium alkoxide i.e., methoxide, ethoxide, tert
  • NONOate refers to a linkable nitric oxide-releasing group such as AcOCH 2 -O-N 2 -N(OOR 7 , OCHOCH 2 -O-N 2 -N(O " ) R 7 R 7 , CH 2 -O-N 2 -N(OOR 7 R 7 and the like.
  • therapeutic agent refers to biologically active molecules such as drugs, vitamins, and other molecules, agents or substances concerned with or contributing to the treatment and cure of illness or contributing to the general well being of a mammal or human.
  • the therapeutic agents can be both known and investigational drugs compiled in drug databases such as the Merck Index, IDdb, Prous Science's Integrity ® , Prous Science Drugs of the FutureTM, The Ensemble ® and the like.
  • the Merck Index is a one-volume encyclopedia of chemicals, drugs and biologicals that contains more than 10,000 monographs. Each monograph in this authoritative reference source is a concise description of a single substance or a small group of closely related compounds.
  • Prous Science is an international health science publishing company, established in 1958 and headquartered in Barcelona, Spain.
  • Prous Science Drugs of the FutureTM contains comprehensive drug monographs providing product information on new compounds, including the synthesis and corresponding schemes, pharmacological action, pharmacokinetics and metabolism, toxicity, clinical studies, manufacturer, and references. Information on compounds is continuously updated as advances in development status are disclosed worldwide.
  • the Prous Science IntegrityTM is a drug R&D portal where knowledge areas are coordinated to provide a harmonious and interrelated whole, which includes Drugs & Biologies, Targets, Organic Synthesis, Experimental Pharmacology, Pharmacokinetics and Metabolism, Clinical Studies, Disease Briefings, Companies & Markets, Literature and Patents.
  • the Investigational Drugs database (IDdb) developed by Thomson Current Drugs, is a pharmaceutical competitor intelligence service. It covers all aspects of investigational drug development, from first patent to eventual launch or discontinuation.
  • the Ensemble® on the Web provides essential information, including chemical structures, on more than 140,000 compounds with demonstrated biological activity in the drag research and development pipeline.
  • vitamin includes vitamin A, vitamin C, thiamine, folic acid, biotin, inositol, nicotinic acid, nicotinamide, riboflavin, pyridoxine, pyridoxal 5-phosphate, ergosterol, vitamin D2, vitamin D3, vitamin D4, vitamin E, menadoxime, menadiol, and vitamin K5.
  • peptide includes large and small peptides, including, but not limited to, targetable small peptides such as a dipeptide, tripeptide, tetrapeptide, etc.
  • ligand means a small molecule that binds to a larger macromolecule, whether or not the ligand actually binds at a metal site. Such ligands can be small peptides.
  • One aspect of the invention is to provide mutual prodrugs of two or three therapeutic agents currently used for use in combination therapy utilizing novel bio- cleavable linkers, water-soluble prodrugs of insoluble and sparingly-soluble therapeutic agents using the same linker technology, and water-soluble double and triple prodrugs of sparingly-soluble therapeutic agents using the same linker technology.
  • the embodiments of the invention may also comprise vitamins and targetable small peptides in addition to or in place of a promoeity to yield targetable prodrugs.
  • the candidate drugs selected for mutual prodrug synthesis can be from one therapeutic category or from different therapeutic categories.
  • the constituent drugs of a mutual prodrug can act on the same biological target with similar mechanism of action or act on different biological targets with different mechanisms of action.
  • the candidate drugs should contain one or more of the essential functional groups such as amino, hydroxyl, keto, or carboxyl groups in their structure.
  • Amino group of the candidate drug can be primary or secondary (both acyclic and cyclic) which include amide-NH, sulfonamide-NH, carbamate-NH, sulfamate-NH, hydrazone-NH, semicarbazone-NH, thiosemicarbazone-NH and also drags containing indole, imidazole, benzimidazole, thiazole, oxozole, pyrrole, pyrazole, triazole, tetrazole, or similar NH-containing heterocylic sub-structures of a more complex drag molecule.
  • hydroxyl group of drags can be of primary, secondary or tertiary nature.
  • Keto group of candidate drugs may be converted first to ketoxime, hydrazone, semicarbazone and then like, before coupling to the linker. Obviously, hydroxyl or amino functions thus generated will be used to form covalent bond between the drug and the linker.
  • the candidates for making mutual prodrugs can be the pairs of drugs that are currently used in combination therapy (including those combination studies at investigational stage) in various therapeutic areas provided each of those drugs possesses the requisite functional group(s). There are a number of therapeutic areas where such combination therapy is applied routinely and successfully.
  • the disulfide bond in the prodrug is expected to be reduced by endogenous sulfahydryl-containing species such as glutathione (GSH) to generate a reactive thiolate anion (i.e., ⁇ eto-mercapto-nitrate), which can trigger further break-down of the linker moiety to release the free drug (via a mechanism as shown Scheme Ml) and NO simultaneously at the same location.
  • GSH glutathione
  • Scheme Ml reactive thiolate anion
  • the release of NO can go via a hypothetical cyclic transient intermediate 'b'.
  • sulfahydryl-dependent NO release from GTN Similar hypothetical mechanism was proposed for NO release from SS-nitrates, which, were also designed on the basis of a sulfahydryl-dependent NO release from GTN. See, for example, Zavorin, S. I. et al., Organic Letters, 2001, 3, 1113, incorporated herein in its entirety .
  • Mutual prodrugs can be made by linking covalently any two of the following: an amino-containing therapeutic agent to another ammo-containing therapeutic agent; an amino-containing therapeutic agent to a hydroxyl-containing therapeutic agent; an amino- containing therapeutic agent to a carboxyl-containing therapeutic agent and its derivative; a hydroxyl-containing therapeutic agent to a carboxyl-containing therapeutic agent and its derivative; an amino-containing therapeutic agent to a carboxyl-containing therapeutic agent and its derivative; an amino-containing therapeutic agent to a keto-containing therapeutic agent or its hydazone, semicarbazone or oxime derivative and the likes;
  • Another aspect of the present invention is to provide new nitrate ester (NO- releasing) prodrugs of many types of existing drugs using novel biocleavable likers. Such prodrugs are expected to exhibit better efficacy and tolerability with reduced side effects compared to the corresponding original drugs.
  • An embodiment of present invention relates to the compounds of formula (I) or pharmaceutically acceptable salts thereof:
  • a and A 1 independently represent a bond, (CH 2 )d, 1 ,2-phenylene, 1,3-phenylene or 1,4- phenylene; d is 1-8;
  • D represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of -OH, -SH, -NHR 1 , -CO 2 H, -CONHR 1 , -
  • D 2 independently represents D ⁇ a peptide, protein, monoclonal antibody, vitamin, R 2 , R 3 ,
  • R 4 NO, NO 2 , a linkable nitric oxide-releasing group comprising a NONOate, a group comprising one or more of water-solubilizing functional groups, or a polymer;
  • E independently represents CH 2 or a bond
  • L 1 and L 2 independently represent a bond, O, S, NR 1 , L, or a linkage selected from the group consisting of:
  • L is R 12 or a group with bonding in any direction, independently selected from the group consisting of:
  • X independently represents a bond, C, O, S, or NR 1 ;
  • Z independently represents a bond, or (CH 2 )J; wherein, j is 1-4;
  • R 1 independently represents a bond, H, (Ci-C 8 )alkyl, (C 5 -Ci 4 )aryl, aralkyl or M 6+ ;
  • R 2 independently represents H, NH 2 , or NHAc;
  • R 3 independently represents H, CO 2 R 5 , CH 2 CO 2 R 5 ,
  • R 4 independently represents H, OH, O-(Ci-Cs)alkyl, OM 6+ , or a group selected from the group consisting of: or arabinolactan,
  • X 2 independently represents O, S, SO, SO 2 , or NR 5 ;
  • R 6 independently represents H, Na + , K + , any other pharmaceutically acceptable metal ion, (Ci-C 8 )alkyl, or (C 3 -C 8 )cycloalkyl,
  • R 7 independently represents at each occurrence same or different R 5 ;
  • R 9 independently represents H, (Ci-C 8 )alkyl or an amino acid; f is 0-6; g is 0-1; h is 1-2000; i is 1-4;
  • R 10 and R 11 independently represent H, (Ci-C 8 )alkyl, (C 3 -C 8 )cycloalkyl, or a group selected from the group consisting of:
  • R 11 represents H or (Ci- C 8 )alkyl, and when R 11 is selected from the above group, R 10 represents H or (Q- C 8 )alkyl;
  • R 12 independently represents a group selected from the group consisting of:
  • X 3 is independently O or NR 7 .
  • D 1 and D 2 of the present invention can be both known and investigational drugs compiled in drug databases such as the Merck Index, IDdb, Prous Science's Integrity ® , Prous Science Drugs of the FutureTM, The Ensemble ® and the like.
  • D 1 and D 2 are the same drugs.
  • D 1 and D 2 are different drugs.
  • Dl is a drug and D -.2 may not be a drug at all.
  • D 2 is an amino-, carboxyl- or hydroxyl- containing group or molecule comprising one or more water solubilizing functional groups selected from the group consisting of hydroxyl, amino, acylamino, carboxyl, sulphate, sulfonate, phosphate, phosphonate, N- acylsulfonamide, N-acylsulfamate, N-acylcarbamate, N-acylcarbamate metallic salts, and amino acids to give water-soluble prodrug.
  • D 2 is an amino-, carboxyl- or hydroxyl- containing group or molecule comprising one or more water solubilizing functional groups selected from the group consisting of hydroxyl, amino, acylamino, carboxyl, sulphate, sulfonate, phosphate, phosphonate, N- acylsulfonamide, N-acylsulfamate, N-acylcarbamate, N-acylcarbamate metallic salts, and amino acids to
  • Another embodiment of the invention is the compound of formula I, wherein D 2 is selected from the group of D, L and DL amino acids consisting of Alanine, Arginine,
  • D 2 represents a polymer selected from the group consisting of arabinogalactan, polyamino acids, polyethylene glycol, polycaprolactone, polyglycolic acid, polylactic acid, polyacrylic acid, poly(2-hydroxyethyl 1 -glutamine), dextran and modified dextrans such as dextran aldehyde, carboxymethyl dextran, arabinogalactane aldehyde, carboxymethyl arabinogalactane, and hyaluronic acid.
  • D 2 represents a polymer selected from the group consisting of arabinogalactan, polyamino acids, polyethylene glycol, polycaprolactone, polyglycolic acid, polylactic acid, polyacrylic acid, poly(2-hydroxyethyl 1 -glutamine), dextran and modified dextrans such as dextran aldehyde, carboxymethyl dextran, arabinogalactane aldehyde, carboxymethyl arabinogalactane, and hyal
  • D 2 is a polyaminoacid selected from group consisting of poly(l-glutamic acid), poly(d- glutamic acid), poly(dl-glutamic acid), poly(l-aspartic acid), poly(d-aspartic acid), poly(dl- aspartic acid), copolymers of the polyaminoacids and polyethylene glycol,
  • D 2 is a peptide, protein or monoclonal antibody for achieving targeted delivery of prodrugs and drugs.
  • Another embodiment of the invention is the compound of formula I, wherein D 2 is a ligand or dipeptide or a dipeptide ligand.
  • D 2 is a dipeptide ligand that is a substrate for intestinal transporters for selective intestinal absorption of the corresponding prodrugs thereby increasing the bioavailability of the prodrugs.
  • D 2 is a targetable small peptide, i.e., dipeptide, tripeptide, tetrapeptide, etc.
  • Another embodiment of the invention is the compound of formula I, wherein D 2 is a vitamin.
  • Such vitamin-conjugated prodrugs are expected to be taken up by the diseased cells via receptor-mediated endocytosis.
  • D 2 is selected from the group of vitamins consisting of vitamin A, vitamin C, thiamine, folic acid, biotin, inositol, nicotinic acid, nicotinamide, riboflavin, pyridoxine, pyridoxal 5-phosphate, ergosterol, vitamin D2, vitamin D3, vitamin D4, vitamin E, menadoxime, menadiol, and vitamin K5.
  • Another embodiment of the invention is the compound of formula I, wherein D 1 and D 2 represent the same therapeutic agent to give a symmetrical double prodrug. Another embodiment of the invention is the compound of formula I, wherein D and D 2 represent different therapeutic agents to give a mutual prodrug. Another embodiment of the invention is the compound of formula (I), wherein D 1 and D 2 can be either from same or different therapeutic class. Another embodiment of the invention is the compound of formula (I), wherein D 1 and D 2 can be same or different therapeutic agents. Such therapeutic agents may have same or different mechanisms of action or they may work on different biological targets or work on different disease conditions.
  • Another embodiment of the invention is the compound of formula I, wherein D 2 is R 2 , R 3 or R 4 .
  • a further embodiment of the invention is the compound of formula I, wherein B is S-S, A and A 1 are CH 2 -CH 2 , E is a bond and D 2 is R 2 , R 3 or R 4 .
  • Another embodiment of the invention is the compound of formula I, wherein a is 0; B is S-S; A and A 1 are CH 2 -CH 2 , E is a bond and D 2 is R 4 .
  • Another embodiment of the invention is the compound of formula I, wherein a is 0; B is S-S; A and A 1 are CH 2 -CH 2 , E is a bond and D 2 is R 4 .
  • Another embodiment of the invention is the compound of formula I, wherein a is
  • B is a bond, (CH 2 )b, or (CH 2 CH 2 O) 0 ; wherein b and c are as defined above.
  • Another embodiment of the invention is the compound of formula I, wherein a is 0, B is a bond, (CH 2 ) b or (CH 2 CH 2 O) 0 and D 2 is R 2 or R 3 or R 4 ; wherein b and c are as defined above.
  • a and A 1 are CH 2 -CH 2, and E is a bond.
  • a and A 1 are 1, 2-phenylene, 1,
  • a and A 1 are CH 2 -CH 2, and E is a bond.
  • a and A 1 are 1, 2-phenylene, 1, 3-phenylene or 1, 4-phenylene, and E is CH 2 .
  • Another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S; A and A 1 are 1, 2-phenylene, 1, 3-phenylene or 1, 4-phenylene; E is CH 2 and D 2 is D 1 Or R 2 or R 3 or R 4 .
  • a further embodiment of the invention is the compound of formula I, wherein B is S-S, A and A 1 are CH 2 -CH 2 , E is a bond and D 2 is D 1 .
  • Yet another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S; A and A 1 are CH 2 -CH 2 , E is a bond and D 2 is a dipeptide ligand.
  • the peptide ligands used in the invention can be substrates for intestinal transporters for selective intestinal absorption of the corresponding prodrugs thereby increasing the bioavailability of the prodrugs.
  • An embodiment of the present invention is the compounds of formula (I), wherein D 1 , L 1 and L 2 are as defined above; A and A 1 are CH 2 ; E is CH 2 ; B is a bond or (CH 2 ) b ; b is 1-6; a is O; and D 2 is D 1 or R 2 or R 4 .
  • Another embodiment of the present invention is the compound of formula (I), L 2 is O; A and A 1 are independently (CH 2 )a, 1,2-phenylene, 1,3-phenylene, or 1,4- phenylene; d is 1-4; B is S-S; a is 0; D 2 is NO 2 . In a further embodiment, when A and A 1 are independently (CH 2 )a, 1,2-phenylene, 1,3-phenylene, or 1,4- phenylene; d is 1-4; B is S-S; a is 0; D 2 is NO 2 . In a further embodiment, when A and A 1
  • E is a bond.
  • a and A 1 are independently 1,2-phenylene, 1,3-phenylene, or 1,4-phenylene.
  • An embodiment of the present invention is the compound of formula (I), wherein D 1 is a hydroxyl or sulfahydryl containing drug molecule such as Drug-OH or Drug-SH, wherein functional groups OH and SH are involved in the formation of L 1 linkages between the drug and the linker; L 2 is O; E is bond, L 1 is a linkage selected from the group consisting of:
  • An embodiment of the present invention is the compound of formula (I), wherein D 1 is a drug molecule having carboxyl (-CO 2 H) as a reactive functional group such as - CO 2 H which is involved in the formation of L 1 linkages between the drug and the linker; L 2 is O; E is bond; L 1 is O or NR 1 or a linkage selected from the group consisting of:
  • D 1 is an antioxidant or free radical scavenger such as a hydroxyl-containing stable radical such a 4-hydroxy-2,2,6,6-tetramethylpiperidin-l-oxyl (4-hydroxy- TEMPO), 4-carboxy -2,2,6,6-tetramethylpiperidin-l-oxyl (4-carboxy-TEMPO) or any other ammo-/carboxyl-/hydroxyl-containing antioxidants or radical/super oxide scavengers, and D 2 is NO 2 .
  • the amino-/carboxyl-/hydroxyl-containing antioxidants and radical/super oxide scavengers can be known or investigational.
  • An embodiment of the present invention is the compound of formula (I), wherein
  • L 1 is x X or ; wherein, X is a bond, O, S or NR 1 ; L 2 is O, E is a bond; A and A 1 are CH 2 CH 2 ; B is S-S; a is O; and D 2 is NO 2 .
  • An embodiment of the present invention is the compounds of formula (I), wherein D ! and L 1 are as defined above; L 2 is O; A is 1,2-phenylene, 1,3-phenylene, or 1,4- phenylene; A 1 is CH 2 ; E is CH 2 ; B is S-S; a is 0 and D 2 is NO 2 .
  • An embodiment of the present invention is the compounds of formula (I), wherein L 2 is O; A and A 1 are CH 2 ; E is CH 2 ; B is a bond or (CH 2 ) b ; b is 1-6; a is O; D 2 is NO 2 and L 1 is a group selected from
  • X is O, S or NR 1 ; Rl is as defined.
  • An embodiment of the invention is the compound of formula I selected from the groups consisting of: A. Prodrugs: (a) From carboxyl-containing drugs:
  • R y1 An amino-, hydroxyl-containing molecule with water-solubilizing groups
  • R 2 H, a bond, CH 2 CH 2 N(CH 3 ) 2 .
  • HCl an Amino acid, or any molecule containing solubilizing groups such as carboxylic acid, sulphonic acid, hydroxyl, amino groups, polyethyleneglycol (PEG), a metal ion such a Na + , Ca 2+ , etc.
  • PEG polyethyleneglycol
  • An embodiment of the invention is a pharmaceutical composition
  • a pharmaceutical composition comprising a therapeutically effective amount of the compound of formula I, or a pharmaceutical salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
  • Another embodiment of the invention is a pharmaceutical composition
  • a pharmaceutical composition comprising a therapeutically effective amount of the compound of formula I selected from the group consisting of I-C1-PD1, 1-C1-PD2, 1-C1-PD3, 1-C1-PD4, 1-Cl-PD4a, I- Cl-PD4b, I-C1-PD5, 1-C1-PD6, 1-C1-PD7, 1-C1-PD8, 1-C1-PD9, 1-C1-PD10, I-Cl- PDI l, I-C1-PD12, 1-C1-PD13, 1-C1-PD14, 1-Cl-PD15a, I-Cl-PD15b, I-A1-PD1, I-Al- PD2, 1-A1-PD3, 1-A1-PD4, 1-A1-PD5, 1-A1-PD6, 1-A1-PD7, 1-A1-PD8, 1-A1-PD9, I-Al- PDlO, I-A1-PD11, 1-A1-PD12, 1-A
  • NOPD2a I-A3-NOPD2b, I-H1-NOPD1, 1-Hl-NOPD2a, I-Hl-NOPD2b, I-H1-NOPD3, I- H1-NOPD4, 1-Hl-N0PD5b, I-H1-NOPD6, 1-H1-NOPD7, 1-H1-NOPD8, 1-H1-NOPD9, I-H1-NOPD10, 1-AA-MPD1, 1-AA-MPD2, 1-AA-MPD3a, I-AA-MPD4, 1-AA-MPD5, I- AA-MPD6, 1-AA-MPD7, 1-AA-MPD8, 1-AA-MPD9, 1-AA-MPD10, 1-AA-MPD11, I- AA-MPD12, 1-AA-MPD13, 1-AA-MPD14, 1-AA-MPD15, 1-AA-MPD16, 1-AA-MPD17, I-AA-MPD18, 1-AA-MPD19, 1-AA-MPD20, 1-AA-MPD21
  • MPD30 1-AH-MPD1, 1-AH-MPD2, 1-AH-MPD3, 1-AH-MPD4, 1-AH-MPD5, 1-AH- MPD6, 1-AH-MPD7, 1-AH-MPD8, 1-AH-MPD9, 1-AH-MPD10, 1-AH-MPD11, I-AH- MPD12, 1-AH-MPD13, 1-AH-MPD14, 1-AH-MPD15, 1-AH-MPD16, 1-AH-MPD17, I- AH-MPD 18, 1-AH-MPD19, 1-AH-MPD20, 1-AH-MPD21, 1-AH-MPD22, 1-AH-MPD23, I-AH-MPD24, 1-AH-MPD25, 1-AH-MPD26, 1-CH-MPD 1 , 1-CH-MPD2, 1-CH-MPD3, I- CH-MPD4, 1-CH-MPD5, and I-CH-MPD6 or a pharmaceutical salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
  • An embodiment of the invention is a method of treating a mammal or human in need thereof comprising administering a therapeutically effective amount of the pharmaceutical composition comprising the compound of formula I.
  • Another embodiment of the invention is use of the above listed novel intermediates in the processes for the preparation of compounds of formula I;
  • Further embodiments include methods of preparation and methods of use of compounds of formula (I) or pharmaceutically acceptable salts thereof.
  • Another embodiment of the invention is process for the preparation of compounds of formula I, or pharmaceutically acceptable salts thereof, wherein the process comprises of: monoprotection of Bis-(2-hydroxyethyl)disulphide (SL-I) with an appropriate hydroxyl protecting group to give a corresponding monoprotected intermediate, conversion of the corresponding monoprotected intermediate to an activated formyl intermediate by treating with phosgene or its equivalent, and reaction of the activated formyl intermediate with an appropriate amino- or hydroxy containing D 1 to give the corresponding compound of formula I.
  • Another embodiment of the invention is a process for the preparation of compounds of formula I, or pharmaceutically acceptable salts thereof , wherein the process comprises of :
  • the invention is a process in which the monoprotected intermediate is LIIx, and the activated formyl intermediate is Lllxy.
  • Another embodiment of the invention is a process for preparation of compounds of formula (I), wherein D 2 is NO 2 or pharmaceutically acceptable salts thereof, wherein the process comprises, mixing a selectively protected and activated Dl with a solution of
  • Another embodiment of the invention is a process for preparation of compounds of formula (I), wherein D 2 is NO 2 or pharmaceutically acceptable salts thereof, wherein a process comprises, converting 2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b) into its formyl halide or imidazolide (LI-4x) by using a phosgene or its equivalent reagent and mixing/reacting the resulting reactive intermediate with a suitable amino- or hydroxy- containing drug in suitable solvent in presence of a suitable base.
  • a process comprises, converting 2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b) into its formyl halide or imidazolide (LI-4x) by using a phosgene or its equivalent reagent and mixing/reacting the resulting reactive intermediate with a suitable amino- or hydroxy- containing drug in suitable solvent in presence of a suitable base.
  • Another embodiment of the invention is a process for preparation of compounds of formula (I), wherein D 2 is NO 2 or pharmaceutically acceptable salt thereof, wherein the process comprises, mixing/reacting a selectively protected and activated drug with a solution of 2-((2-aminoethyl)dithio)ethyl nitrate (LI-5) in a suitable solvent in presence of a suitable coupling agent and/or base.
  • Another embodiment of the invention is a process for preparation of mutual prodrugs of compounds of formula (I), or pharmaceutically acceptable salts thereof, wherein a process comprises,
  • Further embodiments of the invention are processes for the preparation of compounds of formula I 5 or pharmaceutically acceptable salts thereof, wherein the processes comprise of the steps that are generally depicted in the schemes 1-23. Further embodiments include the pharmaceutical composition comprising a therapeutically effective amount of novel intermediates or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
  • Another embodiment of the invention is use of compounds of formula (I) or pharmaceutically acceptable salt thereof, in the treatment of disease conditions originally treatable by the corresponding free drug(s).
  • Another embodiment of the invention is double prodrug of formula (I) selected from the group consisting of: I-AA-MPD5, 1-AA-MPD6, 1-AA-MPD7, and I-AA-MPD8.
  • the present invention also provides mutual prodrugs of formula (I) selected from the group consisiting of: I-CA-MPD1, I-CA-MPD2, I-CA-MPD3, I-CA-MPD4, I-CA-
  • MPDI l I-CA-MPD12, I-CA-MPD13, I-CA-MPD14, I-CA-MPD15, I-CA-MPD16, I- CA-MPD17, I-CA-MPD18, I-CA-MPD19, I-CA-MPD20, I-CA-MPD21, I-CA-MPD22, I-CA-MPD23, I-CA-MPD24, I-CA-MPD25, I-CA-MPD26, I-CA-MPD27, I-CA- MPD28, 1-CA-MPD29, and I-CA-MPD30.
  • the invention provides compounds of formula (I) selected from the group of mutual prodrugs made from amino-containing therapeutic agent and a hydroxyl-containing therapeutic agent such as: I-AH-MPD1, 1-AH-MPD2, 1-AH-MPD3, I-AH-MPD4, I-AH-MPD5, I-AH-MPD6, I-AH-MPD7, I-AH-MPD8, I-AH-MPD9, I- AH-MPDlO, I-AH-MPD11, 1-AH-MPD12, 1-AH-MPD13, I-AH-MPD14, 1-AH-MPD15, I-AH-MPD16, I-AH-MPD17, I-AH-MPD18, I-AH-MPD19, I-AH-MPD20, I-AH- MPD21, 1-AH-MPD22, 1-AH-MPD23, 1-AH-MPD24, 1-AH-MPD25, and I-AH-MPD26.
  • a hydroxyl-containing therapeutic agent such as: I-AH-MPD1,
  • Yet another embodiment of the invention relates to compounds of formula (I) of mutual prodrugs made from a hydroxyl-containing therapeutic agent and a hydroxyl- containing therapeutic agent such as: I-HH-MPD1, I-HH-MPD2, I-HH-MPD3, I-HH- MPD4, I-HH-MPD5, I-HH-MPD6, I-HH-MPD7, I-HH-MPD8, I-HH-MPD9, I-HH- MPDlO, I-HH-MPD11, I-HH-MPD12, I-HH-MPD13, I-HH-MPD14, I-HH-MPD15, I- HH-MPD16, 1-HH-MPD17, and I-HH-MPD18.
  • a hydroxyl-containing therapeutic agent such as: I-HH-MPD1, I-HH-MPD2, I-HH-MPD3, I-HH- MPD4, I-HH-MPD5, I-HH-MPD6, I-HH-MPD7, I-HH-MPD
  • the present invention also provides compounds of formula (I) containing water- soluble prodrugs of insoluble or sparingly-soluble therapeutic agents such as: I-H1-PD1, I-H1-PD2, 1-H1-PD3, 1-H1-PD4, 1-H1-PD5, 1-H1-PD6, 1-H1-PD7, 1-H1-PD8, 1-H1-PD9, I-H1-PD10, 1-H1-PD11, 1-H1-PD12, 1-H1-PD13, 1-A1-PD1, 1-A1-PD2, 1-A1-PD3, I-Al- PD4, 1-A1-PD5, 1-A1-PD6, 1-A1-PD7, 1-A1-PD8, 1-A1-PD9, 1-A1-PD10, I-A1-PD11, I- A1-PD12, I-A1-PD13, I-A1-PD14, I-A1-PD15A, I-Al-PDlAa, I-A1-PD15B, I-Al- PD 15
  • Another embodiment of the invention relates to the compounds of formula (I), selected from the group of NO-releasing prodrugs consisting of: I-Cl -NOPDl, I-Cl- NOPD2, 1-Cl-NOPD3a, I-Cl-NOPD3b, I-C1-NOPD4, 1-Cl-NOPD5a, I-Cl-NOPD5b, I- C1-NOPD6, 1-C1-NOPD7, 1-Cl-NOPD8a, I-Cl-NOPD8b, I-C1-NOPD9, 1-C1-NOPD10, I-Cl-NOPDl la, I-C1-NOPD13, 1-Cl-NOPD14a, I-Cl-NOPD14b, I-Cl-NOPD15b, I-Cl- NOPD 16, I-Cl -NOPD 17a, I-Cl -NOPD 17b, I-C1-NOPD18, I-C1-NOPD19, I-Cl- NOPD20a, I-
  • Another aspect of the invention provides the use of the compounds of formula (I) in combination with a compound used to treat cardiovascular diseases selected from the group consisting of: beta adrenergic blockers, calcium channel blockers, angiotensin II receptor antagonists, antithrombotics, HMGCoA reductase inhibitors, aspirin or nitrooxy derivatives of aspirin, nitrosated beta blockers, nitrosated or nitrosilated calcium channel blockers.
  • Suitable drugs are described in the literature such as the Merck Index, IDdb, Prous Science's Integrity ® , Prous Science Drugs of the FutureTM, The Ensemble ® and the like.
  • Another aspect of the invention provides the use of the pharmaceutical compositions containing compounds of formula (I) in combination with a compound, used to treat other diseases such as cardiovascular diseases, selected from beta adrenergic blockers, calcium channel blockers, angiotensin II receptor antagonists, antithrombotics, HMGCoA reductase inhibitors, aspirin or nitrooxy derivatives of aspirin, nitrosated beta blockers, nitrosated or nitrosilated calcium channel blockers.
  • Pharmaceutical compositions containing two or more of compounds of the invention can be used for the purpose of combination therapy. These pairs of compounds of invention can be from the same therapeutic area or from different therapeutic areas for treating one or more diseases or conditions.
  • the compounds of the invention which have one or more asymmetric carbon atoms, can exist as the optically pure enantiomers, pure diastereomers, enantiomer racemic mixtures, diastereomer racemic mixtures, racemates or racemate mixtures.
  • optically pure enantiomers pure diastereomers
  • enantiomer racemic mixtures pure diastereomers
  • diastereomer racemic mixtures diastereomer racemic mixtures
  • racemates or racemate mixtures are also all the possible isomers, stereoisomers and their mixtures of the compounds of formula (I).
  • Another embodiment of the invention relates to the pharmaceutical composition comprising one or more compounds of formula (I) or pharmaceutically acceptable salts thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
  • Another embodiment of the invention relates to the pharmaceutical composition comprising one or more compounds of formula (I) or pharmaceutically acceptable salts thereof and at least another pharmaceutically active compound.
  • the pharmaceutically active compound can be from the same or different therapeutic areas for treating one or more disease condition(s) together with one or more pharmaceutically acceptable carriers, vehicles or diluents.
  • Another embodiment of the invention is a process for preparation of compounds of formula (I) or pharmaceutically acceptable salts thereof, wherein the process comprises, mixing a selectively protected and activated drug with a solution of 2-((2- hydroxyethyl)dithio)ethyl nitrate in a suitable solvent in presence of a suitable coupling agent.
  • Another embodiment of the invention is a compound or intermediate generated in the above methods and processes.
  • Another embodiment of the invention is a process for preparation of compounds of formula (I) or pharmaceutically acceptable salts thereof, wherein a process comprises, converting 2-((2-hydroxyethyl)dithio)ethyl nitrate into its formyl halide or imidazolide by using a phosgene or its equivalent reagent and mixing/reacting the resulting reactive intermediate with a suitable drug in suitable solvent in presence of a suitable base.
  • Another embodiment of the invention is a process for preparation of compounds of formula (I) or pharmaceutically acceptable salt thereof, wherein the process comprises, mixing/reacting a selectively protected and activated drug with a solution of 2-((2- aminoethyl)dithio)ethyl nitrate (or its acid salt) in a suitable solvent in presence of a suitable coupling agent and/or base.
  • Another embodiment of the invention comprises the novel intermediates formed in the preparation of present invention.
  • Further embodiments include a pharmaceutical composition comprising a therapeutically effective amount of novel intermediates or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
  • Another embodiment of the invention is processes for the preparation of compounds of formula (I) or pharmaceutically acceptable salt thereof, as well as the starting materials and intermediates involved as depicted in schemes 1-23.
  • Another embodiment of the invention is use of compounds of formula (I) or pharmaceutically acceptable salts thereof, in the treatment of disease conditions originally treatable by the corresponding free drugs.
  • Another embodiment of the invention includes but not limited to a pharmaceutical composition
  • a pharmaceutical composition comprising the compounds of formula (I), or pharmaceutically acceptable salt thereof, selected from the group of NO-releasing prodrugs described herein, or more pharmaceutically acceptable carriers, vehicles or diluents.
  • a Mutual Prodrug of desloratadine and pseudoephedrine (I-AA-MPD1) is proposed as a potential treatment option for seasonal allergic rhinitis (SAR).
  • Desloratadine an active metabolite of loratadine
  • Pseudoephedrine is an oral decongestant.
  • a Mutual Prodrug of amlodipine (Pfizer' s Norvasc ® ) and lisinopril (Zeneca's Zestril ® ) (I-AA-MPD2) is proposed as a potential treatment option for hypertension and congestive heart failure.
  • Amlodipine is a calcium channel blocker and is used as an antihypertensive and antianginal agent.
  • Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor and is used for the treatment of hypertension and congestive heart failure.
  • ACE angiotensin-converting enzyme
  • a Mutual Prodrug of amlodipine (Pfizer' s Norvasc ® ) and losartan (Merck's Cozaar ® ) (I-AA-MPD3a) is proposed as a potential treatment option for mild to moderate hypertension.
  • Amlodipine is a calcium channel blocker and is used as an antihypertensive and antianginal agent.
  • Losartan potassium is an angiotensin II blocker and is used for the treatment of hypertension.
  • a combination therapy using these two drugs has been proven to be more effective treatment option than monotherapy using either of these drugs.
  • Examples of mutual prodrugs and double prodrugs of valdecoxib and celecoxib containing a disulfide linker are: I-AA-MPD4 and I-AA-MPD5.
  • Examples of double prodrugs of valdecoxib or celecoxib containing non-disulfide linkers I-AA-MPD6, 1-AA-MPD7, 1-AA-MPD8.
  • Zyprexa ® (I-AA-MPD9) is proposed for potential treatment of patients with Bipolar disorder. Fluoxetine and Olanzapine are used in combination to treat patients with bipolar disorder while being spared the treatment-emergent mania that such patients often get on antidepressant monotherapy.
  • Example of double prodrug of gabapentin is proposed as potential antiepileptic agent: I-AA-MPD10.
  • mutual prodrugs under this category include the following: Mutual prodrugs of valproic acid and other carboxyl-, hydroxyl-, and amino- containing (including amide-, and sulfonamide-containing) anticonvulsant agents such as levetiracetam, lamotrigine, pregabalin, carbamazepine, oxcarbamazepine, licarbazepine, felbamate, topiramate and the like. (Structures are given below).
  • the list also includes investigational antiepileptic agents such as antipamezole, licarbazepine, Eslicarbazepine Acetate (BIA 2-093), fluorofelbamate, isovaleramide (NPS 1776), retigabine (D-23129), safmamide (NW-IOl 5), stiripentol (STP), talampanel (TLP), (2S)-2-[(4R)-2-oxo-4- propylpyrrolidin-l-yl]butanamide 83 alpha (ucb 34714), valrocemide (TV 1901), and the like.
  • investigational antiepileptic agents such as antipamezole, licarbazepine, Eslicarbazepine Acetate (BIA 2-093), fluorofelbamate, isovaleramide (NPS 1776), retigabine (D-23129), safmamide (NW-IOl 5), stiripentol (STP
  • Mutual Prodrugs can be made from combination of any two anti-convulsant agents listed above or any other suitable anticonvulsant agents.
  • Mutual prodrug of gabapentin and naproxen (I-CA-MPD22) is proposed for potential treatment option for neurological pain and inflammation.
  • Metronidazole is an antianaerobic agent and used in combination with antibiotics such as norfloxacin, ciprofloxacin, etc. for the treatment of patients with diarrhea and dysentery of bacterial, amoebic and mixed origin.
  • a mutual prodrug of loperamide and.norflaxacin (I-AH-MPD4) is proposed for potential treatment of diarrhea and dysentery.
  • a mutual prodrug of valdecoxib and tramadol (I-AH-MPD5 and I-AH-MPD6) as a potential therapy in postoperative pain management.
  • a mutual prodrug of gabapentin and tramadol ⁇ (I-AH-MPD7) is proposed for potential treatment of neuropathic pain after spinal cord injury.
  • I-AH-MPD8 A mutual prodrug of venlafaxine and paroxetine (I-AH-MPD8) is proposed for potential treatment of neurological and depression related disorders.
  • Water-soluble prodrugs of insoluble/sparingly-soluble therapeutic agents can be prepared using the same linker technology.
  • Water-soluble prodrugs of metronidazole include: I-H1-PD-2, I-H1-PD-3, I-Hl- PD-4.
  • Water-soluble prodrugs of valdecoxib include: I-A3-PD1, I-A3-PD2a, I-A3- PD2b, I-A3-PD3a, I-A3-PD3b, I-A3-PD4, 1-A3-PD5, 1-A3-PD6, and I-A3-PD7b.
  • Water-soluble prodrugs of paclitaxel include: I-Taxol-PDl, I-Taxol-PD2, 1-Taxol- PD3, 1-Taxol-PD4, 1-Taxol-PD5, 1-Taxol-PD6, and I-S23-PD1.
  • R 1 is H, alkyl, aralkyl, or a metal ion
  • Drugs can be released form the prodrugs and mutual prodrugs via cleavage of bio- labile linker(s) in vivo (cleavage can be either chemical or enzymatic or both) by illustrative mechanisms as shown in Schemes Ml through M5.
  • nitric oxide (NO) and free drug from NO-releasing prodrug(s) of amino-, hydroxyl-, or carboxyl-containing drug(s) are illustratively shown in Schemes Ml .
  • the attack of thiolate ion (from GSH or any other sulfahydryl-containing species) on nitrooxy-containing prodrug would release carboxylic acid-containing free drug, episulfide (d) and the intermediate conjugate (a) according to path 1.
  • the prodrug would be cleaved via path 2 to release the corresponding free drug, the cyclic thiocarbonate intermediate (c) and the intermediate conjugate (a).
  • the cyclic thiocarbonate intermediate may further breakdown into episulfide (d) and carbon dioxide.
  • the reactive episulfide (d) would be further neutralized by glutathione.
  • the nitrate ester- containing intermediate conjugate can further break down in the presence of GSH to glutathione dimer (GS-SG) and transient intermediate (b), which can break down via path 3 to release NO. It is also possible the same transient intermediate can break down via path 4 to yield episulf ⁇ de (d) and a relatively innocuous nitrate anion (NO 3 " ).
  • Scheme Ml Plausible mechanisms of drug release from mutual prodrugs of one carboxyl- containing and one amino-/hydroxyl-containing drug is shown in Scheme M2.
  • D ⁇ D 2 and L 2 are as defined in the text.
  • X m2 is a bond, CH 2 , O, NR ml (R ml is H, alkyl, aryl or a bond),
  • This invention also covers novel bio-labile linkers containing 1 ,4-phenylene group and 1 ,2-phenylene group as shown in Schemes 5 and 6, respectively.
  • the linker is expected to release the free Drug 1 upon glutathione-assisted cleavage and may generate 1,4-quinonemethid (ea) as a byproduct via 1,6-elimination process.
  • the free Drug 2 is expected to be released from the intermediate conjugate (a) as shown in the scheme.
  • the 1,2-phenylene-containing linker is also expected to release free drugs upon glutathione assisted cleavage and genereate 1,2-quinonemethid (eb) as a byproduct via 1,4-elimination process (via pathway 'b').
  • this linker can also cleave via pathway 'a' to generate benzo-monothiocarbonate as a byproduct.
  • the generated byproducts seem to be toxic, they are likely to be quickly neutralized by detoxification enzymes in the body.
  • Diazepam a benzodiazepine tranquilizer
  • a water-soluble acyclic prodrug of diazepam can be made by using our linker technology.
  • reduction of disulfide bond in the prodrug triggers release of open-chain intermediate of diazepam which spontaneously cyclizes to diazepam in vivo.
  • GSH is glutathione (reduced) or any other in vivo bioreductive agent that can reduce the disulfide bond.
  • cleavage of disulfide bond triggers further breakage of the remaining portion of the linker to release the free drugs. In the process, some byproducts are generated and these are either eliminated or further degraded by some biological process. For clarity, the mechanism of cleavage of the linker is shown as occurring in stepwise manner. However, both the steps can possibly occur in a concomitant fashion to release both the drugs simultaneously.
  • Linkers may have additional spacer groups between one side (or both sides) of the linkers and the drug molecule and some of these spacer groups may be cleaved independently by a chemical or enzymatic process to release the drugs prematurely before the cleavage of disulfide linkage.
  • the prodrugs and mutual prodrugs containing such spacer groups may be useful when faster release of drug(s) is desired.
  • Drugs listed in the following list can be converted to NO- releasing prodrugs. This list is in no way limiting the scope of drugs covered in this invention, but given as representative examples. All the amino- (including amide-NH and sulfonamide-NH, carbamate-NH, sulfamate-NH, hydrazone-NH, semicarbazone-NH, thiosemicarbazone- NH, urea-NH, phosphoramide-NH and the like.
  • ANTI-INFLAMMATORY DRUGS Amino-containing (including Amide NH and Sulphonamide NH and
  • Phosphomide NH etc.: Ampiroxicam, Bucolome, Celecoxib, Difenpiramide, Mofebutazone, Nimesulide, Paranyline, Parecoxib, Parsalmide, Piketoprofen, Talniflumate, Tenidap, Terofenamate, and Valdecoxib.
  • Hydroxyl-containing 21-Acetoxypregnenolone, Alclometasone, alfa-Bisabolol, Budesonide, Deflazacort, Diflorasone, Desonide, Desoximetasone, Diflorasone, Diflucortolone, Difiuprednate, Ditazol, Fluazacort, Fluocinonide, Fluocortin Butyl, Fluprednidene Acetate, Glucametacin, Halcinonide, Halobetasol Propionate, Halometasone, Halopredone Acetate, Ibuproxam, Loteprednol Etabonate, Mazipredone, Mometasone Furoate, Oxyphenbutazone, Perisoxal, Rimexolone, Hydroxyl-, and Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Bufexamac, Etof
  • Hydroxyl- and sulphahydryl-containing Tixocortol, Carboxyl- and Amino-containing (including amide NH and sulphonamide NH and phosphomide NH, etc.): Aceclofenac, Alminoprofen, Amfenac, 3-Amino-4- hydroxybutyric Acid, Carprofen, Diclofenac, Enfenamic Acid, Etodolac, Flufenamic Acid, Meclofenamic Acid, Mefenamic Acid, Niflumic Acid, and Tolfenamic Acid.
  • Carboxyl-containing Acemetacin, Acetamidocaproic Acid, Bendazac, Benoxaprofen, Be ⁇ noprofen, Bucloxic Acid , Butibufen, Cinmetacin, Clidanac, Clopirac, Felbinac, Fenbufen, Fenclozic Acid, Fenoprofen, Fentiazac, Flunoxaprofen, Flurbiprofen, Ibuprofen, Indomethacin, Isofezolac, Isoxepac, Ketoprofen, Lonazolac, Loxoprofen, Metiazinic Acid, Mofezolac, Naproxen, Oxaprozin, Pirazolac, Pirprofen, Pranoprofen, Protizinic Acid, Sulindac, Suprofen, Suxibuzone, Tiaprofenic Acid, Tolmetin, and Tropesin.
  • Carboxyl- and Hydroxy 1-containing Balsalazide
  • Olsalazine Olsalazine, Oxaceprol, and Ximoprofen.
  • Amino-, Carboxyl- and Hydroxyl-containing 3-Amino-4-hydroxybutyric Acid, Mesalamine, and Sulfasalazine.
  • Keto-containing Nabumetone, and Piketoprofen.
  • Carboxyl- and keto-contianing Bermoprofen, Bucloxic Acid, Isoxepac,
  • Ketoprofen, Loxoprofen, and Zaltoprofen are Ketoprofen, Loxoprofen, and Zaltoprofen. ANALGESIC AND/OR ANTIPYRETIC DRUGS:
  • Amino-containing Aminochlorthenoxazin, Aminopropylon, Anileridine,
  • Phenacetin Phenazopyridine, Phenocoll, Phenopyrazone, Piminodine, Piritramide,
  • Hydroxyl-containing Aluminum bis(acetylsalicylate), Benzylmo ⁇ hine, Bupreno ⁇ hine, Butorphanol, Chlorobutanol, Ciramadol, Codeine, Desomo ⁇ hine, Dihydrocodeine, Dihydromorphine, Dihydroxyaluminum acetylsalicylate, Dimepheptanol, Eptazocine, Ethylmorphine, Eugenol, Hydroxypethidine, Levo ⁇ hanol, Meptazinol, Metazocine, Mo ⁇ hine, Nalbuphine, Pentazocine, Phenazocine, Phenoperidine, Phenylsalicylate, Salicin, Tramadol, and Viminol.
  • Carboxyl-containing Acetylsalicylsalicylic acid, Alclofenac, Aspirin, Benoxaprofen, 5-Bromosalicylic acid acetate, Cinchophen, Diacerein, Dipyrocetyl, Fosfosal, Ibufenac, Indoprofen, and Salicysulfuric acid.
  • Amino- and Hydroxyl-containing Acetaminophen, Acetaminosalol, Bucetin, Capsaicine, Dezocine, Floctafenine, Glafenine, Isoladol, p-Lactophenetide, Norlevorphanol, No ⁇ norphine, Phenylramidol, Salacetamide, and Salicylamide.
  • Amino- and Carboxyl-containing Actarit, Bumadizone, Clonixin, and Salicylamide O-acetic acid.
  • Carboxyl- and Hydroxyl-containing Diflunisal, Gentisic acid, and Salsalate.
  • Keto-containing Amtolmetin, Dipipanone, Hydrocodone, Isomethadone, Methadone, Norpipanone, and Phenadoxone.
  • Hydroxy- and Keto-containing Hydromorphone, Ketobemidone, Metopon, Oxycodone, and Oxymorphone.
  • Carboxyl- and Keto-containing Clometacin, Ketorolac, and Zomepirac.
  • Amino-containing Alfuzosin, Benzylhydrochlorothiazide, Bethanidine, Bopindolol, Budralazine, Bunazosin, Ciclosidomine, Clonidine, Clopamide,
  • Reserpiline Reserpine, Rilmenidine, Syrosingopine, Tasosartan, Terazosin, Tiamenidine,
  • Hydroxy-containing Ajmaline, Cicletanine, Levcromakalim, Naftopidil, Phenactropinium chloride, and Protoveratrines.
  • Carboxyl-containing Eprosartan, Fosinopril, and Telmisartan,
  • Amino- and Carboxyl-containing Alacepril, gama-Aminobutyric acid, Benazepril, Candesartan, Carmoxirole, Caronapril, Cilazapril, Delapril, Enalapril, Enalaprilat, Imidapril, Lisinopril, Moexipril, Moveltipril, Perindopril, Quinapril, Ramipril, Saralasin, Spirapril, Temocapril, Trandolapril, and Valsartan.
  • Amino- and Hydroxyl-containing Acebutolol, Alprenolol, Amosulalol, Arotinolol, Atenolol, Betaxolol, Bisoprolol, Bosentan, Bucindolol, Bufeniode, Bunitrolol, Bupranolol, Butofilolol, Cadralazine, Celiprolol, Carazolol, Carteolol, Cetamolol, Carvedilol, Epanolol, Indenolol, Nadolol, Dilevalol, Fenoldopam, Guanoxabenz, Labetalol, Losartan, Mepindolol, Metipranolol, Metoprolol, Moprolol, Nebivolol, Olmesartan, Oxprenolol, Penbutolol, Phentolamine, Pildralazin
  • Amino-containing Acedapsone, Acetosulfone sodium, Ambazone, Bacampicillin, Benzylsulfamide, Brodimoprim, Cefcapene pivoxil, Cefpodoxime proxetil, Chloramine- B, Chloramine-T, Capreomycin, Clofazimine, Cyacetacide, Cycloserine, Dapsone, Ethionamide, Furazolium chloride, N2-Formylsulf ⁇ somidme, Furonazide, Isoniazid, Lenampicillin, Linezolide, Mafenide, 4'-(Methylsulfamoyl)sulfanilanilide, Morphazinamide, Nifuradene, Nitrofurantoin, Penamecillin, Penethamate hydriodide, Pexiganan, Pivampicillin, Pivcefalexin, Picloxydine, Protionamide, Pyrazinamide, Solasulfone, Suba
  • Hydroxyl-containing Azithromycin, Chloroxylenol, Chlorquinadol, Clofoctol, Cloxyquin, Diathymosulfone, Glucosulfone sodium, Nifurpirinol, Nifurtoinol, Nitroxoline, Roxarsone, Roxithromycin, Xanthocillin, and Xibornol.
  • Carboxyl-containing (including sulfate, phosphate and phosphonate-containing): Amdinocillin, Cinoxacin, Difloxacin, Fosfomycin, and Hydnocarpic acid.
  • Amino- and Carboxyl-containing (including sulfate-, sulfonic acid-, phosphate and phosphonate-containing): Acediasulfone, Amphomycin, Ampicillin, Azidocillin, Azlocillin, Aztreonam, Bacitracin, Balofioxacin, Betamipron, Carbenicillin, Carindacillin, Carumonam, Cefaclor, Cefazedone, Cefazolin, Cefclidin, Cefditoren, Cefepime, Cefetamet, Cefixime, Cefmenoxime, Cefmetazole, Cefodizime, Ceforanide, Cefotaxime, Cefotetan, Cefotiam, Cefoxitin, Cefozopran, Cefpimizole, Cefpirome, Cefroxadine, Cefsulodin, Ceftazidime, Cefteram, Ceftezole, Ceft
  • Amino- and Hydroxyl-containing Amikacin, p-Aminosalicylic acid hydrazide, Arbekacin, Azidamfenicol, Bambermycins, 5-Bromosalicylhydroxamic acid, Butirosin, Clindamycin, Clomocycline, Chloramphenicol, Cloxacillin, Colistin, Demeclocycline, Deoxydihydrostreptomycin, Dibekacin, Dihydrostreptomycin, Dirithromycin, Doxycycline, Enviomycin, Ethambutol, Forimicins, Gentamycin, Glyconiazide, N4-beta- D-Glucosylsulfanilamide, Gramicidin(s), Isepamicin, Kanamycin(s), Lincomycin, Meclocycline, Methacycline, Micronomicin, Neomycin, Netilmicin, Novobiocin, Paromomycin, Phenyl aminosalicylate, Pi
  • Hydroxyl- and Carboxyl-containing including sulfate, phosphate and phosphonate-containing: Fropenem, Nadifloxacin, Biapenem, Fusidic acid, and Merbromin. Hydroxyl- and Aldehyde-containing: Josamycin, Leucomycins, Midecamycins,
  • Amino-, Hydroxyl-, and Carboxyl-containing including sulfate, phosphate and phosphonate-containing: p-Aminosalicylic acid, Apicycline, Amoxicillin, Apalcillin, Aspoxicillin, Benzoylpas, Cefadroxil, Cefamandole, Cefatrizine, Cefbuperazone, Cefdinir, Cefminox, Cefonicid, Cefoperazone, Cefoselis, Cefpiramide, Cefprozil, Ertapenem, Flomoxef, Imipenem, Lymecycline, Meropenem, Moxalactam, Negamycin, Panipenem, Ritipenem, Salazosulfadimidine, Sulfaloxic acid, 4-Sulfanilamidosalicylic acid, Teicoplanin, Tyrocidine, and Vancomycin.
  • Keto-containing Troleandomycin. Hydroxy- and Keto-containing: Carbomycin, Clarithromycin, Erythromycin, all erythromycin ester derivatives, Oleandomycin, and Telithromycin.
  • Carboxyl- and Keto-containing Fleroxacin, Flumequine, Miloxacin, Nalidixic acid, Ofloxacin, Oxolinic acid, Pefloxacin, Piromidic acid, Prulifloxacin, Rosoxacin, and Rufloxacin.
  • Amino-, hydroxyl-, and Keto-containing Chlortetracycline, Dalfopristin, Guamecycline, Mikamycin, Minocycline, Oxytetracycline, Pristinamycin, Quinupristin, Rolitetracycline, Spectinomycin, and Trospectomycin.
  • Amino-, carboxyl-,and keto-contianing Garenoxacin, Gatifloxacin, Gemifloxacin, Grepafloxacin, Lomefloxacin, Moxifloxacin, Norfloxacin, Pazufloxacin, Pipemidic acid, Sitafloxacin, Sparfloxacin, Tosufloxacin, and Trovafloxacin.
  • Amino-containing Chlordantoin, Exalamide, Flucytosine, Loflucarban, Magenta I, and Pyrrolnitrin.
  • Hydroxy-containing Chlo ⁇ henesin, Ciclopirox, Dermostatin, Filipin, Fluconazole, Fungichromin, Pecilocin, Posaconazole, Ravuconazole, Rubijervine, Siccanin, 2,4,6-Tribromo-m-cresol and Voriconazole.
  • Amino- and Carboxyl-containing Azaserine.
  • Amino- and Hydroxyl-containing Salicylanilide, Acrisorcin (9-Aminoacrindine compound with 4-Hexylresorcinol (1:1)), Anidulafungin, Bromosalicylchloranilide, Buclosamide, Caspofungin, Micafungin, and Tubercidin.
  • Amino-, Carboxyl- and Hydroxyl-containing Natamycin, Amphotericin B, Lucensomycin, and Nystatin.
  • Carbonyl-containing sodium propionate and griseofulvin. Hydroxy- and carbonyl-containing: Viridin.
  • Amino-, hydroxyl-, and carbonyl-containing Perimycin and Mepartricin. Amino-, carboxyl-, hydroxyl-, and carbonyl-containing: Candicidin. ANTIVIPVAL DRUGS:
  • Edoxudine Hydroxy-containing: Edoxudine, Floxuridine, Idoxuridine, Kethoxal, Podophyllotoxin, Sorivudine, Stavudine, Trifluridine, and Zidovudine.
  • Amino-containing Amantadine, Amidinomycin, Atevirdine, Capravirine, Delavirdine, Efavirenz, Famciclovir, Imiquimod, Lamivudine, Methisazone, Moroxydine, Nevirapine, Oseltamivir, Rimantadine, Stallimycin, mantadine, and Valacyclovir.
  • Amino- and Hydroxyl-containing Abacavir, Acyclovir, Adefovir, Amprenavir,
  • Atazanavir Cidofovir, Didanosine, Dideoxyadenosine, Emtricitabine, Entecavir, Indinavir, Lamivudine, Lopinavir, 5-(methylamino)-2-deoxyuridine (MADU), Nelfinavir, Penciclovir, Resiquimod, Ribavirin, Ritonavir, Saquinavir, Tenofovir, Tipranavir, Valganciclovir, Vidarabine, and Zalcitabine.
  • Carboxyl- and Hydroxyl-containing Foscarnet sodium, and Ganciclovir. Amino-, Carboxyl- and Hydroxyl-containing: Zanamivir.
  • Amino-containing Chlorguanide, Chloroquine, Chlorproguanil, Cycloguanil, Pamaquine, Plasmocid, Primaquine, Quinocide, and Tafenoquine.
  • Hydroxyl-containing Artemisinin alcohol, Bebeerines, Cinchonidine, Cinchonine, Dihydroartemisinin, Halofantrine, Lumefantrine, Quinine and Yingzhaosu A.
  • Carboxyl-containing Arteflene and Artesunate.
  • Amino-, and Hydroxyl-containing Amodiaquin, Hydroxychloroquine, Mefloquine, and Pyronaridine. Hydroxyl, and carbonyl-containing: Fosmidomycin.
  • Carbonyl-containing Arteflene.
  • ANTINEOPLASTIC DRUGS
  • Calusterone Capecitabine, CC- 1065, Chromomycins, Diethylstilbestrol, Docetaxel, Doxifluridine, Droloxifene, Dromostanolone, Enocitabine, Epitiostanol, Estramustine,
  • Etanidazole Etoposide, Fenretinide, Flavopiridol, Formestane, Fosfestrol, Fulvestrant,
  • Paclitaxel and other known paclitaxel analogs Plicamycin, Podophyllotoxin, Retinoic acid (including all trans-retinioc acid), Roquinimex, Rubitecan, Seocalcitol, Temoporf ⁇ n,
  • Amino-containing including Amide-NH and Sulphonamide-NH, Carbamate-NH,
  • Sulfamate-NH, and Phosphomide-NH 9-Aminocamptothecin, Aminolevulinic Acid, Amsacrine, Bisantrene, Cactinomycin, Carboquone, Carmofur, Carmustine,
  • Cyclophosphamide dacarbazine, Dactinomycin, Demecolcine, Diaziquone, 6-Diazo-5- oxo-L-norleucine (DON), Edatrexate, Efaproxiral, Eflornithine, Eniluracil, Erlotinib, Fluorouracil, Gefitinib, Gemcitabine, Goserelin, Histamine, Ifosfamide, Imatinib, Improsulfan, Lanreotide, Leuprolide, Liarozole, Lobaplatin, Cisplatin, Carboplatin, Lomustine, Lonafarnib, Mannomustine, Melphalan, Methotrexate, Methyl Aminolevulinate, Miboplatin, Mitoguazone, Mitoxantrone, Nilutamide, Nimustine, Nolatrexed, Oxaliplatin, Pemetrexed, Phenamet, Piritrexim,
  • Both Hydroxy- & Amino- containing (including Amide-NH and Sulphonamide- NH, Carbamate-NH, Sulfamate-NH, and Phosphomide-NH): Ancitabine, Anthramycin, Azacitidine, Bleomycins, Bropirimine, Buserelin, Carubicin, Chlorozotocin, Cladribine, Cytarabine, Daunorubicin, Decitabine, Defosfamide, Docetaxel, Doxorubicin, Ecteinascidins, Epirubicin, Gemcitabine, Hydroxyurea, Idarubicin, Marimastat, 6- Mercaptopurine, Pentostatin, Peplomycin, Perfosfamide, Pirarubicin, Prinomastat, Puromycin, Ranimustine, Streptonigrin, Streptozocin, Tiazofurin, Troxacitabine, Vindesine and Zorubicin. Carboxyl-containing: Butyric acid
  • Amino-containing including some investigational drugs: BTX-51072 (4,4- dimethyl-3,4-dihydro-2H-l,2-benzoselenazine), Carnosine, Melatonin, (+)-R- Pramipexole, and Stobadine.
  • Hydroxyl-containing including some investigational drugs: Ascorbic acid,
  • Carboxyl-containing including some investigational drugs: N-Acetyl L-cysteine,
  • Amino-/Hydroxyl-, and Carboxyl-containing including some investigational drugs: N-Acetyl carnosine, L-Carnitine, and SCMC-Lys (S-carboxymethyl-L-cysteine Lysine salt H 2 O).
  • Amino- and Hydroxyl-containing including some investigational drugs: BN- 82451, and Zeatin.
  • Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Aldioxa, Benexate HCl, Cimetidine, Ebrotidine, Ecabapide,
  • Esaprazole Esaprazole, Esomeprazole, Famotidine, Irsogladine, Lafutidine, Lansoprazole,
  • Carboxyl-containing Acetoxolone, Carbenoxolone, Rebamipide, and Sofalcone.
  • Amino (or Hydroxyl) - and Carboxyl-containing Cetraxate, Ecabet, S- Methylmethionine, Rosaprostol, and Rotraxate.
  • Carbonyl-containing Spizofurone, and Teprenone.
  • Amino-containing including Amide NH and Sulphonamide NH
  • Ethosuximide Ethotoin, Felbamate, Fosphenytoin, Lamotrigine, Levetiracetam, Mephenytoin, Mephobarbital, Metharbital, Methetoin, Nitrazepam, Oxcarbazepine,
  • Phenylmethylbarbituric Acid Phenytoin, Phethenylate Sodium, Primidone, Progabide,
  • Valpromide Zonisamide, 5-Methyl-5-(3-phenanthryl)hydantoin, and 3-Methyl-5- phenylhydantoin.
  • Hydroxyl-containing Ganaxolone.
  • Hydroxyl-, and Amino-containing including Amide NH and Sulphonamide NH and Phosphomide NH: 4-Amino-3-hydroxybutyric Acid, Atrolactamide, and Buramate.
  • Carboxyl- and Amino-Containing including Amide NH and Sulphonamide NH and Phosphomide NH: Gabapentin, Pregabalin, and Vigabatrin.
  • Carboxyl-containing Tiagabine, and Valproic Acid.
  • ANTIP ARKINSON'S Levodopa & Carbidopa.
  • ANTIDEPRESSANT
  • Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Amoxapine, Caroxazone, Demexiptiline, Desipramine, Duloxetine, Fluoxetine, Fluvoxamine, Indalpine, Indeloxazine Hydrochloride, Iproclozide, Iproniazid, Isocarboxazid, Levophacetoperane, Maprotiline, Metapramine, Milnacipran, Minaprine, Moclobemide, Nialamide, Nomifensine, Nortriptyline, Octamoxin, Oxypertine, Paroxetine, Protriptyline, Reboxetine, Rolipram, Sertraline, Tofenacin, Tranylcypromine, Viloxazine, Benmoxine, and Rolicyprine. Hydroxyl-containing: Befloxatone, Bupropion, Fenpentadiol,
  • Carboxyl- and Amino-Containing (including Amide NH and Sulphonamide NH and Phosphomide NH): Amineptine, and Tianeptine.
  • ANTIHISTAMINIC Amide NH and Sulphonamide NH and Phosphomide NH
  • Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Antazoline, Astemizole, Clobenzepam, Desloratadine, Epinastine, Metron S, Mizolastine, and Tritoqualine.
  • Hydroxyl-containing Terfenadine, and N-Hydroxyethylpromethazine Chloride.
  • Carboxyl-containing Acrivastine, Bepotastine, Cetirizine, and Levocabastine,
  • CARDIOPROTECTIVE AGENT Trans-Resveratrol [(E)-3,4',5-trihydroxystilbene).
  • ANTIDIABETIC Metformin, and Nateglinide/Glipizide/Glibenclamide (Glyburide).
  • any amino-, and/or carboxyl-, and/or carbonyl-, and/or hydroxyl-containing drug(s) (both known and investigational drugs) from the following therapeutic areas are covered without any limitation: CENTRAL NERVOUS SYSTEM: Sedatives, Hypnotics, Antidepressants,
  • Antipsychotics and Antimanics Analgesics & Antipyretics, Antimigraine agents, Anticonvulsants, Drugs used in parkinsonism and movement disorders, Drug for dementia, Antiemtics, drugs for Vertigo, CNS Stimulants & activators.
  • EYE Antiinfective eye preparations, Antiinflammatory and antiallergic preparations, antiglucoma drugs and other preparations to cure eye diseases.
  • EAR, NOSE and OROPHARYNX Drugs used aural, nasal and oropharyngeal preparation.
  • CARDIOVASCULAR SYSTEM Antiarrhythemic drugs, Antihypertensives (including alfa/beta-blockers, channel blockers, ACE inhibitors, Angiotensin II receptor antagonists, diuretics, etc.), Antianginals (includinig nitrates, calcium channel blockers, etc.), Drugs for cardiac failure and shock, Vasodilators, Coagulants, Anticoagulants, Thrombolytics and antiplatelet drugs.
  • Antiarrhythemic drugs including alfa/beta-blockers, channel blockers, ACE inhibitors, Angiotensin II receptor antagonists, diuretics, etc.
  • Antianginals includinig nitrates, calcium channel blockers, etc.
  • Drugs for cardiac failure and shock Vasodilators, Coagulants, Anticoagulants, Thrombolytics and antiplatelet drugs.
  • RESPIRATORY SYSTEM Respiratory stimulants, Antitussives, Expectorants, Mucolytics and Decongestants, Antihistamine agents, and antiasthmatics.
  • GASTRO INTESTINAL TRACT Antiulcer and Antisecretory drags (including
  • H 2 receptor antagonists include Proton Pump Iinhibitors, Prostaglandin analogues, etc.), Antacids, Antispasmodics and drugs modifying intestinal motility, Antidiarrhoeals (including antimotility and antimicrobial drugs) and drugs acting on gall bladder.
  • Urinary antiinfectives Urinary antiinfectives, Diuretics, Urinary analgesics & antispasmodics, Antiinfective drugs acting on urethra and vagina, drugs acting on uterus, Drugs for prostatic hypertrophy (including alfa blockers and antiandrogens), Drugs for erectile dysfunction, and Spermicidal & nonhormonal contraceptives.
  • SKIN Emollients and keratolytics, topical antiinfectives, topical antifungals, topical parasiticidals, topical steroids, topical drugs for acne vulgaris, drugs for psoriasis, pigmentation disorders, and Antiseborrhoeics.
  • MUSCULO-SKELETAL DISORDERS Non Steroidal Anti Inflammatory Drugs (NSAIDs) including COX-2 inhibitors, Antiarthritic agents, Immunosuppressants, Topical analgesics, Muscle relaxants and Neuromuscular Drugs.
  • NSAIDs Non Steroidal Anti Inflammatory Drugs
  • COX-2 inhibitors including COX-2 inhibitors, Antiarthritic agents, Immunosuppressants, Topical analgesics, Muscle relaxants and Neuromuscular Drugs.
  • INFECTIONS AND INFESTATIONS Penicillin antibiotics, Cephalosporin antibiotics, Quinolone & Fluoroquinolone antibiotics, Macrolide antibiotics,
  • Anthelminthics & Antiinfestive Drugs, Antimalarials and Antivirals are Anthelminthics & Antiinfestive Drugs, Antimalarials and Antivirals.
  • ENDOCRINE SYSTEM Anabolic and androgenic steroids, Corticosteroids, Oestrogens, Progestogens and Hormonal contraceptives, Fertility Agents, Trophic hormones and related drugs, Thyroid and antithyroid drugs, Antidiabetics and hyperglycaemics.
  • METABOLISM Hypolipidaemic drugs (including f ⁇ bric acid derivatives, statins [(i.e., HMG CoA reductase inhibitors), nicotinic acid group, etc.], Drugs used for Gout and Drugs affecting bone metabolism (including bisphosphonates).
  • NEOPLASTIC DISORDERS Anticancer drugs such as alkylating agents, cytotoxic antibiotics, antimetabolites such as cytarbine, Fludarbine, 5-Fluorouracil,
  • ALLERGY AND IMMUNOLOGY Antiallurgics such as non-sedative antihistamins (e.g., Cetirizine, Desloratadine, Terfenadine, Fexofenadine, etc.), sedative histamines and histamine receptor blockers.
  • non-sedative antihistamins e.g., Cetirizine, Desloratadine, Terfenadine, Fexofenadine, etc.
  • sedative histamines e.g., Cetirizine, Desloratadine, Terfenadine, Fexofenadine, etc.
  • ANAESTHETICS & SURGICALS Local anaesthetics, intravenous anaesthetics, inhalation anaesthetics and muscle relaxants.
  • NO-releasing prodrugs of any two or more drugs from the above lists of potential drugs can be used in combination depending on the medical application/need. While a combination formulation may occassionally consist of more than two drugs (depending on the medical need), the following pairs of drugs are covered in this invention as illustrative pairs of candidate drugs for combination therapy.
  • ANTICANCER Paclitaxel and Doxorubicin, Paclitaxel and Mitomycin C; Paclitaxel and 9-aminocamptothecin, 3-Arninopyridine-2-carboxaldehyde thiosemicarbazone (3-AP)/ 3-Aminopyridine-4-methyl-2-carboxaldehyde thiosemicarbazone (3 -AMP) and another known anticancer drug such as Paclitaxel,
  • Doxorubicin, Mitomycin C and the like CC- 1065 and another known anticancer drug such as Paclitaxel, Doxorubicin, Mitomycin C and the like; Trans-Resveratrol [(E)- 3,4',5-trihydroxystilbene) and another known anticancer drug such as Paclitaxel,
  • Doxorubicin Mitomycin C and the like; Retinoic acid (including all trans-retinoic acid) and Butyric acid. Paclitaxel and Captopril, Doxorubicin and Biotin. 5-Fluorouracil and
  • Cytarabine Edatrexate and Paclitaxel; Cephalosporanic acid and Paclitaxel;
  • Cephalosporin and Paclitaxel Cephalosporin and Paclitaxel; and Paclitaxel and Gemcitabine, ANTIPERKINSON'S: Levodopa and Carbidopa.
  • ANTIBIOTICS Amoxicillin and Clavulanic acid; Ampicillin and Clavulanic acid, Amoxicillin and Pencillinic acid sulfone; Ampicillin and Pencillinic acid sulfone; Olivanic acid (or any carbapenem antbiotic) and a renal dipeptidase (dehydropeptidase I) inhibitor such as 3-substituted Z-2-acylaminopropionic acid and the like.
  • ANTILIPIDEMIC AND HYPERTENSION Lifibrol and
  • Mometasone and Formoterol/Salmeterol Fluticasone and Formoterol/Salmeterol;
  • Diclofenac any known NSAID
  • Misoprostol Diclofenac (any known NSAID) and a proton pump inhibitor such as Omeprazole, Lansoprazol, Rabeprazole, Leminoprazole, Pantoprazole, and the like
  • a known antibacterial agent and a proton pump inhibitor such as Omeprazole
  • ANTIVIRAL HAV/AIDS, PEPATITIS B AND OTHER VIRAL INFECTIONS: Zidovudine and Lamivudine; Triple prodrug of Zidovudine; Lamivudine and Abacavir (Ziagen); Lopinavir and Ritonavir; Lamivudine and Adefovir or its prodrug adefovir dipivoxil; Amprenavir and Zidovudine; Nelfmavir and a nucleoside reverse transcriptase inhibitor such as Zidovudine, Lamivudine, and the like; Stavudine and an antiretroviral agent such as Zidovudine, Lamivudine, and the like; Dideoxyinosine and an antiretroviral agent such as Zidovudine, Lamivudine, and the like; Emtricitabine and Penciclovir/Famciclovir; Acyclovir (or any other known antiviral compound
  • any selected pair of drugs can be in the form of nitrate ester (NO-releasing) prodrug(s) of formula (I) or pharmaceutically acceptable salts thereof and the other drug can be in its native form.
  • NO-releasing prodrug form i.e., NO-Paracetamol and Ibuprofen/ Paracetamol and NO- Ibuprofen/ NO-Paracetamol and NO-Ibuprofen, etc.
  • a pharmaceutical composition consisting of two or more of the above listed/qualified drugs, one of the drugs can be in the form of NO- releasing (nitrooxy derivative) prodrug and the other drug(s) in the combination can be in the form another type of prodrug(s).
  • a pharmaceutical composition containing a combination of one of the above listed/qualified drug(s) and its own prodrug is also covered (i.e., a pharmaceutical composition consisting of NO-Paracetamol and Paracetamol in any proportion).
  • the free drug will be useful for faster onset of action and the prodrug will be useful for extension of the duration of action as it releases the drug in a controlled fashion over a longer period of time.
  • Such combination drug therapy may also minimize the toxicity and other side effects due to excessive plasma concentration of free drug.
  • a pharmaceutical combination may contain a prodrug of one of the above listed/qualified drugs and an another type of prodrug of the same drug (i.e., NO prodrug of pracetamol and mutual prodrug of paracetamol with another drug) and these can be present in any therapeutic proportion depending on the medical need.
  • DMF N,N-Dimethylformamide
  • DSC N,N'-Disuccinimidyl carbonate
  • CDI N,N'-Carbonyldiimidazole
  • DCC N,N'-Dicyclohexylcarbodiimide EDAC.
  • HCl l-Ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride
  • HBTU O-(Benzotriazol- 1 -yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate
  • DIPEA N,N-Diisopropylethylamine
  • PE Petroleum ether
  • the prodrugs described herein can be prepared by any number of methods known/obvious to those skilled in the art.
  • the synthetic approaches and the linkages are chosen depending upon the functional groups such as carboxyl, hydroxyl, amino or carbonyl groups present in the drug molecules to be used.
  • the following illustrative methods, as shown in Schemes 1 through 9, can be utilized to make carbonate, urethane, amide, ester, N-acyl carbamate, N-acyl amide, N-acyl sulfamate, and N-acyl sulfonamide, N-acyl phosphoramide, N-oxycarbonylsulfonamide, N- oxycarbonylcarbamate linkages, etc., between drug(s) and linker(s).
  • the carbonate linkage between the drug and the linker can be made by reacting the hydroxyl-containing drug (alternatively, hydroxyl group of the linker) with phosgene or its equivalents such as diphosgene, triphosgene, N,N'-carbonyldiimidazole (CDI), N,N'-disuccinimidyl carbonate (DSC), 4-nitrophenyl chloroformate and the like, to give a reactive alkoxycarbonyl derivative, where LG is suitable leaving group such as a halide, imidazole, O-succinimide, 4-nitrophenoxide and the like, which can be reacted with hydroxyl group of the linker (alternatively, hydroxyl group of drug if the linker is converted to active alkoxycarbonyl derivative) in the presence of a suitable base and solvent.
  • phosgene or its equivalents such as diphosgene, triphosgene, N,N'-carbonyldiimidazole (
  • Rx and Ry are any monovalent organic radicals
  • urethane linkage(s) As shown in scheme 2, the urethane linkage between the drug and the linker can be made by reacting the hydroxyl-containing linker with phosgene or its equivalents (defined above) to give a reactive alkoxycarbonyl derivative, which can be reacted with amino-containing drug in the presence of a suitable base and solvent. Alternatively, a urethane linkage can be made by adding an alcohol to an isocyanate.
  • an amide or ester linkage between the drug and the linker can be made by reacting a carboxyl-containing drug with an amino- or hydroxyl- containing linker in the presence of a suitable coupling agent, base and solvent.
  • the carboxyl-containing compound can be first converted to reactive carbonyl derivative such as an acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide and the like, which can be treated with amino-containing or hydroxyl- containing linker in the presence of a suitable base and solvent to afford the corresponding amide or ester linkage(s), respectively (see, Bodanszky, M. and
  • Rx, Ry, and Rz are any monovalent organic radicals
  • Suitable coupling agents include DCC, EDCLHCl, BOP, HBTU, TBTU, DCC/HOBT, EDC/HOBT, and the like.
  • Suitable bases and solvents are same as defined above.
  • the linkage such as N-acyl carbamate linkage between the linker and drug can be made as shown in Scheme 4.
  • treatment of an alcohol with phosgene or its equivalent can yield the corresponding carbonochloridate, which upon treatment with ammonia gas can give the corresponding carbamate intermediate.
  • the carbamate nitrogen can be acylated by a suitable carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the like, in the presence of a suitable base to yield the corresponding N-acyl carbamate.
  • N-acyl carbamate can be made by the reaction of an alcohol with N-acyl isocyanate, which can be prepared either by the reaction of the corresponding amide with oxalyl chloride (See, Speziale, A. J. et al., J. Org. Chem. 1962, 27, 31 '42; Speziale, A. J. et al, J. Org. Chem. 1963, 28, 1805-1811) or by the reaction of the corresponding acid chloride with silver cyanate. (See, Hill, AJ. et. al., J. Am. Chem. Soc, 1940, 62, 1595; Kim, D.K. J. Heterocyclic Chem. 1995, 32, 1625).
  • the N-acyl amide linkage between the linker and drug can be made as shown in Scheme 5.
  • the amide nitrogen can be acylated by a suitable carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the • like, in the presence of a suitable base to yield the corresponding N-acyl amide.
  • Rx and Ry are any monovalent organic radicals.
  • the linkage such as N-acyl sulfamate between the linker and drug can be made as shown in Scheme 6.
  • treatment of an alcohol with sulfuryl chloride in the presence of suitable base gives the intermediate sulfochloridate, which can be converted to the corresponding sulfamate.
  • a suitable carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the like, can yield the corresponding N-acyl sulfamate.
  • Rx and Ry are any monovalent organic radicals.
  • N-acyl/oxycarbonyl sulfonamide linkage between the linker and drug can be made as shown in Scheme 7.
  • a sulfonamide nitrogen can be acylated by a suitable
  • carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the like, to yield the corresponding N- acylsulfonamide, which can me metallated using an inorganic base.
  • the sulfonamide nitrogen can be acylated by a suitable formyl chloride derivative such as alkyloxycarbonyl chloride, imidazolide and the like, to yield the corresponding N- alkyloxycarbonyl sulfonamide as shown in the scheme.
  • the same linkage can be made by the reaction of an alcohol with sulfonyl isocyanate which can be prepared by known methods such by treatment of sulfonamide with oxalyl chloride (see, Hans Krzikalla et al., US2666787 or Smith, J. et al., J. Org. Chem. 1965, 30, 1260-1262) or by treatment of sulfonyl chloride with silver cyanate (See, Smith, J. et al., J. Org. Chem. 1965, 30, 1260-1262).
  • Rx, and Ry are any monovalent organic radicals; M is a metal ion; x is 1-4
  • N-oxycarbonylcarbamate (or N-oxycarbonylurea) linkage between the linker and drug can be made as shown in Scheme 8.
  • carbamate nitrogen can be acylated by suitable formyl chloride derivatives such as alkyloxycarbonyl chloride, imidazolide and the like, to yield the corresponding N-alkyloxycarbonylcarbamate as shown in the scheme.
  • the N-oxycarbonylcarbamate (or N- oxycarbonylurea) linkage between the linker and drug can be made by the reaction of an alcohol (or an amine) with carbamoyl isocyanate (IP15A), which can be prepared by known methods such by treatment of carbamate with oxalyl chloride (See, Grehn L, et al, Synthesis, 1988, 922-994) or by treatment of a formyl chloride with silver cyanate (See, Kim, D.K. et al., J. Heterocyclic Chem. 1995, 32, 1625).
  • N- oxycarbonylcarbamate (or N-oxycarbonylurea) can be prepared in two steps.
  • Step 1 reaction of an alcohol or phenol with chlorocarbonyl isocyanate to give N-oxycarbonyl carbamoyl chloride intermediate (IP15B).
  • Step 2 reaction of the intermediate IP15B with the same or another alcohol or phenol or an amine.
  • X NRz Rx, Ry and Rz are any monovalent organic radicals.
  • Nitrate CnitrooXyl or Nitrite (nitrosyloxy) esters are same as defined above.
  • nitrate or nitrite esters can be made as shown in Scheme 9.
  • a nitrate or nitrite ester can be made by treating an alcohol with HNO 3 ZH 2 SO 4 (or HNU 3 /Ac 2 O) or nitrosyl chloride, respectively.
  • a nitrate ester can be made by treating a halide (bromide or iodide is preferred) with silver nitrate in a polar aprotic solvent such as acetonitrile.
  • Rx is any monovalent organic redical.
  • Suitable protecting groups include, but not limited to, acetyl, Boc, Fmoc, benzoyl, pivaloyl, trityl, tetrahydropyranyl (THP), and silyl (TBDMS, TMS, etc.). Obviously, selection of a suitable protecting group is very crucial for the success of a chosen method for the synthesis of prodrugs described in this invention.
  • AMDx is a CONH 2 -containing drugs such as vapromide, levotiracetam, carbamazepine, and the like.
  • SAMDx is a SO 2 NH 2 -containing drugs such as valdecoxib, celecoxib, and the like.
  • Scheme 15 Synthesis of Water-soluble Prodrug(s) using a bio-cleavable linker(s) and spacer linker (s)
  • O X is a bond, O or N; R-X 4 H is an
  • X is a bond, O or N;
  • X 2 -CH 2 X 3 CH 2 - one or more solubilizing groups such as
  • R x H, alkyl, CO 2 H, CH 2 CO 2 H, etc.
  • R x H, alkyl, CO 2 H, CH 2 CO 2 H, etc.
  • Double/Mutual prodrugs described in this invention can be synthesized by any of the approaches depicted in Schemes 17 through 19.
  • Scheme 17 Synthesis of Mutual Prodrug(s) using a bio-cleavable linker(s) and spacer linker (s)
  • R 2 H, a bond, CH 2 CH 2 N(CH 3 ) 2 .
  • HCl an Amino acid, or any molecule containing solubilizing groups such as carboxylic acid, sulphonic acid, hydroxyl, amino groups, polyethyleneglycol (PEG), a metal ion such a Na + , Ca 2+ , etc.
  • Scheme 24 An alternative method for the synthesis of Linker Intermediates LI-2b and LI-5
  • Step 1 Synthesis of 2-((2-bromoethyl)dithio)ethanol (LI-2a) and bis(2- bromoethyl)disulfide (LI-3a): These compounds can be synthesized via bromination of SL-I by a known bromination method.(For a suitable bromination method, see Fruniss, B. S.
  • Method 1 To a solution of SL-I (15g, 97.4 mmol) in DMF (50 mL) was added PPh 3 (25.5g, 97.4 mmol) and cooled to 0 0 C. Bromine (3.33 mL, 64.9 mmol) was added drop- wise and stirred at RT for 18 h. TLC of the mixture showed the mono-bromo derivative LI-2a as the major product with only trace amounts of dibromide LI-3a. The mixture was diluted with water and extracted with EtOAc.
  • Method 3 To a cold suspension of SL-I (20 g, 129 mmol) in DCM (400 mL) was added CBr 4 (42 g, 129 mmol) and stirred for 10 min. PPh 3 (34 g, 129 mmol) was then added and stirred at RT for 14 h. The reaction mixture was concentrated and the residue purified by column chromatography to give 13.5 g (52.3%) of LI-2a and 13.0 g (36%) of LI-3a. These compounds were identical (by TLC, NMR and MS) to those obtained in Methods 1 and 2 described above.
  • the above linker intermediate can also be prepared by the following method: Step 1: TEA (37 ml, 264 mmol) and a solution of (Boc) 2 O (48 g, 220 mmol) in DCM (100 mL) were added to a suspension of cystamine dihydrochloride (20 g, 88.8 mmol) in of DCM (300 mL) and stirred at RT for 15 h.
  • Step 2 A solution of 2-mercaptoethanol (1.44 g, 18.5 mmol) in DCM (10 mL) was added to a mixture of tert-butyl 2-( ⁇ 2-[(tert-butoxycarbonyl)amino]ethyl ⁇ dithio)ethyl carbamate (5.0 g, 14.2 mmol) and TEA (3.87 ml, 27.7 mmol) in DCM (30 mL) and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 2.0 g (56%) of LI-2c was obtained.
  • linker intermediates LI-2b and LI-2c can also be synthesized by following the method outlined in Scheme 24.
  • Example 7
  • the above linker intermediate was also prepared by the following method: TEA (3.56 g, 35.2 mmol) was added to a solution of cysteamine hydrochloride (2g, 17.60 mmol) and LI-3b (4.29g, 17.6mmol) in methanol (25mL) at 0 0 C and stirred at RT for 4 h. To the mixture, which contained the intermediate free amine (LI-5), a solution of (BoC) 2 O (7.68 g, 35.2 mmol) and TEA (3.56 g, 35.2 mmol) in MeOH (1OmL) was added and the mixture was stirred overnight. The reaction mixture was filtered through celite and evaporated to dryness. The residue was purified by column chromatography to afford 0.380 g (7 %) of LI-2f.
  • the above linker intermediate LI-5.TFA was also synthesized as described below: TEA (3.56 g, 35.2mmol) was added drop-wise to a solution of cysteamine hydrochloride (2g, 17.60mmol) and LI-3b (4.29g, 17.6mmol) in MeOH (25mL) at 0 0 C and stirred at RT for 4 h. The mixture was cooled to 0 0 C and a solution of (Boc) 2 O (7.68 g, 35.2mmol) in MeOH (10 mL) was added, followed by TEA (3.56 g, 35.2mmol), and stirred overnight at RT. The reaction mixture was filtered through celite and the filtrate concentrated.
  • prodrug I-C1-PD10 This prodrug was synthesized as described in Scheme 11, Method B. Thus, TEA (0.73 mL, 10 mmol) was added to a suspension of cetirizine dihydrochloride (2.0 g, 4.68 mmol) in DCM (50 mL), followed by a solution of SL-I (0.72 g, 4.67 mmol), DCC (1.13 g, 5.47 mmol) and DMAP (0.112g, 1 mmol) and stirred at RT for 15 h. The mixture was concentrated and the residue, after usual aqueous work- up and chromatographic purification, gave 0.44 g (19%) of I-C1-PD10.
  • Step 1 To a suspension of aspirin (3 g, 16.65 mmol) in benzene (25 mL) and DMF (2 drops) at 0-5 0 C was added oxalyl chloride (1.7 mL, 19.98 mmol) in benzene (5 mL). The reaction mixture was refluxed at 85 0 C for 2 h, cooled to RTe and concentrated to give a yellow oil.
  • Step 2 The yellow oil was dissolved in benzene (30 mL), silver cyanate (2.99 g, 19.98 mmol) was added and the mixture was refluxed for Ih in the dark.
  • Step 3 The reaction mixture was cooled to RT, and a solution of SL-I (2.56 g, 16.65 mmol) in benzene (5 mL). The reaction mixture was stirred for Ih, filtered through celite, concentrated and purified by column chromatography to afford 2.24 g (54%) of I-Cl- PD6.
  • Example 14 Synthesis of prodrug I-Cl-PDll:To a solution of SL-I (7g, 45.45 mmol) and valproic acid (7.85 g, 54.5 mmol) in DCM (80 mL) was added DCC (11.26 g, 54.5 mmol), followed by DMAP (6.65 g, 54.5 mmol), and the resulting suspension was stirred at RT for 18 h. After usual aqueous work-up and chromatographic purification, 2.82 g (22 %) of I-C1-PD11 were obtained as a colorless oil.
  • Example 21 Syntheis of prodrug I-A1-PD5: To a solution of diphosgene (0.99 mL, 8.24 mmol) in DCM (3 mL) at 0 0 C was added a solution of L3I2a (0.5 g, 2.74 mmol) and H ⁇ nig's base (2.39 mL, 13.73 mmol) in DCM (3 mL). The mixture was stirred at 0 0 C for 30 min and concentrated to yield the intermediate L3I3a as a light-yellow semi-solid.
  • Example 22 Synthesis of prodrug I-A1-PD6: To a solution of I-A1-PD8 (1.0 g, 2.63 mmol) in DCM (3 mL) at RT was added CDI (0.46 g, 2.89 mmol) and stirred for 15 h. A suspension of serine methyl ester hydrochloride (0.61 g, 3.95 mmol) in DCM (4 mL) and TEA (1.1 mL, 7.90 mmol) was added and stirring continued for 15 h. After usual aqueous work-up and chromatographic purification, 0.706 g (51%) of I-A1-PD6 were obtained as a colorless oil.
  • Example 23 Synthesis of prodrug I-A1-PD7: To a solutuion of I-A1-PD8 (86 mg, 0.22 mmol) in DCM (9 mL) at RT was added CDI (40 mg, 0.24 mmol) and stirred for 15 h, after which a solution of dimethyl glutamate (80 mg, 0.45 mmol) and TEA (0.06 mL, 0.45 mmol) was added and stirred for 2 d. After usual aqueous work-up and chromatographic purification, 97 mg (74 %) of I-A1-PD7 were obtained as a colourless oil.
  • Example 24 Synthesis of prodrug I-A1-PD9: To a suspension of gabapentin (10 g, 58.4 mmol) in THF (100 mL) at 0 0 C was added IN NaOH (70 mL), followed by (Boc) 2 O. The mixture was stirred at RT for 15 h. After washing with diethyl ether (100 mL x 2), the aqueous layer was acidified with solid KHSO 4 and extracted with EtOAc (100 mL x 2). Organic extracts were washed with brine (100 mL), dried over Na 2 SO 4 and concentrated to afford 10.41g (68 %) of boc-protected gabapentin as a white solid. A mixture of boc-protected gabapentin (5.0 g, 18.45 mmol) and CDI (3.59 g,
  • Example 25 Synthesis of prodrug I-A1-PD10 : A mixture of I-A1-PD8 (1.Og, 2.63 mmol) and CDI (0.469 g, 2.89 mmol) in DMF (3 mL) was stirred for 12 h, after which N,N ' dimethylethylenediamine (0.56mL, 5.26 mmol) and DMAP (0.32 g, 2.63 mmol) was added. The mixture was stirred for 4 h. After usual aqueous work-up and chromatographic purification, 0.763 g (59 %) of were obtained as a yellow oil.
  • Example 29 Synthesis of prodrug I-A1-PD12: To a solution of diphosgene (1.91 mL, 15.81 mmol) in DCM (20 mL) at 0 0 C was added a solution of I-A1-PD8 (4 g, 10.54 mmol) and H ⁇ nig's base (5.5 mL, 31.62 mmol) in DCM (30 mL). The mixture was stirred at RT for 40 min, cooled to 0-5 0 C, and dry ammonia gas was passed through it for 30 min. Reaction mixture was concentrated and, after usual aqueous work-up, 5.3 g (91 %) of I-A1-PD12 were obtained.
  • prodrug I-A1-PD14 Ethyl chloroformate (0.86 g, 7.9 mmol) was added to a solution of S-carbamoylmethyl-S-methylhexanoic acid (M. S. Hoekstra et al., Org. Proc. Res. Dev. 1997, 1, 26-38) (1.0 g, 5.3 mmol) in THF (6 niL) at -10 0 C, followed by TEA (2.4 mL, 17.0 mmol) and the mixture was stirred at -10 0 C for 30 min. A solution of NaN 3 (1.73 g, 26.6 mmol) in water (10 mL) was added and stirred for 2h at -10 0 C.
  • S-carbamoylmethyl-S-methylhexanoic acid M. S. Hoekstra et al., Org. Proc. Res. Dev. 1997, 1, 26-38
  • Example 31 Synthesis of prodrug I-Al-PD15Ba: To a solution of I-A1-PD4 (0.350 g, 0.802 mmol) in DMF (3 mL) at RT was added CDI (0.195g, 1.204 mmol) and stirred at RT for 3 h. This mixture was added to a suspension of methanesulphonamide (0.304 g, 3.2 mmol) in DMF (4 mL) and NaH (0.153 g, 3.2 mmol) at 0 0 C and stirred at RT for 4 h.
  • prodrug I-A2-PD1 To a solution of levetiracetam (1.0 g, 5.87 mmol) in DCE (20 mL) and DCM (4 mL) was added oxalyl chloride (0.61 mL, 7.05 mmol), and heated at 70 0 C for 8h. Reaction mixture was cooled and added to a solution of SL-I (1.81 g, 11.75 mmol) in DCM (15 mL) and stirred at RT overnight. After chromatographic purification, 1.13 g (41%) of I-A2-PD1 were obtained.
  • Example 35 Synthesis of prodrugs I-A3-PD3a and I-A3-PD3b: Step 1: DSC (210 mg, 0.824 mmol) and TEA (0.230 mL, 1.64 mmol) were added to a solution of methyl [(2- hydroxy ethyl)dithio] acetate (lOOmg, 0.549 mmol) in acetonitrile (1 mL) at O 0 C and stirred at RT for 3h. The mixture was concentrated and the residue dissolved DCM. Usual aqueous work-up and chromatographic purification gave the crude intermediate.
  • Step 2 TEA (24mg, 0.236 mmol) and DMAP (13 mg) were added to a mixture of valdecoxib (62mg, 0.195 mmol) and the product obtained from step 1 above in THF (1 mL) and stirred at RT for 3 d. The mixture was concentrated and the residue dissolved in EtOAc. After usual aqueous work-up and chromatographic purification, 53 mg (52%) of I-A3-PD3a obtained.
  • Step 3 The above material was converted to the corresponding mono-, and/or di-sodium salt forms I-A3-PD3b by using standard methods.
  • IM LiOH solution 28 mg in ImL water
  • the mixture was concentrated, the residue diluted with water, acidified with IN HCl ( ⁇ 3 ml, pH ⁇ 3) and extracted with EtOAc. After usual aqueous work-up and chromatographic purification, 20 mg (13%) of product were obtained.
  • Step 3 Synthesis of intermediate LI-10: A solution of LI-9 (1.02 g, 3.80 mmol) in acetonitrile (10 niL) was added to a cold solution of DSC (1.46 g, 5.70 mmol) in acetonitrile (50 mL) followed by TEA (1.58 ml, 11.40 mmol), and stirred overnight at RT. The mixture was concentrated and the residue was taken up in DCM. After usual aqueous work-up, 1.33 g (85%) of LI-10 were obtained.
  • Step 4 Synthesis of I-A3-PD4: TEA (0.194 mL, 1.39 mmol) and DMAP (73 mg, 0.6 mmol) were added to a solution of LI-10 (1.33 g, 3.24 mmol) and valdecoxib (364 mg, 1.16 mmol) in THF (6 mL) and stirred at RT for 5 d. The mixture was concentrated and the residue was taken up in DCM. After usual aqueous work-up and chromatographic purification, 177 mg (12 %) of LI-10 were obtained.
  • Step 2 Synthesis of prodrug intermediate I-S13-PD1: A mixture of valdecoxib (280 mg, 0.892 mmol), DMAP (56 mg, 0.5 mmol) and TEA (150 ⁇ L, 1.06 mmol) in THF (5 mL) was stirred at RT for 4.5 d. The mixture was concentrated and the residue dissolved in EtOAc. After usual aqueous work-up and chromatographic purification, 354 mg (54 %) of I-S13-PD1 were obtained.
  • Step 3 Synthesis of intermediate I-A3-PD1: To a solution of I-S13-PD1 (215 mg, 0.292 mmol) and triisopropylsilane (60 ⁇ L) in 0.75 ml of DCM was added 20%TFA in DCM (0.5 mL) and stirred at RT for 90 min. The mixture was concentrated and the residue purified by column chromatography to give 65 mg (46%) of I-A3-PD1.
  • Step 4 Synthesis of I-A3-PD5-Me-ester: CDI (40mg, 0.243 mmol) was added to a solution of I-A3-PD1 (lOOmg, 0.202 mmol) in DMF (0.5 mL) and stirred at RT for 2.5 h. To this were added a solution of dimethyl glutamate (53 mg, 0.303 mmol) in DMF (0.3 mL) and DMAP (37 mg, 0.303 mmol) and stirred overnight at RT.
  • CDI 40mg, 0.243 mmol
  • Step 5 Synthesis of prodrug I-A3-PD5: IN Lithium hydroxide (1.2 mL, 1.2 mmol) was added to a solution of I-A3-PD5-Me-ester (100 mg, 0.144 mmol) in THF (0.4 mL) at 0 0 C and the mixture allowed to attain ambient temperature. After 30 min, the mixture was concentrated and the residue diluted with water. Acidification with IN HCl, followed by extraction with EtOAc, usual aqueous work-up and chromatographic purification gave 26 mg (26%) of I-A3-PD5.
  • prodrug I-H1-PD1 This prodrug was synthesized as shown in Scheme 14, Method B. Step 1: A solution of metronidazole (5.0 g, 29.22 mmol) and CDI (5.21 g, 32.2 mmol) in
  • Step 2 A solution of the imidazolide of metronidazole (7.32 g) in DMF (30 mL) was
  • Step 2 Synthesis of I-H1-PD5: To a solution of I-S14-PD1 in DCM (15 mL) were added triisopropylsilane (0.446 ml, 2.17 mmol), followed by 10% TFA in DCM (15 mL) and stirred at RT for 30 min. The mixture was concentrated and purified by column chromatography to afford 0.68 g (70%) of prodrug I-H1-PD5.
  • Step 1 To a solution of diphosgene (0.35 mL, 2.93 mmol) in DCM (3mL) was added a solution of LI-Id (0.404 mg, 1.75 mmol), Hunig's base (0.765 mL, 4.39 mmol) and the resulting mixture was stirred at RT for 45 min. The mixture was concentrated, the residue dissolved in DCM (5 mL), cooled in an ice-bath and treated with a solution of paclitaxel (500 mg, 0.585 mmol), Hunig's base (0.765 mL, 4.39 mmol) and DMAP (cat.) in DCM (5 mL) over 5 min and the resulting mixture was stirred at RT for 2 h. The mixture was purified by column chromatography to give 519 mg (78%) of the protected intermediate
  • Step 2 To an ice-cold solution of S22-I2 (60 mg, 0.0532 mmol) in MeOH (1 mL) was added 2 drops of methanol saturated with ammonia gas and the resulting mixture was stirred for 1 h. The reaction mixture was purified by column chromatography to give 38 mg (69%) of I-S22-PD1 as an off white solid.
  • Example 43 Synthesis of prodrug I-S22-PD2: To a solution of I-S22-PD1 (38 mg, 0.0367 mmol) in acetonitrile (0.6 mL) was added succinic anhydride (5 mg, 0.044 mmol) and DMAP (cat.). The resulting mixture was stirred overnight at RT and purified by column chromatography to give 12 mg (29%) of prodrug I-S22-PD2 as an off white solid.
  • Paclitaxel and its prodrug I-S22-PD2 (2 mg each) were suspended in 1 mL water or PBS-buffer (pH 7.4). The suspensions were sonicated for 15 min and centrifuged (13,000 g) for 10 min. The supernatant was analyzed using HPLC.
  • Example 44 Synthesis of mutual prodrug of desloratidine and pseudoephedrine (I-AA-MPD1):
  • Step 2 Synthesis of I-AA-MPD2: CDI (1.23 g, 7.64 mmol) was added to a solution of I-A1-PD2 (Example 18) (3.0 g, 5.09 mmol) in DMF (10 rxiL) and stirred RT for 3.5 h. A solution of lisinopril diethyl ester (2.34 g, 5.09 mmol) in DMF (5 niL) was added and stirred at 65 0 C for 8 h. The reaction was quenched with brine and taken up in EtOAc. After usual aqueous work-up and chromatographic purification, 2.5 g (45%) of I-AA- MPD2 were obtained.
  • Step 1 A solution of SL-I (3.0 g, 19.4 mmol) in DMF (5 mL) was added to a suspension of CDI (9.46 g, 5.83 mmol) in DMF (15 mL) and stirred at RT for 20 h. The mixture was concentrated and the residue purified by column chromatography. The bis-imidazolide obtained was used as such in the next step.
  • Step 2 A solution of the bis-imidazolide (1.0 g, 2.91 mmol) in acetonitrile (3 mL) was added to a dispersion of gabapentin (1.49 g, 8.75 mmol) in IN NaHCO 3 (8 mL) and stirred at RT for 3 d. The mixture was diluted with water, acidified with 2N HCl and extracted with EtOAc. After usual aqueous work-up and chromatographic purification, 1.04 g (65%) of pure I-AA-MPD10 was obtained.
  • Example 56 Synthesis of mutual prodrug of gabapentin ethyl ester and levetiracetam (I-AA-MPD13): To a solution of levetiracetam (1.0 g, 5.87 mmol) in DCE (25 mL) and DCM (5 mL) at RT was added oxalyl chloride (895 mg, 7.05 mmol). The reaction mixture was refluxed for 8 h, after which it was cooled to RT and a solution of I-A1-PD8 (2.67 g, 7.05 mmol) in DCE (20 mL) was added drop-wise. The resulting mixture was stirred at RT for 18 h.
  • Example 61 Synthesis of mutual prodrug of gabapentin ethyl ester and valproic acid (I-AA-MPD27): Step 1: To a solution of I-A1-PD8 (4.0 g, 10.54 mmol) in THF (25 mL) was added CDI (2.22g, 13.7 mmol) and stirred at RT for 90 min. To this was added t-butyl carbazate (1.39 g, 10.54 mmol) and DMAP (1.288 g, 10.54 mmol), and stirred overnight at RT.
  • Step 2 To a solution of the above boc-hydrazide (4.0 g, 7.44 mmol) in DCM (20 mL) was added 50% TFA/DCM (10 mL) and stirred at RT for Ih. DCM was removed under vacuum, the resulting residue triturated with diethyl ether (2 x 20 mL) and dried to give a colorless oil, which was dissolved in THF (20 mL).
  • Step 1 To a solution of nicotinyl chloride hydrochloride (3.16 g, 17.76 mmol) and LI-2c (3 g, 11.84 mmol) in THF (50 mL) was added TEA (8.3 mL, 59.2 mmol) and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 4.14. g (97%) of LI-2c-nicotinate ester was obtained as a colorless oil.
  • Step 2 To a solution of LI-2c-nicotinate ester (0.92 g, 2.50 mmol) in DCM (5 mL) was added 50% TFA/DCM (5 mL) and stirred for Ih. Reaction mixture was concentrated and the residual TFA salt was used as such in Step 3.
  • Step 3 To a solution of valproic acid (0.37 g, 2.56 mmol) in THF (5 mL) was added CDI (0.5 g, 3.08 mmol) and stirred for 2h. This was treated with a solution of the above TFA salt, TEA (0.7 mL, 5.13 mmol) and DMAP (50 mg, 0.41 mmol) in THF (10 mL) and the mixture was stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 0.7 g (71%) of I-CC-MPD1 was obtained as a white solid.
  • Step 2 Synthesis of I-HH-MPD1: Lamivudine (45 mg, 0.196 mmol) and DMAP (48 mg, 0.39 mmol) were added to a solution of I-S17-PDI1 (80 mg, 0.13 mmol) in DMF (1.5 mL) and stirred at RT for 30 min. The mixture was concentrated and purified by column chromatography to give 40 mg (43%) of product I-HH-MPD1.
  • Step 2 The mutual prodrug I-C A-MPDl was synthesized by reacting intermediate I- S17-PDI1 with pseudoephidrine by a procedure similar to that described in Example 64, Step 2.
  • the desired mutual prodrug I-CA-MPD1 was obtained as a colorless gummy , material.
  • Step 2 Synthesis of I-AH-MPD1: A solution of the imidazolide of I-H1-PD1 (100 mg, 0.224 mmol) in DMF (1 mL) was added to a suspension of norfloxacin (86 mg, 0.269 mmol) in DMF (2 mL) and stirred at RT for 60 h. The mixture was concentrated and the residue purified by column chromatography to give 35 mg (22%) of I- AH-MPDl.
  • Example 78 The following mutual prodrugs (Examples 78 - 80) were obtained according to procedures similar to those described in Example 77, with the substitution of the appropriate pairs of amino-containing and hydroxyl-containing therapeutic agents: Example 78
  • Example 80 Synthesis of mutual prodrug of venlafaxine and paroxetine (I-AH-MPD8) The mutual prodrug was synthesized according to the method outlined in Scheme 15 with obvious modifications. The mutual prodrug I-AH-MPD8 was obtained as a white sticky solid. 1 H-NMR was consistent with the expected structure. MS: m/z 812 [M] + . Example 81
  • This prodrug was synthesized as shown in Scheme 11, Method D.
  • oxalyl chloride (1.86 mL, 21.64 mmol) and heated at 70 0 C for 2 h.
  • the mixture was concentrated, the residue was dissolved in THF (30 mL) and treated with a solution of LI-2a (3.61 g, 16.65 mmol), TEA (3.48 mL, 24.97 mmol) and DMAP (361 mg) in THF (20 mL).
  • the resulting mixture was stirred at RT for 2 h and filtered through celite.
  • Step 1 To a suspension of aspirin (1 g, 5.55 mmol) in benzene (15 mL) and DMF (1 drop) at 0-5 0 C was added a solution of oxalyl chloride (0.6 mL, 6.66 mmol) in benzene (5 mL) and stirred at 85 0 C for 2 h. The reaction mixture was concentrated, and the crude acid chloride was used immediately in the next step.
  • Step 2 To a solution of the above acid chloride in benzene (30 mL) was added silver cyanate (998 mg, 6.66 mmol) and refluxed in the dark for 1 h. The mixture, containing 2- acetoxybenzoyl isocyanate, was cooled to RT and used in the next step.
  • Step 3 To the above mixture was added a solution of LI-2b (1.33 g, 6.66 mmol) in benzene (5 mL) and stirred at RT for Ih. The mixture was filtered through celite and concentrated, and the residue was purified by column chromatography to afford 1.2 g (54%) of pure I-Cl-NOPD5a. 1 H-NMR data is consistent with the expected structure.
  • reaction mixture was concentrated and, after usual aqueous work-up, 4.5 g of flurbiprofen amide was obtained as a white solid.
  • oxalyl chloride (1.87g, 14.79mmol) at 0 0 C and refluxed for 16 h.
  • Reaction mixture was cooled to RT and treated with LI-2b (2.45 g, 12.33 mmol) in DCE (1OmL) and stirred overnight. After usual aqueous work-up and chromatographic purification, 0.5 g of I-Cl-NOPD14a were obtained.
  • Example 97 Synthesis of NO-releasing prodrug of ketoprofen (I-C1-NOPD19): This prodrug was synthesized as shown in Scheme 11, Method A according to the method described in Example 90, using as reagents ketoprofen (1.27 g, 5 mmol), CDI (1.21 g, 7.5 mmol) and LI-2b (1 g, 5 mmol). Yield: 0.6 g (51%).
  • Example 102 Synthesis of NO-releasing prodrug of lamotrigine (I-Al-NOPD3a and I-Al-NOPD3b): This prodrug was synthesized as shown in Scheme 12, Method B. Thus, to a suspension of lamotrigine (1 g, 3.90 mmol) in toluene (20 mL) at 120 0 C was added drop-wise a solution of the imidazolide of LI-2b (1.4 g, 4.70 mmol) in THF (10 mL) and refluxed for 6 h. After usual aqueous work-up and chromatographic purification, 340 mg (20%) of I- Al-NOPD-3a/b was obtained. 1 H-NMR data is consistent with the expected structure. MS (ES) + m/z: 481 (M+H) + .
  • Example 103 Synthesis of NO-releasing prodrug of lamotrigine (I-Al-NOPD3a and I-Al-NOPD3b): This prodrug was synth
  • This prodrug was synthesized from celecoxib (6.62 g, 17.35 mmol) according to the procedure described in Example 109 (see Scheme 13, Method B). After usual workup, the crude product was purified by column chromatography to afford 1.55 g (15%) of prodrug I-A3-NOPD2a.
  • Example 111 Synthesis of NO-releasing prodrug of paracetamol (I-H1-NOPD1): This prodrug was synthesized as shown in Scheme 14, Method B. Thus, to a solution of paracetamol (2.0 g, 13.24 mmol) in THF (20 mL) was added CDI (2.36 g, 14.57 mmol) and the mixture was stirred at RT for 3 h.
  • Step 2 To a mixture of LI-5.TFA (2.68 mmol) and TEA (1.08 g, 10.72 mmol) in DCM (10 mL) at 0 0 C was added the imidazolide of metronidazole (0.78 g, 2.95 mmol) and stirred at RT for 48 h. The reaction mixture was quenched with water and extracted with DCM. After usual aqueous work-up and chromatographic purification, 50 mg (4.3%) of I-H1-NOPD6 was obtained.

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Abstract

The invention provides the compounds of formula (I) or pharmaceutically acceptable salts thereof. The invention also provides pharmaceutical compositions comprising one or more compounds of formula (I) or intermediates thereof and one more of pharmaceutically acceptable carriers, vehicles or diluents. The invention further provides methods of preparation and methods of use of prodrugs including NO-releasing prodrugs, double prodrugs and mutual prodrugs comprising the compounds of formula (I).

Description

PRODRUGS CONTAINING NOVEL BIO-CLEAVABLE LINKERS
This application takes priority from US Provisional Application USSN: 60/604,632 filed 26 August 2004 and Indian Provisional Application 779/MUM/2005 filed 01 July 2005 and are herein incorporated in their entirety. Field of the Invention
The present invention relates to compositions of prodrugs, including NO-releasing prodrugs, codrugs, double prodrugs and mutual prodrugs, containing bio-labile linkers and linkages, processes for their preparation and pharmaceutical compositions containing them and their use.
Background of the Invention
A prodrug is an active drug chemically transformed into a per se inactive derivative which by virtue of chemical or enzymatic attack is converted to the parent drug within the body before or after reaching the site of action. The process of converting an active drug into inactive form is called drug latentiation. Prodrugs can be carrier-linked- prodrugs and bioprecursors. The carrier-linked prodrug results from a temporary linkage of the active molecule with a transport moiety. Such prodrugs are less active or inactive compared to the parent active drug. The transport moiety will be chosen for its non- toxicity and its ability to ensure the release of the active principle with efficient kinetics. Whereas the bioprecursors result from a molecular modification of the active principle itself by generation of a new molecule that is capable of being a substrate to the metabolizing enzymes releasing the active principle as a metabolite.
Prodrugs are prepared to alter the drug pharmacokinetics, improve stability and solubility, decrease toxicity, increase specificity, and increase duration of the pharmacological effect of the drug. By altering pharmacokinetics the drug bioavailability is increased by increasing absorption, distribution, biotransformation, and excretion of the drug. Limited intestinal absorption, distribution, fast metabolism, and toxicity are some of the causes of failure of drug candidates during development. Avoidance of the foreseeable or proven pharmacokinetic defects thus assumes considerable significance in drug research. Accordingly, prodrugs play a significant role in drug research as well. In designing the prodrugs, it is important to consider the following factors: a) the linkage between the carrier and the drug is usually a covalent bond, b) the prodrug is inactive or less active than the active principle, c) the prodrug synthesis should not be expensive, d) the prodrug has to be reversible or bioreversible derivative of the drug, and e) the carrier moiety must be non-toxic and inactive when released.
Prodrugs are usually prepared by: a) formation of ester, hemiesters, carbonate esters, nitrate esters, amides, hydroxamic acids, carbamates, imines, mannich bases, and enamines of the active drug, b) functionalizing the drug with azo, glycoside, peptide, and ether functional groups, c) use of polymers, salts, complexes, phosphoramides, acetals, hemiacetals, and ketal forms of the drug. For example, see Andrejus Korolkovas's, "Essentials of Medicinal Chemistry", pp. 97-118.
The discovery and characterization of endothelium-derived nitric oxide (NO) was the subject of the 1998 Nobel Prize in Medicine and Physiology. NO is a major signaling molecule with important biological roles. See, for example, Kerwin, Jr., J. F. et al., J. Med. Chem. 1995, 38, 4343, and Williams, R. J. P., Chem. Soc. Rev., 1996, 77. The major biological functions of NO include controlling blood pressure, smoothing muscle tone and inhibition of platelet adherence and aggregation, assisting the immune system in destroying tumor cells and intracellular pathogens and participating in neuronal synaptic transmission. See, for example, Moncada, S. et al., Pharmacol. Rev. 1991, 43, 109; Bredt, D.S. et al., Anuu. Rev. Biochem., 1994, 63, 175; Schmidt, H. H. W. et al., Cell 1994, 78, 919; Feldman, P. L. et al., Chem. and Eng. News. 1993, 71 (20th December issue), 26; and Wilsonm E. K., Chem. and Eng. News. 2004 (8th March issue), 39. Endogenously, NO is produced from arginine by the catalytic action of nitric oxide synthase. See, for example, Nathan, C. et al., Cell 1994, 78, 915, and Marietta, M. A., Cell 1994, 78, 927. NO is a free radical as well as a scavenger of free radicals. NO reacts quickly with ubiquitously generated reactive oxygen species (ROS) such as superoxide (O2 ") to generate a nefarious peroxynitrite (ONOO") molecule, which is implicated in many human diseases such as diabetes, heart disease, Alzheimer's disease and multiple sclerosis. In this setting, NO is often viewed as pathogenic. However, the chemistry of NO can also be a significant factor in lessening the injury mediated by reactive oxygen species (ROS) and reactive nitrogen oxide species (RNOS). There is a relationship between NO and oxidation, nitrosation and nitration reactions. A number of factors determine whether NO promotes, abates or interconnects these chemistries. See, for example, Espay, et al., A chemical perspective on the interplay between NO, reactive oxygen species, and reactive nitrogen oxide species, Ann N. Y. Acad. Sci. 2002, 962, 195.
Thus, by being a free radical, along with the ability to scavenge other free radicals, NO is placed in a pivotal regulatory position. Insight into these pathophysiological processes and signaling are highly relevant to develop therapeutics.
NO deficiency has been implicated in the genesis and evolution of several disease states. In patients with cardiovascular problems, the production of superoxide is increased and level or location of NO synthesis is disrupted thereby causing cellular dysfunction as a result of vasoconstriction of blood vessels, which can lead to, if prolonged, cell damage or death. Agents that act to maintain the normal balance between NO and superoxide in vascular endothelial cells may prove particularly useful in this regard. See, for example, Stokes, K., et al., Free Radic. Bio. Med., 2002, 33, 1026-1036.
Nutritional and pharmacological therapies that enhance the bioactivity or production of NO have been shown to improve endothelium-dependent vasodilation, reduce symptoms, and slow the progression of atherosclerosis. Some of the strategies for NO modulation encompass anti-inflammatory, sexual dysfunction, and cardiovascular indications. Apart from newly developed drugs, several commonly used cardiovascular drugs exert their beneficial action, at least in part, by modulating the NO pathway. Pharmacological compounds that release NO have been useful tools for evaluating the pivotal role of NO in cardiovascular physiology and therapeutics. NO-DONORS: There are a wide variety of structurally dissimilar organic compounds that act as
NO donors and release NO in solution. Some NO donors, such as isoamyl nitrite, nitroglycerine (GTN) and sodium nitroprusside, have been used in cardiovascular medicine long before their biochemical mechanism was understood. The common mode of action for these drugs is liberation of NO, which evokes relaxation of smooth muscle through activation of guanylate cyclase with subsequent formation of cGMP. The relative importance of enzymatic versus non-enzymatic pathways for NO release, the identity of the actual NO-generating enzymes and the existence of competing metabolic events are additional important determinants of the different NO donor classes. Pharmacological compounds that release NO constitute two broad classes of compounds: those that release NO or one of its redox congeners spontaneously and those that require enzymatic metabolism to generate NO. See, for example, Ignarro, L. J. et al., Nitric oxide donors and cardiovascular agents modulating the bioactivity of nitric oxide: an overview, Circ. Res. 2002, 90, 21-28.
Nitroglycerine/glycerine trinitrate (GTN) and compounds referred to as nitrovasodilators or NO donors are frequently used in the treatment of ischemic heart disease. The common mode of action for these drugs is liberation of NO, which evokes relaxation of smooth muscle through activation of guanylate cyclase with subsequent formation of cGMP. However, early development of tolerance to nitrate therapy, particularly during acute myocardial infarction, has been the clinically significant drawback with GTN and some of the other available organic nitrates. This is a significant clinical problem and there exists a need for novel nitrate-based anti-anginal agents, which do not cause the problem of nitrate tolerance.
There are a number of new examples of organic nitrates in which an alkyl or aralkyl mononitrate is covalently linked to an existing drug molecule. Existing drugs from a large number of therapeutic areas such as anti-inflammatory, antiallergic, antibiotic, anticancer, antidiabetic, antiviral, antihypertensive, antianginal, anticonvulsant, analgesic, antiasthmatic, antidepressant, antidiarrheal, antiinfective, antimigraine, antipsychotic, antipyratic, antiulcerative, antithrombotic, etc., were made and evaluated. Some of Nicox's patents include: Synthesis and evaluation of nitrooxy derivatives of NSAIDs (WO 9412463, WO 0230867, WO 0292072, WO 0313499 and WO 0384550), aspirin (WO 9716405, WO 0044705 and WO 0104082), paracetamol (WO 0112584 and WO 0230866), antiepileptic agents (WO 0300642 and WO 0300643), COX-2 inhibitors (WO 0400781 and WO 0400300), statins (WO 04105754), ACE inhibitors (WO 04110432 and WO 04106300), and of known drugs used for the treatment of disease conditions resulting from oxidative stress and endothelial dysfunction (WO 0061537). Most of these nitrate esters were shown to possess not only superior or equal efficacy when compared to the original drug but also exhibit much-reduced side effects. In fact, because of their superior efficacy combined with reduced toxicity, a few of such nitrate ester-containing drug conjugates are successfully passing through various stages of clinical trials. Some of Nicox's nitrooxy derivatives of drugs which are in clinical trials include: NCX 4016 (Phase II, peripheral vascular diseases), NCX 701 (Phase II, Acute pain), HCT 1026 (Phase I, Alzheimer's disease), HCT 3012 (Phase II, Osteoarthritis), NCX 285 (IND, Osteoarthritis), NCX 1022 (Phase Ha completed, Dermatitis), NCX 1020 (Phase I, Asthma/COPD), NCX 1000 (Phase I, Portal hypertension), and NCX 1510 (Phase II, Allergic rhinitis).
US5767134 and US20050002942A1 disclosed a few disulfide-containing prodrugs/folate-drug conjugates. WO 9842661, US 5807847, WO 0054756 and WO 0149275 reported a few nitrooxy derivatives of organic molecules containing sulfahydryl or disulfide group which are called "SS-nitrates". These references are incorporated herein by reference.
Representative examples from WO 9842661 have shown superior vasorelaxant activity and no tolerance was observed to the cGMP-increasing effects of those compounds under the same experimental conditions used for the induction of in vivo tolerance. WO 0149275 reports drug conjugates where an anti-inflammatory drug is covalently linked to the έetø-mercapto-nitrate via thioester bond. Biotransformation pathways proposed for NO release from GTN have largely been heme-dependent or sulfahydryl-dependent. See, for examples, Thatcher, G. R. J. et al., Chem.Soc. Rev. 1998, 27, 331 and reference cited therein, and Bennett, B M. et al., Trends Pharmacol, Sci. 1994, 15, 245. These references are incorporated herein by reference. A mutual prodrug is the association in a unique molecule of two drugs, usually synergistic, attached to each other, one drug being the carrier for the other and vice versa. The embodiments of the invention also provide mutual prodrugs, which are prodrugs of two or three therapeutic agents currently used/potential for use in combination therapy utilizing novel bio-cleavable linkers, water-soluble prodrugs of insoluble/sparingly- soluble therapeutic agents using the same linker technology and water-soluble double and triple prodrugs of sparingly-soluble therapeutic agents or any of the prodrugs linked to NO-releasing agent using the same linker technology. Summary of the Invention
Present invention relates to the compounds of formula (I) or pharmaceutically acceptable salts thereof:
Figure imgf000007_0001
Formula (I) wherein, a is 0-2;
B independently represents a bond, (CH2)b, (CH2CH2O)C, S-S, S-S=O, S-SO2 or S-S=NH; b is 1-6; c is 1-1000;
A and A1 independently represent a bond, (CH2)a, 1,2-phenylene, 1,3-phenylene or 1,4- phenylene; d is 1-8;
D1 represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of -OH, -SH, -NHR1, -CO2H, -CONHR1, - ■
OC(=O)NHR\ -SO2NHR1, -OSO2NHR1, -N(R^CC=O)NHR1 and -N(R^SO2NHR1;
D2 independently represents D1, a peptide, protein, monoclonal antibody, vitamin, R2, R3, R4, NO, NO2, a linkable nitric oxide-releasing group comprising a NONOate, a group comprising one or more of water-solubilizing functional groups, or a polymer;
E independently represents CH2 or a bond;
L1 and L2 independently represent a bond, O, S, NR1, L, or a linkage selected from the group consisting of:
Figure imgf000008_0001
L is R12 or a group with bonding in any direction, independently selected from the group consisting of:
Figure imgf000008_0002
and YV^X^^ '
R1
X independently represents a bond, C, O, S, or NR1;
Y independently represents a bond, C=O, C=S, S=O, SO2, PC=O)XR1, or (CH2)a; Z independently represents a bond, or (CH2)J; wherein, j is 1-4; R1 independently represents a bond, H, (C1-Cs)alkyl, (Cs-Cu)SIyI, aralkyl or M6+; R2 independently represents H, NH2, or NHAc; R3 independently represents H, CO2R5, CH2CO2R5,
R4 independently represents H, OH, 0-(Ci-C8)alkyl, 0Me+, or a group selected from the group consisting of:
Figure imgf000009_0001
\ I — OH Amino-functionalized Amino-modified dextran or arabinolactan,
OH R I44NN water-soluble polymers
OH
H
Figure imgf000009_0002
Figure imgf000010_0001
M independently represents Na, K or a pharmaceutically acceptable metal ion, e = l-3,
R5 independently represents at each occurrence H, Me+, (Ci-C8)alkyl, (C3-Cs)cycloalkyl, substituted (C5-Ci4)aryl, hetero(C2-C14)aryl, C(=O)(CH2)fCHR9CO2R5 ; CH2C(=O)OR5, P
Figure imgf000010_0002
X2 independently represents O, S, SO, SO2, or NR5;
R6 independently represents H, Na+, K+, any other pharmaceutically acceptable metal ion, (Ci-C8)alkyl, or (C3-C8)cycloalkyl,
R7 independently represents at each occurrence same or different R5; R8 independently represents CH2, O, NR4, S, S=O or O=S=O; R9 independently represents H, (Ci-C8)alkyl or an amino acid; f is 0-6; g is 0-1; h is 1-2000; i is 1-4;
R10and R11 independently represent H, (Ci-C8)alkyl, (C3-C8)cycloalkyl, or a group selected from the group consisting of:
Figure imgf000012_0001
with a proviso that when R10 is selected from the above group, R11 represents H or (C1- C8)alkyl, and when R11 is selected from the above group, R10 represents H or (Ci- C8)alkyl; R12 independently represents a group selected from the group consisting of:
Figure imgf000013_0001
Figure imgf000014_0001
and X3 is independently O or NR7.
Another embodiment of the invention is a pharmaceutical composition comprising one or more compounds of formula I or intermediates thereof and one more of pharmaceutically acceptable carriers, vehicles or diluents. Further embodiments include methods of preparation and methods of use of prodrugs including NO-releasing prodrugs, double prodrugs and mutual prodrugs comprising the compounds of formula I. Detailed Description of the Invention The present invention characterizes compositions, methods of preparation and methods of use of prodrugs, NO-releasing prodrugs, mutual prodrugs, double prodrugs, and codrugs.
The compounds of the present invention are prodrugs or mutual prodrugs in which known therapeutic agents or potential therapeutic agents are linked covalently to novel biocleavable linkers.
The compounds of the present invention also include NO-releasing prodrugs in which a therapeutic agent is linked covalently to nitrooxy (nitrate ester) group via a novel bio-cleavable linker containing a strategically placed disulfide group at β-position to the nitrate ester. The present invention also characterizes composition of NO-releasing prodrugs (i.e., nitrooxy ester or nitrate ester prodrugs), processes for their preparation, pharmaceutical composition containing them and their use.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Listed below are definitions of various terms used to describe the compounds of the present invention. These definitions apply to the term as they are used throughout the specification (unless they are otherwise limited in specific instances) either individually or part of a larger group.
The term "amino-containing" refers to drug/carrier molecule with NH functional groups such as amino (both primary and secondary), amide, urea, sulfonamide, carbamate, phosphoramadite, sulfamate, hydrazone, semicarbazone, thiosemicarbazone, hydrazide, carbazate and the like. This also includes NH-containing heterocylic compounds such as imidazoles, benzimidazoles, pyrazoles, benzpyrazols, pyrrols, indoles, triazoles, tetrazoles, benzotriazoles, benzotetrazoles and their derivatives. These NH-containing heterocyclic compounds can be sub-structures of more complex drug/carrier molecules. Amino group of the candidate drug can be primary or secondary (both acyclic and cyclic) which include amide-NH, sulfonamide-NH, carbamate-NH, sulfamate-NH, hydrazide-NH, hydrazone-NH, semicarbazone-NH, thiosemicarbazone- NH, urea-NH and also drugs containing indole, imidazole, benzimidazole, thiazole, oxozole, pyrrole, pyrazole, triazole, tetrazole, or similar NH-containing heterocylic sub¬ structures of a more complex drug molecule. The term "hydroxyl-containing" refers to drug/carrier molecules with hydroxyl groups (primary, secondary and tertiary) including hydroxyl groups of hydroxamic acids and ketoximes derived from keto-containing molecules. Hydroxyl group of drugs can be of primary, secondary or tertiary nature.
The term "sulfahydryl-containing" refers to drug/carrier with free sulfahydryl (SH) group.
The term "halo" refers to fluoro, chloro, bromo, and iodo. The term "halide" refers to fluoride, chloride, bromide, and iodide. The term "alkyl" refers to acyclic alkyl chains. For example, the term "C1-C8 alkyl" refers to methyl, ethyl, propyl, isopropyl, butyl, cyclobutyl, s-butyl, and t-butyl, ,pentyl, hexyl, heptyl, octyl, and the like.
The term "cycloalkyl" refers to cyclic alkyl chains, e.g., the term "C3-C8 cycloalkyl" refers to cyclopropyl, cyclooctyl, cyclopentyl, cyclohexyl, cycloheptyl, , cyclooctyl and the like.
The term "aryl" refers to phenyl, naphthyl and the like. The term "aralkyl" refers to benzyl, phenethyl and the like.
The term "alkoxy" refers to both acyclic and cyclic Ci-C8 alkyloxy. For example, the term "Ci-C8 alkyloxy" refers to methoxy, ethoxy, propoxy, isopropoxy, cyclopropoxy, butoxy, cyclobutoxy, s-butoxy, and t-butoxy, cyclopentyloxy, pentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, cycloheptyloxy, octyloxy, cyclooctyloxy and the like.
The term "heterocyclic" and "heteroaryl" refers to both saturated and unsaturated 5- and 6-membered rings (including benzo-fused) containing from 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. All of these rings may be substituted with up to three substituents independently selected from the group consisting of amino, halo, alkoxy, alkyl, cyano, nitro, hydroxyl, sulfahydryl, carboxyl and the like, Saturated rings include, for example, pyrrolidinyl, piperidinyl, piperazinyl, tetrahydrofiiryl, oxazolidinyl, dioxanyl, pyranyl, and the like. Benzofused saturated rings include indolinyl, 1,2,3,4-tetrahydroquinolinyl, 1,2,3,4-tetrahydroisoquinolinyl and the like. Unsaturated rings include furyl, thienyl, pyridinyl, pyrrolyl, N-methylpyrrolyl, oxazolyl, isoxazolyl, pyrazolyl, imidazolyl, tetrazolyl, triazolyl, oxadiazolyl, thiadiazolyl, thiazolyl, pyrimidinyl, pyrazinyl, pyridazinyl, and the like. Benzofused unsaturated rings include isoquinolinyl, benzoxazolyl, benzthiazolyl, quinolinyl, benzofuranyl, thionaphthyl, indolyl and the like.
The term "substituted alkyl" refers to acylic and cyclic alkyl groups substituted with one or more of groups such as alkyl, aryl, hydroxy, alkoxy, cyano, carboxyl, sulfahydryl, alkylthio, amino, nitro, halo, carbonyl, carbamato, sulfamato, sulfonato, sulfato, and the like.
The term "substituted aryl" refers to aryl groups substituted (including fused) with one or more of groups such as alkyl, aryl, hydroxy, alkoxy, cyano, carboxyl, sulfahydryl, .alkylthio, amino, nitro, halo, carbonyl, carbamato, sulfamato, sulfonato, sulfato, and the like.
The term "amino acid" refers to molecules containing one or more amino and carboxyl groups. Examples of alfa-amino acids (D-, L- and DL- amino acids) -include natural alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. Other examples include beta-amino acids and known unnatural amino acids.
The term "amino acid ester" as used in this specification refers to an amino acid where the carboxyl group is substituted with a Ci-C8 alkyl group. That is, the alkyl group when taken together with the carboxyl group forms a Ci -C6 alkyl ester. It is appreciated that some amino acids (e.g., aspartic acid and glutamic acid) have two carboxyl groups these may form mono- and di-esters.
The term "protecting group" (PG) refers to an 'amino protecting group' or a 'hydroxyl protecting group' or a 'carboxyl protecting group' and the like.
The term "amino protecting group" refers to a group that selectively blocks or protects the amino functionality in presence of other functional groups on the molecule.
Examples of such amino-protecting groups include the formyl group, the trityl group, the phthalimido group, the acetyl group, the trifluoroacetyl group, the chloroacetyl, bromoacetyl, and iodoacetyl groups, urethane-type blocking groups such as benzyloxycarbonyl ("CBZ"), 9-fluorenylmethoxycarbonyl ("FMOC"), tert- butoxycarbonyl ("BOC"), trichloroethylcarbonyl and the like. Additional examples of amino protecting groups are described by T. W. Greene, "Protective Groups in Organic Synthesis", John Wiley and Sons, New York, N.Y., 1991. Molecules with two or more amino groups may form mono-, di-, tri-, poly-, protected derivatives depending on the reaction conditions used.
The term "hydroxyl protecting group" refers to a group that selectively blocks or protects hydroxyl functionality in presence of other reactive functional groups on the molecule. Examples of such hydroxyl-protecting groups include, for example, ether groups including methyl and substituted methyl ether groups such as methyl ether, methoxymethyl ether, methylthiomethyl ether, tert-buylthiomethyl ether, triphenylmethyl, tetrahydropuranyl (THP), (phenyldimethylsilyl)methoxy-methyl ether, benzyloxymethyl ether, p-methoxybenzyloxy-methyl ether, and tert-butoxymethyl ether; substituted ethyl ether groups such as ethoxyethyl ether, l-(2-chloroethoxy)-ethyl ether, 2,2,2-trichloroethoxymethyl ether, and 2-(trimethylsilyl)ethyl ether; isopropyl ether groups; phenyl and substituted phenyl ether groups such as phenyl ether, p-chlorophenyl ether, p-methoxyphenyl ether, and 2,4-dinitrophenyl ether; benzyl and substituted benzyl ether groups such as benzyl ether, p-methoxybenzyl ether, o-nitrobenzyl ether, and 2,6- dichlorobenzyl ether; and alkylsilyl ether groups such as trimethyl-, triethyl- and triisopropylsilyl ethers, mixed alkylsilyl ether groups such as dimethylisopropylsilyl ether, tert-butyldimethylsilyl ether and diethylisopropylsilyl ether; and ester protecting groups such as acetate ester, formate ester, benzylformate ester, mono-, di-, and trichloroacetate esters, pivalate ester, phenoxyacetate ester, and p-chlorophenoxyacetate, benzyloxycarbonate, 9-fluorenylmethoxycarbonate, tert-butoxycarbonate, trichloroethylcarbonate, carbamate, sulfamate and the like. Additional examples of hydroxyl protecting groups are described by T. W. Greene, "Protective Groups in Organic Synthesis", John Wiley and Sons, New York, N.Y., 1991. Molecules with two or more hydroxyl groups may form mono- and di-esters/ethers depending on the reaction condition. The term "carboxyl protecting group" refers to a group that selectively blocks or protects carboxyl functionality in presence of other reactive functional groups on the molecule. Examples of such carboxyl-protecting groups include, for example (substituted) alkyl esters such methyl ester, ethyl ester, t-butyl ester, (substituted) benzyl ester, trichloroethyl ester, and the like. Additional examples of carboxylic acid protecting groups are described T. W. Greene, "Protective Groups in Organic Synthesis", John Wiley and Sons, New York, N.Y., 1991. Molecules with two or more carboxylic acid groups may form mono-, di-, tri-, tetra-, poly- protected derivatives depending upon the reaction conditions used. The term "carbonyl activating group" refers to leaving group ("LG") of a carboxyl derivative that is easily replaced by an incoming nucleophile. Such "LG" groups include, but are not limited to, (substituted) alkoxy, aryloxy, nitrogen containing unsaturated heterocycles such as N-oxybenzotriazole, imidazolyl, o/p-nitrophenoxy, pentachloro- phenoxy, N-oxysuccinimide, N,N'-dicyclohexylisoure-O-yl, N-hydroxy-N- methoxyamino, and the like; acetates, formates, sulfonates such as methanesulfonate, ethanesulfonate, benzenesulfonate, or p-toluenesulfonate, and the like; and halides especially fluoride, chloride, bromide, or iodide.
The term "carbonyl activating reagent" refers to a reagent that converts the carbonyl of a carboxylic acid group into one that is more susceptible to nucleophilic attack and includes, but is not limited to, such reagents as those found in "The Peptides", Gross and Meienhofer, Eds., Academic Press (1979), Ch. 2, and M. Bodanszky, "Principles of Peptide Synthesis", 2.sup.nd Ed., Springer- Verlag Berlin Heidelberg, 1993, hereafter referred to as "The Peptides" and "Peptide Synthesis" respectively. Carbonyl group (i.e., aldehyde or keto group) of candidate drugs may be converted first to aldoxime, ketoxime, hydrazone, semicarbazone and the like, before coupling to the linker. Specifically, carbonyl activating reagents include thionyl bromide, thionyl chloride, oxalyl chloride, and the like; esters of alcohols such as nitrophenol, pentachlorophenol, and the like; and compounds such as l,l'-carbonyldiimidazole (CDI), benzotriazole, imidazole, N-hydroxysuccinimide, dicyclohexylcarbodiimide (DCC), EDC, phosgene or its equivalents, N, N-dimethylaminopyridine (DMAP) and the like. The terms "phosgene or its equivalents" refer to phosgene or it equivalents such as diphosgene, triphosgene, CDI, DSC, BTBC, alkoxycarbonyl chlorides, o/p- nitrosubstituted phenoxycarbonyl chlorides, and the like.
In general, the term "pharmaceutical" when used as an adjective means substantially non-toxic to living organisms.
The terms "pharmaceutically acceptable metal ions or salts" refer to salts of the compounds of this invention, which are substantially non-toxic to living organisms. See, e.g., Berge, S. M. et al., "Pharmaceutical Salts", J. Pharm. Sci., 66:1, 1977. Typical pharmaceutical salts include those salts prepared by reaction of the compounds of this invention with an inorganic or organic acid or base. Such salts are known as acid addition or base addition salts respectively. These pharmaceutical salts frequently have enhanced solubility characteristics compared to the compound from which they are derived, and thus are often more amenable to formulation as liquids or emulsions. Examples of pharmaceutically acceptable salts are those with inorganic bases such as sodium, potassium, calcium, magnesium, and hydroxides, and the like, or with organic bases such as lysine, arginine, triethylamine, dibenzylamine, piperidine, and the like.
The term "suitable solvent" refers to a solvent that is inert to the ongoing reaction and sufficiently solubilizes the reactants to effect the desired reaction. Examples of suitable solvents include but are not limited to, dichloromethane, chloroform, 1,2- dichloroethane, diethyl ether, tert-butylmethyl ether, acetonitrile, ethyl acetate, 1,3- dimethyl-2-imidazolidinone, tetrahydrofuran, dimethylformamide, benzene, toluene, xylene, N-dimethylacetamide, N-methylpyrrolidine, chlorobenzene, dimethylsulfoxide, dimethoxyethane, water, methanol, ethanol, isopropanol, pyridine, nitromethane, mixtures thereof, and the like. The term "suitable base" refers to a base, which acts as a proton trap for any protons, which may be produced as a byproduct of the desired reaction, or to a base, which provides a reversible deprotonation of an acidic proton from the substrate and is reactive enough to effect the desired reaction without significantly effecting any undesired reactions. Examples of such bases include, but are not limited to, carbonates, bicarbonates, and hydroxides (e.g., lithium, sodium, potassium, magnesium, calcium and the like), sodium/potassium/calcium hydride, sodium/potassium alkoxide (i.e., methoxide, ethoxide, tert-butoxide and the like), triethylamine, diisopropylethylamine, N- methylpyrrolidine, N-methylmorpholine, tetramethylguinidine, or aromatic nitrogen containing heterocycles such pyridine, 4-(dimethylamino)pyridine (DMAP), and the like. The term "NONOate" refers to a linkable nitric oxide-releasing group such as AcOCH2-O-N2-N(OOR7, OCHOCH2-O-N2-N(O") R7R7, CH2-O-N2-N(OOR7 R7 and the like.
The term "therapeutic agent" refers to biologically active molecules such as drugs, vitamins, and other molecules, agents or substances concerned with or contributing to the treatment and cure of illness or contributing to the general well being of a mammal or human. The therapeutic agents can be both known and investigational drugs compiled in drug databases such as the Merck Index, IDdb, Prous Science's Integrity®, Prous Science Drugs of the Future™, The Ensemble® and the like. The Merck Index is a one-volume encyclopedia of chemicals, drugs and biologicals that contains more than 10,000 monographs. Each monograph in this authoritative reference source is a concise description of a single substance or a small group of closely related compounds. Prous Science is an international health science publishing company, established in 1958 and headquartered in Barcelona, Spain. Prous Science Drugs of the Future™, produced by Prous Science Publishers, contains comprehensive drug monographs providing product information on new compounds, including the synthesis and corresponding schemes, pharmacological action, pharmacokinetics and metabolism, toxicity, clinical studies, manufacturer, and references. Information on compounds is continuously updated as advances in development status are disclosed worldwide. The Prous Science Integrity™ is a drug R&D portal where knowledge areas are coordinated to provide a harmonious and interrelated whole, which includes Drugs & Biologies, Targets, Organic Synthesis, Experimental Pharmacology, Pharmacokinetics and Metabolism, Clinical Studies, Disease Briefings, Companies & Markets, Literature and Patents. The Investigational Drugs database (IDdb), developed by Thomson Current Drugs, is a pharmaceutical competitor intelligence service. It covers all aspects of investigational drug development, from first patent to eventual launch or discontinuation. The Ensemble® on the Web provides essential information, including chemical structures, on more than 140,000 compounds with demonstrated biological activity in the drag research and development pipeline.
The term "vitamin" includes vitamin A, vitamin C, thiamine, folic acid, biotin, inositol, nicotinic acid, nicotinamide, riboflavin, pyridoxine, pyridoxal 5-phosphate, ergosterol, vitamin D2, vitamin D3, vitamin D4, vitamin E, menadoxime, menadiol, and vitamin K5.
The term "peptide" includes large and small peptides, including, but not limited to, targetable small peptides such as a dipeptide, tripeptide, tetrapeptide, etc.
The term "ligand" means a small molecule that binds to a larger macromolecule, whether or not the ligand actually binds at a metal site. Such ligands can be small peptides.
One aspect of the invention is to provide mutual prodrugs of two or three therapeutic agents currently used for use in combination therapy utilizing novel bio- cleavable linkers, water-soluble prodrugs of insoluble and sparingly-soluble therapeutic agents using the same linker technology, and water-soluble double and triple prodrugs of sparingly-soluble therapeutic agents using the same linker technology. The embodiments of the invention may also comprise vitamins and targetable small peptides in addition to or in place of a promoeity to yield targetable prodrugs.
The candidate drugs selected for mutual prodrug synthesis can be from one therapeutic category or from different therapeutic categories. Similarly, the constituent drugs of a mutual prodrug can act on the same biological target with similar mechanism of action or act on different biological targets with different mechanisms of action.
To be considered for prodrug synthesis, the candidate drugs should contain one or more of the essential functional groups such as amino, hydroxyl, keto, or carboxyl groups in their structure.
Amino group of the candidate drug can be primary or secondary (both acyclic and cyclic) which include amide-NH, sulfonamide-NH, carbamate-NH, sulfamate-NH, hydrazone-NH, semicarbazone-NH, thiosemicarbazone-NH and also drags containing indole, imidazole, benzimidazole, thiazole, oxozole, pyrrole, pyrazole, triazole, tetrazole, or similar NH-containing heterocylic sub-structures of a more complex drag molecule. Similarly, hydroxyl group of drags can be of primary, secondary or tertiary nature. Keto group of candidate drugs may be converted first to ketoxime, hydrazone, semicarbazone and then like, before coupling to the linker. Obviously, hydroxyl or amino functions thus generated will be used to form covalent bond between the drug and the linker.
The candidates for making mutual prodrugs can be the pairs of drugs that are currently used in combination therapy (including those combination studies at investigational stage) in various therapeutic areas provided each of those drugs possesses the requisite functional group(s). There are a number of therapeutic areas where such combination therapy is applied routinely and successfully.
On the basis of the proposed sulfahydryl-dependent mechanism of NO-release from GTN, we have designed the compounds and prodrugs of the present invention where a suitable drug molecule is linked covalently to a nitrooxy (nitrate ester) group via a bio-labile linker containing strategically located disulfide bond at Z?efø-position to nitrate ester. In vivo, the disulfide bond in the prodrug is expected to be reduced by endogenous sulfahydryl-containing species such as glutathione (GSH) to generate a reactive thiolate anion (i.e., δeto-mercapto-nitrate), which can trigger further break-down of the linker moiety to release the free drug (via a mechanism as shown Scheme Ml) and NO simultaneously at the same location. It is possible, as depicted in the mechanism Scheme Ml, the release of NO can go via a hypothetical cyclic transient intermediate 'b'. Similar hypothetical mechanism was proposed for NO release from SS-nitrates, which, were also designed on the basis of a sulfahydryl-dependent NO release from GTN. See, for example, Zavorin, S. I. et al., Organic Letters, 2001, 3, 1113, incorporated herein in its entirety .Mutual prodrugs can be made by linking covalently any two of the following: an amino-containing therapeutic agent to another ammo-containing therapeutic agent; an amino-containing therapeutic agent to a hydroxyl-containing therapeutic agent; an amino- containing therapeutic agent to a carboxyl-containing therapeutic agent and its derivative; a hydroxyl-containing therapeutic agent to a carboxyl-containing therapeutic agent and its derivative; an amino-containing therapeutic agent to a carboxyl-containing therapeutic agent and its derivative; an amino-containing therapeutic agent to a keto-containing therapeutic agent or its hydazone, semicarbazone or oxime derivative and the likes; a hydroxyl-containing therapeutic agent to a keto-containing therapeutic agent via its hydrazone, semicarbazone, or oxime derivative and the likes. Another aspect of the present invention is to provide new nitrate ester (NO- releasing) prodrugs of many types of existing drugs using novel biocleavable likers. Such prodrugs are expected to exhibit better efficacy and tolerability with reduced side effects compared to the corresponding original drugs. An embodiment of present invention relates to the compounds of formula (I) or pharmaceutically acceptable salts thereof:
Figure imgf000024_0001
Formula (I) wherein, a is 0-2;
B independently represents a bond, (CH2)b, (CH2CH2O)C, S-S, S-S=O, S-SO2 or S-S=NH; b is 1-6; c is 1-1000;
A and A1 independently represent a bond, (CH2)d, 1 ,2-phenylene, 1,3-phenylene or 1,4- phenylene; d is 1-8;
D represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of -OH, -SH, -NHR1, -CO2H, -CONHR1, -
OC(=O)NHR', -SO2NHR1, -OSO2NHR1, -N(R1)C(=O)NHR1 and -N(R^SO2NHR1; D2 independently represents D^ a peptide, protein, monoclonal antibody, vitamin, R2, R3,
R4, NO, NO2, a linkable nitric oxide-releasing group comprising a NONOate, a group comprising one or more of water-solubilizing functional groups, or a polymer;
E independently represents CH2 or a bond;
L1 and L2 independently represent a bond, O, S, NR1, L, or a linkage selected from the group consisting of:
Figure imgf000025_0001
L is R12 or a group with bonding in any direction, independently selected from the group consisting of:
Figure imgf000025_0002
X independently represents a bond, C, O, S, or NR1;
Y independently represents a bond, C=O, C=S, S=O, SO2, P(=0)XR\ or (CH2)d; Z independently represents a bond, or (CH2)J; wherein, j is 1-4; R1 independently represents a bond, H, (Ci-C8)alkyl, (C5-Ci4)aryl, aralkyl or M6+; R2 independently represents H, NH2, or NHAc; R3 independently represents H, CO2R5, CH2CO2R5,
R4 independently represents H, OH, O-(Ci-Cs)alkyl, OM6+, or a group selected from the group consisting of:
Figure imgf000026_0001
or arabinolactan,
Figure imgf000026_0002
.
Figure imgf000027_0001
M independently represents Na, K or a pharmaceutically acceptable metal ion, e = l-3,
R5 independently represents at each occurrence H, M6+, (C]-C8)alkyl, (C3-C8)cycloalkyl, substituted (C5-Ci4)aryl, hetero(C2-C14)aryl, C(=O)(CH2)fCHR9CO2R5, CH2C(=O)OR5, P(=O)(OR5)2 ,
Figure imgf000027_0002
X2 independently represents O, S, SO, SO2, or NR5;
R6 independently represents H, Na+, K+, any other pharmaceutically acceptable metal ion, (Ci-C8)alkyl, or (C3-C8)cycloalkyl,
R7 independently represents at each occurrence same or different R5; R8 independently represents CH2, O, NR4, S, S=O or O=S=O; R9 independently represents H, (Ci-C8)alkyl or an amino acid; f is 0-6; g is 0-1; h is 1-2000; i is 1-4;
R10and R11 independently represent H, (Ci-C8)alkyl, (C3-C8)cycloalkyl, or a group selected from the group consisting of:
Figure imgf000029_0001
Figure imgf000029_0002
with a proviso that when R10 is selected from the above group, R11 represents H or (Ci- C8)alkyl, and when R11 is selected from the above group, R10 represents H or (Q- C8)alkyl; R12 independently represents a group selected from the group consisting of:
Figure imgf000030_0001
Figure imgf000031_0001
X3 is independently O or NR7.
D1 and D2 of the present invention can be both known and investigational drugs compiled in drug databases such as the Merck Index, IDdb, Prous Science's Integrity®, Prous Science Drugs of the Future™, The Ensemble® and the like. In a double prodrug, D1 and D2 are the same drugs. In a mutual prodrug, D1 and D2 are different drugs. In some prodrugs, only Dl is a drug and D -.2 may not be a drug at all. The -OH, -SH, -NH2, - NHR1, -CO2H, -CONHR1, -OCC=O)NHR1, -SO2NHR1, -OSO2NHR1, -N(R^CC=O)NHR1 and -N(R^SO2NHR1 functional groups in D1 and D2 of formula I participate in the formation of linkages between the drug and the linker. Accordingly, some of the atoms or groups in L1 and L2 may come from the corresponding D1, D2 or linker.
Another embodiment of the invention is the compound of formula I, wherein D2 is an amino-, carboxyl- or hydroxyl- containing group or molecule comprising one or more water solubilizing functional groups selected from the group consisting of hydroxyl, amino, acylamino, carboxyl, sulphate, sulfonate, phosphate, phosphonate, N- acylsulfonamide, N-acylsulfamate, N-acylcarbamate, N-acylcarbamate metallic salts, and amino acids to give water-soluble prodrug.
Another embodiment of the invention is the compound of formula I, wherein D2 is selected from the group of D, L and DL amino acids consisting of Alanine, Arginine,
Asparagine, Aspartic acid, Cysteine, Glutamine, Glutamic acid, Glycine, Histidine,
Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine,
Tryptophan, Tyrosine, and Valine.
Another embodiment of the invention is the compound of formula I, wherein D2 represents a polymer selected from the group consisting of arabinogalactan, polyamino acids, polyethylene glycol, polycaprolactone, polyglycolic acid, polylactic acid, polyacrylic acid, poly(2-hydroxyethyl 1 -glutamine), dextran and modified dextrans such as dextran aldehyde, carboxymethyl dextran, arabinogalactane aldehyde, carboxymethyl arabinogalactane, and hyaluronic acid. Yet another embodiment of the invention is the compound of formula I, wherein
D2 is a polyaminoacid selected from group consisting of poly(l-glutamic acid), poly(d- glutamic acid), poly(dl-glutamic acid), poly(l-aspartic acid), poly(d-aspartic acid), poly(dl- aspartic acid), copolymers of the polyaminoacids and polyethylene glycol,
Another embodiment of the invention is the compound of formula I, wherein the polymer has a molecular weight of about 5000 to about 100,000 Daltons. Yet another embodiment of the invention is the compound of formula I, wherein the polymer has a molecular weight of about 10,000 to about 50,000 Daltons.
In a further embodiment D2 is a peptide, protein or monoclonal antibody for achieving targeted delivery of prodrugs and drugs. Another embodiment of the invention is the compound of formula I, wherein D2 is a ligand or dipeptide or a dipeptide ligand. In a further embodiment D2 is a dipeptide ligand that is a substrate for intestinal transporters for selective intestinal absorption of the corresponding prodrugs thereby increasing the bioavailability of the prodrugs. In a further embodiment D2 is a targetable small peptide, i.e., dipeptide, tripeptide, tetrapeptide, etc. Another embodiment of the invention is the compound of formula I, wherein D2 is a vitamin. Such vitamin-conjugated prodrugs are expected to be taken up by the diseased cells via receptor-mediated endocytosis. In a further embodiment of the invention is a compound of formula I, wherein D2 is selected from the group of vitamins consisting of vitamin A, vitamin C, thiamine, folic acid, biotin, inositol, nicotinic acid, nicotinamide, riboflavin, pyridoxine, pyridoxal 5-phosphate, ergosterol, vitamin D2, vitamin D3, vitamin D4, vitamin E, menadoxime, menadiol, and vitamin K5.
Another embodiment of the invention is the compound of formula I, wherein D1 and D2 represent the same therapeutic agent to give a symmetrical double prodrug. Another embodiment of the invention is the compound of formula I, wherein D and D2 represent different therapeutic agents to give a mutual prodrug. Another embodiment of the invention is the compound of formula (I), wherein D1 and D2 can be either from same or different therapeutic class. Another embodiment of the invention is the compound of formula (I), wherein D1 and D2 can be same or different therapeutic agents. Such therapeutic agents may have same or different mechanisms of action or they may work on different biological targets or work on different disease conditions.
Another embodiment of the invention is the compound of formula I, wherein D2 is R2, R3 or R4. Another embodiment of the invention is the compound of formula I, wherein a is 0, B is S-S, S-S=O, S-SO2 or S-S=NH. Yet another embodiment of the invention is the compound of formula I, wherein a is 0, B is S-S or S-S=O, S-SO2 and D2 is R2 or R3 or R4. A further embodiment of the invention is the compound of formula I, wherein B is S-S, A and A1 are CH2-CH2, E is a bond and D2 is R2, R3 or R4. Another embodiment of the invention is the compound of formula I, wherein a is 0; B is S-S or S-S=O, S-SO2; A and A1 are CH2-CH , E is a bond and D2 is R4. Another embodiment of the invention is the compound of formula I, wherein a is 0; B is S-S; A and A1 are CH2-CH2, E is a bond and D2 is R4. Another embodiment of the invention is the compound of formula I, wherein a is
0, B is a bond, (CH2)b, or (CH2CH2O)0 ; wherein b and c are as defined above. Another embodiment of the invention is the compound of formula I, wherein a is 0, B is a bond, (CH2)b or (CH2CH2O)0 and D2 is R2 or R3 or R4; wherein b and c are as defined above.
Yet another embodiment of the invention is the compound of formula I, wherein a is 0; B is S-S or S-S=O, S-SO2; D1 and D2 are drug molecule or R2 or R4 containing carboxyl group; L1 and L2 are independently selected from the following linkages:
>γ /YV" VZ-γ'Xv
Figure imgf000034_0001
Figure imgf000034_0002
wherein, X, R1, Z are as defined above; and Y is C=O. In another embodiment, A and A1 are CH2-CH2, and E is a bond. In a further embodiment, A and A1 are 1, 2-phenylene, 1,
3-phenylene or 1, 4-phenylene, and E is CH2.
Yet another embodiment of the invention is the compound of formula I, wherein a is 0; B is S-S or S-S=O, S-SO2; D1 and D2 are drug molecule or R2 or R4 containing amino- or hydroxyl group; L1 and L2 are independently selected from the following linkages:
Figure imgf000034_0003
wherein, X, R1, Z are as defined; and Y is C=O. In another embodiment, A and A1 are CH2-CH2, and E is a bond. In a further embodiment, A and A1 are 1, 2-phenylene, 1, 3-phenylene or 1, 4-phenylene, and E is CH2.
Yet another embodiment of the invention is the compound of formula I, wherein a is 0, B is S-S or S-S=O, S-SO2 and D2 is D1. Another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S or S-S=O, S-SO2; A and A1 are CH2- CH2, E is a bond and D2 is D . Another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S or S-S=O, S-SO2; A and A1 are 1, 2-phenylene, 1,3- phenylene or 1, 4-phenylene; E is CH2 and D2 is D1Or R2 or R3 or R4. Another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S; A and A1 are 1, 2-phenylene, 1, 3-phenylene or 1, 4-phenylene; E is CH2 and D2 is D1Or R2 or R3 or R4. A further embodiment of the invention is the compound of formula I, wherein B is S-S, A and A1 are CH2-CH2, E is a bond and D2 is D1. Yet another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S or S-S=O, S-SO2; A and A1 are CH2-CH2, E is a bond and D2 is a dipeptide ligand. Yet another embodiment of the invention is the compound of formula I, wherein a is O; B is S-S; A and A1 are CH2-CH2, E is a bond and D2 is a dipeptide ligand. The peptide ligands used in the invention can be substrates for intestinal transporters for selective intestinal absorption of the corresponding prodrugs thereby increasing the bioavailability of the prodrugs. An embodiment of the present invention is the compounds of formula (I), wherein D1, L1 and L2 are as defined above; A and A1 are CH2; E is CH2; B is a bond or (CH2)b ; b is 1-6; a is O; and D2 is D1 or R2 or R4.
Another embodiment of the present invention is the compound of formula (I), wherein E, D1 and L1 are as defined; L2 is O; A and A1 are independently (CH2)d, 1,2- phenylene, 1, 3-phenylene, or 1, 4-phenylene; d is 1-4; B is S-S, S-S=O, S-SO2 or S- S=NH; a is O; D2 is NO, NO2 or a nitric oxide releasing molecule such as NONOate. In a further embodiment, D2 is a NONOate selected from the group consisting of:
Figure imgf000036_0001
In yet another embodiemnt, when D2 is one of the above NONOates, B is S-S.
Another embodiment of the present invention is the compound of formula (I), L2 is O; A and A1 are independently (CH2)a, 1,2-phenylene, 1,3-phenylene, or 1,4- phenylene; d is 1-4; B is S-S; a is 0; D2 is NO2. In a further embodiment, when A and A1
CH2-CH2, E is a bond. In yet another embodiment, when E is CH2, A and A1 are independently 1,2-phenylene, 1,3-phenylene, or 1,4-phenylene.
Yet another embodiment of the present invention is the compound of formula (I), wherein D1 is a amino containing drug molecule having the following reactive functional groups which are involved in the formation of L1 linkages between the drug and the linker: -NH2, -NHR1, -CONHR1, -0-C(K))NHR1, -SO2NHR1, -OSO2NHR1, - NR1Q=O)NHR1 or -N(R^SO2NHR1; L2 is O; E is bond; L1 is linkages selected from the group consisting of:
Figure imgf000036_0002
wherein, X is independently a bond, O or NR1, Y is C=O or SO2, A and A1 are CH2 CH2, B is S-S, a is O and D2 is NO2.
An embodiment of the present invention is the compound of formula (I), wherein D1 is a hydroxyl or sulfahydryl containing drug molecule such as Drug-OH or Drug-SH, wherein functional groups OH and SH are involved in the formation of L1 linkages between the drug and the linker; L2 is O; E is bond, L1 is a linkage selected from the group consisting of:
Figure imgf000036_0003
wherein, X is independently a bond, O or NR1, Rl is not a bond, Y is C=O or SO2, A and A1 are CH2CH2; B is S-S; a is 0; and D2 is NO2.
An embodiment of the present invention is the compound of formula (I), wherein D1 is a drug molecule having carboxyl (-CO2H) as a reactive functional group such as - CO2H which is involved in the formation of L1 linkages between the drug and the linker; L2 is O; E is bond; L1 is O or NR1 or a linkage selected from the group consisting of:
Figure imgf000037_0001
,VzVi
Figure imgf000037_0002
wherein, X is independently a bond, O or NR1, R1 is not a bond; Y is C=O or SO2; A and A1 are CH2CH2; B is S-S; a is O and D2 is NO2.
Another embodiment of the present invention is the compounds of formula (I), wherein D1 is an antioxidant or free radical scavenger such as a hydroxyl-containing stable radical such a 4-hydroxy-2,2,6,6-tetramethylpiperidin-l-oxyl (4-hydroxy- TEMPO), 4-carboxy -2,2,6,6-tetramethylpiperidin-l-oxyl (4-carboxy-TEMPO) or any other ammo-/carboxyl-/hydroxyl-containing antioxidants or radical/super oxide scavengers, and D2 is NO2. The amino-/carboxyl-/hydroxyl-containing antioxidants and radical/super oxide scavengers can be known or investigational.
An embodiment of the present invention is the compound of formula (I), wherein
L1 is x X or
Figure imgf000037_0003
; wherein, X is a bond, O, S or NR1; L2 is O, E is a bond; A and A1 are CH2CH2; B is S-S; a is O; and D2 is NO2. An embodiment of the present invention is the compounds of formula (I), wherein D! and L1 are as defined above; L2 is O; A is 1,2-phenylene, 1,3-phenylene, or 1,4- phenylene; A1 is CH2; E is CH2; B is S-S; a is 0 and D2 is NO2.
An embodiment of the present invention is the compounds of formula (I), wherein L2 is O; A and A1 are CH2; E is CH2; B is a bond or (CH2)b ; b is 1-6; a is O; D2 is NO2 and L1 is a group selected from
Figure imgf000038_0001
wherein, X is O, S or NR1; Rl is as defined.
An embodiment of the invention is the compound of formula I selected from the groups consisting of: A. Prodrugs: (a) From carboxyl-containing drugs:
ion
Figure imgf000039_0001
Figure imgf000039_0002
(b) From amino-containing drugs:
Figure imgf000040_0001
or any water- hydroxyl, etc.]
Figure imgf000041_0001
Figure imgf000042_0001
Ry1 = An amino-, hydroxyl-containing molecule with water-solubilizing groups
I-A2-PD5
Figure imgf000043_0001
Figure imgf000044_0001
amino group I-A3-PD6
sulfonamide
Figure imgf000044_0002
containing drug such as valdecoxib, celecoxib, and the like. I-A3-PD7b
(c) From hydroxyl-containing drugs:
Figure imgf000044_0003
Figure imgf000045_0001
= side-chain groups water- and carboxyl,
Figure imgf000045_0002
Figure imgf000046_0001
A PRODRUG OF ISOTAXEL I-S23-PD1
Y = O, NR1 (R1 = H, Alkyl, Aralkyl, Cycloalkyl), (CH2)nC(=O) (n=l-6), (CH2)nCO2- Z = C=O, SO2, P(=O)YR3 (R3 = H or a metal ion)
R2 = H, a bond, CH2CH2N(CH3)2. HCl, an Amino acid, or any molecule containing solubilizing groups such as carboxylic acid, sulphonic acid, hydroxyl, amino groups, polyethyleneglycol (PEG), a metal ion such a Na+, Ca 2+, etc. B. NO-releasing Prodrugs
(a) From carboxyl-containing drugs
Figure imgf000048_0001
Figure imgf000049_0001
I-C1-NOPD18 I-Cl-NOPD17b
Figure imgf000049_0002
I-C1-NOPD19 I-Cl-NOPD20a
Figure imgf000049_0003
I-C1-NOPD21 I-Cl-NOPD20b
etc.
Figure imgf000049_0004
(b) From amino-containing drugs
Figure imgf000050_0001
Figure imgf000050_0002
I-A2-NOPDla I-A2-NOPDlb
Figure imgf000050_0003
Figure imgf000051_0001
I-A3-NOPD2a I-A3-NOPD2b
(c) From hydroxyl-containing drugs
Figure imgf000052_0001
C. Mutual or Double Prudrugs
(a) From two amino-containing drugs
Figure imgf000053_0001
H or Alkyl),
Figure imgf000053_0002
I-AA-MPD3a (Raal= H)
Figure imgf000053_0003
Figure imgf000054_0001
I-AA-MPD13
Figure imgf000055_0001
Figure imgf000055_0002
Figure imgf000056_0001
Figure imgf000056_0002
(b) From two carboxyl-containing drugs
Figure imgf000057_0001
(c) From two hydroxyl-containing drugs
Figure imgf000058_0001
Figure imgf000059_0001
Figure imgf000060_0001
(d) From an amino-containing drug and a carboxyl-containing drug:
Figure imgf000061_0001
Figure imgf000062_0001
Figure imgf000063_0001
(e) Mutual prodrugs of one carboxyl-containing and one hydroxyl-containing drugs
Figure imgf000064_0001
(f) Mutual prodrugs of one amino-containing and one hydroxyl-containing drugs
Figure imgf000065_0001
Figure imgf000066_0001
Figure imgf000067_0001
Figure imgf000068_0001
I-AH-MPD20
Figure imgf000069_0001
An embodiment of the invention is a pharmaceutical composition comprising a therapeutically effective amount of the compound of formula I, or a pharmaceutical salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
Another embodiment of the invention is a pharmaceutical composition comprising a therapeutically effective amount of the compound of formula I selected from the group consisting of I-C1-PD1, 1-C1-PD2, 1-C1-PD3, 1-C1-PD4, 1-Cl-PD4a, I- Cl-PD4b, I-C1-PD5, 1-C1-PD6, 1-C1-PD7, 1-C1-PD8, 1-C1-PD9, 1-C1-PD10, I-Cl- PDI l, I-C1-PD12, 1-C1-PD13, 1-C1-PD14, 1-Cl-PD15a, I-Cl-PD15b, I-A1-PD1, I-Al- PD2, 1-A1-PD3, 1-A1-PD4, 1-A1-PD5, 1-A1-PD6, 1-A1-PD7, 1-A1-PD8, 1-A1-PD9, I-Al- PDlO, I-A1-PD11, 1-A1-PD12, 1-A1-PD13, 1-A1-PD14, 1-A1-PD15A, I-Al-PD15Aa, I- A1-PD15B, I-Al-PD15Bb, I-A1-PD16, 1-A1-PD17, 1-A2-PD1, 1-A2-PD2, 1-A2-PD2b, I- A2-PD3a, I-A2-PD3b, I-A2-PD4, 1-A2-PD5, 1-A3-PD1, 1-A3-PD2a, I-A3-PD2b, I-A3- PD3a, I-A3-PD3b, I-A3-PD4, 1-A3-PD5, 1-A3-PD6, 1-A3-PD7b, I-H1-PD1, 1-H1-PD2, I- H1-PD3, 1- H1-PD4, 1- H1-PD5, 1- H1-PD6, 1- H1-PD7, 1- H1-PD8, 1- H1-PD9, 1- Hl- PDlO, I- Hl-PDIl, I- H1-PD12, 1- H1-PD13, 1-Taxol-PDl, I-Taxol-PD2, 1-Taxol-PD3, I-Taxol-PD4, 1-Taxol-PD5, 1-Taxol-PD6, 1-S23-PD1, 1-C1-NOPD1, 1-C1-NOPD2, 1-Cl- NOPD3a, I-Cl-NOPD3b, I-C1-NOPD4, 1-Cl-NOPD5a, I-Cl-NOPD5b, I-C1-NOPD6, I- C1-NOPD7, 1-Cl-NOPD8a, I-Cl-NOPD8b, I-C1-NOPD9, 1-C1-NOPD10, 1-Cl- NOPDlIa, I-C1-NOPD13, 1-Cl-NOPD14a, I-Cl-NOPD14b, I-Cl-NOPD15b, I-Cl- NOPD 16, 1-C 1 -NOPD 17a, I-C 1 -NOPD 17b, I-C 1 -NOPD 18, 1-C 1 -NOPD 19, 1-Cl- NOPD20a, I-Cl-NOPD20b, I-C1-NOPD21, 1-C1-NOPD22, 1-Cl-NOPD23b, I-Cl- NOPD24, 1-C1-NOPD25, 1-C1-NOPD26, 1-A1-NOPD1, 1-A1-N0PD2, 1-A1-NOPD3A, I-A1-NOPD3B, I-A1-NOPD4, 1-A1-NOPD5, 1-A1-NOPD6, 1-A1-NOPD7, 1-Al- NOPD8, 1-A1-NOPD9, 1-Al-NOPDlOa, I-Al-NOPDlOb, I-A2-NOPDla, I-A2- NOPDIb, I-A2-NOPD2a, I-A2-NOPD2b, I-A3-NOPDla, I-A3-NOPDlb, I-A3-
NOPD2a, I-A3-NOPD2b, I-H1-NOPD1, 1-Hl-NOPD2a, I-Hl-NOPD2b, I-H1-NOPD3, I- H1-NOPD4, 1-Hl-N0PD5b, I-H1-NOPD6, 1-H1-NOPD7, 1-H1-NOPD8, 1-H1-NOPD9, I-H1-NOPD10, 1-AA-MPD1, 1-AA-MPD2, 1-AA-MPD3a, I-AA-MPD4, 1-AA-MPD5, I- AA-MPD6, 1-AA-MPD7, 1-AA-MPD8, 1-AA-MPD9, 1-AA-MPD10, 1-AA-MPD11, I- AA-MPD12, 1-AA-MPD13, 1-AA-MPD14, 1-AA-MPD15, 1-AA-MPD16, 1-AA-MPD17, I-AA-MPD18, 1-AA-MPD19, 1-AA-MPD20, 1-AA-MPD21, 1-AA-MPD22, 1-AA- MPD23, 1-AA-MPD24, 1-AA-MPD25, 1-AA-MPD26, 1-AA-MPD27, 1-CC-MPD1, 1-CC- MPD2, 1-CC-MPD3, 1-CC-MPD4, 1-CC-MPD5, 1-CC-MPD6, 1-HH-MPD1, 1-HH- MPD2, 1-HH-MPD3, 1-HH-MPD4, 1-HH-MPD5, 1-HH-MPD6, 1-HH-MPD7, I-HH- MPD8, 1-HH-MPD9, 1-HH-MPD10, 1-HH-MPD11, 1-HH-MPD12, 1-HH-MPD13, 1-HH- MPD14, 1-HH-MPD15, 1-HH-MPD16, 1-HH-MPD17, 1-HH-MPD18, 1-HHAH-TMPD1, I-CA-MPD1, 1-CA-MPD2, 1-CA-MPD3, 1-CA-MPD4, 1-CA-MPD5, 1-CA-MPD6, 1-CA- MPD7, 1-CA-MPD8, 1-CA-MPD9, 1-CA-MPD10, 1-CA-MPD11, 1-CA-MPD12, 1-CA- MPD13, 1-CA-MPD14, 1-CA-MPD15, 1-CA-MPD16, 1-CA-MPD17, 1-CA-MPD18, I- CA-MPD19, 1-CA-MPD20, 1-CA-MPD21, 1-CA-MPD22, 1-CA-MPD23, 1-CA-MPD24, I-CA-MPD25, 1-CA-MPD26, 1-CA-MPD27, 1-CA-MPD28, 1-CA-MPD29, 1-CA-
MPD30, 1-AH-MPD1, 1-AH-MPD2, 1-AH-MPD3, 1-AH-MPD4, 1-AH-MPD5, 1-AH- MPD6, 1-AH-MPD7, 1-AH-MPD8, 1-AH-MPD9, 1-AH-MPD10, 1-AH-MPD11, I-AH- MPD12, 1-AH-MPD13, 1-AH-MPD14, 1-AH-MPD15, 1-AH-MPD16, 1-AH-MPD17, I- AH-MPD 18, 1-AH-MPD19, 1-AH-MPD20, 1-AH-MPD21, 1-AH-MPD22, 1-AH-MPD23, I-AH-MPD24, 1-AH-MPD25, 1-AH-MPD26, 1-CH-MPD 1 , 1-CH-MPD2, 1-CH-MPD3, I- CH-MPD4, 1-CH-MPD5, and I-CH-MPD6 or a pharmaceutical salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
An embodiment of the invention is a method of treating a mammal or human in need thereof comprising administering a therapeutically effective amount of the pharmaceutical composition comprising the compound of formula I.
Another embodiment of the invention is the below listed novel intermediates:
Figure imgf000073_0001
Figure imgf000074_0001
2-((2-(før^Butoxycarbonylamino)ethyl)- 2-((2-Aminoethyl)disulfanyl)- disulfanyl)ethyl carbonochloridate (LI-7) ethanol (SL-2)
Figure imgf000074_0002
Methyl 2-((2-hydroxyethyl)- Methyl 2-((2-(chlorocarbonyloxy)- disulfanyl)acetate (L3I2a) ethyl)disulfanyl)acetate (L3I3a)
Figure imgf000074_0003
2-Methyl-6-oxo-7-oxa- 10,11 -dithia-2,5- diazatridecan-13-yl acetate (LI-8)
Figure imgf000074_0004
2-((2-((2,5-Dioxopyrrolidin-l-yloxy)carbonyloxy)ethyl)- disulfanyl)ethyl 2-(dimethylamino)ethylcarbamate (LI-10)
Another embodiment of the invention is use of the above listed novel intermediates in the processes for the preparation of compounds of formula I;
Further embodiments include methods of preparation and methods of use of compounds of formula (I) or pharmaceutically acceptable salts thereof.
Another embodiment of the invention is process for the preparation of compounds of formula I, or pharmaceutically acceptable salts thereof, wherein the process comprises of: monoprotection of Bis-(2-hydroxyethyl)disulphide (SL-I) with an appropriate hydroxyl protecting group to give a corresponding monoprotected intermediate, conversion of the corresponding monoprotected intermediate to an activated formyl intermediate by treating with phosgene or its equivalent, and reaction of the activated formyl intermediate with an appropriate amino- or hydroxy containing D1 to give the corresponding compound of formula I. Another embodiment of the invention is a process for the preparation of compounds of formula I, or pharmaceutically acceptable salts thereof , wherein the process comprises of :
-converting carboxy containing Dl into an activated intermediate comprising acyl halide, imidazolide or isocyanate, and -reacting the activated intermediate with a linker intermediate to obtain the compound of formula I.
In another embodiment, the invention is a process in which the monoprotected intermediate is LIIx, and the activated formyl intermediate is Lllxy.
Another embodiment of the invention is a process for preparation of compounds of formula (I), wherein D2 is NO2 or pharmaceutically acceptable salts thereof, wherein the process comprises, mixing a selectively protected and activated Dl with a solution of
2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b) in a suitable solvent in presence of a suitable coupling agent.
Another embodiment of the invention is a process for preparation of compounds of formula (I), wherein D2 is NO2 or pharmaceutically acceptable salts thereof, wherein a process comprises, converting 2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b) into its formyl halide or imidazolide (LI-4x) by using a phosgene or its equivalent reagent and mixing/reacting the resulting reactive intermediate with a suitable amino- or hydroxy- containing drug in suitable solvent in presence of a suitable base. Another embodiment of the invention is a process for preparation of compounds of formula (I), wherein D2 is NO2 or pharmaceutically acceptable salt thereof, wherein the process comprises, mixing/reacting a selectively protected and activated drug with a solution of 2-((2-aminoethyl)dithio)ethyl nitrate (LI-5) in a suitable solvent in presence of a suitable coupling agent and/or base. Another embodiment of the invention is a process for preparation of mutual prodrugs of compounds of formula (I), or pharmaceutically acceptable salts thereof, wherein a process comprises,
A ) monoprotection of Bis-(2-hydroxyethyl)disulphide (SL-I) with an appropriate hydroxyl protecting group to give the corresponding monoprotected intermediate LI-Ix,
B) reaction of formyl linker intermediate LI- lxy with amino or hydroxyl containing drug (D1) to obtain the prodrug of formula I with free hydroxyl group on the linker,
C) conversion of the intermediate obtained in the step B into activated formyl halide or imidazolide derivative, and D) reaction of the intermediate obtained in the step C with the drug D2 to obtain the mutual prodrug of formula I.
Further embodiments of the invention are processes for the preparation of compounds of formula I5 or pharmaceutically acceptable salts thereof, wherein the processes comprise of the steps that are generally depicted in the schemes 1-23. Further embodiments include the pharmaceutical composition comprising a therapeutically effective amount of novel intermediates or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
Another embodiment of the invention is use of compounds of formula (I) or pharmaceutically acceptable salt thereof, in the treatment of disease conditions originally treatable by the corresponding free drug(s).
It should be understood that while this invention has been described herein in terms of specific embodiments set forth in detail, such embodiments are presented by way of illustration of the general principles of the invention, and the invention is not necessarily limited thereto. Certain modifications and variations in any given material, process step or chemical formula will be readily apparent to those skilled in the art without departing from the true spirit and scope of the present invention, and all such modifications and variations should be considered within the scope of the claims that follow. The contents of the articles, patents, and patent applications, and all other documents mentioned or cited herein, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. Yet another embodiment of the invention is a compound of formula I containing an amino-containing therapeutic agent selected from the group consisiting of: I-AA- MPDl , I-AA-MPD2, 1-AA-MPD3, and I-AA-MPD4.
Another embodiment of the invention is double prodrug of formula (I) selected from the group consisting of: I-AA-MPD5, 1-AA-MPD6, 1-AA-MPD7, and I-AA-MPD8.
The present invention also provides mutual prodrugs of formula (I) selected from the group consisiting of: I-CA-MPD1, I-CA-MPD2, I-CA-MPD3, I-CA-MPD4, I-CA-
MPD5, I-CA-MPD6, I-CA-MPD7, I-CA-MPD8, I-CA-MPD9, I-CA-MPD10, I-CA-
MPDI l, I-CA-MPD12, I-CA-MPD13, I-CA-MPD14, I-CA-MPD15, I-CA-MPD16, I- CA-MPD17, I-CA-MPD18, I-CA-MPD19, I-CA-MPD20, I-CA-MPD21, I-CA-MPD22, I-CA-MPD23, I-CA-MPD24, I-CA-MPD25, I-CA-MPD26, I-CA-MPD27, I-CA- MPD28, 1-CA-MPD29, and I-CA-MPD30.
In another embodiment, the invention provides compounds of formula (I) selected from the group of mutual prodrugs made from amino-containing therapeutic agent and a hydroxyl-containing therapeutic agent such as: I-AH-MPD1, 1-AH-MPD2, 1-AH-MPD3, I-AH-MPD4, I-AH-MPD5, I-AH-MPD6, I-AH-MPD7, I-AH-MPD8, I-AH-MPD9, I- AH-MPDlO, I-AH-MPD11, 1-AH-MPD12, 1-AH-MPD13, I-AH-MPD14, 1-AH-MPD15, I-AH-MPD16, I-AH-MPD17, I-AH-MPD18, I-AH-MPD19, I-AH-MPD20, I-AH- MPD21, 1-AH-MPD22, 1-AH-MPD23, 1-AH-MPD24, 1-AH-MPD25, and I-AH-MPD26. Yet another embodiment of the invention relates to compounds of formula (I) of mutual prodrugs made from a hydroxyl-containing therapeutic agent and a hydroxyl- containing therapeutic agent such as: I-HH-MPD1, I-HH-MPD2, I-HH-MPD3, I-HH- MPD4, I-HH-MPD5, I-HH-MPD6, I-HH-MPD7, I-HH-MPD8, I-HH-MPD9, I-HH- MPDlO, I-HH-MPD11, I-HH-MPD12, I-HH-MPD13, I-HH-MPD14, I-HH-MPD15, I- HH-MPD16, 1-HH-MPD17, and I-HH-MPD18.
The present invention also provides compounds of formula (I) containing water- soluble prodrugs of insoluble or sparingly-soluble therapeutic agents such as: I-H1-PD1, I-H1-PD2, 1-H1-PD3, 1-H1-PD4, 1-H1-PD5, 1-H1-PD6, 1-H1-PD7, 1-H1-PD8, 1-H1-PD9, I-H1-PD10, 1-H1-PD11, 1-H1-PD12, 1-H1-PD13, 1-A1-PD1, 1-A1-PD2, 1-A1-PD3, I-Al- PD4, 1-A1-PD5, 1-A1-PD6, 1-A1-PD7, 1-A1-PD8, 1-A1-PD9, 1-A1-PD10, I-A1-PD11, I- A1-PD12, I-A1-PD13, I-A1-PD14, I-A1-PD15A, I-Al-PDlAa, I-A1-PD15B, I-Al- PD 15Bb, I-A1-PD16, I-A1-PD17, I-A2-PD1, I-A2-PD2, I-A2-PD2b, I-A2-PD3a, I-A2- PD3b, I-A2-PD4, 1-A2-PD5, 1-A3-PD1, 1-A3-PD2a, I-A3-PD2b, I-A3-PD3a, I-A3-PD3b, I-A3-PD4, I-A3-PD5, I-A3-PD6, I-A3-PD7b, I-H1-PD1, I-H1-PD2, I- H1-PD3, I- Hl- PD4, I- H1-PD5, I- H1-PD6, I- H1-PD7, I- H1-PD8, I- H1-PD9, I- Hl-PDlO, I- Hl- PDl 1, 1- H1-PD12, 1- H1-PD13, 1-Taxol-PDl, I-Taxol-PD2, 1-Taxol-PD3, 1-Taxol-PD4, I-Taxol-PD5, 1-Taxol-PD6, and I-S23-PD1.
Another embodiment of the invention relates to the compounds of formula (I), selected from the group of NO-releasing prodrugs consisting of: I-Cl -NOPDl, I-Cl- NOPD2, 1-Cl-NOPD3a, I-Cl-NOPD3b, I-C1-NOPD4, 1-Cl-NOPD5a, I-Cl-NOPD5b, I- C1-NOPD6, 1-C1-NOPD7, 1-Cl-NOPD8a, I-Cl-NOPD8b, I-C1-NOPD9, 1-C1-NOPD10, I-Cl-NOPDl la, I-C1-NOPD13, 1-Cl-NOPD14a, I-Cl-NOPD14b, I-Cl-NOPD15b, I-Cl- NOPD 16, I-Cl -NOPD 17a, I-Cl -NOPD 17b, I-C1-NOPD18, I-C1-NOPD19, I-Cl- NOPD20a, I-Cl-NOPD20b, I-C1-NOPD21, I-C1-NOPD22, I-Cl-NOPD23b, I-Cl- NOPD24, I-C1-NOPD25, I-C1-NOPD26, I-A1-NOPD1, I-A1-NOPD2, I-A1-NOPD3A, I-A1-NOPD3B, I-A1-NOPD4, I-A1-NOPD5, I-A1-NOPD6, I-A1-NOPD7, I-Al- NOPD8, I-A1-NOPD9, I-Al-NOPDlOa, I-Al-NOPDlOb, I-A2-NOPDla, I-A2- NOPDIb, I-A2-NOPD2a, I-A2-NOPD2b, I-A3-NOPDla, I-A3-NOPDlb, I-A3- NOPD2a, I-A3-NOPD2b, I-H1-NOPD1, 1-Hl-NOPD2a, I-Hl-NOPD2b, I-H1-NOPD3, I- H1-NOPD4, I-Hl-NOPD5b, I-H1-NOPD6, I-H1-NOPD7, I-H1-NOPD8, I-H1-NOPD9, I-H1-NOPD10.
Another aspect of the invention provides the use of the compounds of formula (I) in combination with a compound used to treat cardiovascular diseases selected from the group consisting of: beta adrenergic blockers, calcium channel blockers, angiotensin II receptor antagonists, antithrombotics, HMGCoA reductase inhibitors, aspirin or nitrooxy derivatives of aspirin, nitrosated beta blockers, nitrosated or nitrosilated calcium channel blockers. Suitable drugs are described in the literature such as the Merck Index, IDdb, Prous Science's Integrity®, Prous Science Drugs of the Future™, The Ensemble® and the like.
Another aspect of the invention provides the use of the pharmaceutical compositions containing compounds of formula (I) in combination with a compound, used to treat other diseases such as cardiovascular diseases, selected from beta adrenergic blockers, calcium channel blockers, angiotensin II receptor antagonists, antithrombotics, HMGCoA reductase inhibitors, aspirin or nitrooxy derivatives of aspirin, nitrosated beta blockers, nitrosated or nitrosilated calcium channel blockers. Pharmaceutical compositions containing two or more of compounds of the invention can be used for the purpose of combination therapy. These pairs of compounds of invention can be from the same therapeutic area or from different therapeutic areas for treating one or more diseases or conditions.
The compounds of the invention, which have one or more asymmetric carbon atoms, can exist as the optically pure enantiomers, pure diastereomers, enantiomer racemic mixtures, diastereomer racemic mixtures, racemates or racemate mixtures. Within the scope of the invention are also all the possible isomers, stereoisomers and their mixtures of the compounds of formula (I).
Another embodiment of the invention relates to the pharmaceutical composition comprising one or more compounds of formula (I) or pharmaceutically acceptable salts thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents. Another embodiment of the invention relates to the pharmaceutical composition comprising one or more compounds of formula (I) or pharmaceutically acceptable salts thereof and at least another pharmaceutically active compound. The pharmaceutically active compound can be from the same or different therapeutic areas for treating one or more disease condition(s) together with one or more pharmaceutically acceptable carriers, vehicles or diluents.
Further embodiments include methods of use of compounds of formula (I) or pharmaceutically acceptable salts thereof.
Another embodiment of the invention is a process for preparation of compounds of formula (I) or pharmaceutically acceptable salts thereof, wherein the process comprises, mixing a selectively protected and activated drug with a solution of 2-((2- hydroxyethyl)dithio)ethyl nitrate in a suitable solvent in presence of a suitable coupling agent. Another embodiment of the invention is a compound or intermediate generated in the above methods and processes.
Another embodiment of the invention is a process for preparation of compounds of formula (I) or pharmaceutically acceptable salts thereof, wherein a process comprises, converting 2-((2-hydroxyethyl)dithio)ethyl nitrate into its formyl halide or imidazolide by using a phosgene or its equivalent reagent and mixing/reacting the resulting reactive intermediate with a suitable drug in suitable solvent in presence of a suitable base.
Another embodiment of the invention is a process for preparation of compounds of formula (I) or pharmaceutically acceptable salt thereof, wherein the process comprises, mixing/reacting a selectively protected and activated drug with a solution of 2-((2- aminoethyl)dithio)ethyl nitrate (or its acid salt) in a suitable solvent in presence of a suitable coupling agent and/or base.
Another embodiment of the invention comprises the novel intermediates formed in the preparation of present invention. Further embodiments include a pharmaceutical composition comprising a therapeutically effective amount of novel intermediates or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
Another embodiment of the invention is processes for the preparation of compounds of formula (I) or pharmaceutically acceptable salt thereof, as well as the starting materials and intermediates involved as depicted in schemes 1-23.
Another embodiment of the invention the novel intermediates obtained in the preparation of compounds of formula I, wherein the intermediates are selected from:
Figure imgf000081_0001
Figure imgf000082_0001
2-((2-(fert-Butoxycarbonylamino)ethyl)- 2-((2-Aminoethyl)disulfanyl)- disulfanyl)ethyl carbonochloridate (LI-7) ethanol (SL-2)
Figure imgf000082_0002
Methyl 2-((2-hydroxyethyl)- Methyl 2-((2-(chlorocarbonyloxy)- disulfanyl)acetate (L3I2a) ethyl)disulfanyl)acetate (L3I3a)
Figure imgf000082_0003
2-Methyl-6-oxo-7-oxa-10,l l-dithia-2,5- diazatridecan-13-yl acetate (LI-8)
Figure imgf000082_0004
2-((2-((2,5-Dioxopyrrolidin- 1 -yloxy)carbonyloxy)ethyl)- disulfanyl)ethyl 2-(dimethylamino)ethylcarbamate (LI-IO)
Another embodiment of the invention is use of compounds of formula (I) or pharmaceutically acceptable salts thereof, in the treatment of disease conditions originally treatable by the corresponding free drugs.
Another embodiment of the invention includes but not limited to a pharmaceutical composition comprising the compounds of formula (I), or pharmaceutically acceptable salt thereof, selected from the group of NO-releasing prodrugs described herein, or more pharmaceutically acceptable carriers, vehicles or diluents.
It should be understood that while this invention has been described herein in terms of specific embodiments set forth in detail, such embodiments are presented by way of illustration of the general principles of the invention, and the invention is not necessarily limited thereto. Certain modifications and variations in any given material, process step or chemical formula will be readily apparent to those skilled in the art without departing from the true spirit and scope of the present invention, and all such modifications and variations should be considered within the scope of the claims that follow. The contents of the articles, patents, and patent applications, and all other documents mentioned or cited herein, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. POTENTIAL EXAMPLES OF MUTUAL PRODRUGS/CODRUGS:
Mutual prodrugs made from an amino-containing therapeutic agent and another amino-containing therapeutic agent:
A Mutual Prodrug of desloratadine and pseudoephedrine (I-AA-MPD1) is proposed as a potential treatment option for seasonal allergic rhinitis (SAR). Desloratadine (an active metabolite of loratadine) is a new, non-sedating, long-acting histamine antagonist and has been shown effective in the treatment of nasal and non- nasal symptoms associated with SAR. Pseudoephedrine is an oral decongestant.
A Mutual Prodrug of amlodipine (Pfizer' s Norvasc®) and lisinopril (Zeneca's Zestril®) (I-AA-MPD2) is proposed as a potential treatment option for hypertension and congestive heart failure. Amlodipine is a calcium channel blocker and is used as an antihypertensive and antianginal agent. Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor and is used for the treatment of hypertension and congestive heart failure. A combination therapy using these two drugs has been proven to be more effective treatment option than monotherapy using either of these drugs.
A Mutual Prodrug of amlodipine (Pfizer' s Norvasc®) and losartan (Merck's Cozaar®) (I-AA-MPD3a) is proposed as a potential treatment option for mild to moderate hypertension. Amlodipine is a calcium channel blocker and is used as an antihypertensive and antianginal agent. Losartan potassium is an angiotensin II blocker and is used for the treatment of hypertension. A combination therapy using these two drugs has been proven to be more effective treatment option than monotherapy using either of these drugs. Examples of mutual prodrugs and double prodrugs of valdecoxib and celecoxib containing a disulfide linker are: I-AA-MPD4 and I-AA-MPD5. Examples of double prodrugs of valdecoxib or celecoxib containing non-disulfide linkers: I-AA-MPD6, 1-AA-MPD7, 1-AA-MPD8.
A Mutual Prodrug of fluoxetine (Lilly's Prozac®) and olanzapine (Lilly's
Zyprexa®) (I-AA-MPD9) is proposed for potential treatment of patients with Bipolar disorder. Fluoxetine and Olanzapine are used in combination to treat patients with bipolar disorder while being spared the treatment-emergent mania that such patients often get on antidepressant monotherapy.
Example of double prodrug of gabapentin is proposed as potential antiepileptic agent: I-AA-MPD10.
Figure imgf000084_0001
Mutual prodrugs made from an amino-containing therapeutic agent and a carboxyl-containing therapeutic agent: A mutual prodrug of cetirizine and pseudoephedrine (I-CA-MPD1) is proposed for treatment of rhinitis. Cetirizine is an antihistamine and pseudoephedrine is a nasal decongestant.
Mutual prodrugs of gabapentin and valproic acid are potential antiepileptic agents. This same kind of prodrug may be a potential treatment option for patients with bipolar disorder and other mental illnesses. The following are some of the examples:
Figure imgf000085_0001
Other illustrative examples of mutual prodrugs under this category include the following: Mutual prodrugs of valproic acid and other carboxyl-, hydroxyl-, and amino- containing (including amide-, and sulfonamide-containing) anticonvulsant agents such as levetiracetam, lamotrigine, pregabalin, carbamazepine, oxcarbamazepine, licarbazepine, felbamate, topiramate and the like. (Structures are given below). The list also includes investigational antiepileptic agents such as antipamezole, licarbazepine, Eslicarbazepine Acetate (BIA 2-093), fluorofelbamate, isovaleramide (NPS 1776), retigabine (D-23129), safmamide (NW-IOl 5), stiripentol (STP), talampanel (TLP), (2S)-2-[(4R)-2-oxo-4- propylpyrrolidin-l-yl]butanamide 83 alpha (ucb 34714), valrocemide (TV 1901), and the like.
Figure imgf000086_0001
GABAPENTIN VIGABATPJN PREGAB
Figure imgf000086_0003
Figure imgf000086_0002
CARBAMAZEPINE OXCARBAMAZEPINE LICARBAZEPINE BIA 2-093
Figure imgf000086_0004
FELBAMATE TOPIRAMATE LEVETIRACETAM ZONISAMIDE
Figure imgf000086_0005
Figure imgf000086_0006
VALPROIC ACID LAMOTRIGINE
Mutual Prodrugs can be made from combination of any two anti-convulsant agents listed above or any other suitable anticonvulsant agents. Mutual prodrug of gabapentin and naproxen (I-CA-MPD22) is proposed for potential treatment option for neurological pain and inflammation. Mutual prodrugs made from an amino-containing therapeutic agent and a hydroxyl-containing therapeutic agent:
Mutual prodrugs of norfloxacin and metronidazole (I-AH-MPD1, 1-AH-MPD2, 1-
AH-MPD3) are proposed for potential treatment of diarrhea and dysentery of bacterial, amoebic and mixed origin. Metronidazole is an antianaerobic agent and used in combination with antibiotics such as norfloxacin, ciprofloxacin, etc. for the treatment of patients with diarrhea and dysentery of bacterial, amoebic and mixed origin.
A mutual prodrug of loperamide and.norflaxacin (I-AH-MPD4) is proposed for potential treatment of diarrhea and dysentery. A mutual prodrug of valdecoxib and tramadol (I-AH-MPD5 and I-AH-MPD6) as a potential therapy in postoperative pain management.
A mutual prodrug of gabapentin and tramadol ■ (I-AH-MPD7) is proposed for potential treatment of neuropathic pain after spinal cord injury.
A mutual prodrug of venlafaxine and paroxetine (I-AH-MPD8) is proposed for potential treatment of neurological and depression related disorders.
Mutual prodrugs made from a hydroxyl-containing therapeutic agent and another hydroxyl-containing therapeutic agent:
Mutual prodrugs of zidovudine (AZT/Retrovir) and lamivudine (3TC/Epivir) (I- HH-MPDl, I-HH-MPD2) are proposed as a potential treatment option for HIV and other viral infections.
POTENTIAL EXAMPLES OF WATER-SULUBLE PRODRUGS:
Water-soluble prodrugs of insoluble/sparingly-soluble therapeutic agents can be prepared using the same linker technology.
Water-soluble prodrugs of metronidazole include: I-H1-PD-2, I-H1-PD-3, I-Hl- PD-4.
Water-soluble prodrugs of valdecoxib include: I-A3-PD1, I-A3-PD2a, I-A3- PD2b, I-A3-PD3a, I-A3-PD3b, I-A3-PD4, 1-A3-PD5, 1-A3-PD6, and I-A3-PD7b.
Water-soluble prodrugs of paclitaxel include: I-Taxol-PDl, I-Taxol-PD2, 1-Taxol- PD3, 1-Taxol-PD4, 1-Taxol-PD5, 1-Taxol-PD6, and I-S23-PD1. POTENTIAL EXAMPLES OF NO-RELEASING PRODRUGS: In the following potential examples, X is O, NR1 (R1= H, alkyl) or a bond; Y is CO, SO2, PC=O)XR1 or bond; R1 is H, alkyl, aralkyl, or a metal ion; A is a bond, 1,4-/1,3- /1,2-phenylene or (CH2)O (° = 0-6) and m is 1-2 unless otherwise stated; Prodrugs of Valproic Acid (Anticonvulsant):
Figure imgf000088_0001
DRUGS CONTAINING REACTIVE PRIMARY AND SECONDARY AMINES, AMIDE-NH, UREA-NH, SULFONAMIDE-NH, SULFAMATE-NH, AND CARBAMATE-NH:
Figure imgf000088_0002
Prodrugs of Gabapentin (Anticonvulsant):
Figure imgf000088_0003
Prodrugs of Lamotrigine Prodrugs of Carbamazepine (Anticonvulsant): (Anticonvulsant) :
Figure imgf000089_0001
NO-Releasing Prodrugs of Paracetamol/Acetaminophen (Analgesic and Antipyretic):
Figure imgf000089_0002
ADDITIONAL POTENTIAL EXAMPLES:
In the following additional potential examples, X is O, NR1 (R1= H, alkyl) or a bond; Y is CO, SO2, PC=O)XR1 or bond; R1 is H, alkyl, aralkyl, or a metal ion; A is a bond, 1,4-/1, 3-/1, 2-phenylene or (CH2)0 (o = 0-6) and m is 1-2 unless otherwise stated; NO-Releasing Prodrugs of Nicotinamide:
Figure imgf000090_0001
NO-Releasing Prodrugs of NSAIDs:
NO-Releasing Prodrugs of Aspirin
Figure imgf000090_0002
NO-Releasing Prodrugs of Paracetamol
Figure imgf000090_0003
NO-Releasing Prodrugs of Mesalamine
Figure imgf000091_0001
NO-Releasing Prodrugs of Naproxen
Figure imgf000091_0002
NO-Releasing Prodrugs of Flurbiprofen
Figure imgf000091_0003
NO-Releasing Prodrugs of Ketoprofen
Figure imgf000092_0002
NO-Releasing Prodrugs of Indomethacin
Figure imgf000093_0001
NO-Releasing Prodrugs of Ibuprofene
Figure imgf000093_0002
NO-Releasing Prodrugs of Ketorolac
Figure imgf000093_0003
NO-Releasing Prodrugs of Diclofenac
Figure imgf000094_0001
NO-Releasing Prodrugs of Glucocorticoids:
NO-Releasing Prodrug of Prednisolone
Figure imgf000094_0002
NO-Releasing Prodrug of Ursodeoxycholic Acid
Figure imgf000094_0003
NO-Releasing Prodrug of Hydrocortisone
Figure imgf000095_0001
NO-Releasing Prodrug of Budesonide
Figure imgf000095_0002
NO-Releasing Prodrugs of Antioxidants and /or Free Radical Scavengers:
NO-Releasing Prodrug of TEMPOL (4-hvdroxy-TEMPO*):
Figure imgf000096_0001
NO-Releasing Prodrugs of Vitamin E (alfa-tocopheroD:
Figure imgf000096_0002
NO-Releasing Prodrugs of Edaravone (3-methyl-l-phenyl-2-pyrazolin-5one*):
H3C
Figure imgf000096_0003
NO-Releasing Prodrugs of Antibiotics:
NO-Releasing Prodrugs of Metronidazole
Figure imgf000097_0001
NO-Releasing Prodrugs of Norfloxacin:
Figure imgf000097_0002
NO-Releasing Prodrugs of Antiepileptic Agents:
NO-Releasing Prodrugs of Valproic Acid
Figure imgf000097_0003
NO-Releasing Prodrug of Gabapentin
Figure imgf000098_0001
NO-Releasing Prodrug of Levetiracetam
Figure imgf000098_0002
NO-Releasing Prodrug of Lamotrigine
Figure imgf000098_0003
NO-Releasing Prodrug of Carbamazepine
Figure imgf000099_0001
Plausible Mechanisms of Drug Release from Prodrugs
Drugs can be released form the prodrugs and mutual prodrugs via cleavage of bio- labile linker(s) in vivo (cleavage can be either chemical or enzymatic or both) by illustrative mechanisms as shown in Schemes Ml through M5.
Plausible mechanisms for concomitant release of nitric oxide (NO) and free drug from NO-releasing prodrug(s) of amino-, hydroxyl-, or carboxyl-containing drug(s) are illustratively shown in Schemes Ml . Thus, the attack of thiolate ion (from GSH or any other sulfahydryl-containing species) on nitrooxy-containing prodrug would release carboxylic acid-containing free drug, episulfide (d) and the intermediate conjugate (a) according to path 1. If the prodrugs are made from amino-, or hydroxyl-containing drugs, then the prodrug would be cleaved via path 2 to release the corresponding free drug, the cyclic thiocarbonate intermediate (c) and the intermediate conjugate (a). The cyclic thiocarbonate intermediate may further breakdown into episulfide (d) and carbon dioxide. The reactive episulfide (d) would be further neutralized by glutathione. The nitrate ester- containing intermediate conjugate can further break down in the presence of GSH to glutathione dimer (GS-SG) and transient intermediate (b), which can break down via path 3 to release NO. It is also possible the same transient intermediate can break down via path 4 to yield episulfϊde (d) and a relatively innocuous nitrate anion (NO3 ").
'a'
Figure imgf000100_0001
X = O, NR (R = H or alkyl or a group linked to the drug) or a bond
Drug-
S
Released
Figure imgf000100_0002
'b'
NO3 " + de
Figure imgf000100_0003
Scheme Ml Plausible mechanisms of drug release from mutual prodrugs of one carboxyl- containing and one amino-/hydroxyl-containing drug is shown in Scheme M2.
Re
Figure imgf000101_0001
g2
'd' Released Drug2
Scheme M2
Plausible mechanism of drug release from prodrugs (including mutual and NO- releasing prodrugs of amino-, hydroxyl-and carboxyl-containing drugs) containing modified bio-labile linkers is shown in Scheme M3. Thus, the thiolate anion derived from the attack of glutathione on disulfide of the prodrug may trigger cyclization to release the free drug (Dl-XmlH) and a stable six-membered (or five-membered, if X1"2 is a bond) thio-lactone intermediate.
Figure imgf000102_0001
Prodrug
D^ D2 and L2 are as defined in the text.
Xml = O, NRl (R1= a bond, H, alkyl, or a metal ion), CONR1,
SO2NR1, P(O)NR1, OC(O)NR1, OSO2NRWd the like.
Xm2 is a bond, CH2, O, NRml(Rml is H, alkyl, aryl or a bond),
S, SO, SO2 and the like
Figure imgf000102_0002
Scheme M3
Plausible mechanisms of drug release from double/mutual prodrugs containing additional linkages to couple two hydroxyl-containing drugs are shown in Scheme M4. Thus, the thiolate anion generated by the attack of glutathione on disulfide bond of the prodrug triggers further cleavage as shown to release the free drug (D '-OH) and a five- membered 2-imidazolidone. Through in vitro decomposition studies, we have found that the drug release from this type of prodrug is more facile when R group is an alkyl group.
Figure imgf000103_0001
Released Drug
Scheme M4
This invention also covers novel bio-labile linkers containing 1 ,4-phenylene group and 1 ,2-phenylene group as shown in Schemes 5 and 6, respectively. As depicted in Scheme M5, the linker is expected to release the free Drug1 upon glutathione-assisted cleavage and may generate 1,4-quinonemethid (ea) as a byproduct via 1,6-elimination process. Similarly, the free Drug2 is expected to be released from the intermediate conjugate (a) as shown in the scheme.
'a' Rel
Figure imgf000103_0002
d Drug2
Scheme M5 As depicted in Scheme M6, the 1,2-phenylene-containing linker is also expected to release free drugs upon glutathione assisted cleavage and genereate 1,2-quinonemethid (eb) as a byproduct via 1,4-elimination process (via pathway 'b'). However, this linker can also cleave via pathway 'a' to generate benzo-monothiocarbonate as a byproduct. Although the generated byproducts seem to be toxic, they are likely to be quickly neutralized by detoxification enzymes in the body.
Figure imgf000105_0001
Scheme M6 Scheme M7: Plausible mechanism of diazepam formation from an acyclic prodrug of diazepam
Figure imgf000106_0001
Open-chain intermediate DIAZEPAM Water-soluble acyclic prodrug design for Diazepam
Diazepam, a benzodiazepine tranquilizer, is very sparingly water-soluble drug and a water-soluble acyclic prodrug of diazepam can be made by using our linker technology. As shown in the Scheme M7, reduction of disulfide bond in the prodrug triggers release of open-chain intermediate of diazepam which spontaneously cyclizes to diazepam in vivo.
Where GSH is glutathione (reduced) or any other in vivo bioreductive agent that can reduce the disulfide bond. As illustrated, cleavage of disulfide bond triggers further breakage of the remaining portion of the linker to release the free drugs. In the process, some byproducts are generated and these are either eliminated or further degraded by some biological process. For clarity, the mechanism of cleavage of the linker is shown as occurring in stepwise manner. However, both the steps can possibly occur in a concomitant fashion to release both the drugs simultaneously. As illustrated in Scheme M3 and M4, Linkers may have additional spacer groups between one side (or both sides) of the linkers and the drug molecule and some of these spacer groups may be cleaved independently by a chemical or enzymatic process to release the drugs prematurely before the cleavage of disulfide linkage. The prodrugs and mutual prodrugs containing such spacer groups may be useful when faster release of drug(s) is desired. LISTS QF CANDIDATE DRUGS USEFUL FOR PRODRUG SYNTHRSTS:
Drugs listed in the following list can be converted to NO- releasing prodrugs. This list is in no way limiting the scope of drugs covered in this invention, but given as representative examples. All the amino- (including amide-NH and sulfonamide-NH, carbamate-NH, sulfamate-NH, hydrazone-NH, semicarbazone-NH, thiosemicarbazone- NH, urea-NH, phosphoramide-NH and the like. See above, for the description of "amino- containing drugs"), carboxyl-, hydroxyl-(including oxime-OH), and carbonyl (both aldehyde and keto groups)-containing drugs under various therapeutic categories as listed in Merck Index (13th editions) and other data bases such as prous science's ensemble, integrity, and the like and also all the qualified (i.e., amino-, and /or hydroxyl-, and/or carboxyl-, and/or carbonyl-containing) investigational drugs as listed in databases such Merck Index (13th editions), iddb, ensemble, integrity, and the like, are covered under this invention without any limitation. ANTI-INFLAMMATORY DRUGS: Amino-containing (including Amide NH and Sulphonamide NH and
Phosphomide NH, etc.): Ampiroxicam, Bucolome, Celecoxib, Difenpiramide, Mofebutazone, Nimesulide, Paranyline, Parecoxib, Parsalmide, Piketoprofen, Talniflumate, Tenidap, Terofenamate, and Valdecoxib.
Hydroxyl-containing: 21-Acetoxypregnenolone, Alclometasone, alfa-Bisabolol, Budesonide, Deflazacort, Diflorasone, Desonide, Desoximetasone, Diflorasone, Diflucortolone, Difiuprednate, Ditazol, Fluazacort, Fluocinonide, Fluocortin Butyl, Fluprednidene Acetate, Glucametacin, Halcinonide, Halobetasol Propionate, Halometasone, Halopredone Acetate, Ibuproxam, Loteprednol Etabonate, Mazipredone, Mometasone Furoate, Oxyphenbutazone, Perisoxal, Rimexolone, Hydroxyl-, and Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Bufexamac, Etofenamate, Fepradinol, Ibuproxam, Isoxicam, Lornoxicam, Meloxicam, Oxametacine, Piroxicam, and Tenoxicam. Hydroxyl- and sulphahydryl-containing: Tixocortol, Carboxyl- and Amino-containing (including amide NH and sulphonamide NH and phosphomide NH, etc.): Aceclofenac, Alminoprofen, Amfenac, 3-Amino-4- hydroxybutyric Acid, Carprofen, Diclofenac, Enfenamic Acid, Etodolac, Flufenamic Acid, Meclofenamic Acid, Mefenamic Acid, Niflumic Acid, and Tolfenamic Acid.
Carboxyl-containing: Acemetacin, Acetamidocaproic Acid, Bendazac, Benoxaprofen, Beπnoprofen, Bucloxic Acid , Butibufen, Cinmetacin, Clidanac, Clopirac, Felbinac, Fenbufen, Fenclozic Acid, Fenoprofen, Fentiazac, Flunoxaprofen, Flurbiprofen, Ibuprofen, Indomethacin, Isofezolac, Isoxepac, Ketoprofen, Lonazolac, Loxoprofen, Metiazinic Acid, Mofezolac, Naproxen, Oxaprozin, Pirazolac, Pirprofen, Pranoprofen, Protizinic Acid, Sulindac, Suprofen, Suxibuzone, Tiaprofenic Acid, Tolmetin, and Tropesin. Carboxyl- and Hydroxy 1-containing: Balsalazide, Enoxolone, Fendosal,
Olsalazine, Oxaceprol, and Ximoprofen.
Amino-, Carboxyl- and Hydroxyl-containing: 3-Amino-4-hydroxybutyric Acid, Mesalamine, and Sulfasalazine.
Keto-containing: Nabumetone, and Piketoprofen. Carboxyl- and keto-contianing: Bermoprofen, Bucloxic Acid, Isoxepac,
Ketoprofen, Loxoprofen, and Zaltoprofen. ANALGESIC AND/OR ANTIPYRETIC DRUGS:
Amino-containing: Aminochlorthenoxazin, Aminopropylon, Anileridine,
Antrafenine, Benorylate, Benzpiperylon, p-Bromoacetanilide, Butacetin, Carsalam, Difenamizole, Etersalate, Ethenzamide, Ethoxazene, Flipirtine, Isonixin, Nifenazone,
Phenacetin, Phenazopyridine, Phenocoll, Phenopyrazone, Piminodine, Piritramide,
Propacetamol, Ramifenazone, Piperylone, Salverine, and Tinoridine.
Hydroxyl-containing: Aluminum bis(acetylsalicylate), Benzylmoφhine, Buprenoφhine, Butorphanol, Chlorobutanol, Ciramadol, Codeine, Desomoφhine, Dihydrocodeine, Dihydromorphine, Dihydroxyaluminum acetylsalicylate, Dimepheptanol, Eptazocine, Ethylmorphine, Eugenol, Hydroxypethidine, Levoφhanol, Meptazinol, Metazocine, Moφhine, Nalbuphine, Pentazocine, Phenazocine, Phenoperidine, Phenylsalicylate, Salicin, Tramadol, and Viminol.
Carboxyl-containing: Acetylsalicylsalicylic acid, Alclofenac, Aspirin, Benoxaprofen, 5-Bromosalicylic acid acetate, Cinchophen, Diacerein, Dipyrocetyl, Fosfosal, Ibufenac, Indoprofen, and Salicysulfuric acid. Amino- and Hydroxyl-containing: Acetaminophen, Acetaminosalol, Bucetin, Capsaicine, Dezocine, Floctafenine, Glafenine, Isoladol, p-Lactophenetide, Norlevorphanol, Noπnorphine, Phenylramidol, Salacetamide, and Salicylamide.
Amino- and Carboxyl-containing: Actarit, Bumadizone, Clonixin, and Salicylamide O-acetic acid.
Carboxyl- and Hydroxyl-containing: Diflunisal, Gentisic acid, and Salsalate.
Keto-containing: Amtolmetin, Dipipanone, Hydrocodone, Isomethadone, Methadone, Norpipanone, and Phenadoxone.
Hydroxy- and Keto-containing: Hydromorphone, Ketobemidone, Metopon, Oxycodone, and Oxymorphone.
Carboxyl- and Keto-containing: Clometacin, Ketorolac, and Zomepirac.
Amino- Carboxyl- and Keto-containing: Bromfenac. ANTIHYPERTENSIVE DRUGS:
Amino-containing: Alfuzosin, Benzylhydrochlorothiazide, Bethanidine, Bopindolol, Budralazine, Bunazosin, Ciclosidomine, Clonidine, Clopamide,
Cyclopenthiazide, Debrisoquin, Edeseφidine, Diazoxide, Dihydralazine, Doxazosin,
Endralazine, Guanabenz, Guanacline, Guanazodine, Guanethidine, Guanochlor,
Guanadrel, Guanfacine, Guanoxan, Hydracarbazine, Hydralazine, Hydroflumethiazide,
Indapamide, Indoramin, Irbesartan, Ketanserin, Lofexidine, Mebutamate, Mecamylamine, Methyl 4-pridyl ketone thiosemicarbazone, Mibefradil, Minoxidil,
Monatepil, Moxonidine, Pheniprazine, Pinacidil, Prazosin, Raubasine, Rescinnamine,
Reserpiline, Reserpine, Rilmenidine, Syrosingopine, Tasosartan, Terazosin, Tiamenidine,
Todralazine, Tolonidine, Tripamide, and Urapidil.
Hydroxy-containing: Ajmaline, Cicletanine, Levcromakalim, Naftopidil, Phenactropinium chloride, and Protoveratrines.
Carboxyl-containing: Eprosartan, Fosinopril, and Telmisartan,
Amino- and Carboxyl-containing: Alacepril, gama-Aminobutyric acid, Benazepril, Candesartan, Carmoxirole, Caronapril, Cilazapril, Delapril, Enalapril, Enalaprilat, Imidapril, Lisinopril, Moexipril, Moveltipril, Perindopril, Quinapril, Ramipril, Saralasin, Spirapril, Temocapril, Trandolapril, and Valsartan. Amino- and Hydroxyl-containing: Acebutolol, Alprenolol, Amosulalol, Arotinolol, Atenolol, Betaxolol, Bisoprolol, Bosentan, Bucindolol, Bufeniode, Bunitrolol, Bupranolol, Butofilolol, Cadralazine, Celiprolol, Carazolol, Carteolol, Cetamolol, Carvedilol, Epanolol, Indenolol, Nadolol, Dilevalol, Fenoldopam, Guanoxabenz, Labetalol, Losartan, Mepindolol, Metipranolol, Metoprolol, Moprolol, Nebivolol, Olmesartan, Oxprenolol, Penbutolol, Phentolamine, Pildralazine, Pindolol, Propranolol, Rescimetol, Sulfinalol, Talinolol, Tertatolol, Timolol, and Trimazosin.
Amino-, Hydroxyl- and Carboxyl-containing: Methyldopa, and Sampatrilat, Sulfahydryl-and Carboxyl-containing: Captopril, and Omapatrilat, Carbonyl-containing: Aranidipine, and Eplereήone, ANTIBIOTICS:
All the known amino-, hydroxyl-, and carboxyl-containing antibiotics such as Amoxicillin, Ampicillin, Olivanic acid, Metronidazole, and the like as listed in Merck Index. 13th edition and other drug databases integrity, ensemble, iddb, and the like. These antibiotics can be used in combination with beta-lactamase inhibitor such as clavulanic acid, penicillinic acid sulfone and the like. The following lists of antibacterial and antifungal agnets are given for clarity. ANTIBACTERIAL AGENTS:
Amino-containing: Acedapsone, Acetosulfone sodium, Ambazone, Bacampicillin, Benzylsulfamide, Brodimoprim, Cefcapene pivoxil, Cefpodoxime proxetil, Chloramine- B, Chloramine-T, Capreomycin, Clofazimine, Cyacetacide, Cycloserine, Dapsone, Ethionamide, Furazolium chloride, N2-Formylsulfϊsomidme, Furonazide, Isoniazid, Lenampicillin, Linezolide, Mafenide, 4'-(Methylsulfamoyl)sulfanilanilide, Morphazinamide, Nifuradene, Nitrofurantoin, Penamecillin, Penethamate hydriodide, Pexiganan, Pivampicillin, Pivcefalexin, Picloxydine, Protionamide, Pyrazinamide, Solasulfone, Subathizone, 4,4'-Sulfϊnyldianiline, Sulfoxone sodium, 4'- Sulfanilylsulfanilamide, Sulfoniazide, Sulfabenzamide, Sulfacetamide,
Sulfachlorpyridazine, Sulfacytine, Sulfadiazine, Sulfadicramide, Sulfadimethoxine, Sulfadoxine, Sulfaethidole, Sulfaguanidine, Sulfaguanole, Sulfalene, Sulfamerazine, Sulfameter, Sulfamethazine, Sulfamethizole, Sulfamethomidine, Sulfamethoxazole, Sulfamethoxypyridazine, Sulfamethylthiazole, Sulfametrole, Sulfamidochrysoidine, Sulfamoxole, Sulfanilamide, p-Sulfanilylbenzylamine, Sulfanilylurea, N-Sulfanily 1-3,4- xylamide, Sulfaperine, Sulfaphenazole, Sulfaproxyline, Sulfapyrazine, Sulfasomizole, Sulfasymazine, Sulfathiazole, Sulfathiourea, Sulfisomidine, Sulfisoxazole, Sultamicillin, Sulfatolamide, Talampicillin, Taurolidine, Tetroxoprim, Thiazosulfone, Thiacetazone, Tiocarlide, and Trimethoprim.
Hydroxyl-containing: Azithromycin, Chloroxylenol, Chlorquinadol, Clofoctol, Cloxyquin, Diathymosulfone, Glucosulfone sodium, Nifurpirinol, Nifurtoinol, Nitroxoline, Roxarsone, Roxithromycin, Xanthocillin, and Xibornol.
Carboxyl-containing (including sulfate, phosphate and phosphonate-containing): Amdinocillin, Cinoxacin, Difloxacin, Fosfomycin, and Hydnocarpic acid.
Amino- and Carboxyl-containing (including sulfate-, sulfonic acid-, phosphate and phosphonate-containing): Acediasulfone, Amphomycin, Ampicillin, Azidocillin, Azlocillin, Aztreonam, Bacitracin, Balofioxacin, Betamipron, Carbenicillin, Carindacillin, Carumonam, Cefaclor, Cefazedone, Cefazolin, Cefclidin, Cefditoren, Cefepime, Cefetamet, Cefixime, Cefmenoxime, Cefmetazole, Cefodizime, Ceforanide, Cefotaxime, Cefotetan, Cefotiam, Cefoxitin, Cefozopran, Cefpimizole, Cefpirome, Cefroxadine, Cefsulodin, Ceftazidime, Cefteram, Ceftezole, Ceftibuten, Ceftizoxime, Ceftriaxone, Cefuroxime, Cefuzonam, Cephacetrile sodium, Cephalexin, Cephaloglycin, Cephaloridine, Cephalosporin C, Cephalothin, Cephapirin sodium, Cephradine, Cilastatin, Ciproflaxacin, Clinafioxacin, Clometocillin, Cyclacillin, Dicloxacillin, Enoxacin, Epicillin, Fenbenicillin, Floxacillin, Hetacillin, Loracarbef, Metampicillin, Methicillin, Mezlocillin, Nafcillin, Noprysulfamide, Opiniazide, Oxacillin, Penicillin(s), Penimepicycline, Phenethicillin, Phthalylsulfacetamide, Phthalylsulfathiazole, Piperacillin, Propicillin, Quinacillin, Succinylsulfathiazole, Succisulfone, Sulbenicillin, Sulfachrysoidine, Sulfanilic acid, Temocillin, Ticarcillin, and Tigemonam.
Amino- and Hydroxyl-containing: Amikacin, p-Aminosalicylic acid hydrazide, Arbekacin, Azidamfenicol, Bambermycins, 5-Bromosalicylhydroxamic acid, Butirosin, Clindamycin, Clomocycline, Chloramphenicol, Cloxacillin, Colistin, Demeclocycline, Deoxydihydrostreptomycin, Dibekacin, Dihydrostreptomycin, Dirithromycin, Doxycycline, Enviomycin, Ethambutol, Forimicins, Gentamycin, Glyconiazide, N4-beta- D-Glucosylsulfanilamide, Gramicidin(s), Isepamicin, Kanamycin(s), Lincomycin, Meclocycline, Methacycline, Micronomicin, Neomycin, Netilmicin, Novobiocin, Paromomycin, Phenyl aminosalicylate, Pipacycline, Polymyxin, Primycin, Ramoplanin, Ribostamycin, Rifabutin, Rifalazil, Rifamide, Rifamycin SV, Rifampin, Rifapentine, Rifaximin, Ristocetin, Salinazid, Sancycline, Sisomicin, Streptolydigin, Streptomycin, Streptonicozid, 2-p-Sulfanilylanilinoethanol, Thiamphenicol, Thiostrepton, Tobramycin, Tuberactinomycin, Viomycin, and Virginiamycin.
Hydroxyl- and Carboxyl-containing (including sulfate, phosphate and phosphonate-containing): Fropenem, Nadifloxacin, Biapenem, Fusidic acid, and Merbromin. Hydroxyl- and Aldehyde-containing: Josamycin, Leucomycins, Midecamycins,
Miokamycin, Rokitamycin, and Spiramycin.
Amino-, Hydroxyl-, and Carboxyl-containing (including sulfate, phosphate and phosphonate-containing): p-Aminosalicylic acid, Apicycline, Amoxicillin, Apalcillin, Aspoxicillin, Benzoylpas, Cefadroxil, Cefamandole, Cefatrizine, Cefbuperazone, Cefdinir, Cefminox, Cefonicid, Cefoperazone, Cefoselis, Cefpiramide, Cefprozil, Ertapenem, Flomoxef, Imipenem, Lymecycline, Meropenem, Moxalactam, Negamycin, Panipenem, Ritipenem, Salazosulfadimidine, Sulfaloxic acid, 4-Sulfanilamidosalicylic acid, Teicoplanin, Tyrocidine, and Vancomycin.
Keto-containing: Troleandomycin. Hydroxy- and Keto-containing: Carbomycin, Clarithromycin, Erythromycin, all erythromycin ester derivatives, Oleandomycin, and Telithromycin.
Hydroxy-, Aldehyde-, and Keto-containing: Rosaramicin.
Amino- and Keto-containing: Porfiromycin.
Carboxyl- and Keto-containing: Fleroxacin, Flumequine, Miloxacin, Nalidixic acid, Ofloxacin, Oxolinic acid, Pefloxacin, Piromidic acid, Prulifloxacin, Rosoxacin, and Rufloxacin.
Amino-, hydroxyl-, and Keto-containing: Chlortetracycline, Dalfopristin, Guamecycline, Mikamycin, Minocycline, Oxytetracycline, Pristinamycin, Quinupristin, Rolitetracycline, Spectinomycin, and Trospectomycin. Amino-, carboxyl-,and keto-contianing: Garenoxacin, Gatifloxacin, Gemifloxacin, Grepafloxacin, Lomefloxacin, Moxifloxacin, Norfloxacin, Pazufloxacin, Pipemidic acid, Sitafloxacin, Sparfloxacin, Tosufloxacin, and Trovafloxacin.
Sulfahydryl-containing: Pyrithione. ANTIFUNGAL AGENTS:
Amino-containing: Chlordantoin, Exalamide, Flucytosine, Loflucarban, Magenta I, and Pyrrolnitrin.
Hydroxy-containing: Chloφhenesin, Ciclopirox, Dermostatin, Filipin, Fluconazole, Fungichromin, Pecilocin, Posaconazole, Ravuconazole, Rubijervine, Siccanin, 2,4,6-Tribromo-m-cresol and Voriconazole.
Carboxyl-containing: Undecylenic acid (10-undecenoic acid), and Propionic acid,
Amino- and Carboxyl-containing: Azaserine.
Amino- and Hydroxyl-containing: Salicylanilide, Acrisorcin (9-Aminoacrindine compound with 4-Hexylresorcinol (1:1)), Anidulafungin, Bromosalicylchloranilide, Buclosamide, Caspofungin, Micafungin, and Tubercidin.
Amino-, Carboxyl- and Hydroxyl-containing: Natamycin, Amphotericin B, Lucensomycin, and Nystatin.
Carbonyl-containing: sodium propionate and griseofulvin. Hydroxy- and carbonyl-containing: Viridin.
Amino-, hydroxyl-, and carbonyl-containing: Perimycin and Mepartricin. Amino-, carboxyl-, hydroxyl-, and carbonyl-containing: Candicidin. ANTIVIPVAL DRUGS:
Hydroxy-containing: Edoxudine, Floxuridine, Idoxuridine, Kethoxal, Podophyllotoxin, Sorivudine, Stavudine, Trifluridine, and Zidovudine.
Amino-containing: Amantadine, Amidinomycin, Atevirdine, Capravirine, Delavirdine, Efavirenz, Famciclovir, Imiquimod, Lamivudine, Methisazone, Moroxydine, Nevirapine, Oseltamivir, Rimantadine, Stallimycin, mantadine, and Valacyclovir. Amino- and Hydroxyl-containing: Abacavir, Acyclovir, Adefovir, Amprenavir,
Atazanavir, Cidofovir, Didanosine, Dideoxyadenosine, Emtricitabine, Entecavir, Indinavir, Lamivudine, Lopinavir, 5-(methylamino)-2-deoxyuridine (MADU), Nelfinavir, Penciclovir, Resiquimod, Ribavirin, Ritonavir, Saquinavir, Tenofovir, Tipranavir, Valganciclovir, Vidarabine, and Zalcitabine.
Carboxyl- and Hydroxyl-containing: Foscarnet sodium, and Ganciclovir. Amino-, Carboxyl- and Hydroxyl-containing: Zanamivir.
ANTIMALARIAL:
Amino-containing: Chlorguanide, Chloroquine, Chlorproguanil, Cycloguanil, Pamaquine, Plasmocid, Primaquine, Quinocide, and Tafenoquine.
Hydroxyl-containing: Artemisinin alcohol, Bebeerines, Cinchonidine, Cinchonine, Dihydroartemisinin, Halofantrine, Lumefantrine, Quinine and Yingzhaosu A.
Carboxyl-containing: Arteflene and Artesunate.
Amino-, and Hydroxyl-containing: Amodiaquin, Hydroxychloroquine, Mefloquine, and Pyronaridine. Hydroxyl, and carbonyl-containing: Fosmidomycin.
Carbonyl-containing: Arteflene. ANTINEOPLASTIC DRUGS:
Hydroxy-containing: Aclacinomycins, Arzoxifene, Batimastat, Broxuridine,
Calusterone, Capecitabine, CC- 1065, Chromomycins, Diethylstilbestrol, Docetaxel, Doxifluridine, Droloxifene, Dromostanolone, Enocitabine, Epitiostanol, Estramustine,
Etanidazole, Etoposide, Fenretinide, Flavopiridol, Formestane, Fosfestrol, Fulvestrant,
Gemcitabine, Irinotecan, Melengestrol, Menogaril, Miltefosine, Mitobronitol, Mitolactol,
Mopidamol, Nitracrine, Nogalamycin, Nordihydroguaiaretic Acid, Olivomycins,
Paclitaxel and other known paclitaxel analogs, Plicamycin, Podophyllotoxin, Retinoic acid (including all trans-retinioc acid), Roquinimex, Rubitecan, Seocalcitol, Temoporfϊn,
Teniposide, Tenuazonic Acid, Topotecan, Valrubicin, Vinblastine, Vincristine, and
Zosuquidar.
Amino-containing (including Amide-NH and Sulphonamide-NH, Carbamate-NH,
Sulfamate-NH, and Phosphomide-NH): 9-Aminocamptothecin, Aminolevulinic Acid, Amsacrine, Bisantrene, Cactinomycin, Carboquone, Carmofur, Carmustine,
Cyclophosphamide, Dacarbazine, Dactinomycin, Demecolcine, Diaziquone, 6-Diazo-5- oxo-L-norleucine (DON), Edatrexate, Efaproxiral, Eflornithine, Eniluracil, Erlotinib, Fluorouracil, Gefitinib, Gemcitabine, Goserelin, Histamine, Ifosfamide, Imatinib, Improsulfan, Lanreotide, Leuprolide, Liarozole, Lobaplatin, Cisplatin, Carboplatin, Lomustine, Lonafarnib, Mannomustine, Melphalan, Methotrexate, Methyl Aminolevulinate, Miboplatin, Mitoguazone, Mitoxantrone, Nilutamide, Nimustine, Nolatrexed, Oxaliplatin, Pemetrexed, Phenamet, Piritrexim, Procarbazine, Raltitrexed, Tariquidar, Temozolomide, Thiamiprine, Thioguanine, Tipifarnib, Tirapazamine, 3- Aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP)/ 3-Aminopyridine-4- methyl-2-carboxaldehyde thiosemicarbazone (3-AMP/Triapine /OCX-191/OCX-0191), Trimetrexate, Uracil Mustard, Uredepa ([Bis(l-aziridinyl)phosphinyl]carbamic acid ethyl ester, ethyl carbamate and Meturedepa.
Both Hydroxy- & Amino- containing (including Amide-NH and Sulphonamide- NH, Carbamate-NH, Sulfamate-NH, and Phosphomide-NH): Ancitabine, Anthramycin, Azacitidine, Bleomycins, Bropirimine, Buserelin, Carubicin, Chlorozotocin, Cladribine, Cytarabine, Daunorubicin, Decitabine, Defosfamide, Docetaxel, Doxorubicin, Ecteinascidins, Epirubicin, Gemcitabine, Hydroxyurea, Idarubicin, Marimastat, 6- Mercaptopurine, Pentostatin, Peplomycin, Perfosfamide, Pirarubicin, Prinomastat, Puromycin, Ranimustine, Streptonigrin, Streptozocin, Tiazofurin, Troxacitabine, Vindesine and Zorubicin. Carboxyl-containing: Butyric acid.
ANTIOXIDANTS/FREE RADICAL SCAVENGERS:
Amino-containing (including some investigational drugs): BTX-51072 (4,4- dimethyl-3,4-dihydro-2H-l,2-benzoselenazine), Carnosine, Melatonin, (+)-R- Pramipexole, and Stobadine. Hydroxyl-containing (including some investigational drugs): Ascorbic acid,
Curcumin, Dexanabinol, Edaravon, (-) Epigallocatechin Gallate, Emoxipin, Hydroxytyrosol, Idebenone, Luteolin, Nicanartine, NZ-419, Oxyresveratrol, Probucol (including probucol prodrugs such as AGI- 1067 and AGI- 1096), Quercetin, Reductic acid, Silybin, Tempol (4-Hydroxy-TEMPO), and alfa-Tocopherol (Vitamin E). Carboxyl-containing (including some investigational drugs): N-Acetyl L-cysteine,
Alfa-Lipoic acid, Raxofelast, and Tetomilast. Amino-/Hydroxyl-, and Carboxyl-containing (including some investigational drugs): N-Acetyl carnosine, L-Carnitine, and SCMC-Lys (S-carboxymethyl-L-cysteine Lysine salt H2O).
Amino- and Hydroxyl-containing (including some investigational drugs): BN- 82451, and Zeatin.
BENZODIAZEPINE TRANQUILIZERS AND HYPNOTICS:
Diazepam, Triazolam, Alprazolam, and the like. ANTIULCER AGENTS:
Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Aldioxa, Benexate HCl, Cimetidine, Ebrotidine, Ecabapide,
Esaprazole, Esomeprazole, Famotidine, Irsogladine, Lafutidine, Lansoprazole,
Omeprazole, Pantoprazole, Pirenzepine, Polaprezinc, Rabeprazole, Ranitidine,
Roxatidine, and Troxipide.
Hydroxyl (and Keto and Keto and/or Carboxyl) -containing: Enprostil, Misoprostol, Ornoprostil, Plaunotol, Rioprostil, Trimoprostil, and Oryzanol A.
Carboxyl-containing: Acetoxolone, Carbenoxolone, Rebamipide, and Sofalcone.
Amino (or Hydroxyl) - and Carboxyl-containing: Cetraxate, Ecabet, S- Methylmethionine, Rosaprostol, and Rotraxate.
Carbonyl-containing: Spizofurone, and Teprenone. ANTICONVULSANTS:
Amino-containing (including Amide NH and Sulphonamide NH and
Phosphomide NH, etc.): Acetylpheneturide, Albutoin, N-benzyl-3-chloropropionamide,
Carbamazepine, Cinromide, Clonazepam, Decimemide, Dimethadione, Doxenitoin,
Ethosuximide, Ethotoin, Felbamate, Fosphenytoin, Lamotrigine, Levetiracetam, Mephenytoin, Mephobarbital, Metharbital, Methetoin, Nitrazepam, Oxcarbazepine,
Oxicarbamazepine, Phenacemide, Phenetharbital, Pheneturide, Phenobarbital,
Phenylmethylbarbituric Acid, Phenytoin, Phethenylate Sodium, Primidone, Progabide,
Remacemide, Rufmamide, Suclofenide, Sulthiame, Talampanel, Tetrantoin, Topiramate,
Valpromide, Zonisamide, 5-Methyl-5-(3-phenanthryl)hydantoin, and 3-Methyl-5- phenylhydantoin.
Hydroxyl-containing: Ganaxolone. Hydroxyl-, and Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH): 4-Amino-3-hydroxybutyric Acid, Atrolactamide, and Buramate.
Carboxyl- and Amino-Containing (including Amide NH and Sulphonamide NH and Phosphomide NH): Gabapentin, Pregabalin, and Vigabatrin. Carboxyl-containing: Tiagabine, and Valproic Acid.
ANTIP ARKINSON'S: Levodopa & Carbidopa. ANTIDEPRESSANT:
Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Amoxapine, Caroxazone, Demexiptiline, Desipramine, Duloxetine, Fluoxetine, Fluvoxamine, Indalpine, Indeloxazine Hydrochloride, Iproclozide, Iproniazid, Isocarboxazid, Levophacetoperane, Maprotiline, Metapramine, Milnacipran, Minaprine, Moclobemide, Nialamide, Nomifensine, Nortriptyline, Octamoxin, Oxypertine, Paroxetine, Protriptyline, Reboxetine, Rolipram, Sertraline, Tofenacin, Tranylcypromine, Viloxazine, Benmoxine, and Rolicyprine. Hydroxyl-containing: Befloxatone, Bupropion, Fenpentadiol, Hypericin,
Opipramol, Pyrisuccideanol, Toloxatone, and Venlafaxine.
Hydroxyl-, and Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH): S-Adenosylmethionine, 5-Hydroxytryptophan, and Roxindole.
Carboxyl- and Amino-Containing (including Amide NH and Sulphonamide NH and Phosphomide NH): Amineptine, and Tianeptine. ANTIHISTAMINIC
Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Antazoline, Astemizole, Clobenzepam, Desloratadine, Epinastine, Metron S, Mizolastine, and Tritoqualine. Hydroxyl-containing: Terfenadine, and N-Hydroxyethylpromethazine Chloride.
Hydroxyl-, and Amino-containing (including Amide NH and Sulphonamide NH and Phosphomide NH, etc.): Cetoxime.
Carboxyl-containing: Acrivastine, Bepotastine, Cetirizine, and Levocabastine,
Carboxyl- and Hydroxyl-containing: Fexofenadine. ANTICANCER, ANTIOXIDATIVE, ANTIINFLAMMATORY, AND
CARDIOPROTECTIVE AGENT: Trans-Resveratrol [(E)-3,4',5-trihydroxystilbene). ANTIDIABETIC: Metformin, and Nateglinide/Glipizide/Glibenclamide (Glyburide).
It should be understood that while the lists of names of various categories of drugs have been included above, such lists are presented in a way of illustration of the structural features of the qualifying drugs in this invention and therefore, the number and types of listed drugs are not necessarily limited thereto. In principal, any amino-, and /or carboxyl, and/or carbonyl-, and/or hydroxyl-containing drug (from both known and investigational drugs), irrespective of its therapeutic category and their mechanism of action, as listed in drug databases such as Merck Index, prous science's ensemble, integrity, iddb, and the like, are generally covered within the true spirit and scope of the present invention. For clarity, in addition to the above lists of drugs, any amino-, and/or carboxyl-, and/or carbonyl-, and/or hydroxyl-containing drug(s) (both known and investigational drugs) from the following therapeutic areas are covered without any limitation: CENTRAL NERVOUS SYSTEM: Sedatives, Hypnotics, Antidepressants,
Antipsychotics and Antimanics, Analgesics & Antipyretics, Antimigraine agents, Anticonvulsants, Drugs used in parkinsonism and movement disorders, Drug for dementia, Antiemtics, drugs for Vertigo, CNS Stimulants & activators.
EYE: Antiinfective eye preparations, Antiinflammatory and antiallergic preparations, antiglucoma drugs and other preparations to cure eye diseases.
EAR, NOSE and OROPHARYNX: Drugs used aural, nasal and oropharyngeal preparation.
CARDIOVASCULAR SYSTEM: Antiarrhythemic drugs, Antihypertensives (including alfa/beta-blockers, channel blockers, ACE inhibitors, Angiotensin II receptor antagonists, diuretics, etc.), Antianginals (includinig nitrates, calcium channel blockers, etc.), Drugs for cardiac failure and shock, Vasodilators, Coagulants, Anticoagulants, Thrombolytics and antiplatelet drugs.
RESPIRATORY SYSTEM: Respiratory stimulants, Antitussives, Expectorants, Mucolytics and Decongestants, Antihistamine agents, and antiasthmatics. GASTRO INTESTINAL TRACT: Antiulcer and Antisecretory drags (including
H2 receptor antagonists, Proton Pump Iinhibitors, Prostaglandin analogues, etc.), Antacids, Antispasmodics and drugs modifying intestinal motility, Antidiarrhoeals (including antimotility and antimicrobial drugs) and drugs acting on gall bladder.
GENITO URINARY SYSTEM: Urinary antiinfectives, Diuretics, Urinary analgesics & antispasmodics, Antiinfective drugs acting on urethra and vagina, drugs acting on uterus, Drugs for prostatic hypertrophy (including alfa blockers and antiandrogens), Drugs for erectile dysfunction, and Spermicidal & nonhormonal contraceptives.
SKIN: Emollients and keratolytics, topical antiinfectives, topical antifungals, topical parasiticidals, topical steroids, topical drugs for acne vulgaris, drugs for psoriasis, pigmentation disorders, and Antiseborrhoeics.
MUSCULO-SKELETAL DISORDERS: Non Steroidal Anti Inflammatory Drugs (NSAIDs) including COX-2 inhibitors, Antiarthritic agents, Immunosuppressants, Topical analgesics, Muscle relaxants and Neuromuscular Drugs.
INFECTIONS AND INFESTATIONS: Penicillin antibiotics, Cephalosporin antibiotics, Quinolone & Fluoroquinolone antibiotics, Macrolide antibiotics,
Chloramphenicol, Tetracycline antibiotics, Sulfonamides, Antianaerobics such as
Metronidazole, Antitubercular drugs, Antileprosy drugs, Antifungals, Antiprotozoals,
Anthelminthics & Antiinfestive Drugs, Antimalarials and Antivirals.
ENDOCRINE SYSTEM: Anabolic and androgenic steroids, Corticosteroids, Oestrogens, Progestogens and Hormonal contraceptives, Fertility Agents, Trophic hormones and related drugs, Thyroid and antithyroid drugs, Antidiabetics and hyperglycaemics.
NUTRITION: Vitamins, Amino acids, Anti-obesity drugs
METABOLISM: Hypolipidaemic drugs (including fϊbric acid derivatives, statins [(i.e., HMG CoA reductase inhibitors), nicotinic acid group, etc.], Drugs used for Gout and Drugs affecting bone metabolism (including bisphosphonates).
NEOPLASTIC DISORDERS: Anticancer drugs such as alkylating agents, cytotoxic antibiotics, antimetabolites such as cytarbine, Fludarbine, 5-Fluorouracil,
Mercaptopurine, Thioguanine, etc., Vinca alkaloids and Etoposide, Taxanes, Topoisomerase 1 inhibitors, Cytotoxic immunosuppressants, Immunostmulants, Cytoprotectives such as Amifostine, Oestrogens, Progestogens, hormon antagonists and other antineoplastic drugs.
ALLERGY AND IMMUNOLOGY: Antiallurgics such as non-sedative antihistamins (e.g., Cetirizine, Desloratadine, Terfenadine, Fexofenadine, etc.), sedative histamines and histamine receptor blockers.
ANAESTHETICS & SURGICALS: Local anaesthetics, intravenous anaesthetics, inhalation anaesthetics and muscle relaxants.
DRUG COMBINATIONS:
It is appreciated that NO-releasing prodrugs of any two or more drugs from the above lists of potential drugs can be used in combination depending on the medical application/need. While a combination formulation may occassionally consist of more than two drugs (depending on the medical need), the following pairs of drugs are covered in this invention as illustrative pairs of candidate drugs for combination therapy.
ANTICANCER: Paclitaxel and Doxorubicin, Paclitaxel and Mitomycin C; Paclitaxel and 9-aminocamptothecin, 3-Arninopyridine-2-carboxaldehyde thiosemicarbazone (3-AP)/ 3-Aminopyridine-4-methyl-2-carboxaldehyde thiosemicarbazone (3 -AMP) and another known anticancer drug such as Paclitaxel,
Doxorubicin, Mitomycin C and the like; CC- 1065 and another known anticancer drug such as Paclitaxel, Doxorubicin, Mitomycin C and the like; Trans-Resveratrol [(E)- 3,4',5-trihydroxystilbene) and another known anticancer drug such as Paclitaxel,
Doxorubicin, Mitomycin C and the like; Retinoic acid (including all trans-retinoic acid) and Butyric acid. Paclitaxel and Captopril, Doxorubicin and Biotin. 5-Fluorouracil and
Cytarabine. Edatrexate and Paclitaxel; Cephalosporanic acid and Paclitaxel;
Cephalosporin and Paclitaxel; and Paclitaxel and Gemcitabine, ANTIPERKINSON'S: Levodopa and Carbidopa.
ANTIBIOTICS: Amoxicillin and Clavulanic acid; Ampicillin and Clavulanic acid, Amoxicillin and Pencillinic acid sulfone; Ampicillin and Pencillinic acid sulfone; Olivanic acid (or any carbapenem antbiotic) and a renal dipeptidase (dehydropeptidase I) inhibitor such as 3-substituted Z-2-acylaminopropionic acid and the like. ANTILIPIDEMIC AND HYPERTENSION: Lifibrol and
Lovastatin/Pravastatin/Fluvastatin/Atorvastatin/Simvastatin; Ezetimibe and Lovastatin/ Pravastatin/ Fluvastatin/Atorvastatin/Simvastatin;
Amlodipine and Lovastatin/Pravastatin/Fluvastatin/Atorvastatin/Simvastatin. ANTIDIABETIC: Metformin and Nateglinide/Glipizide/Glibenclamide
(Glyburide)
ANTIDIABETIC AND HYPERTENSION: Metformin and
Lovastatin/Pravastatin/Fluvastatin/Atorvastatin/Simvastatin.
ANTIASTHMATIC, ALLERGIC RHINITIS AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD): Pseudoephedrine and
Fexofenadine/Cetirizine/Desloratadine/Epinastine; Salbutamol and Ipratropium bromide;
Mometasone and Formoterol/Salmeterol; Fluticasone and Formoterol/Salmeterol;
Budesonide and Formoterol/Salmeterol.
ANTIARTHRITIS, INFLAMMATION AND ULCERS: Diclofenac (any known NSAID) and Misoprostol; Diclofenac (any known NSAID) and a proton pump inhibitor such as Omeprazole, Lansoprazol, Rabeprazole, Leminoprazole, Pantoprazole, and the like; A known antibacterial agent and a proton pump inhibitor such as Omeprazole,
Lansoprazol, Rabeprazole, Leminoprazole, Pantoprazole, and the like; Naproxen (or any known NSAID) and Prophenazone; Acetaminophen and chlorzoxazone/metaxalone/mephenoxalone.
ANTIVIRAL (HIV/AIDS, PEPATITIS B AND OTHER VIRAL INFECTIONS): Zidovudine and Lamivudine; Triple prodrug of Zidovudine; Lamivudine and Abacavir (Ziagen); Lopinavir and Ritonavir; Lamivudine and Adefovir or its prodrug adefovir dipivoxil; Amprenavir and Zidovudine; Nelfmavir and a nucleoside reverse transcriptase inhibitor such as Zidovudine, Lamivudine, and the like; Stavudine and an antiretroviral agent such as Zidovudine, Lamivudine, and the like; Dideoxyinosine and an antiretroviral agent such as Zidovudine, Lamivudine, and the like; Emtricitabine and Penciclovir/Famciclovir; Acyclovir (or any other known antiviral compound) and a bile acid such as cholate, deoxycholate, chenodeoxycholate, and ursodeoxycholate (for targeting bile acid transporters for enhanced oral bioavailability of the drug; Triple and prodrug of Zidovudine, Lamivudine and Efavirenz. In addition to the above list of drugs, the the present invention also covers newer drugs with the above mentioned active functional groups as listed in the Merck index
(13th edition) and other drug databases such as Prous Science's ensemble, integrity and the investigational drugs as listed in databases such as iddb, ensemble, integrity, and the like without any limitation.
It shoud be understood that either or both of any selected pair of drugs (in any proportion) can be in the form of nitrate ester (NO-releasing) prodrug(s) of formula (I) or pharmaceutically acceptable salts thereof and the other drug can be in its native form. For clarity, let us assume that Ibuprofen and Paracetamol are present as active principles in a pharmaceutical compoisition. Then, either or both of these drugs can be in their NO- releasing prodrug form (i.e., NO-Paracetamol and Ibuprofen/ Paracetamol and NO- Ibuprofen/ NO-Paracetamol and NO-Ibuprofen, etc.) and they can be present in any proportion.
It should also be understood that a pharmaceutical composition consisting of two or more of the above listed/qualified drugs, one of the drugs can be in the form of NO- releasing (nitrooxy derivative) prodrug and the other drug(s) in the combination can be in the form another type of prodrug(s).
It should also be understood that a pharmaceutical composition containing a combination of one of the above listed/qualified drug(s) and its own prodrug is also covered (i.e., a pharmaceutical composition consisting of NO-Paracetamol and Paracetamol in any proportion). In such pharmaceutical combinations, the free drug will be useful for faster onset of action and the prodrug will be useful for extension of the duration of action as it releases the drug in a controlled fashion over a longer period of time. Such combination drug therapy may also minimize the toxicity and other side effects due to excessive plasma concentration of free drug. It should also be understood that a pharmaceutical combination may contain a prodrug of one of the above listed/qualified drugs and an another type of prodrug of the same drug (i.e., NO prodrug of pracetamol and mutual prodrug of paracetamol with another drug) and these can be present in any therapeutic proportion depending on the medical need. EXPERIMENTAL
ABBREVIATIONS USED:
BOP : Benzotriazol- 1 -yl-oxy-?m(dimethylamino)phosphonium hexafluorophosphate
DMF: N,N-Dimethylformamide DSC: N,N'-Disuccinimidyl carbonate
CDI: N,N'-Carbonyldiimidazole
DTE: Dithioerythritol
DTT: Dithiothreitol
DCC: N,N'-Dicyclohexylcarbodiimide EDAC. HCl: l-Ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride
HBTU: O-(Benzotriazol- 1 -yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate
TBTU: O-(Benzotriazol-l-yl)-N,N,N',N'-tetramethyluroni\αm tetrafluoroborate
EtOH: Ethanol
Et2O: Diethyl ether THF: Tetrahydrofuran
DMSO: Dimethyl sulfoxide
TEA: Triethylamine
DIPEA: N,N-Diisopropylethylamine
DCM: Dichloromethane EtOAc: Ethyl acetate
DME: Dimethoxyethane
MeOH: Methanol
PE: Petroleum ether
RT: Room temperature TFA: Trifluoroacetic acid
HOBT: N-Hydroxybenzotriazole
SYNTHETIC METHODS:
The prodrugs described herein can be prepared by any number of methods known/obvious to those skilled in the art. The synthetic approaches and the linkages are chosen depending upon the functional groups such as carboxyl, hydroxyl, amino or carbonyl groups present in the drug molecules to be used. The following illustrative methods, as shown in Schemes 1 through 9, can be utilized to make carbonate, urethane, amide, ester, N-acyl carbamate, N-acyl amide, N-acyl sulfamate, and N-acyl sulfonamide, N-acyl phosphoramide, N-oxycarbonylsulfonamide, N- oxycarbonylcarbamate linkages, etc., between drug(s) and linker(s). Methods of making carbonate linkagefs):
As depicted in the scheme 1, the carbonate linkage between the drug and the linker can be made by reacting the hydroxyl-containing drug (alternatively, hydroxyl group of the linker) with phosgene or its equivalents such as diphosgene, triphosgene, N,N'-carbonyldiimidazole (CDI), N,N'-disuccinimidyl carbonate (DSC), 4-nitrophenyl chloroformate and the like, to give a reactive alkoxycarbonyl derivative, where LG is suitable leaving group such as a halide, imidazole, O-succinimide, 4-nitrophenoxide and the like, which can be reacted with hydroxyl group of the linker (alternatively, hydroxyl group of drug if the linker is converted to active alkoxycarbonyl derivative) in the presence of a suitable base and solvent.
Figure imgf000124_0001
Rx and Ry are any monovalent organic radicals; Scheme 1
Bases such as triethylamine, diisopropylethylamine, 4-(dimethylamino)pyridine (DMAP), and the like, can be used. Suitable solvents include CH2Cl2, CHCl3, DMF, THF, ACN, ethyl acetate, ethyl ether and the like. Method(s) of making urethane linkage(s): As shown in scheme 2, the urethane linkage between the drug and the linker can be made by reacting the hydroxyl-containing linker with phosgene or its equivalents (defined above) to give a reactive alkoxycarbonyl derivative, which can be reacted with amino-containing drug in the presence of a suitable base and solvent. Alternatively, a urethane linkage can be made by adding an alcohol to an isocyanate.
Figure imgf000125_0002
Suitable bases and solvents are same as defined above. Methodfs) of making amide or ester linkagefs):
As shown in the Scheme 3, an amide or ester linkage between the drug and the linker can be made by reacting a carboxyl-containing drug with an amino- or hydroxyl- containing linker in the presence of a suitable coupling agent, base and solvent.
Alternatively, the carboxyl-containing compound can be first converted to reactive carbonyl derivative such as an acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide and the like, which can be treated with amino-containing or hydroxyl- containing linker in the presence of a suitable base and solvent to afford the corresponding amide or ester linkage(s), respectively (see, Bodanszky, M. and
Bodanszky, A., The Practice of Peptide Synthesis, Springer-Verlag, New York, 1984)
Figure imgf000125_0001
Rx, Ry, and Rz are any monovalent organic radicals; Scheme 3
Suitable coupling agents include DCC, EDCLHCl, BOP, HBTU, TBTU, DCC/HOBT, EDC/HOBT, and the like. Suitable bases and solvents are same as defined above. Method(s) of making N-acyl carbamate and N-acyl urea linkage:
The linkage such as N-acyl carbamate linkage between the linker and drug can be made as shown in Scheme 4. Thus, treatment of an alcohol with phosgene or its equivalent can yield the corresponding carbonochloridate, which upon treatment with ammonia gas can give the corresponding carbamate intermediate. The carbamate nitrogen can be acylated by a suitable carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the like, in the presence of a suitable base to yield the corresponding N-acyl carbamate. Alternatively, N-acyl carbamate can be made by the reaction of an alcohol with N-acyl isocyanate, which can be prepared either by the reaction of the corresponding amide with oxalyl chloride (See, Speziale, A. J. et al., J. Org. Chem. 1962, 27, 31 '42; Speziale, A. J. et al, J. Org. Chem. 1963, 28, 1805-1811) or by the reaction of the corresponding acid chloride with silver cyanate. (See, Hill, AJ. et. al., J. Am. Chem. Soc, 1940, 62, 1595; Kim, D.K. J. Heterocyclic Chem. 1995, 32, 1625).
Figure imgf000126_0001
Scheme 4
Suitable bases and solvents are same as defined above. Method(s) of making N-acyl amide linkage:
The N-acyl amide linkage between the linker and drug can be made as shown in Scheme 5. Thus, the amide nitrogen can be acylated by a suitable carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the • like, in the presence of a suitable base to yield the corresponding N-acyl amide.
Figure imgf000127_0001
Rx and Ry are any monovalent organic radicals. Scheme 5
Suitable bases and solvents are same as defined above. Methodfs*) of making N-acyl sulfamate linkage:
The linkage such as N-acyl sulfamate between the linker and drug can be made as shown in Scheme 6. Thus, treatment of an alcohol with sulfuryl chloride in the presence of suitable base gives the intermediate sulfochloridate, which can be converted to the corresponding sulfamate. Acylation of sulfamate nitrogen with a suitable carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the like, can yield the corresponding N-acyl sulfamate. ,
Figure imgf000127_0002
Rx and Ry are any monovalent organic radicals. i Q Scheme 6
Suitable bases and solvents are same as defined above. MethodCs) of making N-acyl/oxycarbonyl sulfonamide linkages:
The N-acyl/oxycarbonyl sulfonamide linkage between the linker and drug can be made as shown in Scheme 7. Thus, a sulfonamide nitrogen can be acylated by a suitable
15 carboxylic acid derivatives such as anhydride or acid halide, a succinimide ester, a pentafluorophenyl ester, an imidazolide, and the like, to yield the corresponding N- acylsulfonamide, which can me metallated using an inorganic base. Similarly, the sulfonamide nitrogen can be acylated by a suitable formyl chloride derivative such as alkyloxycarbonyl chloride, imidazolide and the like, to yield the corresponding N- alkyloxycarbonyl sulfonamide as shown in the scheme. Alternatively, the same linkage can be made by the reaction of an alcohol with sulfonyl isocyanate which can be prepared by known methods such by treatment of sulfonamide with oxalyl chloride (see, Hans Krzikalla et al., US2666787 or Smith, J. et al., J. Org. Chem. 1965, 30, 1260-1262) or by treatment of sulfonyl chloride with silver cyanate (See, Smith, J. et al., J. Org. Chem. 1965, 30, 1260-1262).
Figure imgf000128_0001
S9 IP14
Rx, and Ry are any monovalent organic radicals; M is a metal ion; x is 1-4
Scheme 7 Suitable bases and solvents are same as defined above.
Method(s) of making N-oxycarbonylcarbamate and N-oxycarbonylurea linkages:
The N-oxycarbonylcarbamate (or N-oxycarbonylurea) linkage between the linker and drug can be made as shown in Scheme 8. Thus, carbamate nitrogen can be acylated by suitable formyl chloride derivatives such as alkyloxycarbonyl chloride, imidazolide and the like, to yield the corresponding N-alkyloxycarbonylcarbamate as shown in the scheme. Alternatively, the N-oxycarbonylcarbamate (or N- oxycarbonylurea) linkage between the linker and drug can be made by the reaction of an alcohol (or an amine) with carbamoyl isocyanate (IP15A), which can be prepared by known methods such by treatment of carbamate with oxalyl chloride (See, Grehn L, et al, Synthesis, 1988, 922-994) or by treatment of a formyl chloride with silver cyanate (See, Kim, D.K. et al., J. Heterocyclic Chem. 1995, 32, 1625). Alternatively, N- oxycarbonylcarbamate (or N-oxycarbonylurea) can be prepared in two steps. Step 1 : reaction of an alcohol or phenol with chlorocarbonyl isocyanate to give N-oxycarbonyl carbamoyl chloride intermediate (IP15B). Step 2: reaction of the intermediate IP15B with the same or another alcohol or phenol or an amine. (For a review on chemistry of chlorocarbonyl isocyanate, see, Gorbatenko, V. I. Tetrahedron, 1993, 49, 3227).
Figure imgf000129_0001
PΠA, X = O
Pl IB. X = NRz Rx, Ry and Rz are any monovalent organic radicals.
Scheme 8
Suitable bases and solvents are same as defined above. Method(s) of making Nitrate CnitrooXyl or Nitrite (nitrosyloxy) esters:
The nitrate or nitrite esters can be made as shown in Scheme 9. Thus, a nitrate or nitrite ester can be made by treating an alcohol with HNO3ZH2SO4 (or HNU3/Ac2O) or nitrosyl chloride, respectively. Alternatively, a nitrate ester can be made by treating a halide (bromide or iodide is preferred) with silver nitrate in a polar aprotic solvent such as acetonitrile.
Figure imgf000130_0001
A nitrite ester IP16
P12
Rx is any monovalent organic redical. Scheme 9
Compounds (Prodrugs) of the formula (I) containing bio-cleavable linkers and linkages can be synthesized by various methods obvious to those skilled in the art. As a matter of illustration, any of the approaches shown in the following schemes can be used to make such prodrugs of the formula (I) described herein.
Monoprotection of diol or aminoalcohol or diamino compounds [i.e., linker(s)] with suitable protecting groups and their selective removal at appropriate stage of the synthesis are carried out as described in Theodora W. Greene and Peter G.M. Wuts, "Protective Groups in Organic Synthesis", 3rd edition, John Wiley and Sons, Inc. New York (1999), the disclosures of which are incorporated herein by reference. Suitable protecting groups (PGs) include, but not limited to, acetyl, Boc, Fmoc, benzoyl, pivaloyl, trityl, tetrahydropyranyl (THP), and silyl (TBDMS, TMS, etc.). Obviously, selection of a suitable protecting group is very crucial for the success of a chosen method for the synthesis of prodrugs described in this invention.
Synthesis of appropriately derivatized/modified bio-labile linker is shown in Scheme 10.
Scheme 10: Synthesis of appropriately derivatized/modified linker intermediates
Figure imgf000131_0001
(LI-3b)
Figure imgf000131_0002
Figure imgf000131_0003
Some of the methods for the synthesis of prodrugs (including NO-releasing prodrugs) of carboxyl-, amino-, and hydroxyl-containing drugs are shown in Schemes 11 through 14. Scheme 11: Synthesis of Prodrugs of Carboxyl-containing Drugs
NH Ac, etc.]
linkage
Figure imgf000132_0001
NO2, etc.]
Scheme 12: Synthesis of Prodrugs of Amino- containing Drags
Drag Ac,
Drag
Figure imgf000133_0001
Scheme 13: Synthesis of Prodrugs of Amide/Sulfonamide-containing Drugs:
Drug ^ . NH2 [see Scheme 4 or Scheme 11, Method I] Drug ^, NCO Method A
O o π
D
Figure imgf000134_0001
[Y = C=O or SO2; R = H, Acetyl, ChloroAcetyl, Trityl, THP, NO2, etc.]
Prodrug of an Amide/Sulfonamide-containing Drug with N-oxycarbonylamide/sulfonamide linkage
AMDx is a CONH2-containing drugs such as vapromide, levotiracetam, carbamazepine, and the like. SAMDx is a SO2NH2-containing drugs such as valdecoxib, celecoxib, and the like.
Scheme 14: Synthesis of Prodrugs of Hydroxyl-containing Drugs A) Prodrugs with carbonate and carbamate linkages:
Figure imgf000135_0001
I-S14-PD2
Prodrug of a Hydroxyl-containing Drug with urethane linkage [x = Drug Number; R = H, Ac, Chloro Ac, Trityl, THP, NO2, etc.]
B) Prodrugs with N-oxycarbonylcarbamate linkage:
Drag Ac,
Figure imgf000135_0002
HDx HDI3x
Some of the methods for the synthesis of prodrugs (including NO-releasing prodrugs and water-soluble prodrugs) are shown in Schemes 15 and 16. Scheme 15: Synthesis of Water-soluble Prodrug(s) using a bio-cleavable linker(s) and spacer linker (s)
or R-X4]
etc.]
Figure imgf000136_0001
Drug1^ I-S15-PD2
'X Y ^CO2H O X is a bond, O or N; R-X4H is an
I-S15-PD3 amino/hydroxyl-containing molecule with
X is a bond, O or N; X2 = -CH2X3CH2- one or more solubilizing groups such as
[X3 = (CH2)n (n = 0-4), O, S, SO, SO2, NRX amino, carboxyl, hydroxyl, sulfate, phosphate
(Rx = H, alkyl, CO2H, CH2CO2H, etc.) and the like. (including bis-phosphonate), and the like.
Scheme 16: Synthesis of Prodrugs containing a biocleavable linker and various types linkages
Figure imgf000137_0001
Double/Mutual prodrugs described in this invention can be synthesized by any of the approaches depicted in Schemes 17 through 19. Scheme 17: Synthesis of Mutual Prodrug(s) using a bio-cleavable linker(s) and spacer linker (s)
Figure imgf000138_0001
Scheme 18: Synthesis of Double/Mutual Prodrug(s) with additional linkers
Figure imgf000139_0001
Schemes 1-15]
Figure imgf000139_0002
Figure imgf000139_0003
I-S18-MPD2
Scheme 19: Synthesis of Mutual Prodrag(s) using modified bio-cleavable linker(s)
H
Figure imgf000140_0001
[X = O, S, N]
Figure imgf000140_0002
[X = O or S or N; Y = CO, SO2] [X = O or S or N; Y = CO, SO2] A Mutual Prodrug A Mutual Prodrug Scheme 20: Synthesis of Mutual Prodrag(s) using modified bio-cleavable linker(s)
Figure imgf000141_0001
As a matter of illustration, mutual prodrug of desloratadine and pseudoephidrine was synthesized as depicted in Scheme 21.
Scheme 21: A Mutual Prodrug of Desloratadine and Pseudoephedrine
Figure imgf000142_0001
Scheme 22: Synthesis of a water-soluble prodrug of paclitaxel
Figure imgf000143_0001
I-S22-PD2
Scheme 23: Generation of Paclitaxel from a Prodrug of Isotaxel
Figure imgf000144_0001
PACLITAXEL
Y = O, NR1 (R1 = H, Alkyl, Aralkyl, Cycloalkyl), (CH2)nC(=O) (n=l-6), (CH2)nCO;f Z = C=O, SO2, P(=O)YR3 (R3 = H or a metal ion)
R2 = H, a bond, CH2CH2N(CH3)2. HCl, an Amino acid, or any molecule containing solubilizing groups such as carboxylic acid, sulphonic acid, hydroxyl, amino groups, polyethyleneglycol (PEG), a metal ion such a Na+, Ca 2+, etc. Scheme 24: An alternative method for the synthesis of Linker Intermediates LI-2b and LI-5
Figure imgf000145_0001
LI-5
Example 1
Synthesis of 2-[(2-hydroxyethyl)dithio]ethyl acetate (LI-Ia):
Acetic anhydride (5.67 ml, 56.87 mmol) and pyridine (40.4 ml, 499 mmol) were added to a solution of 2-(hydroxyethyl)disulfide (SL-I, 15.39 g, 99.78 mmol) in DCM (350 mL) at RT and the mixture was stirred at RT for 16 h. The mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, afforded 8.16 g (42%) of LI-Ia as a pale yellow oil. 1H-NMR (300 MHz, CDCl3): δ 2.00 (bs, IH), 2.08(s, 3H), 2.80-2.95 (m, 4H), 3.89 (t, 2H, J = 6 Hz), 4.35 (t, 2H, J = 6 Hz), MS: (m/z) 219 [M]+. Example 2
Synthesis of 2- { [2-(tetrahydro-2H-pyran-2-yloxy)ethyl]dithio} ethanol (LI-Ib): This compound was synthesized by a method described by K. F. Bernady et al., J. Org. Chem., 1979, 44, 1438. Dihydropyran (8.41 g, 100 mmol) was added to a solution of SL- 1 (15.4 g, 100 mmol) in DCM (200 mL) at 0-5 0C, followed by PTSA (-5%) and stirred at RT for 5 h. The mixture, after usual aqueous work-up and chromatographic purification, afforded 14.5 g (50%) of LI-Ib. 1H-NMR (300 MHz, CDCl3): δ 1.5-1.9 (m, 6H), 2.88 (t, 2H, J = 6 Hz), 2.94 (t, 2H, J - 6 Hz), 3.45-3.57 (m, IH), 3.67-3.78 (m,lH), 3.85-4.05 (m, 2H), 3.90 (t, 2H, J = 6 Hz), 4.65 (s, IH). Example 3 Synthesis of 2-{[2-(Trityloxy)ethyl]dithio}ethanol (LI-Ic): This compound was synthesized by a method described by O. Hernandez et al, Tetrahedron Letters, 1981, 22, 1491-1494. Thus, 8.58 g (21.4 mmol) of 4- dimethylamino-N-triphenylmethylpyridinium chloride (A.V. Bhatia et al., Organic Synthesis, 1997, 75, 184-185) was added to a solution of SL-I (3.0 g, 19.45 mmol) in DCM (90 mL) and stirred at RT for 24 h. The mixture, after usual aqueous work-up and chromatographic purification, afforded 2.86 g (37%) of LI-Ic. 1H-NMR (300 MHz, CDCl3): δ 2.70 (t, 2H, J = 6.0 Hz), 2.88 (t, 2H, J = 6.0 Hz), 3.39 (t, 2H, J = 6.0 Hz), 3.80 (q, 2H, J = 6.0 Hz), 7.24-7.33 (m, 10H), 7.44-7.46 (m, 5H). MS (m/z): 396 [M]+. Example 4 Synthesis of chloroacetic acid 2-(2-hydroxyethyldisulfanyl)ethyl ester (LI-Id):
To a solution of SL-I (23 g, 150 mmol) in DCM (250 mL) at 0 0C were added TEA (10.12 g, 100 mmol) and chloroacetyl chloride (11.3 g, 100 mmol) and stirred overnight at RT. The reaction mixture was concentrated and purified by column chromatography to afford 8.3 g (37%) of LI-Id. 1H-NMR (300 MHz, CDCl3): δ 2.88 (t, 2H, J = 5.7 Hz), 2.95 (t, 2H, J = 6.6 Hz), 3.89 (t, 2H, J = 5.7 Hz), 4.09 (s, 2H), 4.47 (t, 2H, J = 6.6 Hz). Example 5
Synthesis of 2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b) and 2,2'-bis(ethyl nitrate)disulfide (LI-3b): These intermediates were synthesized in two steps as shown in Scheme 10. : Step 1: Synthesis of 2-((2-bromoethyl)dithio)ethanol (LI-2a) and bis(2- bromoethyl)disulfide (LI-3a): These compounds can be synthesized via bromination of SL-I by a known bromination method.(For a suitable bromination method, see Fruniss, B. S. et al., Vogel's Text Book of Practical Organic Chemistry, 5th edition, Pearson Education, Singapore, 1989; pp 559-579). The following methods were explored: Method 1: To a solution of SL-I (15g, 97.4 mmol) in DMF (50 mL) was added PPh3 (25.5g, 97.4 mmol) and cooled to 0 0C. Bromine (3.33 mL, 64.9 mmol) was added drop- wise and stirred at RT for 18 h. TLC of the mixture showed the mono-bromo derivative LI-2a as the major product with only trace amounts of dibromide LI-3a. The mixture was diluted with water and extracted with EtOAc. After usual aqueous work-up and chromatographic purification, 3.65 g (26%) of LI-2a were obtained. 1H-NMR (300 MHz, CDCl3): δ 1.82 (s, IH), 2.88 (t, 2H, J = 5.8 Hz), 3.08 (t, 2H, J = 7.90 H), 3.63 (t, 2H, J = 7.90 Hz), 3.90 (t, 2H, J = 5.8 Hz).
Method 2: To a solution of SL-I (40 g, 0.26 mol) in DCM (400 mL) at 0 0C was added a solution of PBr3 (24.62 mL, 0.26 mol) in DCM (50 mL) and the mixture was stirred at RT for 15 h. TLC indicated formation of LI-3a as the major product with trace amounts of LI-2a. The reaction was quenched by the addition of water and extracted with DCM. After usual aqueous work-up and chromatographic purification, 33 g (45.3%) of LI-3a were obtained. 1H-NMR (500 MHz, CDCl3): δ 3.1-3.15 (m, 4H), 3.60-3.66 (m, 4H). MS (Cl)+ m/z: 277.69 [M+H]+, 279.66. An alternative synthesis of LI-3a has been reported. (Sharma, M. et al, Bioorg. Med. Chem. Lett., 2004, 14, 5347-5350).
Method 3: To a cold suspension of SL-I (20 g, 129 mmol) in DCM (400 mL) was added CBr4 (42 g, 129 mmol) and stirred for 10 min. PPh3 (34 g, 129 mmol) was then added and stirred at RT for 14 h. The reaction mixture was concentrated and the residue purified by column chromatography to give 13.5 g (52.3%) of LI-2a and 13.0 g (36%) of LI-3a. These compounds were identical (by TLC, NMR and MS) to those obtained in Methods 1 and 2 described above.
Synthesis of 2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b): To a solution of LI-2a (2g, 9.21 mmol) in acetonitrile (15 mL) was added AgNO3 (1.88g, 11.05 mmol) portion-wise and the mixture was stirred at RT in the dark for 45 min. The reaction mixture was filtered through celite and the filtrate was concentrated. The residue, after usual aqueous work-up and chromatographic purification gave 1.46 g (74%) crude LI-2b which was used for the next reaction without further purification. An analytical sample was obtained by chromatographic purification. 1H-NMR (300 MHz, CDCl3): δ 2.89 (t, 2H, J = 6.0 Hz), 2.98 (t, 2H, J = 7.5 Hz), 3.90 (t, 2H, J = 6.0 Hz), 4.74 (t, 2H, J = 7.5 Hz); MS (EI)+ (m/z): 199 [M]+.
Synthesis of 2,2'-bis(ethyl nitrate)disulfide (LI-3b): AgNO3 (8.01 g, 47.12 mmol) was added portion- wise to a solution of LI-3a (6.0 g, 21.42 mmol) in acetonitrile (40 mL) at RT in the dark and stirred for 30 min. The mixture was filtered through celite and the filtrate was concentrated in vacuo at 35 0C to afford 4.6 g (88%) of LI-3b, which was used without further purification. An analytical sample was obtained by chromatographic purification (3-15% EtOAc in petroleum ether). 1H-NMR (300 MHz, CDCl3): δ 3.10 (t, 4H, J = 6.7 Hz), 4.71 (t, 4H, J = 6.7 Hz). MS (EI)+ m/z: 244 [M]+. Example 6
Synthesis of tert-butyl 2-[(2-hydroxyethyl)dithio]ethylcarbamate (LI-2c): To a solution of cysteamine hydrochloride (15 g, 132 mmol) in MeOH (130 mL) at 0-5 0C was added TEA (37 mL, 264 mmol), followed by a solution of SL-I (20.4 g, 132 mmol) in DCM (50 mL) and stirred at RT for 6 h. The mixture, which contained the intermediate SL-2, was cooled and (Boc)2O (63.4 g, 290.4 mmol) was added and stirred overnight. MeOH was removed under vacuum. After usual aqueous work-up and chromatographic purification, LI-2c was obtained as a colorless oil (14.6 g, 44%).
The above linker intermediate can also be prepared by the following method: Step 1: TEA (37 ml, 264 mmol) and a solution of (Boc)2O (48 g, 220 mmol) in DCM (100 mL) were added to a suspension of cystamine dihydrochloride (20 g, 88.8 mmol) in of DCM (300 mL) and stirred at RT for 15 h. The mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, gave 30 g (96%) of tert-butyl 2-({2-[(tet-butoxycarbonyl)amino]ethyl}dithio)ethylcarbamate as a white solid. 1H-NMR (300 MHz, CDCl3): δ 1.43 (s, 18H), 2.78 (t, 4H, J = 6.3Hz), 3.44 (q, 4H, J = 6.0 Hz ), 5.00 (bs,lH). MS (m/z): 353.18 [M+H]+, 375.24 [M+Na]+. Step 2: A solution of 2-mercaptoethanol (1.44 g, 18.5 mmol) in DCM (10 mL) was added to a mixture of tert-butyl 2-({2-[(tert-butoxycarbonyl)amino]ethyl}dithio)ethyl carbamate (5.0 g, 14.2 mmol) and TEA (3.87 ml, 27.7 mmol) in DCM (30 mL) and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 2.0 g (56%) of LI-2c was obtained. 1H-NMR (300MHz, CDCl3): δ 1.43 (s, 9H ), 2.79 ( t, 2H, J = 6.5Hz ), 2.87 (t, 2H, J = 5.7Hz ), 3.48 (q, 2H, J = 6Hz ), 3.88 (t, 2H, J = 5.5 Hz), 4.8 (bs,lH). MS (m/z): 254 [M+H]+, 276.13 [M+Na]+.
Removal of the Boc group of LI-2c was accomplished as described in Example 10 to afford the TFA salt, LI-2c.TFA.
Obviously, the linker intermediates LI-2b and LI-2c can also be synthesized by following the method outlined in Scheme 24. Example 7
Synthesis of 2-Boc-aminoethyl-2'-methansulfonyloxyethyl disulfide (LI-2d): To an ice- cold solution of LI-2c (9 g, 35.52 mmol) in DCM (80 mL) and TEA (9.9 mL, 71.04 mmol) was added methanesulfonyl chloride (4.2 mL, 53.28 mmol). The reaction mixture was stirred at 0-5 0C for 45 min, then diluted with DCM. After usual aqueous work-up and chromatographic purification, 13.38 g of LI-2d were obtained, which was pure enough for further use. 1H-NMR (300 MHz, CDCl3): δ 1.43 (s, 9H), 2.80 (t, 2H, J = 6.4 Hz), 2.98 (t, 2H, 5.7 Hz), 3.05 (s, 3H), 3.35-3.45 (m, 2H), 4.45 (t, 2H, J = 6.7 Hz), 4.78 (br s, IH). Example 8
Synthesis of 2-Boc-aminoethyl-2'-bromoethyl disulfide (LI-2e): To a solution of LI-2d (13 g, 39.27 mmol) in acetone (100 mL) at RT was added LiBr (6.82 g, 78.54 mmol) and stirred under reflux for 1 h. The reaction mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, afforded 8.8 g (78%) of LI-2e. 1H-NMR (300 MHz, CDCl3): δ 1.44 (s, 9H), 2.80 (t, 2H, J = 6.32 Hz), 3.06 (t, 2H, J = 6.73 Hz), 3.44 (q, 2H), 3.61 (t, 2H, J = 7.62 Hz), 4.87 (br s, IH). MS (EI)+ m/z: 317 [M+H]+. Example 9 Synthesis of 2-((2-Boc-aminoethyl)dithio)ethyl nitrate (LI-2f): To a solution of LI-2e (8 g, 25.3 mmol) in acetonitrile (80 mL) was added AgNO3 (5.16 g, 30.36 mmol) portion- wise and stirred at RT for 1 h in the dark. The mixture was filtered through celite and the filtrate was concentrated. The residue obtained was purified by column chromatography to afford 6.34 g (84%) of LI-2f. 1H-NMR (300 MHz, CDCl3): δ 1.44 (s, 9H), 2.80 (t, 2H, J = 6.32 Hz), 3.06 (t, 2H, J = 6.73 Hz), 3.44 (q, 2H), 4.70 (t, 2H, J = 7.62 Hz), 4.87 (br s, IH). MS ( EI)+ m/z: 299 [M+H]+.
The above linker intermediate was also prepared by the following method: TEA (3.56 g, 35.2 mmol) was added to a solution of cysteamine hydrochloride (2g, 17.60 mmol) and LI-3b (4.29g, 17.6mmol) in methanol (25mL) at 0 0C and stirred at RT for 4 h. To the mixture, which contained the intermediate free amine (LI-5), a solution of (BoC)2O (7.68 g, 35.2 mmol) and TEA (3.56 g, 35.2 mmol) in MeOH (1OmL) was added and the mixture was stirred overnight. The reaction mixture was filtered through celite and evaporated to dryness. The residue was purified by column chromatography to afford 0.380 g (7 %) of LI-2f. Example 10
Synthesis of 2-((2-Aminoethyl)dithio)ethyl nitrate.TFA salt (LI-5.TFA): To an ice- cold solution of LI-2f (2 g, 6.7 mmol) in DCM (20 mL) was added TFA (5 mL) and stirred at room temperature for 1 h. The mixture was concentrated, the residue was triturated with ether and concentrated to remove traces of TFA and finally dried to afford LI-5.TFA, which was used as such in further reactions.
The above linker intermediate LI-5.TFA was also synthesized as described below: TEA (3.56 g, 35.2mmol) was added drop-wise to a solution of cysteamine hydrochloride (2g, 17.60mmol) and LI-3b (4.29g, 17.6mmol) in MeOH (25mL) at 0 0C and stirred at RT for 4 h. The mixture was cooled to 0 0C and a solution of (Boc)2O (7.68 g, 35.2mmol) in MeOH (10 mL) was added, followed by TEA (3.56 g, 35.2mmol), and stirred overnight at RT. The reaction mixture was filtered through celite and the filtrate concentrated. The residue was purified by column chromatography to afford 0.38 g (7.25%) of LI-2f, which was identical (TLC and 1H-NMR) to that obtained in Example 9. Removal of the Boc group from LI-2f to give LI-5.TFA was accomplished as described in Example 10. Example 11 Synthesis of methyl r(2-hvdroxyethyl)dithiolacetate (L3I2a): Methyl mercaptoacetate (10.32 g, 97.4 mmol) was added to a solution of SL-I (10.0 g, 64.93 mmol) in DCM (150 mL) at RT, followed by TEA (18 mL, 129 mmol) and the mixture was stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 2.7 g (22.9 %) of L3I2a were obtained. 1H-NMR (300 MHz, CDCI3): δ 2.95 (t, 2H, J = 2.5 Hz), 3.49 (s, 2H), 3.76 (s, 3H), 3.86 (q, 2H, J = 5.64). MS (m/z): 182 [M+H]+. Example 12
Synthesis of prodrug I-C1-PD10: This prodrug was synthesized as described in Scheme 11, Method B. Thus, TEA (0.73 mL, 10 mmol) was added to a suspension of cetirizine dihydrochloride (2.0 g, 4.68 mmol) in DCM (50 mL), followed by a solution of SL-I (0.72 g, 4.67 mmol), DCC (1.13 g, 5.47 mmol) and DMAP (0.112g, 1 mmol) and stirred at RT for 15 h. The mixture was concentrated and the residue, after usual aqueous work- up and chromatographic purification, gave 0.44 g (19%) of I-C1-PD10. 1H-NMR (300 MHz, CDCl3): δ 2.50 (bs, 4H), 2.80 (bs, 6H), 2.87 (t, 2H, J = 6.09 Hz), 2.94 (t, 2H, J = 7.32 Hz), 3.75 (m, 2H), 3.86 (t, 2H, J = 6.12 Hz), 4.13 (s, 2H), 4.24 (s, IH), 4.40 (t, 2H, J = 6.09 Hz) and 7.22-7.35 (m, 9H). MS (m/z): 527 [M+H]+. Example 13
Synthesis of prodrug I-C1-PD6: Step 1: To a suspension of aspirin (3 g, 16.65 mmol) in benzene (25 mL) and DMF (2 drops) at 0-5 0C was added oxalyl chloride (1.7 mL, 19.98 mmol) in benzene (5 mL). The reaction mixture was refluxed at 85 0C for 2 h, cooled to RTe and concentrated to give a yellow oil. Step 2: The yellow oil was dissolved in benzene (30 mL), silver cyanate (2.99 g, 19.98 mmol) was added and the mixture was refluxed for Ih in the dark. Step 3: The reaction mixture was cooled to RT, and a solution of SL-I (2.56 g, 16.65 mmol) in benzene (5 mL). The reaction mixture was stirred for Ih, filtered through celite, concentrated and purified by column chromatography to afford 2.24 g (54%) of I-Cl- PD6. 1H NMR (CDCl3, 300 MHz): δ 2.12 (s, 3H), 2.83-2.91 (m, 4H), 3.84 (t, J = 5.9 Hz, 2H), 4.27 (t, J = 5.16 Hz, 2H), 6.20 (br s, IH), 7.06 (d, J = 8.21 Hz, IH), 7.19 (t, J = 7.55 Hz, IH)5 7.59 (t, J = 7.24 Hz, IH), 7.97 (d, J = 6.82 Hz, IH). MS: m/z 360.06 [M+H]+, 377.05 [M+NH4f, 382.01 [M+Naf, 357.96 [M-H]". Example 14 Synthesis of prodrug I-Cl-PDll:To a solution of SL-I (7g, 45.45 mmol) and valproic acid (7.85 g, 54.5 mmol) in DCM (80 mL) was added DCC (11.26 g, 54.5 mmol), followed by DMAP (6.65 g, 54.5 mmol), and the resulting suspension was stirred at RT for 18 h. After usual aqueous work-up and chromatographic purification, 2.82 g (22 %) of I-C1-PD11 were obtained as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 0.86-0.93 (m, 6H), 1.22-1.29 (m, 8H), 1.32-1.59 (m,4H), 2.37 (m,lH), 3.89 (t, 2H, J = 5.7 Hz), 4.35(t, 2H, J = 6.5 Hz). Example 15
Synthesis of prodrug I-C1-PD13: To a solution of valpromide (5 g, 34.9 mmol) in DCE (50 mL) was added oxalyl chloride (3.7 mL, 41.88 mmol) at 0 0C and refluxed for 16 h. The mixture was added to a solution of SL-I (10.76 g, 69.8 mmol) in DCE (80 mL) and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 5.01 g (44%) of I-C1-PD13 were obtained as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 0.89 (t, 6H, J = 7.21 Hz), 1.23-1.66 (m, 9H), 2.90 (t, 2H, 5.82 Hz), 2.97 (t, 2H, J= 6.46Hz), 3.90 (t, 2H, J= 5.82Hz), 4.44 (t, 2H, J= 6.48 Hz), 7. 61 (br s, IH) Example 16 Synthesis of prodrug I-C1-PD14: To a cold solution of diphosgene (0.9 mL, 7.14 mmol) in DCM (5 mL) was added a solution of I-C1-PD11 (1 g, 3.57 mmol) and DIPEA (1.9 mL, 10.71 mmol) in DCM (5 mL). The reaction mixture was stirred at RT for 30 min. DCM and excess phosgene were removed under vacuum and the resulting solid was dissolved in DCM (5 mL). To it was added a suspension of methanesulfonamide (0.41 g, 4.284 mmol) and DIPEA (1.9 mL, 10.71 mmol) in DCM (5 mL) at 0-5 0C and the mixture was stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 1.1 g (77%) of I-C1-PD14 were obtained as a white solid. 1H NMR (CDCl3, 300 MHz): δ 0.89 (t, 6H, J = 7.22 Hz), 1.27-1.63 (m, 8H), 2.34-2.43 (m, IH), 2.90 (t, 2H, J = 7.0 Hz), 2.96 (t, 2H, J = 6.13 Hz), 3.30 (s, 3H), 4.36 (t, 2H, J = 6.98 Hz), 4.45 (t, 2H, J = 6.14 Hz). MS: (ES+) m/z 402 [M+H]+, 419 [M+NH4]+, 424 [M+Na]+, 440 [M+K]+; (ES-) 401 [M-H]-. Example 17 Synthesis of prodrug I-A1-PD1:
This prodrug was synthesized as shown in Scheme 14, Method B. Thus, to a solution of amlodipine (18.75 g, 45.86 mmol) in DCM (100 mL) at 0 0C was added triphosgene (4.62 g, 15.59 mmol) followed by TEA (7.71 g, 76.35 mmol) in DCM (10 mL) and stirred at RT for 3 h. To this was added a solution of LI-Ia (9.0 g, 48.86 mmol) and TEA (4.63 g, 45.86 mmol) in DCM (10 mL) at 0 0C and stirred at RT for 3 d. The mixture was concentrated and the residue purified by column chromatography to yield 23 g (79.5%) of I-Al-PDl. 1H-NMR (300 MHz, CDCl3): δ 1.16 (t, 3H, J = 7.5 Hz), 2.05 (s, 3H), 2.34 (s, 3H), 2.86-2.94 (m, 4H), 3.43-3.45 (m, 2H), 3.59-3.62 (m, 5H), 4.0-4.35 (m, 4H), 4.30-4.35 (m, 4H), 4.69 (q, 2H, J = 15 Hz), 5.20 (bs, IH), 5.38 (s, IH), 7.01-7.34 (m, 4H). MS (m/z): 631 [M+H]+, 653 [M+Na]+. Example 18 Synthesis of prodrug I-A1-PD2: To a solution of I-Al-PDl (23.0 g, 36.45 mmol) in MeOH (250 mL) at 0 0C was added a solution of K2CO3 (7.54 g, 54.67 mmol) in water (55 mL) and stined for 10 min. The mixture was concentrated and purified by column chromatography to afford 18 g (83.8%) of the intermediate I-A1-PD2. 1H-NMR (300 MHz, CDCl3): δ 1.16 (t, 3H, J = 6 Hz), 2.35 (s, 3H), 2.84-2.88 (t, 2H, J = 6 Hz), 2.90- 2.94 (t, 2H, J = 6 Hz), 3.44 (bs, 2H), 3.59-3.61 (bs, 5H), 3.84-3.91 (m, 2H), 4.0-4.03 (q, 2H, J = 3.11 Hz), 4.33 (bs, 2H), 4.69 (q, 2H, J = 15 Hz), 5.28 (bs, IH), 5.37 (s, IH), 7.12- 7.36 (m, 4H). MS (ES+): m/z 589 [M+], 611 [M+Na]+. Example 19
Synthesis of prodrug I-Al-PD3:To a suspension of lamotrigine (13.09 g, 51.02 mmol) in toluene (100 mL) at 110 0C was added a solution of LI-lxy (synthesized from LI-Ia and CDI, as described in Scheme 10) (16.27 g, 56.12 mmol) in THF (50 mL) and stirred at 110 0C overnight. The reaction mixture was purified by column chromatography to give 6.0 g (24%) of I-A1-PD3 as a white solid. 1H NMR (CD3OD, 300 MHz) δ 2.04, (s, 3H), 2.96-3.02 (m, 4H), 4.30-4.35 (m, 2H), 4.45 (t, 2H), 7.38-7.45 (m, 2H), 7.67-7.69 (m, IH). MS: (ES+) m/z 477.9 (M+H)+, 499.9 (M +Na)+. Example 20
Synthesis of prodrug I-A1-PD4 :To a solution of I-A1-PD3 (2 g, 4.18 mmol) in MeOH (15 mL) and THF (5mL) at 0 0C was added a solution Of K2CO3 (0.886 g, 6.276 mmol) in water (5 mL) and stirred at 0 0C for 3 h. After usual aqueous work-up and chromatographic purification, 1.1 g (60%) of I-A1-PD4 were obtained as a white solid. 1H NMR (DMSO d6, 300 MHz): δ 2.75-2.82 (m, 2H), 2.96-3.0 (m, 2H), 3.0 (s, IH), 3.6 (t, 2H, J = 6.3Hz), 4.30 (t, 2H, J = 6.6 Hz) 7.38-7.49 (m, 2H), 7.72-7.75 (m, IH). MS: (ES +) m/z 436 (M+H)+, 457 (M +Na)+. Example 21 Syntheis of prodrug I-A1-PD5: To a solution of diphosgene (0.99 mL, 8.24 mmol) in DCM (3 mL) at 0 0C was added a solution of L3I2a (0.5 g, 2.74 mmol) and Hϋnig's base (2.39 mL, 13.73 mmol) in DCM (3 mL). The mixture was stirred at 0 0C for 30 min and concentrated to yield the intermediate L3I3a as a light-yellow semi-solid. A solution of a mixture of gabapentin ethyl ester hydrochloride (0.77g, 3.29 mmol) and Hϋnig's base (1.7 mL, 9.79 mmol) in DCM (6 mL) was added to the intermediate L3I3a at RT and stirred for 15 h. After usual aqueous work-up and chromatographic purification, 0.34 g (30 %) of I-A1-PD5 were obtained as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 1.26 (t, 3H, J = 6 Hz), 1.22-1.51 (m, 10 H), 2.26 (s, 2H), 2.96 (t, 2H, J= 6 Hz), 3.18 (d, 2H, J= 6 Hz), 3.49 (s, 2H), 3.82 (s, 3H), 4.09 (q, 2H, J = 6 Hz), 4.29 (t, 2H, J = 6 Hz), 5.39 (bs IH). MS: (ES+) m/z 408 (M+H)+, 430 (M+Na)+ ; (ESO m/z 406 (M-H)". Example 22 Synthesis of prodrug I-A1-PD6: To a solution of I-A1-PD8 (1.0 g, 2.63 mmol) in DCM (3 mL) at RT was added CDI (0.46 g, 2.89 mmol) and stirred for 15 h. A suspension of serine methyl ester hydrochloride (0.61 g, 3.95 mmol) in DCM (4 mL) and TEA (1.1 mL, 7.90 mmol) was added and stirring continued for 15 h. After usual aqueous work-up and chromatographic purification, 0.706 g (51%) of I-A1-PD6 were obtained as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 1.25 (t, 3H, J = 7.1 Hz), 1.35-1.51 (m, 10H), 2.28(s, 2H), 2.91-2.98 (m, 4H), 3.16 (d, 2H, J = 9Hz), 3.78 (s, 3H), 3.94-4.38 (m, 9H), 5.5 (bs, IH), 6.0 (bs, IH). MS: (ES)+: m/z 525 (M+H)+, 547 (M+Na)+. (ES)": m/z 523 (M-H)+. Example 23 Synthesis of prodrug I-A1-PD7: To a solutuion of I-A1-PD8 (86 mg, 0.22 mmol) in DCM (9 mL) at RT was added CDI (40 mg, 0.24 mmol) and stirred for 15 h, after which a solution of dimethyl glutamate (80 mg, 0.45 mmol) and TEA (0.06 mL, 0.45 mmol) was added and stirred for 2 d. After usual aqueous work-up and chromatographic purification, 97 mg (74 %) of I-A1-PD7 were obtained as a colourless oil. 1H NMR (CDCl3, 300 MHz): δ 1.25 (t, 3H, J=7.13 Hz), 1.36-2.5 (m, 16H), 2.93(t, 4H, J = 6.46 Hz), 3.19 (d, 2H, J = 6.67), 3.67 (s, 3H), 3.74 (s, 3H), 4.12 (q, 2H, J = 7.13 Hz), 4.25-4.44 (m, 5H), 5.4 (bs, IH), 5.65 (bs, IH). MS: (ES+) m/z 581 (M+H)+, 603 (M+Na)+; (ES") m/z 571 (M-H)". Example 24 Synthesis of prodrug I-A1-PD9: To a suspension of gabapentin (10 g, 58.4 mmol) in THF (100 mL) at 0 0C was added IN NaOH (70 mL), followed by (Boc)2O. The mixture was stirred at RT for 15 h. After washing with diethyl ether (100 mL x 2), the aqueous layer was acidified with solid KHSO4 and extracted with EtOAc (100 mL x 2). Organic extracts were washed with brine (100 mL), dried over Na2SO4 and concentrated to afford 10.41g (68 %) of boc-protected gabapentin as a white solid. A mixture of boc-protected gabapentin (5.0 g, 18.45 mmol) and CDI (3.59 g,
22.14 mmol) in DCM (75 mL) was stirred for 15 h. The mixture was concentrated and dissolved in acetonitrile (50 mL), followed by the addition of 30 % aqueous solution of ammonia (50 mL) and stirred for 1.5 h at RT. After usual aqueous work-up, 4.5 g (90 %) of boc-protected gabapentin-amide were obtained as a white solid.
To a solution of boc-protected gabapentin-amide (2.59 g, 9.61 mmol) in DCM (12 mL) at 0 0C was added solution of TFA (4mL) in DCM (4 mL) and stirred for 2.5 h at RT. The mixture was concentrated and dissolved in DCM (20 mL). This was treated successively with Hunig's base (6.7 mL, 38.46 mmol) and LI-Ia (1.45g, 7.39 mmol), and stirred at RT for 3 h. After usual aqueous work-up and chromatographic purification, 1.19 g (41 %) of I-A1-PD9 were obtained as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 1.28-1.48 (m, 10H), 2.06 (s, 3H), 2.15 (s, 2H), 2.91 (t, 4H, J = 6.0 Hz), 3.23 (d, 2H, J = 6.0 Hz), 4.28-4.38(m, 4H), 5.7(bs, IH). MS: (ES)+ m/z 393(M+H)+; (ES)" m/z 392(M- H)-.
Example 25 Synthesis of prodrug I-A1-PD10 : A mixture of I-A1-PD8 (1.Og, 2.63 mmol) and CDI (0.469 g, 2.89 mmol) in DMF (3 mL) was stirred for 12 h, after which N,N'dimethylethylenediamine (0.56mL, 5.26 mmol) and DMAP (0.32 g, 2.63 mmol) was added. The mixture was stirred for 4 h. After usual aqueous work-up and chromatographic purification, 0.763 g (59 %) of were obtained as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 1.25 (t, 3H, J = 6.0 Hz), 1.28-1.53 (m, 10H), 2.24 (s, 6H), 2.29 (s, 2H), 2.42 (t, 2H, J = 6.0 Hz), 2.92 (t, 4H, J = 6.0 Hz), 3.20(d, 2H, J = 6.0 Hz), 3.26 (q, 4H, J = 6.0 Hz), 4.13 (q, 2H, J = 7.0 Hz), 4.31 (t, 4H, J = 6.0Hz), 7.26 (bs, IH). MS: (ES)+ m/z 494 (M+H)+, 516 (M+Na)+; (ES)- m/z 492 (M-H)". Example 26 Synthesis of prodrug I-A1-PD11: A mixture of LI-Ia (2.0 g, 10.20 mmol) and CDI (1.98 g, 12.24 mmol) in DCM (12 mL) was stirred for 2 h and concentrated. The residue was dissolved in acetonitrile, and a suspension of gabapentin (2.62 g, 15.30 mmol) in saturated NaHCO3 (15 mL) was added. The mixture was stirred at RT for 15 h. Acetonitrile was removed by distillation and the basic aqueous portion was washed with diethyl ether (100 mL x 2). The aqueous layer was acidified using 2N HCl and extracted in EtOAc (60 mL x 3). The organic layer was concentrated and the residue was purified by chromatographic purification, 1.76 g (43 %) of I-A1-PD11 were obtained as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 1.27-1.68 (m, 10H), 2.07 (s, 3H), 2.31 (s, 2H), 2.92 (t, 4H, J = 6.0 Hz), 3.22 (d, 2H, J = 9.0 Hz), 4.31-4.35 (m, 4H), 5.43 (bs, IH). MS: (ES)" m/z 392 (M-H)". Example 27 Synthesis of prodrug I-A1-PD13: This prodrug was synthesized as shown in Scheme 12, Method B. Thus, to a solution of diphosgene (7.02 mL, 58.18 mmol) in DCM (20 mL) at 0 0C was added a solution of LI-Ia (5.71 g, 29.09 mmol) and Hϋnig's base (25.3 mL, 145.45 mmol) in DCM (30 mL) and stirred at RT for 40 min. The mixture was concentrated and a mixture of gabapentin ethyl ester hydrochloride (7.546 g, 32 mmol) and Hϋnig's base (11.15 mL, 64 mmol) in DCM (50 mL) was added and stirred overnight. Reaction mixture was concentrated and, after usual aqueous work-up and column chromatography, 8.42 g (67 %) of I-A1-PD13 were obtained. 1H NMR (CDCl3, 300 MHz): δ 1.22 (t, 3H, J = 7.3 Hz), 1.27-1.68 (m, 10H), 2.06 (s, 3H), 2.27 (s, 2H), 2.91 (t, 4H, J = 6.6 Hz), 3.19 (d, 2H, J = 6.7 Hz), 4.08 - 4.15 (q, 2H, J = 7.1 Hz), 4.27-4.34 (q, 4H, J = 6.4 Hz), 5.4 (bs, IH). MS: m/z 422 [M+H]+, 444 [M+Naf. Example 28
Synthesis of prodrug I-A1-PD8: To an ice-cold solution of I-A1-PD13 (8.0 g, 18.98 mmol) in MeOH (30 mL) was added a solution Of K2CO3 (5.24 g, 37.96 mmol) in water (38 mL). After 15 min, the mixture was concentrated. After usual aqueous work-up, 5.0 g (69 %) of I-A1-PD8 were obtained. 1H NMR (CDCl3, 300 MHz): δ 1.25 (t, 3H, J = 7.11 Hz), 1.30-1.71 (m, 10H), 2.87-2.94 (m, 4H), 2.27 (s, 2H), 3.18 (d, 2H, J = 6.6 Hz), 3.87 (t, 2H, J = 5.7 Hz), 4.09-4.16 (q, 2H, J = 7.12 Hz), 4.31 (t, 2H, J = 6.51 Hz), 5.44 (bs, IH). MS: m/z 380 [M+H]+, 402 [M+Na]+. Example 29 Synthesis of prodrug I-A1-PD12: To a solution of diphosgene (1.91 mL, 15.81 mmol) in DCM (20 mL) at 0 0C was added a solution of I-A1-PD8 (4 g, 10.54 mmol) and Hϋnig's base (5.5 mL, 31.62 mmol) in DCM (30 mL). The mixture was stirred at RT for 40 min, cooled to 0-5 0C, and dry ammonia gas was passed through it for 30 min. Reaction mixture was concentrated and, after usual aqueous work-up, 5.3 g (91 %) of I-A1-PD12 were obtained. 1H NMR (CDCl3, 300 MHz): δ 1.23 (t, 3H, J = 7.1 Hz), 1.27-1.79 (m, 10H), 2.28 (s, 2H), 2.91-3.03 (m, 4H), 3.19 (d, 2H, J = 6.7 Hz), 4.12 (q, 2H, J = 7.1 Hz), 4.31 (t, 4H, J = 6.4 Hz), 5.4 (t, IH, J = 6.0 Hz). MS: m/z 423 [M+H]+, 446 [M+Na]+. Example 30
Synthesis of prodrug I-A1-PD14: Ethyl chloroformate (0.86 g, 7.9 mmol) was added to a solution of S-carbamoylmethyl-S-methylhexanoic acid (M. S. Hoekstra et al., Org. Proc. Res. Dev. 1997, 1, 26-38) (1.0 g, 5.3 mmol) in THF (6 niL) at -10 0C, followed by TEA (2.4 mL, 17.0 mmol) and the mixture was stirred at -10 0C for 30 min. A solution of NaN3 (1.73 g, 26.6 mmol) in water (10 mL) was added and stirred for 2h at -10 0C. The reaction mixture was brought to RT and extracted with EtOAc (3 x 25 mL), washed with water (2 x 25 mL), dried over Na2SO4 and concentrated. Toluene (20 mL) was added to the residue and refluxed for 6 h. After cooling to RT, a solution of and SL-I (825 mg, 5.3 mmol) in DCM (10 mL) was added and stirred at RT for 14 h. After usual aqueous work-up and chromatographic purification, 318 mg (17 %) of I-A1-PD14 were obtained as a colorless oil. 1H NMR (300 MHz, CDCl3): δ 0.89-0.95 (m, 6H), 1.25-1.29 (m, 2H), 1.62-1.71 (m, IH), 2.04-2.1 (m, 1 H), 2.38 (d, J = 5.2 Hz, 2H), 2.87-2.95 (m, 4H), 3.05- 3.36 (m, 2H), 3.88 (t, J = 5.7 Hz, 2H), 4.34 (t, J = 6.2 Hz, 2H), 5.06 (br s, IH). MS: m/z 338 [M]+. Example 31 Synthesis of prodrug I-Al-PD15Ba: To a solution of I-A1-PD4 (0.350 g, 0.802 mmol) in DMF (3 mL) at RT was added CDI (0.195g, 1.204 mmol) and stirred at RT for 3 h. This mixture was added to a suspension of methanesulphonamide (0.304 g, 3.2 mmol) in DMF (4 mL) and NaH (0.153 g, 3.2 mmol) at 0 0C and stirred at RT for 4 h. The reaction was quenched with ice and, after usual aqueous work-up and chromatographic purification, 0.12 g (26%) of I-Al-PD15Ba were obtained as a white solid. 1H NMR (CDCl3 + CD3OD, 300MHz): δ 2.83- 2.90 (m, 4H), 3.10 (s, 3H), 4.26-4.36 (m, 4H), 7.19- 7.28 (m, 2H), 7.48-7.51 (m, IH). MS: (ES "*) m/e 556.96 (M+H)+, 578.92 (M +Na)+. Example 32
Synthesis of prodrug I-A1-PD16: CDI (4 g, 24.7 mmol) was added to a solution of LI- 2c (4 g, 15.8 mmol) in THF (30 mL) and stirred at RT for 2 h. Then, a solution of gabapentin (4 g, 23.4 mmol) in 20 % NaHCO3 solution (10 mL) was added and stirred overnight at RT. The reaction mixture was neutralized with 0.5N HCl (pH ~ 4), extracted with EtOAc (4 x 40 mL), dried over Na2SO4, concentrated and purified by column chromatography to afford 4.7 g (66 %) of I-S12-PD2 as a colorless oil. 1H NMR (300 MHz, CDCl3): δ 1.45-1.49 (br s, 19H), 2.35 (s, 2H), 2.80-2.97 (m, 4H), 3.24 (d, J = 5.7 Hz, 2H), 3.46 (m, 2H) 4.33 (t, J = 5.7 Hz, 2H), 5.0 (br s, IH), 5.71 (br s, IH). MS: (m/z) [ES]" 449.1 [M-H]+; [ES]+ 451.2 [M+H]+.
EtOAc saturated with HCl gas (5mL) was added to I-S12-PD2 (0.55 g, 1.22 mmol) and stirred at RT for 1O h. Solvent was removed under reduced pressure and purified by preparative HPLC to give 425 mg (90 %) of I-A1-PD16 as a colorless liquid. 1H NMR (300 MHz, CD3OD): δ 1.52 (br s, 10H), 2.4 (s, 2H), 2.98-3.09 (m, 4H), 3.27- 3.34 (m, 2H), 3.61 (s, 2H), 4.5 (t, J = 6.0 Hz, 2H). MS: [ES]+ m/z 351.0 [M+H]+. Example 33
Synthesis of prodrug I-A2-PD1: To a solution of levetiracetam (1.0 g, 5.87 mmol) in DCE (20 mL) and DCM (4 mL) was added oxalyl chloride (0.61 mL, 7.05 mmol), and heated at 70 0C for 8h. Reaction mixture was cooled and added to a solution of SL-I (1.81 g, 11.75 mmol) in DCM (15 mL) and stirred at RT overnight. After chromatographic purification, 1.13 g (41%) of I-A2-PD1 were obtained. 1H NMR (CDCl3, 300 MHz): δ (ppm): 0.87 (t, J = 7.3 Hz, 3H), 1.84-2.04 (m, 4H,), 2.41 (t, J = 6.9 Hz, 2H,), 2.69 (bs, IH), 2.87-2.95 (m, 4H), 3.02-3.11 (m, IH), 3.65-3.75 (m, IH), 3.85- 3.95 (m, 2H), 4.06-4.12 (m, IH), 4.34-4.41 (m, 2H), 8.69 (bs, IH). MS: (ES+): m/z 351.0 [M+H]+; 372.9 [M+Na]+. Example 34
Synthesis of prodrug I-A3-PD1: To a solution of I-S13-PD1 (which was synthesized as described in Example 37, Step 2) (215 mg, 0.292 mmol) and triisopropylsilane (60 μL) in 0.75 mL of DCM was added 20 % TFA in DCM (0.5 mL) and stirred at RT for 90 min. The mixture was concentrated and the residue purified by column chromatography to give 65 mg (46%) of I-A3-PD1. 1H-NMR (300 MHz, CDCl3): δ 2.51 (s, 3H), 2.85-2.92 (m, 4H), 3.87 (t, 2H, J = 4.5 Hz), 4.37 (t, 2H, J = 6.0 Hz), 7.25-7.43 (m, 7H), 8.01 (d, 2H, J = 3.0 Hz). MS (m/z): 493 [M-H]", 517 [M+Naf. Example 35 Synthesis of prodrugs I-A3-PD3a and I-A3-PD3b: Step 1: DSC (210 mg, 0.824 mmol) and TEA (0.230 mL, 1.64 mmol) were added to a solution of methyl [(2- hydroxy ethyl)dithio] acetate (lOOmg, 0.549 mmol) in acetonitrile (1 mL) at O 0C and stirred at RT for 3h. The mixture was concentrated and the residue dissolved DCM. Usual aqueous work-up and chromatographic purification gave the crude intermediate. Step 2: TEA (24mg, 0.236 mmol) and DMAP (13 mg) were added to a mixture of valdecoxib (62mg, 0.195 mmol) and the product obtained from step 1 above in THF (1 mL) and stirred at RT for 3 d. The mixture was concentrated and the residue dissolved in EtOAc. After usual aqueous work-up and chromatographic purification, 53 mg (52%) of I-A3-PD3a obtained. 1H- NMR (300 MHz, CDCl3): δ 2.51 (s, 3H), 2.97 (t, 2H, J = 6.0 Hz), 3.48 (s, 2H), 3.76 (s, 3H), 4.37 (t, 2H, J = 6.0 Hz), 7.33-7.40 (m, 7H), 8.03-8.12 (m, 2H). MS (m/z): 521 [M-H]".
Step 3: The above material was converted to the corresponding mono-, and/or di-sodium salt forms I-A3-PD3b by using standard methods. Thus, to a cold solution of the above compound (150 mg, 0.287 mmol) in THF (1 mL) was added IM LiOH solution (28 mg in ImL water) and stirred overnight at RT. The mixture was concentrated, the residue diluted with water, acidified with IN HCl (~3 ml, pH ~3) and extracted with EtOAc. After usual aqueous work-up and chromatographic purification, 20 mg (13%) of product were obtained. 1H- NMR (300 MHz, CDCl3): δ 2.49 (s, 3H), 2.70-2.89 (m, 4H), 4.23- 4.33 (m, 2H), 7.28-7.38 (m, 7H), 8.01-8.03 (m, 2H). Example 36 Synthesis of prodrug I-A3-PD4: This prodrug was synthesized as described in Scheme 13, Method B.
Step 1 : Synthesis of intermediate LI-8:
CDI (1.65 g, 10.19 mmol) was added to a solution of LI-Ia (2.0 g, 10.19 mmol) in DMF (10 mL) and stirred at RT for 3 h. N,N-Dimethylethylenediamine (1.2 mL, 11.12 mmol) was added and stirred for 2 h. The mixture was concentrated and the residue taken up in EtOAc. After usual aqueous work-up and chromatographic purification, 1.3 g (41%) LI-8 were obtained. 1H-NMR (300 MHz, CDCl3): δ 2.07 (s, 3H), 2.31 (bs, 6H), 2.51 (t, 2H, J = 6.0 Hz), 2.91 (t, 4H, J = 6.0 Hz), 3.31 (q, 2H, J = 6.0 Hz), 4.28-4.34 (m, 4H), 5.52 (bs, IH). MS (m/z): 333 [M+Na]+. Step 2: Synthesis of intermediate LI-9: To a solution of LI-8 (1.3 g, 4.18 mmol) in MeOH (7 mL) was added a 1.25M solution Of K2CO3 (5 mL) and stirred at RT for Ih. The mixture was concentrated and the residue was taken up in DCM. After usual aqueous work-up, 1.02 g (91%) of product were obtained. 1H-NMR (300 MHz, CDCl3): δ 2.29 (s, 6H), 2.54 (t, 2H, J = 6.0 Hz), 2.86-2.99 (m, 4H), 3.33 (q, 2H, J = 5.0 Hz), 3.86 (t, 2H, J = 6.0 Hz), 4.31 (t, 2H, J = 6.0 Hz), 5.71 (bs, IH). MS (m/z): 269 [M+H]+. This product was used as such in the next step.
Step 3: Synthesis of intermediate LI-10: A solution of LI-9 (1.02 g, 3.80 mmol) in acetonitrile (10 niL) was added to a cold solution of DSC (1.46 g, 5.70 mmol) in acetonitrile (50 mL) followed by TEA (1.58 ml, 11.40 mmol), and stirred overnight at RT. The mixture was concentrated and the residue was taken up in DCM. After usual aqueous work-up, 1.33 g (85%) of LI-10 were obtained.
Step 4: Synthesis of I-A3-PD4: TEA (0.194 mL, 1.39 mmol) and DMAP (73 mg, 0.6 mmol) were added to a solution of LI-10 (1.33 g, 3.24 mmol) and valdecoxib (364 mg, 1.16 mmol) in THF (6 mL) and stirred at RT for 5 d. The mixture was concentrated and the residue was taken up in DCM. After usual aqueous work-up and chromatographic purification, 177 mg (12 %) of LI-10 were obtained. 1H-NMR (300 MHz, CDCl3): δ 2.46 (s, 3H), 2.85-2.95 (m, 10H), 3.28 (t, 2H, J = 6.0 Hz), 3.65 (q, 2H, J = 3.0 Hz), 4.22- • 4.28 (m, 4H), 7.22-7.41 (m, 7H), 7.94 (d, 2H J = 9.0 Hz). MS (m/z): 609 [M+H]+. This product was converted to water-soluble hydrochloride salt form using standard methods. Example 37 Synthesis of prodrug I-A3-PD5: This prodrug was synthesized as shown in Scheme 13, Method B. Step 1 : Synthesis of prodrug intermediate LI-lxy:
Figure imgf000160_0001
A solution of LI-Ic (1.0 g, 2.52 mmol) in acetonitrile (10 mL) was added to a solution of DSC (0.96 g, 3.78 mmol) in acetonitrile (20 mL) and stirred for 10 min. After cooling to 0 0C, TEA (1 ml, 7.57 mmol) was added and stirred at RT for 3.5 h. The solution was concentrated and the residue was taken up in DCM. After usual aqueous work-up, the crude product obtained was used as such in the next step.
Step 2: Synthesis of prodrug intermediate I-S13-PD1: A mixture of valdecoxib (280 mg, 0.892 mmol), DMAP (56 mg, 0.5 mmol) and TEA (150 μL, 1.06 mmol) in THF (5 mL) was stirred at RT for 4.5 d. The mixture was concentrated and the residue dissolved in EtOAc. After usual aqueous work-up and chromatographic purification, 354 mg (54 %) of I-S13-PD1 were obtained. 1H-NMR (300 MHz, CDCl3): δ 2.47 (s, 3H), 3.32-3.41 (m, 4H), 4.28 (t, 2H, J = 6.0 Hz), 4.47 (t, 2H, J = 6.0 Hz), 7.20-7.61 (m, 22H), 8.00 (d, 2H, J = 9.0 Hz). MS (m/z): 736 [M-H]".
Step 3: Synthesis of intermediate I-A3-PD1: To a solution of I-S13-PD1 (215 mg, 0.292 mmol) and triisopropylsilane (60 μL) in 0.75 ml of DCM was added 20%TFA in DCM (0.5 mL) and stirred at RT for 90 min. The mixture was concentrated and the residue purified by column chromatography to give 65 mg (46%) of I-A3-PD1. 1H-NMR (300 MHz, CDCl3): δ 2.51 (s, 3H), 2.85-2.92 (m, 4H), 3.87 (t, 2H, J = 4.5 Hz), 4.37 (t, 2H, J = 4.5 Hz), 7.25-7.43 (m, 7H), 8.01 (d, 2H, J = 3.0 Hz). MS (m/z): 493 [M-H]", 517
Step 4: Synthesis of I-A3-PD5-Me-ester: CDI (40mg, 0.243 mmol) was added to a solution of I-A3-PD1 (lOOmg, 0.202 mmol) in DMF (0.5 mL) and stirred at RT for 2.5 h. To this were added a solution of dimethyl glutamate (53 mg, 0.303 mmol) in DMF (0.3 mL) and DMAP (37 mg, 0.303 mmol) and stirred overnight at RT. The mixture was dissolved in EtOAc and, after usual aqueous work-up and chromatographic purification, 110 mg (78%) of I-A3-PD5-Me-ester were obtained 1H- NMR (300 MHz, CDCl3): δ 1.71-1.91 (m, 2H), 2.38-2.42 (m, 2H), 2.44 (s, 3H), 2.84-2.95 (m, 4H), 3.66 (s, 3H), 3.67 (s, 3H), 4.31^1.34 (m, 4H), 4.43-4.52 (m, IH), 7.31-7.41 (m, 7H), 8.02 (d, 2H, J = 9.0 Hz). MS (m/z): 694 [M-H]-. Step 5: Synthesis of prodrug I-A3-PD5: IN Lithium hydroxide (1.2 mL, 1.2 mmol) was added to a solution of I-A3-PD5-Me-ester (100 mg, 0.144 mmol) in THF (0.4 mL) at 0 0C and the mixture allowed to attain ambient temperature. After 30 min, the mixture was concentrated and the residue diluted with water. Acidification with IN HCl, followed by extraction with EtOAc, usual aqueous work-up and chromatographic purification gave 26 mg (26%) of I-A3-PD5. 1H-NMR (300 MHz, CD3OD): δ 1.82-1.97 (m, IH), 2.05-2.13 (m, IH), 2.30-2.40 (m, 2H), 2.48 (s, 3H), 2.84 - 2.94 (m, 4H), 4.06 - 4.08 (m, IH), 4.15 - 4.22 (m, 4H), 7.30 (d, 2H, J = 9 Hz), 7.35 - 7.41 (m, 5H), 7.92 (d, 2H, J = 9.0 Hz). MS (nVz): 666 [M-H]". Example 38
Synthesis of prodrug I-H1-PD1: This prodrug was synthesized as shown in Scheme 14, Method B. Step 1: A solution of metronidazole (5.0 g, 29.22 mmol) and CDI (5.21 g, 32.2 mmol) in
DCM (100 mL) was stirred overnight at RT. After usual aqueous work-up, 7.32 g of the imidazolide of metronidazole were obtained, which was used as such in the next step.
Step 2: A solution of the imidazolide of metronidazole (7.32 g) in DMF (30 mL) was
■ added to a solution of SL-I (6.39 g, 41.43 mmol) in DMF (10 mL) and stirred at 60 0C for 2.5 h. The mixture was concentrated and the residue was taken up in DCM. After usual aqueous work-up and chromatographic purification, 6.32 g (65%) of I-H1-PD1 were obtained. 1H-NMR (300 MHz, CDCl3): δ 2.15 (bs, IH), 2.52 (s, 3H), 2.83-2.92 (m, 4H), 3.84-3.92 (m, 2H), 4.34 (t, 2H, J = 6.0 Hz), 4.51 (t, 2H, J = 3.0 Hz), 4.53-4.62 (m, 2H), 7.96 (s, IH). Example 39
Synthesis of I-H1-PD14: This prodrug was synthesized as described in Scheme 14, Method C. Thus, TEA (0.915 mL, 6.56 mmol) and DMAP (cat.) were added to a solution of LI-2C.TFA (541 mg, 3.94 mmol) and the imidazolide of metronidazole (synthesis described in Example 114) (870 mg, 3.28 mmol) in DMF (2 mL) and the mixture was heated at 60 0C for 3.5 h. The mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, gave 546 mg (48%) of I- H1-PD14. 1H-NMR (300 MHz, CDCl3): δ 2.48 (s, 3H)12.76-2.96 (m, 4H), 3.46 (q, 2H, J = 6.0 Hz), 3.87 (t, 2H, J = 6.0 Hz), 4.41 (t, 2H, J = 6.0 Hz), 4.57 (t, 2H, J = 4.5 Hz), 7.90 (s, IH). MS (m/z): 351[M+H]+. Example 40 Synthesis of prodrug I-H1-PD2: This prodrug was synthesized as described in Scheme 14, Method C. Thus, CDI (180 mg, 1.1 mmol) was added to a solution of I-H1-PD14 (350 mg, 1.0 mmol) in DMF (2 mL) and stirred at RT for 4 h. NJSI- Dimethylethylenediamine (88 mg, 1.0 mmol) was added and stirred for 3 h. The mixture was concentrated and the residue purified by column chromatography to afford 175 mg (38%) of I-H1-PD2. 1H-NMR (300 MHz, CDCl3): δ 2.28 (s, 3H), 2.49 (s, 6H), 2.51-2.55 (m, 2H), 2.81 (t, 2H, J = 6.0 Hz), 2.89 (t, 2H, J = 6.0 Hz), 3.27-3.33 (m, 2H), 3.46 (q, 2H, J = 6.0 Hz), 4.29 (t, 2H, J = 6.0 Hz), 4.40 (t, 2H, J = 4.5 Hz), 4.57 (t, 2H, J = 4.5 Hz), 5.55 (bs, IH), 7.94 (s, IH). MS (m/z): 465[M+H]+. This product was converted to water- soluble hydrochloride salt form using a standard method. Example 41
Synthesis of prodrug I-H1-PD5: This prodrug was synthesized as described in Scheme 14, Method A. ■ Step 1: Synthesis of Intermediate I-S14-PD1: A solution of the imidazolide of LI-Ic (1.6 g, 2.98 mmol) in acetonitrile (10 mL) was added to a solution of zudovudine (1.0 g, 3.74 mmol) in acetonitrile (20 mL) at RT, followed by DMAP (0.914 g, 7.48 mmol) and stirred for 24 h. The mixture was concentrated and the residue, after usual aqueous work¬ up and chromatographic purification, gave 1.62 g (79%) of intermediate I-S14-PD1. 1H- NMR (300 MHz, CDCl3): δ 1.95 (s, 3H), 2.35-2.45 (m, 2H), 2.78 (t, 2H, J= 6.6 Hz), 2.87 (t, 2H, J= 6.33 Hz), 3.38 (t, 2H, J= 6.33 Hz), 4.05 (m, IH), 4.25 (m, IH), 4.35 - 4.41 (m, 4H), 6.20 (t, IH, J= 6.16), 7.21- 7.33 (m, 9H), 7.42-7.48 (m, 6H) and 8.49 (s, IH). MS (m/z): 712 [M+ Na]+.
Step 2: Synthesis of I-H1-PD5: To a solution of I-S14-PD1 in DCM (15 mL) were added triisopropylsilane (0.446 ml, 2.17 mmol), followed by 10% TFA in DCM (15 mL) and stirred at RT for 30 min. The mixture was concentrated and purified by column chromatography to afford 0.68 g (70%) of prodrug I-H1-PD5. 1H-NMR (300 MHz, CDCl3): δ 1.93 (s, 3H), 2.30 (bs, IH), 2.41-2.48 (m, 2H), 2.88 (t, 2H, J= 6.1 Hz), 2.96 (t, 2H, J= 6.6 Hz), 3.88 (t, 2H, J= 5.8 Hz), 4.05 (m, IH), 4.29 (m, IH), 4.30-4.48 (m, 4H), 6.18 (t, IH, J= 6.3 Hz), 7.34 (s, IH) and 9.11 (s, IH). MS (m/z): 448 [M+H]+, 470 [M+Na]+. Example 42
Synthesis of prodrug I-S22-PD1: This prodrug was synthesized in two steps as shown in Scheme 22.
Step 1 : To a solution of diphosgene (0.35 mL, 2.93 mmol) in DCM (3mL) was added a solution of LI-Id (0.404 mg, 1.75 mmol), Hunig's base (0.765 mL, 4.39 mmol) and the resulting mixture was stirred at RT for 45 min. The mixture was concentrated, the residue dissolved in DCM (5 mL), cooled in an ice-bath and treated with a solution of paclitaxel (500 mg, 0.585 mmol), Hunig's base (0.765 mL, 4.39 mmol) and DMAP (cat.) in DCM (5 mL) over 5 min and the resulting mixture was stirred at RT for 2 h. The mixture was purified by column chromatography to give 519 mg (78%) of the protected intermediate
S22-I2 as an off-white solid. 1U NMR (500 MHz, CDCl3): δ 1.14 (s, 3H), 1.28 (s, 3H),
1.68 (s, 3H), 2.04 (s, 3H), 2.23 (s, 3H), 2.37 - 2.45 (m, 2H), 2.46 (s, 3H), 2.50 - 2.52 (m,
2H), 2.90 - 2.95 (m, 4H), 3.82 (d, IH, J = 7.0 Hz), 4.05 (s, 2H), 4.21 (d, IH, J = 8.5 Hz), 4.32 (d, IH, J = 8.0 Hz), 4.40 - 4.42 (m, 5H), 4.97 (d, IH, J = 9.5 Hz), 5.29 (s, IH), 5.43 (d, IH, J = 2.5 Hz), 5.69 (d, IH, J = 7.0 Hz), 6.00 (dd, IH, J = 9.5 Hz, 2.5 Hz), 6.26-6.29 (m, 2H), 7.02 (d, IH, J = 9.5 Hz), 7.38 - 7.61 (m, HH), 7.75 (d, 2H, J = 7.5 Hz), 8.15 (d, 2H, J = 7.5 Hz).
Step 2: To an ice-cold solution of S22-I2 (60 mg, 0.0532 mmol) in MeOH (1 mL) was added 2 drops of methanol saturated with ammonia gas and the resulting mixture was stirred for 1 h. The reaction mixture was purified by column chromatography to give 38 mg (69%) of I-S22-PD1 as an off white solid. 1H NMR (500 MHz, CDCl3): δ 1.14 (s, 3H), 1.23 (s, 3H), 1.68 (s, 3H), 1.91 (s, 3H), 2.23 (s, 3H), 2.38 - 2.42 (m, 2H), 2.46 (s, 3H), 2.50 - 2.58 (m, 2H), 2.84 (t, 2H, J = 5.4 Hz), 2.94 (t, 2H, J = 6.5 Hz), 3.82 (t, 3H, J = 6.0 Hz), 4.20 (d, IH, J = 8.5 Hz), 4.31 (d, IH, J = 8.5 Hz), 4.35 - 4.41 (m, 3H), 4.97 (d, IH, J = 7.5 Hz), 5.44 (d, IH, J = 2.5 Hz), 5.69 (d, IH, 7.0 Hz), 6.0 (dd, IH, J = 9.25 Hz, 2.25 Hz), 6.22-6.29 (m, 2H), 7.08 (d, IH, J = 9.5 Hz), 7.36-7.60 (m, HH), 7.78 (d, 2H, J = 7.5 Hz), 8.14 (d, 2H, J = 7.5 Hz). Example 43 Synthesis of prodrug I-S22-PD2: To a solution of I-S22-PD1 (38 mg, 0.0367 mmol) in acetonitrile (0.6 mL) was added succinic anhydride (5 mg, 0.044 mmol) and DMAP (cat.). The resulting mixture was stirred overnight at RT and purified by column chromatography to give 12 mg (29%) of prodrug I-S22-PD2 as an off white solid. 1H NMR (500 MHz, CDCl3): δ 1.14 (s, 3H), 1.25 (s, 3H), 1.68 (s, 3H), 1.91 (s, 3H), 2.22 (s, 3H), 2.36 - 2.41 (m, IH), 2.49 (s, 3H), 2.57 - 2.63 (m, 5H), 2.86 - 2.89 (m, 2H), 2.93 (t, 2H, J = 6.5 Hz), 3.79 (d, IH, J = 7.0 Hz), 4.20 - 4.44 (m, 7H), 4.98 (d, IH, J = 8.0 Hz), 5.53 (d, IH, 3.0 Hz), 5.69 (d, IH, J = 7.0 Hz), 6.02 (dd, IH, J = 9.5 Hz, J = 3.0 Hz), 6.26-
6.29 (m, 2H), 7.20 (d, IH, J = 9.0 Hz), 7.33 - 7.62 (m, HH), 7.74 (d, 2H, J = 7.5 Hz), 8.14 (d, 2H, J = 7.5 Hz). MS (ES+) m/z: 1134.44 [M+H]+; 1156.56 [M+Na]+.
Water solubility: Paclitaxel and its prodrug I-S22-PD2 (2 mg each) were suspended in 1 mL water or PBS-buffer (pH 7.4). The suspensions were sonicated for 15 min and centrifuged (13,000 g) for 10 min. The supernatant was analyzed using HPLC.
HPLC: Waters RP18 column (150 x 3.9 mM, X-Terra); DAD-HP Agilent (Model 1100); eluent: CH3CNrH2O (gradient 0-100% acetonitrile in 0-15 min). The uv-detector was set at 210 nM. The concentrations were determined by measuring the relative area of paclitaxel or I-S22-PD2. It was observed that the solubility of I-S22-PD2 was 20 times more than that of paclitaxel. (i.e, ~0.2 mg/mL).
The following double/mutual prodrugs (Examples 44 - 80) were synthesized by the methods depicted in Schemes 17-21, using appropriate therapeutic agents and obvious modifications: Example 44 Synthesis of mutual prodrug of desloratidine and pseudoephedrine (I-AA-MPD1):
This mutual prodrug was synthesized as depicted in Scheme 21. The compound I- AA- MPDl was obtained as a colorless gum. 1H-NMR (300 MHz, CDCl3): δ 1.00 (d, 3H, J = 6.9 Hz), 2.27-2.51 (m, 4H), 2.74-2.97 (m, 9H), 3.28-3.41(m, 4H), 3.79 (bs, 2H), 4.28-
4.30 (m, 4H), 4.57 (m, IH), 7.04-7.44 (m, 9H), 8.26-8.33 (m, 2H). MS (m/z): 682 [M+H]+.
Example 45
Synthesis of mutual prodrug of amlodipine and lisinopril (I-AA-MPD2): Step 1 : Synthesis of diethyl ester of lisinopril:
To a suspension of lisinopril (10.0 g, 22.62 mmol) in ethanol (150 mL) was added SOCl2 (4.95 mL, 67.94 mmol) and refluxed for 1.5 h. An additional 1 mL of SOCl2 was added to the mixture every hour for 4 h. The mixture was concentrated and azeotroped with benzene. The resulting hydrochloride was basified with saturated NaHCO3 and extracted with EtOAc. Usual aqueous work-up gave 12.86 g of lisinopril diethyl ester, which was used without purification. 1H-NMR (300 MHz, CDCl3): δ 1.23-1.64 (m, 10H), 1.89-2.3 (m, 6H), 2.63-2.66 (m, 2H), 2.80 (bs, 2H), 3.19 (t, 2H, J = 7.5 Hz), 3.36-3.59 (m, 6H), 4.12-4.19 (m, 4H), 4.4-4.5 (m, IH), 7.14-7.28 (m, 5H). MS [m/z]: 462.4 [M+H]+.
Step 2: Synthesis of I-AA-MPD2: CDI (1.23 g, 7.64 mmol) was added to a solution of I-A1-PD2 (Example 18) (3.0 g, 5.09 mmol) in DMF (10 rxiL) and stirred RT for 3.5 h. A solution of lisinopril diethyl ester (2.34 g, 5.09 mmol) in DMF (5 niL) was added and stirred at 65 0C for 8 h. The reaction was quenched with brine and taken up in EtOAc. After usual aqueous work-up and chromatographic purification, 2.5 g (45%) of I-AA- MPD2 were obtained. 1H-NMR (300 MHz, CDCl3): δ 1.17 (t, 3H, J = 7.5 Hz), 1.24-1.30 (m, 7H), 1.45-1.80 (m, 7H), 1.90-2.30 (m, 7H), 2.36 (s, 3H), 2.70 (bs, 2H), 2.89-2.95 (m, 4H), 3.10-3.20 (bs, 3H), 3.40-3.70 (m, 9H), 4.00-4.40 (m, 10H), 4.47-4.53 (m, IH), 4.68- 4.73 (q, 2H, J = 13 Hz), 5.30 (bs, IH), 5.39 (s, IH), 5.65 (bs,lH), 7.15-7.36 (m, 9H). MS (m/z): 1076 [M+H]+, 1098 [M+Naf. Example 46
Synthesis of mutual prodrug of amlodipine and losartan (I-AA-MPD3a): This mutual prodrug was synthesized as described in Example 34, with obvious modifications, using the appropriate amino containing therapeutic agents. The product I- AA-MPD3a was obtained as a cream color solid. 1H-NMR (300 MHz, CDCl3): δ 0.86 (t, 3H, J = 6.6Hz), 1.16 (t, 3H, J = 7.1 Hz), 1.31 (m, 2H), 1.60 (m, 2H), 2.31 (s, 3H), 2.48 (t, 2H, J = 7.9 Hz), 2.80-2.92 (m, 4H), 3.40 (m, 4H), 3.56 (s, 3H), 4.01 (m, 2H), 4.32 (m, 4H), 4.68 (q, 2H, J = 6.5 Hz), 5.00 (s, 2H), 5.14 (s, 2H), 5.37 (s, IH), 6.90 (d, IH, J = 7.8 Hz), 7.02- 7.22 (m, 5H), 7.33-7.43 (m, 3H), 7.50-7.60 (m, 2H). MS (m/z) : 1037 [M-H]". Example 47
Synthesis of mutual prodrug of celecoxib and valdecoxib (I-AA-MPD4): This mutual prodrug was synthesized by reacting the imidazolide intermediate of I-A3- PDl with valdecoxib according to method described in Scheme 17 with appropriate modifications. This mutual prodrug I-AA-MPD4 was obtained as a white solid. 1H-NMR (300 MHz, CDCl3): δ 2.16 (s, 3H), 2.29 (s, 3H), 2.71 (bs, 4H), 4.14 (bs, 4H), 6.69 (s, 2H), 7.02-7.33 (m, 14H), 7.97 (d, 3H, J = 9.0 Hz). MS (m/z): 900 [M-H]". Example 48
Synthesis of double prodrug of valdecoxib (I-AA-MPD5):
This double prodrug was synthesized by reacting I-A3-PD1 and valdecoxib using the method B described in Scheme 13. The double prodrug I-AA-MPD5 was obtained as an off white solid. 1H-NMR (300 MHz, CDCl3): δ 2.40 (s, 6H), 2.82 (bs, 4H), 4.20 (bs, 4H),
7.20-7.35 (m, 14H), 7.97 (d, 4H, J = 9.0 Hz). MS (m/z): 833[M-H]".
Example 49
Synthesis of double prodrug of valdecoxib (I-AA-MPD8a): This mutual prodrug was synthesized using succinic anhydride and valdecoxib according to method B described in Scheme 13 with appropriate modifications. This double prodrug
I-AA-MPD8a was obtained as an off-white solid. 1H-NMR (300 MHz, CDCl3): δ 2.46 (s,
6H), 2.58 (s, 4H), 7.25-7.37 (m, 16H), 7.95 (d, 2H J = 9.0 Hz). MS (m/z): 709 [M-H]".
Example 50 Synthesis of double prodrug of valdecoxib (I-AA-MPD8b) :
This mutual prodrug was synthesized using glutaric anhydride and valdecoxib according to method B described in Scheme 13 with appropriate modifications. This double prodrug
I-AA-MPD8b was obtained as a colorless gum. 1H-NMR (300MHz, CDCl3 + CD3OD): δ
1.68-1.74 (m, 2H), 2.15 (t, 4H, J = 4.5 Hz), 2.38 (s, 6H), 7.01 (bs, IH), 7.17-7.30 (m, 14H), 7.50 (bs, IH), 7.88 (d, 4H, J = 8.58 Hz). MS (m/z): 723 [M-H]".
Example 51
Synthesis of mutual prodrug of olanzapine and fluoxetine (I-AA-MPD9):
This mutual prodrug was made according to Scheme 17 with appropriate modifications.
This mutual prodrug I-AA-MPD9 was obtained as a yellow gum. 1H-NMR (300 MHz, CDCl3): δ 2.05-2.20 (m, 2H), 2.40 (s, 3H), 2.44 (s, 3H), 2.50-2.90 (m, 12H), 3.30-3.80
(m, 4H), 4.10-4.50 (m, 4H), 5.20 (bs, IH), 6.42 (s, IH), 6.87 (d, 2H, J = 8.52 Hz), 7.04-
7.36 (m, 9H), 7.42 (d, 2H, J = 8.67 Hz). MS (m/z): 828 [M+H]+.
Example 52
Synthesis of double prodrug of gabapentin (I- AA-MPDlOa): This double prodrug was synthesized as described below: Step 1: A solution of SL-I (3.0 g, 19.4 mmol) in DMF (5 mL) was added to a suspension of CDI (9.46 g, 5.83 mmol) in DMF (15 mL) and stirred at RT for 20 h. The mixture was concentrated and the residue purified by column chromatography. The bis-imidazolide obtained was used as such in the next step. Step 2: A solution of the bis-imidazolide (1.0 g, 2.91 mmol) in acetonitrile (3 mL) was added to a dispersion of gabapentin (1.49 g, 8.75 mmol) in IN NaHCO3 (8 mL) and stirred at RT for 3 d. The mixture was diluted with water, acidified with 2N HCl and extracted with EtOAc. After usual aqueous work-up and chromatographic purification, 1.04 g (65%) of pure I-AA-MPD10 was obtained. 1H-NMR (300 MHz, CDCl3): δ 1.20- 1.47 (m, 20H), 2.33 (s, 4H), 2.96 (t, 4H, J = 5.48 Hz), 3.23 (d, 4H, J = 6.5 Hz), 4.31 (t, 4H, J = 6.0 Hz), 5.55 (t, 2H, J = 6.6 Hz),. ESI - MS (m/z) : 547 [M-H]". Example 53
Synthesis of double prodrug of gabapentin ethyl ester (I-AA-MPDlOb): A mixture of I-A1-PD8 (2.0 g, 5.26 mmol) and Hunig's base (2.75 mL, 15.8 mmol) in DCM (8 mL) was added to a solution of diphosgene (1.27 mL, 10.53 mmol) in DCM (4 mL) at 0 0C and stirred for 30 min. The mixture was concentrated, dissolved in DCM (10 mL) and treated with a solution of gabapentin ethyl ester hydrochloride (1.86 g, 7.88 mmol) and Hunig's base (2.74 mL, 15.77 mmol) in DCM (10 mL). The mixture was stirred for 3 h. After usual aqueous work-up, the crude material was purified by preparative HPLC to afford 2.2 g (69 %) of I-AA-MPDlOb as a colorless oil. 1H-NMR (300 MHz, CDCl3): δ 1.25 (t, 6H, J = 6.0 Hz), 1.35-1.67 (m, 20H), 2.33 (s, 4H), 2.91 (t, 4H, J = 6.0 Hz), 3.18 (d, 4H, J = 6.0 Hz), 4.12 (q, 4H, J = 6.0 Hz), 4.29 (t, 4 H, J = 6.0 Hz) 5.42 (bs, 2H). MS : ES+ m/z 605 [M+H]+, 627 [M+Na]+. Example 54 Synthesis of mutual prodrug of lamotrigine and gabapentin (I-AA-MPD11):
To a solution of I-A1-PD4 (4.5 g, 10.32 mmol) in acetonitrile (40 mL) at RT was added CDI (2.0 g, 12.38 mmol) and stirred for 3 h. To this was added a solution of gabapentin (2.12 g, 12.38 mmol) in 10 ml of 1% NaHCO3 solution and the mixture was stirred at RT for 24 h. After usual aqueous work-up and chromatographic purification, 2.6 g (40 %) of I-AA-MPD11 was obtained as an off white solid. 1H NMR (CD3OD, 300 MHz): δ 1.14- 1.48 (m, 10H), 2.28 (s, 2H), 2.99 (t, 2H, J = 6.0 Hz), 3.06 (t, 2H, J = 6.3Hz), 3.22 (s, 2H), 4.31 (t, 2H, J = 6.0 Hz), 4.46 (t, 2H, J = 6.3 Hz), 7.39-7.49 (m, 2H), 7.69-7.71 (m, IH). MS: (ES +) m/z 633.1 (M+H)+, 655.1 (M +Na)+. Example 55
Synthesis of mutual prodrug of gabapentin ethyl ester and lamotrigine (I-AA-MPD12): To a suspension of lamotrigine (2.70 g, 10.55 mmol) and DMAP (1.28 g, 10.55 mmol) in toluene (40 mL) at 110 0C was added a solution of the imidazolide of I-A1-PD4 (4.99 g, 10.55 mmol) THF (20 mL) and stirred overnight at 110 0C. The reaction mixture was purified by column chromatography to afford 0.85 g (12 %) of I-AA-MPD12 as a white solid. * HNMR (CDCl3, 300 MHz) δ 1.24 (t, 2H, J = 7.2 Hz), 1.36- 1.77 (m, 10H), 2.29 (s, 2H), 2.93-3.03 (m, 4H), 3.22 (d, 2H, J = 6.6 Hz), 4.11 (q, 2H, J = 7.2 Hz), 4.34 (t, 2H, J = 6.6 Hz), 4.47 (t, 2H, J= 6.3 Hz), 5.65 (t, IH ), 7.34-7.41 (m, 2H), 7.60-7.63 (m, IH). MS: ES+ m/z 661 (M+H)+, 682 (M+Na)+. Example 56 Synthesis of mutual prodrug of gabapentin ethyl ester and levetiracetam (I-AA-MPD13): To a solution of levetiracetam (1.0 g, 5.87 mmol) in DCE (25 mL) and DCM (5 mL) at RT was added oxalyl chloride (895 mg, 7.05 mmol). The reaction mixture was refluxed for 8 h, after which it was cooled to RT and a solution of I-A1-PD8 (2.67 g, 7.05 mmol) in DCE (20 mL) was added drop-wise. The resulting mixture was stirred at RT for 18 h. After usual aqueous work-up and chromatographic purification, 1.63 g (48%) of I-AA- MPD13 was obtained as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 0.87 (t, 3H, J = 7.4 Hz), 1.25 (t, 3H, J = 7.1 Hz), 1.34-1.52 (m, 10H), 1.82-2.01 (m, 4H), 2.28 (s, 2H), 2.40 (t, 2H, J = 7.0 Hz), 2.89-2.94 (m, 4H), 3.04-3.11 (m, IH), 3.19 (d, 2H, J = 6.6 Hz), 3.66- 3.75 (m, IH), 4.07-4.16 (m, 3H), 4.27-4.35 (m, 4H), 5.48 (t, IH, J = 6.5 Hz), 8.18 (bs, IH). MS: (ES+): m/z 576.1 [M+H]+; 598.1 [M+Naf. (ES"): m/z 574.2 [M-H]+. Example 57
Synthesis of mutual prodrug of gabapentin ethyl ester and valproic acid (I-AA-MPD14): This mutual prodrug was synthesized according method outlined in Scheme 18. This mutual prodrug I-AA-MPD14 was obtained as oil. MS (m/z): 592 [M+H]+. Example 58 Synthesis of mutual prodrug of gabapentin ethyl ester and valproic acid (I-AA-MPD15): This mutual prodrug was synthesized according method outlined in Scheme 18. The mutual prodrug I-AA-MPD15 was obtained as a yellow oil. MS (m/z): 620 [M+H]+. Example 59
Synthesis of mutual prodrug of gabapentin ethyl ester and valproic acid (I-AA-MPD16): To a suspension of valpromide (750 mg, 5.24 mmol) in DCE (15 mL) at 0-5 0C was added oxalyl chloride (0.5 mL, 6.29 mmol) and refluxed overnight. The reaction mixture was cooled to RT, treated with a solution of I-A1-PD8 (2.18 g, 5.76 mmol) in DCE (2 mL) and stirred at RT for 2 h. The reaction mixture was purified by column chromatography to afford 1.61 g (51%) of I-AA-MPD16 as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 0.89 (t, 6H, J = 7.09 Hz), 1.25 (t, 3H5 J = 6.96 Hz), 1.31-1.69 (m, 18H), 2.29 (s, 3H), 2.89-2.99 (m, 4H), 3.20 (d, 2H, J = 6.47 Hz), 4.13 (q, 2H), 4.33 (t, 2H, J = 6.71 Hz), 4.40 (t, 2H, J = 5.97 Hz), 5.54 (t, IH), 8.29 (br s, IH). MS: ES+ m/z 549 [M+H]+, 571 [M+Na]+. Example 60 Synthesis of double prodrug of valproic acid (I-AA-MPD22) :
To a suspension of valpromide (3.0 g, 20.95 mmol) in DCE (30 mL) at 0-5 0C was added oxalyl chloride (1.3 mL, 15.08 mmol) and refluxed overnight. The reaction mixture was cooled to RT, a solution of SL-I (0.808 g, 5.24 mmol) in DCE (3 mL) was added and stirred overnight. After usual work-up and chromatographic purification, 1.97 g (43%) of I-AA-MPD22 were obtained as a white solid. 1H NMR (CDCl3, 300 MHz): δ 0.89 (t, 12H, J = 7.18 Hz), 1.28-1.66 (m, 16H), 2.94-2.95 (m, 2H), 3.02 (t, 6H, J = 6.51 Hz), 4.42 (t, 4H, J = 6.47 Hz). MS: m/z 493.2 [M+H]+, 510.0 [M+NH4]+, 515.10 [M+Naf. Example 61 Synthesis of mutual prodrug of gabapentin ethyl ester and valproic acid (I-AA-MPD27): Step 1: To a solution of I-A1-PD8 (4.0 g, 10.54 mmol) in THF (25 mL) was added CDI (2.22g, 13.7 mmol) and stirred at RT for 90 min. To this was added t-butyl carbazate (1.39 g, 10.54 mmol) and DMAP (1.288 g, 10.54 mmol), and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 4.0 g (91%) of the intermediate boc-hydrazide was obtained as a colorless gummy material. 1H NMR (CDCl3, 300 MHz): δ 1.25 (t, 3H, J = 7.1 Hz), 1.43 (s, 9H), 1.31-1.74 (m, 10H), 2.30 (s, 2H), 2.90-3.01 (m, 4H), 3.20 (d, 2H, J = 6.6 Hz), 4.17 (q, 2H, J = 7.1 Hz), 4.32 (t, 2H, J = 6.5 Hz), 4.39 (t, 2H, J = 6.5 Hz), 5.42 (br s, IH), 6.04 (br s, IH), 6.98 (br s, IH). Step 2: To a solution of the above boc-hydrazide (4.0 g, 7.44 mmol) in DCM (20 mL) was added 50% TFA/DCM (10 mL) and stirred at RT for Ih. DCM was removed under vacuum, the resulting residue triturated with diethyl ether (2 x 20 mL) and dried to give a colorless oil, which was dissolved in THF (20 mL). To the above solution at 0-5 0C was added TEA (2.1 mL, 14.88 mmol), valproic acid (1.18 g, 8.184 mmol), DCC (2.3 g, 11.16 mmol) and DMAP (0.909 g, 7.44 mmol) and the mixture was stirred overnight at RT. The mixture was filtered, concentrated and purified by column chromatography to afford 2.59 g (51 %) of I-AA-MPD27 as a colorless gummy material. 1H NMR (CDCl3, 300 MHz): δ 0.85 (t, 6H, J = 7.2 Hz), 1.3 (t, 6H, J = 7.11 Hz), 1.21-1.80 (m, 26H), 2.2- 2.3 (m, IH), 2.35 (s, 2H), 2.81-2.94 (m, 4H), 3.21 (d, 2H, J = 6.6 Hz), 3.65-3.68 (m, IH), 4.19 (q, 2H, J - 7.11 Hz), 4.36 (t, 2H, J = 6.51 Hz), 4.39 (t, 2H, J = 6.51 Hz), 5.51 (t, IH), 8.17 (s, IH). MS: m/z 712 [M+Naf, 728 [M+K]+, 688 [M-H]". Example 62
Synthesis of mutual prodrug of valproic acid and nicotinic acid (I-CC-MPD1): Step 1: To a solution of nicotinyl chloride hydrochloride (3.16 g, 17.76 mmol) and LI-2c (3 g, 11.84 mmol) in THF (50 mL) was added TEA (8.3 mL, 59.2 mmol) and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 4.14. g (97%) of LI-2c-nicotinate ester was obtained as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 1.43 (s, 9H), 2.82 (t, 2H, J = 6.31 Hz), 3.42-3.48 (q, 2H), 4.62 (t, 2H, J = 6.59 Hz), 7.29-7.33 (m, IH), 8.30 (d, IH, J = 7.95 Hz), 8.78 (dd, IH, J = 4.86, 1.72 Hz), 9.23 (d, IH, J = 2.13 Hz). MS: m/z 358 [M+H]+, 381 [M+Naf, 739 [2M+Na]+. Step 2: To a solution of LI-2c-nicotinate ester (0.92 g, 2.50 mmol) in DCM (5 mL) was added 50% TFA/DCM (5 mL) and stirred for Ih. Reaction mixture was concentrated and the residual TFA salt was used as such in Step 3.
Step 3: To a solution of valproic acid (0.37 g, 2.56 mmol) in THF (5 mL) was added CDI (0.5 g, 3.08 mmol) and stirred for 2h. This was treated with a solution of the above TFA salt, TEA (0.7 mL, 5.13 mmol) and DMAP (50 mg, 0.41 mmol) in THF (10 mL) and the mixture was stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 0.7 g (71%) of I-CC-MPD1 was obtained as a white solid. 1H NMR (CDCl3, 500 MHz): δ 0.88 (t, 6H, J = 7 Hz), 1.25-1.59 (m, 8H), 2.06-2.08 (rα, IH), 2.86 (t, 2H, J = 6 Hz), 3.05 (t, 2H, J = 7 Hz), 3.58-3.61 (q, 2H, J = 9.0 Hz), 4.63 (t, 2H, J = 6.5 Hz), 7.40-7.42 (m, IH), 8.30 (dt, IH, J = 8.0, 2.0 Hz), 8.79 (dd, IH, J = 5.0, 2.0 Hz), 9.23 (d, IH, J = 0.5 Hz). MS: m/z 385 [M+H]+, 407 [M+Naf, 423 [M+K]+. Example 63
Synthesis of mutual prodrug of valproic acid and nicotinic acid (I-CC-MPD2): This mutual prodrug was synthesized as described in Example 62, with obvious modifications. 0.612 g (41%) of I-CC-MPD2 was obtained as a white solid. 1H NMR (CDCl3, 300 MHz): δ 0.89 (t, 6H, J = 7.23 Hz), 1.24-1.62 (m, 8H), 2.34-2.42 (m, IH), 2.92 (t, 2H, J = 6.83 Hz), 2.98 (t, 2H, J = 6.04 Hz), 3.78-3.84 (q, 2H), 4.37 (t, 2H, J = 6.79 Hz), 7.36-7.41 (m, IH), 8.15 (d, IH, J = 7.92 Hz), 8.73 (d, IH, J = 4.78 Hz), 9.02 (s, IH). MS: m/z 385 [M+H]+, 419 [MH-HCl]+, 383 [M-H]". Example 64 Synthesis of mutual prodrug of zidovudine and lamivudine (I-HH-MPD1): Step l: Synthesis of intermediate I-S17-PDI1:
4-Nitrophenyl chloroformate (0.27 g, 1.34 mmol) was added to a solution of the I-Hl- PD5 (0.4 g, 0.89 mmol) and pyridine (76 μL, 1 mmol) in DCM (10 niL) and stirred at RT for 15 h. The mixture was concentrated and the residue purified by column chromatography to give 0.29 g (53%) of I-S17-PDI1. 1H-NMR (300 MHz, CDCl3): δ 1.93 (s, 3H), 2.45 (m, 2H), 2.97-3.06 (m, 4H), 4.05 (m, IH), 4.41 (m, IH), 4.40-4.49 (m, 4H), 4,54 (t, 2H, J = 6.5 Hz), 6.17 (t, IH, J = 6.0 Hz), 7.33 (s, IH), 7.39 (d, 2H, J= 4.8 Hz), 8.28 (d, 2H, J = 4.8 Hz) and 8.50 (s, IH). MS (m/z): 635 [M+Naf. Step 2: Synthesis of I-HH-MPD1: Lamivudine (45 mg, 0.196 mmol) and DMAP (48 mg, 0.39 mmol) were added to a solution of I-S17-PDI1 (80 mg, 0.13 mmol) in DMF (1.5 mL) and stirred at RT for 30 min. The mixture was concentrated and purified by column chromatography to give 40 mg (43%) of product I-HH-MPD1. 1H-NMR (300 MHz, CDCl3): δ 1.90 (s, 3H), 2.45 (t, 2H, J = 6.1 Hz), 3.05 (t, 4H, J = 6.2 Hz), 3.20 (m, IH), 3.53 (m, IH), 4.08 (m, IH), 4.30-4.80 (m, 8H), 5.45 (t, IH, J = 3.0 Hz), 5.90 (d, IH, J = 7.5 Hz), 6.17 (t, IH), 6.30 (t, IH), 7.55 (s, IH) and 7.90 (d, IH, J = 7.50 Hz). MS (m/z): 725 [M+Naf. Example 65
Synthesis of mutual prodrug of zidovudine and lamivudine (I-HH-MPD2b): This mutual prodrug was synthesized according to the method outlined in Scheme 18. The mutual prodrug I-HH-MPD2b was obtained as a white solid. 1H-NMR (300 MHz, CDCl3): δ 1.97 (s, 3H), 2.42 (m, 2H), 2.90-2.94 (m, 16H), 3.06 (m, IH), 3.40-3.44 (m, 8H), 3.50-3.56 (m, IH), 3.71-3.73 (m, IH), 4.95 (m, IH), 4.27-4.30 (m, 4H), 4.37-4.49 (m, 4h), 5.32 (t, IH, J = 5.1 Hz), 5.83 (d, IH, J = 6.6 Hz), 6.07 (m, IH), 6.33 (bs, IH), 7.20-7.25 (m, IH), 7.74 (m, IH). MS (m/z): 954 [MH-Na]+. Example 66 Synthesis of mutual prodrug of cetirizine and pseudoephedrine (I-CA-MPD1): Step 1 : Synthesis of intermediate I-S17-PDI1:
This intermediate was prepared by reacting I-C1-PD10 with p-nitrophenyl chloroformate by a procedure similar to that described in Example 64. The desired intermediate I-S17- PDIl was obtained as a gum. 1H-NMR (300 MHz, CDCl3): δ 2.49-2.71 (m, 10H), 2.95 (t, 2H, J = 6.6Hz), 3.01 (t, 2H, J = 6.5 Hz), 3.73 (bs, 2H), 4.13 (s, 2H), 4.22 (s, IH), 4.41 (t, 2H, J = 6.6 Hz), 4.53 (t, 2H, J = 6.6 Hz), 7.18-7.40 (m, 11 H), 8.28 (d, 2H, J = 7.1 Hz). Step 2: The mutual prodrug I-C A-MPDl was synthesized by reacting intermediate I- S17-PDI1 with pseudoephidrine by a procedure similar to that described in Example 64, Step 2. The desired mutual prodrug I-CA-MPD1 was obtained as a colorless gummy , material. 1H-NMR (300 MHz, CDCl3): δ 0.99-1.09 (d, 3H, J = 6.6 Hz), 2.45 (bs, 4H), 2.68 (bs, 6H), 2.90 (s, 3H), 2.91-2.94 (m, 4H), 3.71 (bs, 3H), 4.11 (s, 2H), 4.18 (s, IH), 4.26-4.41 (m, 4H), 4.56 (m, 2H), 7.17- 7.35 (m, 12H). MS (m/z): 716 [M+ H]+. Example 67 Synthesis of mutual prodrug of gabapentin ethyl ester and naproxen (I-CA-MPD5): This mutual prodrug was synthesized by reacting I-A1-PD8 and Naproxen using Scheme 11, Method B. This mutual prodrug was obtained as colorless oil. 1H-NMR (300 MHz, CDCl3): δ 1.25 (t, 3H, J = 7.1 Hz), 1.30-1.55 (m, 10H), 1.57 (d, 3H, J = 7.1 Hz), 2.27 (s, 2H), 2.84 (q, 4H, J = 6.4 Hz), 3.18 (d, 2H, J = 6.7 Hz), 3.80-3.88 (m, IH), 3.91 (s, 3H), 4.12 (q, 2H, J = 7.1 Hz), 4.20-4.40 (m, 4H), 5.35 (bt, IH), 7.05-7.20 (m, 2H), 7.39 (dd, IH, J = 1.8 Hz, 8.4 Hz), 7.60-7.73 (m, 3H). MS (m/z): 592 [M+H]+, 614 [M+Na]+. Example 68
Synthesis of mutual prodrug of valproic acid and nicotinic acid (I-CA-MPD14): This mutual prodrug .was synthesized using valpromide and nicotinyl chloride hydrochloride, according to the methods described in Scheme 13 and Scheme 17, with obvious modifications. 1.0 g of the mutual prodrug I-CA-MPD14 was obtained as a yellow oil. 1H NMR (CD3OD, 300 MHz): δ 0.87 (t, 6H, J = 6 Hz), 1.26-1.75 (m, 9H), 2.83 (s, IH), 2.95-3.0 (m, 4H), 3.81 (t, 2H, J = 6 Hz), 4.44 (t, 2H, J = 6 Hz), 7.0 (s, IH), 7.4 (bs, IH), 7.42 (m, IH), 8.20 (d, IH), 8.65-8.74 (bs, 2H), 9.0 (s, IH). MS: ES+ m/z 428.1 [M+H]+, 450.1 [M+Naf. Example 69
Synthesis of mutual prodrug of valproic acid and nicotinic acid (I-CA-MPD15): To a solution of I-C1-PD13 (1.5 g, 4.63 mmol) and nicotinyl chloride hydrochloride (0.99 g, 5.56 mmol) in THF (25 mL) was added TEA (2 mL, 13.89 mmol) at 0 0C and stirred for 20 h at RT. After usual aqueous work-up and chromatographic purification, 1.0 g (83%) of I-CA-MPD15 was obtained as a yellow viscous liquid. 1H NMR (CD3OD, 500 MHz): δ 0.89 (t, 6H, J = 5.0 Hz), 1.29-1.33 (m, 8H), 1.64 (bs, 2H), 3 (t, 2H, J = 5.0 Hz), 3.07 (t, 2H, J = 5.0 Hz), 4.42 (t, 2H, J = 5.0 Hz), 4.63 (t, 2H, J = 5.0 Hz), 7.41-7.43 (m, IH), 8.31 (bs, IH), 8.78 (bs, IH), 9.26 (s, IH). MS: ES+ m/z 429 [M+H]+,
Figure imgf000174_0001
Example 70
Synthesis of mutual prodrug of gabapentin ethyl ester and nicotinic acid (I-CA-MPD18): To a solution of I-S12-PD2 (synthesized as described in Scheme 12, Method C) (3.76 g, 7.64 mmol) in THF (30 mL) was added nicotinyl chloride hydrochloride (1.5 g, 8.40 mmol), followed by TEA (4.26 mL, 30.56 mmol) and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 0.87 g (23 %) of I-CA-MPD18 was obtained as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 1.24 (t, 3H, J = 6.0 Hz), 1.27- 1.47 (m, 10H), 2.27 (s, 2H), 2.90-3.17 (m, 4H), 3.16 (d, 2H, J = 6.0 Hz), 3.79 (q, 2H, J = 6.0 Hz), 4.10 (q, 2H, J = 6.0 Hz), 4.36 (t, 2H, J = 6.0 Hz), 5.56 (bt, IH, J = 6.0 Hz), 7.32- 7.38 (m, IH), 8.17(d, IH, J = 9.0 Hz), 8.71 (d, IH, J = 6.0 Hz), 9.07 (s, IH). MS: (ES)+ m/z 484 (M+H)+, 506 (M+Na)+ ; (ES)" m/z 482 (M-H)+. Example 71
Synthesis of mutual prodrug of levetiracetam and valproic acid (I-CA-MPD19): To a solution of levetiracetam (1.0 g, 5.87 mmol) in DCE (2OmL) and DCM (4mL) was added oxalyl chloride (894 mg, 7.05 mmol) and heated at 80 0C for 7h. The reaction mixture was cooled to RT, a solution of I-C1-PD11 (1.97 g, 7.05 mmol) in DCE (1OmL) was added and stirred at RT for 18 h. After usual aqueous work-up and chromatographic purification, 1.73 g (61 %) of I-CA-MPD19 was obtained as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 0.85-0.91 (m, 9H), 1.24-1.62 (m, 8H), 1.80-2.05 (m, 4H), 2.34- 2.44 (m, 3H), 2.91 (t, 4H, J = 6.0 Hz), 3.03-3.12 (m, IH), 4.06-4.09 (m, IH), 4.31-4.36 (m, 4H), 8.32 (bs, IH). MS: (ES+) m/z 477.1 [M+H]+, 498.9 [M+Na]+ (ES)" m/z 475.0 [M-H]". Example 72
Synthesis of mutual prodrug of gabapentin ethyl ester and valproic acid (I-CA-MPD21): This mutual prodrug was synthesized by following a route depicted in Scheme 19, with obvious modifications. The mutual prodrug I-CA-MPD21 was obtained as a colorless oil. 1H-NMR (CDCl3, 300 MHz): δ 0.81 (t, 6H, J = 7.19 Hz), 1.15-1.60 (m, 21H), 2.20 (s, 2H), 2.25-2.35 (m, IH), 2.84 (t, 4H, J = 6.6 Hz), 3.11 (d, 2H, J = 6.7 Hz), 4.05 (q, 2H, J = 7.16 Hz and 17.3 Hz), 4.15-4.25 (m, 4H), 5.43 (bt, IH). MS (m/z): 506 [M+H]+, 528 [M+Na]+. I Example 73
Synthesis of mutual prodrug of gabapentin ethyl ester and nicotinic acid (I-CA-MPD22): To a suspension of nicotinyl chloride hydrochloride (0.35 g, 1.97 mmol) in THF (3 mL) at 0 0C was added TEA (0.82 mL, 5.91 mmol). After 5 min, a solution of I-A1-PD8 (0.5g, 1.31 mmol) and TEA (0.27 mL, 1.97 mmol) in THF (4 mL) was added and stirred overnight at RT. The mixture was purified by column chromatography to afford 0.573 g (90 %) of I-CA-MPD22 as a yellow oil. 1H NMR (CDCl3, 300 MHz): δ 1.24 (t, 3H, J = 6.0 Hz), 1.27-1.47 (m, 10H), 2.27 (s, 2H), 2.94 (t, 2H, J = 6.0 Hz), 3.07 (t, 2H, J = 6.0 Hz), 3.19 (d, 2H, J = 6.0 Hz), 4.12 (q, 2H, J = 6.0 Hz), 4.32 (t, 2H, J = 6.0 Hz), 4.62 (t, 2H, J = 6.0 Hz), 5.29 (bs, IH), 7.36-7.42 (m, IH), 8.30 (t, IH, J = 3.0 Hz), 8.78 (dd, IH, J = 1.69 Hz), 9.24(s, IH). MS: (ES)+ m/z 485 (M+H)+, 507 (M+Na)+. Example 74
Synthesis of mutual prodrug of lamotrigine and valproic acid (I-CA-MPD23): To a suspension of lamotrigine (0.455 g, 1.78 mmol) and DMAP (0.217 g, 1.78 mmol) in toluene (10 mL) at 110 0C was added a solution of the imidazolide of I-Cl-PDll (0.665 5 g, 1.78 mmol) in THF (5 mL). The reaction was stirred at 110 0C overnight and purified by column chromatography to afford 0.20 g (20%) of I-CA-MPD23 as a white solid. 1H NMR (300 MHz, CDCl3): δ 0.86-0.90 (m, 6H), 1.20-1.44 (m, 6H), 1.53-1.62 (m, 2H), 2.36-2.39 (m, IH), 2.90-3.0 (m, 4H), 4.34 (t, 2H, J = 6.3 Hz), 4.46 (t, 2H J = 6.6 Hz), 7.36-7.38 (m, 2H), 7.60-7.63 (m, IH). MS: (ES +) m/z 562 (M+H)+, 585 (M +Na)+.
10 Example 75
Synthesis of mutual prodrug of lamotrigine and nicotinic acid (I-CA-MPD24): A solution of I-A1-PD4 (0.5 g, 1.14 mmol) and TEA (0.5 mL, 2.87 mmol) in THF (5 mL) was added to a suspension of nicotinyl chloride (0.305 g, 1.71 mmol) and 0.5 mL TEA in THF (5 mL). The mixture was stirred at RT for 24 h. After usual aqueous work-
15 up and chromatographic purification, 0.15 g (14%) of I-CA-MPD24 were obtained as a white solid. 1H NMR (CDCl3, 500MHz): δ 3.06 (t, 2H, J = 6.5Hz), 3.10 (t, 2H, J = 6.5 Hz), 4.49 (t, 2H, J = 6.5 Hz), 4.65 (t, 2H, J = 6.5 Hz), 7.38-7.43 (m, 3H), 7.60-7.62 (m, IH), 8.33-8.36 (m, IH), 8.81 (m, IH), 9.35 (bs, IH). MS: (ES +) m/z 540.9 (M+H)+. Example 76
20 Synthesis of mutual prodrug of lamotrigine and nicotinic acid (I-CA-MPD25):
J This mutual prodrug was synthesized using lamotrigine and nicotinyl chloride hydrochloride, according to the methods outlined in Scheme 12 and Scheme 17. 0.8 g (44%) of I-CA-MPD25.HC1 were obtained as an off white solid. 1H NMR (D2O, 500MHz): δ 2.93 (t, 2H, J = 6.5 Hz), 3.10 (t, 2H, J = 6.0Hz), 3.69 (t, 2H, J = 6.5Hz), 4.49
25 (m, 2H), 7.37-7.43 (m, 3H), 7.69-7.71 (m, IH), 8.05-8.07 (m, IH), 8.78-8.79 (m, IH), 9.30 (bs, IH). MS: (ES +) m/z 539.9 (MH-H)+, 561.8 (M +Na)+. Example 77
Synthesis of mutual prodrug of metronidazole and norfloxacin (I- AH-MPDl): Step 1 : Synthesis of imidazolide of I-H1-PD1 :
30 CDI (319 mg, 1.97 mmol) was added to a solution of I-H1-PD1 (577 mg, 1.64 mmol) in DMF (8 mL) and stirred at RT for 4 h. The mixture was concentrated and the residue purified by column chromatography to give 395 mg (54%) of the imidazolide of I-Hl- PDl. 1H-NMR (300 MHz, CDCl3): δ 2.50 (s, 3H), 2.92 (t, 2H, J = 6.0 Hz), 3.00-3.10 (m, 2H), 4.36 (t, 2H, J = 3.0 Hz), 4.47-4.51 (m, 2H), 4.57-4.70 (m, 4H), 7.07 (s, IH), 7.43 (s, IH), 7.95 (s, IH), 8.15 (s, IH). MS (m/z): 446 [M+H]+. Step 2: Synthesis of I-AH-MPD1: A solution of the imidazolide of I-H1-PD1 (100 mg, 0.224 mmol) in DMF (1 mL) was added to a suspension of norfloxacin (86 mg, 0.269 mmol) in DMF (2 mL) and stirred at RT for 60 h. The mixture was concentrated and the residue purified by column chromatography to give 35 mg (22%) of I- AH-MPDl. 1H- NMR (300 MHz, CDCl3): δ 1.59 (t, 3H J = 7.5 Hz), 2.53 (s, 3H), 2.86-2.97 (m, 4H), 3.27-3.30 (m, 4H), 3.72 (t, 4H, J = 4.5 Hz), 4.32-4.40 (m, 6H), 4.48-4.52 (m, 2H), 4.59- 4.63 (m, 2H), 6.85 (d, IH, J = 6.0 Hz), 7.96 (s, IH), 8.09 (d, IH J = 12.0 Hz), 8.68 (s, IH). MS (m/z): 697 [M+H]+.
The following mutual prodrugs (Examples 78 - 80) were obtained according to procedures similar to those described in Example 77, with the substitution of the appropriate pairs of amino-containing and hydroxyl-containing therapeutic agents: Example 78
Synthesis of mutual prodrug of metronidazole and norfloxacin (I-AH-MPD3b): The mutual prodrug I-AH-MPD3b was obtained as a yellow solid. 1H-NMR (300MHz, CDCl3): δ 1.59 (t, 3H, J = 7.1 Hz), 2.49 (s, 3H), 2.82-2.98 (m, 10H), 3.30 (t, 4H, J = 4.5 Hz), 3.39 (bs, 4H), 3.72 (t, 4H, J = 4.8 Hz), 4.38 (dt, 8H, J = 26.2, 6.4 Hz), 4.61 (t, 2H, J = 4.8 Hz), 6.86 (d, IH, J = 6.4 Hz), 7.95 (s, IH), 8.07 (bd, IH, J= 12.8 Hz,), 8.67 (s, IH), 14.9 (s, IH). MS (m/z): 811.26 [M+H]+. Example 79 Synthesis of mutual prodrug of gabapentin and tramadol (I-AH-MPD7): The mutual prodrug was synthesized according to the method in Scheme 15 with obvious modifications. The mutual prodrug I-AH-MPD7 was obtained as a colorless gummy material. 1H-NMR (300 MHz, CDCl3): δ 1.25 (t, 3H, J = 7.1 Hz), 1.32-2.45 (m, 30H), 2.91-2.99 (m, 4H), 3.16 (t, 2H, J = 7.3 Hz), 3.80 (s, 3H), 4.08-4.15 (q, 2H, J = 7.1 Hz), 4.28-4.40 (m, 4H), 5.4 (t, IH), 6.74-6.81 (m, 3H), 7.23-7.29 (t, IH, J = 8 Hz). MS (m/z): 669.30 [M+H]+. Example 80 Synthesis of mutual prodrug of venlafaxine and paroxetine (I-AH-MPD8) The mutual prodrug was synthesized according to the method outlined in Scheme 15 with obvious modifications. The mutual prodrug I-AH-MPD8 was obtained as a white sticky solid. 1H-NMR was consistent with the expected structure. MS: m/z 812 [M]+. Example 81
Synthesis of NO-releasing prodrug of Valproic acid (I-C1-NOPD1): This prodrug was synthesized as shown in Scheme 11, Method B using as reagents valproic acid (725 mg, 5.03 mmol), LI-2b (1 g, 5.03 mmol), TEA (611 mg, 6.04 mmol), DCC (1.25 g, 6.04 mmol) and DMAP (100 mg). Yield: 832 mg (51%). 1H-NMR (300 MHz, CDCl3): δ 0.89 (t, 6H, J = 7.09 Hz), 1.22-1.77 (m, 8H), 2.36-2.40 (m, IH), 2.93- 3.00 (m, 4H), 4.34 (t, 2H, J = 6.8 Hz), 4.70 (t, 2H, J = 6.35 Hz). MS (CI)+ m/z: 326 [M+H]+. Example 82 Synthesis of NO-releasing prodrug of valproic acid (I-Cl-NOPD3a): This prodrug was prepared as shown in Scheme 13, Method A. Thus, to a stirred mixture of valproyl isocyanate, which was freshly prepared from valpromide (0.7 g, 4.90 mmol [valpromide was synthesized from valproic acid by using known methods as shown in Scheme 11, Method I) using a known method (see J. Org. Chem., 1962, 27, 3742) in DCM (20 mL) at RT was added a solution of LI-2b (0.976 g, 4.90 mmol) in DCM (5 mL) drop-wise and stirred at RT for 2 h. The mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, afforded 0.6 g (33%) of prodrug I-Cl-NOPD3a. 1H-NMR data is consistent with the expected structure. MS: [ES]+ m/z 391 [M+Na]+, 407.2 [M+K]+; [EI]+ m/z 368 [M + H]+. Example 83 Synthesis of NO-releasing prodrug of aspirin (I-C1-NOPD4):
This prodrug was synthesized as shown in Scheme 11, Method D. Thus, to a solution of aspirin (3.0 g, 16.65 mmol) in THF (30 mL) at 0 0C was added oxalyl chloride (1.86 mL, 21.64 mmol) and heated at 70 0C for 2 h. The mixture was concentrated, the residue was dissolved in THF (30 mL) and treated with a solution of LI-2a (3.61 g, 16.65 mmol), TEA (3.48 mL, 24.97 mmol) and DMAP (361 mg) in THF (20 mL). The resulting mixture was stirred at RT for 2 h and filtered through celite. The filtrate was concentrated and the residue purified by column chromatography to afford 3.06 g (48%) of the bromide SIl-Il. 1H-NMR (300 MHz, CDCl3): δ 2.35 (s, 3H), 3.01-3.12 (m, 4H), 3.61 (t, 2H, J = 6.5 Hz), 4.53 (t, 2H, J = 6.0 Hz), 7.11 (dd, IH, J = 8 Hz, 1 Hz), 7.32 (t, IH, J = 7.6 Hz), 7.57 (t, IH, J = 7.6 Hz), 8.03 (dd, IH, J = 7.8 Hz, 1.6 Hz). MS (ES+) m/z: 403.92 (M+Na)+.
To a solution of SIl-Il (2.0 g, 5.27 mmol) in acetonitrile (20 mL) at 0 0C was added AgNO3 (1.07 g, 6.32 mmol) in the dark. The mixture was stirred at RT for 1.5 h, filtered through celite and concentrated. The residue, after usual aqueous work-up and chromatographic purification, afforded 0.965 g (50%) pure I-C1-NOPD4. 1H-NMR (300 MHz, CDCl3): δ 2.36 (s, 3H), 2.98 (t, 2H, J = 6.8 Hz), 3.05 (t, 2H, J = 6.4 Hz), 4.54 (t, 2H, J = 6.4 Hz), 4.70 (t, 2H, J = 6.8 Hz), 7.12 (d, IH, J = 8 Hz), 7.33 (t, IH, J = 7.6 Hz), 7.59 (t, IH, J = 7.5 Hz), 8.03 (dd, IH, J = 7.8 Hz, 1 Hz). MS (ES)+ m/z: 379.11 (M+NH4)+, 383.98 (M+Na)+. Example 84 Synthesis of NO-releasing prodrug of aspirin (I-Cl-NOPD5a):
As shown in Scheme 11, Method H, this prodrug was synthesized in three steps: Step 1: To a suspension of aspirin (1 g, 5.55 mmol) in benzene (15 mL) and DMF (1 drop) at 0-5 0C was added a solution of oxalyl chloride (0.6 mL, 6.66 mmol) in benzene (5 mL) and stirred at 85 0C for 2 h. The reaction mixture was concentrated, and the crude acid chloride was used immediately in the next step.
Step 2: To a solution of the above acid chloride in benzene (30 mL) was added silver cyanate (998 mg, 6.66 mmol) and refluxed in the dark for 1 h. The mixture, containing 2- acetoxybenzoyl isocyanate, was cooled to RT and used in the next step. Step 3: To the above mixture was added a solution of LI-2b (1.33 g, 6.66 mmol) in benzene (5 mL) and stirred at RT for Ih. The mixture was filtered through celite and concentrated, and the residue was purified by column chromatography to afford 1.2 g (54%) of pure I-Cl-NOPD5a. 1H-NMR data is consistent with the expected structure. MS (ES+) m/z: 404.98 [M+H]+, 426.94 [M+Na]+, 442.97 [M+K]+, (ES") m/z: 403.01 [M- H]-. Example 85
Synthesis of sodium salt of NO-releasing prodrug of aspirin (I-Cl-NOPD5b): To a suspension of 60% sodium hydride (45 mg, 1.3 mmol) in THF (0.5 niL) was added solution of I-Cl-NOPD5a (500 mg, 1.24 mmol) in THF (1.5 mL). After stirring for 5 min, THF was removed under vacuum, the residue was washed with dry Et2O (4 x 3 mL) to remove unreacted starting material and dried in vacuum to afford 410 mg (78%) of I- Cl-NOPDSb as an off-white solid. 1H NMR (D2O, 500 MHz): δ 2.28 (s, 3H), 2.93-2.97 (m, 4H), 4.33 (t, 2H, J = 6.0 Hz), 4.68 (t, 2H, J = 7.2 Hz), 7.07 (d, IH, J = 8.0 Hz), 7.26 (t, IH, J = 7.5 Hz), 7.41 (t, IH, J = 9.0 Hz), 7.57 (d, IH, J = 7.5 Hz). MS: m/z 427.0
Figure imgf000180_0001
Example 86 Synthesis of NO-releasing prodrug of aspirin (I-C1-NOPD6):
This prodrug was synthesized as shown in Scheme 11, Method E. Thus, to a solution of aspirin (1.2Og, 6.70 mmol) in DCM (15 mL) at 0 0C was added oxalyl chloride (0.74 mL, 8.65 mmol) and stirred at RT for 1.5 h. The mixture was concentrated and the residual acid chloride was treated with LI-5.TFA (6.70 mmol) in DCM (14 mL), followed by drop-wise addition of TEA (3.73 mL, 26.81 mmol) at 0 0C. The mixture was stirred at RT for 4 h and concentrated. The residue, after usual aqueous work-up and chromatographic purification, gave 0.822g (34 %) of I-C1-NOPD6. 1H-NMR (300 MHz, CDCl3): δ 2.35 (s, 3H), 2.92 (t, 2H, J = 6.11 Hz), 2.98 (t, 2H, J = 6.0Hz), 3.76 (q, 2H, J = 6.0 Hz), 4.71 (t, 2H, J = 6.0 Hz), 6.70 (bs, IH), 7.10 (d, IH, J = 9.0 Hz), 7.31-7.33 (m, IH), 7.48-7.50 (m, IH), 7.78 (d, IH, J = 6.0 Hz). MS (EI)+ m/z: 361 (M+H)+. Example 87
Synthesis of NO-releasing prodrug of nicotinic acid (I-C1-NOPD7): This prodrug was synthesized as shown in Scheme 11, Method C. Thus, to a suspension of nicotinyl chloride hydrochloride (2.68 g, 15.07 mmol) in THF (10 mL) at 0 0C was added a solution of LI-2b (2.Og, 10.05 mmol) and TEA (5.6 mL, 40.2 mmol) in THF (7 mL) and stirred at RT for 15 h. The mixture was filtered, concentrated and the residue purified by column chromatography to afford 2.23 g (73%) of pure I-C1-NOPD7. 1H- NMR (300 MHz, CDCl3): δ 3.01 (t, 2H, J = 4.75 Hz), 3.09 (t, 2H, J =6.5 Hz), 4.63 (t, 2H, J = 5.25 Hz), 4.70 (t, 2H, J =4.75 Hz), 7.39 - 7.42 (m, IH), 8.29-8.31 (dt, IH, J = 8 Hz, 2 Hz), 8.78-8.80 (dd, IH, J = 2 Hz), 9.23 (d, IH, J = 2Hz). MS (ES)+ m/z: 305 (M+H)+ Example 88
Synthesis of NO-releasing prodrug of nicotinamide (I-Cl-NOPD8a): This prodrug was synthesized from nicotinamide (1 g, 8.18 mmol) according to the procedure described in Example 77 (see Scheme 11, Method I or Scheme 13, Method A). After usual workup, the crude product was purified by column chromatography to afford 0.1 g (3.5%) of prodrug I-Cl-NOPD8a. 1H-NMR (300 MHz, CDCl3): δ 2.97-3.0 (m, 4H), 4.51 (t, 2H, J = 6.3 Hz), 4.73 (t, 2H, J = 6.7 Hz), 7.38-7.48 (m, IH), 8.16-8.22 (m, IH), 8.71-8.79 (m, 2H), 9.04 (s, IH). MS [ES]+ m/z: 348 [M+H]+, 370 [M+Naf. Example 89 Synthesis of NO-releasing prodrug of nicotinic acid (I-C 1-NOPD9) :
This prodrug was synthesized as shown in Scheme 11, Method F. Thus, TEA (6.92 niL, 50.55 mmol) was added to a suspension of nicotinyl chloride hydrochloride (3.0 g, 16.85 mmol) and cysteamine hydrochloride (2.11 g, 18.53 mmol) in DCM (30 niL) at 0 0C and stirred at RT for 4 h. The mixture was concentrated and the residue dissolved in MeOH (20 niL). To this solution at 0 0C was added a solution of LI-3b (4.11 g, 16.85 mmol) in MeOH (5 mL), followed by TEA (4.61 mL, 33.70 mmol) and stirred overnight at RT. The mixture was filtered through celite, concentrated and the residue was purified by column chromatography to afford 3 g (58%) of pure I-C1-NOPD9. 1H-NMR (300 MHz, DMSO-d6): 2.94 (t, 2H, J = 6.7 Hz), 3.09 (t, 2H, J = 6.3 Hz), 3.56 (q, 2H, J = 6.3 Hz), 4.73 (t, 2H, J = 6.3 Hz), 7.49-7.53 (m,lH), 8.16-8.19 (m, IH), 8.69-8.70 (m, IH), 8.87 (br t, IH), 8.98 (s,lH). MS (ES+) m/z: 304 (M+H)+, 326 (M+Na)+. Example 90
Synthesis of NO-releasing prodrug of naproxen (I-C1-NOPD10): This prodrug was synthesized as shown in Scheme 11, Method B. Thus, to a solution of naproxen (2.23 g, 9.7 mmol) and LI-2b (1.93 g, 9.7 mmol) in THF (70 mL) at RT were added DCC (3 g, 14.55 mmol) and DMAP (1.78 g, 14.55 mmol) and stirred overnight. The mixture was filtered and concentrated, and the residue purified by column chromatography to afford 1.03 g (25%) of pure I-C1-NOPD10. 1H-NMR (300 MHz, CDCl3): δ 1.59 (d, 3H, J = 7.16 Hz), 2.81 (t, 2H, J = 6.77 Hz), 2.87 (t, 2H, J = 6.42 Hz), 3.85-3.88 (m, IH), 3.91 (s, 3H), 4.33 (t, 2H, J = 5.26 Hz), 4.53 (t, 2H, J = 6.79 Hz), 7.10- 7.16 (m, 2H), 7.41 (d, IH, J = 1.7Hz), 7.69 (t, 3H, J = 8.55 Hz). Example 91
Synthesis of NO-releasing prodrug of naproxen (I-C1-NOPD12):
This prodrug was synthesized as shown in Scheme 11, Method E. Thus, to a solution of naproxen (1.698 g, 7.37 mmol) in chloroform (20 mL) at 0-5 0C was added oxalyl chloride (0.8 mL, 8.844 mmol), followed by 2-3 drops of DMF. The mixture was stirred at RT for 90 min and concentrated. This acid chloride (~7.37 mmol) was treated with LI- 5.TFA (6.7 mmol) in THF (20 mL) and cooled to 0 0C. To this was added TEA (5.6 mL, 40 mmol) and stirred at RT for 3 h. The mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, afforded 0.409 g (14%) of pure I-C1-NOPD12. 1H-NMR (CDCl3, 300 MHz): δ 1.24 (d, 3H), 2.87 (t, 2H, J = 6.5 Hz), 2.93 (t, 2H, J = 6.7 Hz), 3.64 (q, 2H, 7.5 Hz), 3.76 (m, IH), 3.88 (s, 3H), 4.70 (t, 2H, J = •6.6 Hz), 4.79 (br s, IH), 6.97-7.08 (m, 3H), 7.35-7.46 (m, 3H). Example 92 Synthesis of NO-releasing prodrug of flurbiprofen (I-C1-NOPD13):
This prodrug was synthesized as shown in Scheme 11, Method A, using as reagents flurbiprofen (4.0 g, 16.37 mmol), CDI (3.97 g, 24.56 mmol) and LI-2b (3.25 g, 16.37 mmol). Yield: 3 g (43%). 1H-NMR (300 MHz, CDCl3): δ 1.56 (d, 3H, J = 7.2 Hz), 2.80- 3.0 (m, 4H, J = 5.67 Hz), 3.78 (q, IH, J = 7.10 Hz), 4.36 (m, 2H), 4.66 (t, 2H, J = 6.78), 7.11-7.54 (m, 8H). Example 93
Synthesis of NO-releasing prodrug of flurbiprofen (I-Cl-NOPD14a): This prodrug was synthesized as shown in Scheme 11, Method I. Thus, to a solution of flurbiprofen (5.0 g, 20.46 mmol) in benzene (50 mL), was added oxalyl chloride (3.11 g, 24.55 mmol) at 0 0C and 2 drops of DMF and stirred at RT for 20 hrs. Benzene was removed under vacuum and the residue was diluted with DCM (5OmL). The reaction mixture was cooled to 0 0C and dry ammonia was passed for 30 min. The reaction mixture was concentrated and, after usual aqueous work-up, 4.5 g of flurbiprofen amide was obtained as a white solid. To a solution of flurbiprofen amide (3.0 g, 12.33 mmol) in DCM (70 mL) was added oxalyl chloride (1.87g, 14.79mmol) at 0 0C and refluxed for 16 h. Reaction mixture was cooled to RT and treated with LI-2b (2.45 g, 12.33 mmol) in DCE (1OmL) and stirred overnight. After usual aqueous work-up and chromatographic purification, 0.5 g of I-Cl-NOPD14a were obtained. 1H NMR (CDCI3, 300 MHz): δ 1.55 (d, 3H, J = 6.9 Hz), 2.94-2.97 (bs, 4H), 4.38-4.47 (bs, 3H), 4.68 (t, 2H, J = 6.6 Hz), 7.13-7.55 (bs, 8H) MS: ES+ m/z 469.03 [M+H]+, 467.16 [M-H]+. Example 94
Synthesis of NO-releasing prodrug of flurbiprofen (I-Cl-NOPD15b): This prodrug was synthesized as shown in Scheme 11, Method A. Thus, to a solution of flurbiprofen (2.5 g, 10.23 mmol) in THF (30 mL) was added CDI (3.31 g, 20.46 mmol) and stirred at RT for 16 h. To this was added LI-5.TFA (3.64 g, 10.23 mmol) in THF (15 mL), followed by TEA (2.85 mL, 20.46 mmol) and stirred for 16 h. After usual work-up and chromatographic purification, 1.5 g (91%) of I-Cl-NOPD15b were obtained. 1H NMR (CDCI3, 300 MHz): δ 1.5 (d, 3H, J= 6.9 Hz), 2.82 (t, 2H, J = 6.3 Hz), 2.92 (t, 2H, J = 6.9 Hz), 3.50 (m, 3H), 4.6 (t, 2H, J = 6.6 Hz), 5.8 (s, IH), 7.11-7.55 (bs, 8H). MS: ES+ m/z 425.21 [M+H]+, 423.11 [M-H]+. Example 95
Synthesis of NO-releasing prodrug of indomethacin (I-C1-NOPD16): This prodrug was synthesized as shown in Scheme 11, Method A. Thus, to a solution of indomethacin (2.0 g, 5.59 mmol) in chloroform (25 mL) was added CDI (1.09 g, 6.71 mmol) and stirred for 2h. A solution of LI-2b (1.22 g, 6.15 mmol) and DMAP (751 mg, 6.15 mmol) in chloroform (5 mL) was added, and the mixture was stirred at RT for 16 h. After usual aqueous work-up and chromatographic purification, 2.02 g (67%) of pure I- C1-NOPD16 was obtained. 1H-NMR (300 MHz, CDCl3): δ 2.39 (s, 3H), 2.88-2.95 (m, 4H), 3.69 (s, 2H), 3.84 (s, 3H), 4.38 (t, 2H, J = 6.3 Hz), 4.63 (t, 2H, J = 6.6 Hz), 6.67 (dd, IH, J = 2.4, 8.7 Hz), 6.87 (d, IH, J = 8.7 Hz), 6.96 (d, IH, J = 2.1 Hz), 7.47 (d, 2H, J = 8.4 Hz), 7.67 (d, 2H, J = 8.4 Hz). MS (ES+) m/z: 539.2 [M+H]+, 560.79 [M+Na]+. Example 96
Synthesis of NO-releasing prodrug of indomethacin (I-C1-NOPD18): This prodrug was synthesized as shown in Scheme 11, Method A. Thus, to a solution of indomethacin (3.01 g, 8.42 mmol) in THF (50 mL) at RT was added CDI (1.64 g, 10.10 mmol). After 1 h, LI-5.TFA (3 g, 8.42 mmol) was added at 0 0C, followed by TEA (5.9 mL, 42.1 mmol) and DMAP (0.6 g, 4.91 mmol). The reaction mixture was stirred at RT for 2 d. After usual aqueous work-up and chromatographic purification, 3.16 g (70%) of I-C1-NOPD18 were obtained as yellow solid. 1H NMR (CDCl3, 300 MHz): δ 2.38 (s, 3H), 2.79 (t, 2H, J = 6.3 Hz), 2.86 (t, 2H, J = 6.9 Hz), 3.54 (q, 2H, J = 6.0 Hz), 3.66 (s, 2H), 3.83 (s, 3H), 4.61 (t, 2H, J = 6.6 Hz), 6.01 (bs, IH), 6.71 (dd, IH, J = 2.1, 9.0 Hz), 6.9 (dd, 2H, J = 3.3, 8.1 Hz), 7.49 (d, 2H, J = 8.4 Hz, 2H), 7.66 (d, 2H, J = 8.4 Hz). MS: m/z 538.10 [M+H]+, 560.1 [M+Na]+. Example 97 Synthesis of NO-releasing prodrug of ketoprofen (I-C1-NOPD19): This prodrug was synthesized as shown in Scheme 11, Method A according to the method described in Example 90, using as reagents ketoprofen (1.27 g, 5 mmol), CDI (1.21 g, 7.5 mmol) and LI-2b (1 g, 5 mmol). Yield: 0.6 g (51%). 1H-NMR (300 MHz, CDCl3): δ 1.55 (d, 3H, J = 7.0 Hz), 2.80-2.95 (m, 4H), 3.82 (q, IH, J = 6.7 Hz), 4.35 (t, 2H, J = 6.1 Hz), 4.64 (t, 2H, J = 6.5 Hz), 7.40-7.85 (m, 9H). MS (ES+) m/z: 436.06
Figure imgf000184_0001
Example 98
Synthesis of NO-releasing prodrug of ketoprofen (I-Cl-NOPD20a): This prodrug was synthesized as shown in Scheme 11, Method I. Thus, to a solution of the amide of ketoprofen (1.78 g, 7 mmol) in DCE (70 mL) was added oxalyl chloride (1.0 g, 8.4 mmol) at 0 0C and refiuxed for 16 h. After cooling to RT, a solution of LI-2B (1.4 g, 7 mmol) in DCE (10 mL) was added and stirred for 20 h. After usual aqueous work-up and chromatographic purification, 0.6 g (17 %) of I-Cl-NOPD20a was obtained as a pale yellow gum. 1H NMR (CDCl3, 300 MHz): δ 1.47 (d, 3H, J = 6.96 Hz), 3.00 (bs, 4H), 4.00 (q, IH, J = 6.81 Hz), 4.39 (t, 2H, J = 6.21 Hz), 4.68 (bs, 2H), 7.47-7.77 (bs, 9H). MS: ES+ m/z 478[M+H]+, 477.15[M-H]+. Example 99
Synthesis of NO-releasing prodrug of diclofenac (I-C1-NOPD22): This prodrug was synthesized as shown in Scheme 11, Method B, using as reagents diclofenac (1.0 g, 3.378 mmol), LI-2b (0.68 g, 3.37 mmol), DMF (8 mL), DCC (0.835 g, 4.054 mmol) and DMAP (0.082 g, 0.675 mmol). Yield: 0.35 g (22 %). 1H-NMR (300 MHz, CDCl3): δ 2.91-3.04 (m, 4H), 3.85 (s, 2H), 4.42 (t, 2H, J = 6.6 Hz), 4.72 (t, 2H, J = 6.6 Hz), 6.56 (d, IH, J= 8.1 Hz), 6.82 (s,lH), 6.94-7.03 (m, 2H) , 7.12-7.27 (m,2H), 7.35 (d, IH, J= 8.1Hz). MS (ES+) m/z: 476.90 [M+H]+, 498.86 [M+Naf. Example 100
Synthesis of NO-releasing prodrug of flurbiprofen (I-C1-NOPD26): This prodrug was synthesized as outlined in Scheme 20. Thus, to a solution of S20-I1 (0.8 g, 2.90 mmol) in THF (10 mL) and DMF (10 mL) was added the cesium salt of flurbiprofen (1.2 g, 3.19 mmol) and stirred at RT for 2 h. After usual aqueous work-up and chromatographic purification, 1.13 g (80 %) of I-C1-NOPD26 was obtained as a light yellow semi solid. 1H NMR (500 MHz, CDCl3): δ 1.58 (d, 3H, J = 7.5 Hz), 2.88- 2.94 (m, 4H), 3.88 (q, IH, J= 7.0 Hz), 4.40 (t, 2H, J = 6.5 Hz), 4.64-4.68 (m, 4H), 7.14- 7.54 (m, 8H). MS: m/z 501.1 [M+NH4]+, 506.1 [M+Naf. Example 101
Synthesis of NO-releasing prodrug of gabapentin ethyl ester (I-A1-NOPD1): This prodrug was synthesized as shown in Scheme 12, Method A. Thus, to a stirred solution of diphosgene (0.88 mL, 7.37 mmol) in DCM (3 mL) at 0 0C was added drop- wise a solution of LI-2a (0.80 g, 3.68 mmol) & Hunig's base (1.92 mL, 11.85 mmol) in DCM (1 mL). The mixture was stirred at 0 0C for 30 min and concentrated. The residue was dissolved in DCM (4 mL) and treated with gabapentin ethyl ester hydrochloride (0.95 g, 4.05 mmol) & Hunig's base (1.39 mL, 8.05 mmol). The mixture was stirred at RT for 3 h and concentrated. The residue, after usual aqueous work-up, gave 1.6 g (98 %) of I-S12-I1. 1H-NMR data is consistent with the expected structure. MS (ES+) m/z: 444 [M+H]+, 465.9 [M+Na]+.
To a stirred solution of I-S12-I1 (1.3 g, 2.94 mmol) in acetonitrile (8 mL) at RT was added silver nitrate (0.6 g, 3.52 mmol) portion-wise and stirred at RT for 2.5 h. After filtration through celite, the filtrate was concentrated and the residue purified by column chromatography to afford 0.561 g (45 %) of prodrug I-A1-NOPD1. 1H-NMR data is consistent with the expected structure. MS (ES+) m/z: 425 (M+H)+, 447 (M+Na)+. Example 102 Synthesis of NO-releasing prodrug of lamotrigine (I-Al-NOPD3a and I-Al-NOPD3b): This prodrug was synthesized as shown in Scheme 12, Method B. Thus, to a suspension of lamotrigine (1 g, 3.90 mmol) in toluene (20 mL) at 120 0C was added drop-wise a solution of the imidazolide of LI-2b (1.4 g, 4.70 mmol) in THF (10 mL) and refluxed for 6 h. After usual aqueous work-up and chromatographic purification, 340 mg (20%) of I- Al-NOPD-3a/b was obtained. 1H-NMR data is consistent with the expected structure. MS (ES)+ m/z: 481 (M+H)+. Example 103
Synthesis of NO-releasing prodrug of nicotinic hydrazide (I-A1-NOPD4): This prodrug was synthesized from nicotinic hydrazide (235 mg, 1.70 mmol) according to the procedure described in Example 109 (see Scheme 13, Method B). After usual workup, the crude product was purified by column chromatography to afford 0.21 g (34%) of prodrug I-A1-NOPD4. 1H-NMR (300 MHz, DMSO-d6): δ 3.02 (t, 2H, J = 5.8 Hz), 3.10 (t, 2H, J = 6.1 Hz), 4.28 (t, 2H, J = 5.8 Hz), 4.76 (t, 2H, J = 6.1 Hz), 7.51-7.55 (dd, IH, J = 4.8 Hz, 7.7 Hz), 8.17 (d, IH, J = 7.8 Hz), 8.74 (d, IH, J = 3.8 Hz), 8.98 (s, IH), 9.44 (bs, IH), 10.54 (bs, IH). MS (EI)+ m/z: 363 [M+H]+. Example 104 Synthesis of NO-releasing prodrug of lisinopril dimethyl ester (I-A1-NOPD5) :
This prodrug was synthesized from lisinopril dimethyl ester hydrochloride (1.10 g, 2.56 mmol) according to the procedure described in Example 101 (see Scheme 12, Method B). After usual workup, the crude product was purified by column chromatography to afford 0.76 g (67%) of prodrug I-A1-NOPD5. 1H-NMR (300 MHz, CDCl3): δ 1.49-1.54 (m, 2H), 1.93-2.07 (m, 8H), 2.12-2.28 (m, IH), 2.64-2.68 (m, 2H), 2.91-3.0 (m, 4H), 3.18- 3.25 (m, 3H), 3.42-3.47 (m, IH), 3.52-3.55 (m, 2H), 3.69 (s, 3H), 3.73 (s, 3H), 4.28 (t, J = 6.3 Hz, 2H), 4.47-5.05 (m, IH), 4.69 (t, J = 6.8 Hz, 2H), 5.22 (bt, IH), 7.14-7.19 (m, 3H), 7.23-7.28 (m, 2H). MS (EI)+ m/z: 659 [M+H]+. Example 105 Synthesis of NO-releasing prodrug of omeprazole (I-A1-NOPD6):
This prodrug was synthesized as shown in Scheme 12, Method B. To an ice-cold solution of diphosgene (0.3 mL, 2.48 mmol) in toluene at 0 0C, was added a mixture of LI-2b (0.5 g, 2.51 mmol) and TEA (0.42 mL, 3.0 mmol) in toluene (3 mL) and stirred for 2 h. In a separate flask, omeprazole (0.867 g, 2.50 mmol) was dissolved in THF (5 mL), cooled to 0 0C and NaH (0.059 g, 2.5 mmol) was added. The mixture was stirred for 30 min, the above reaction mixture was added dropwise to it and stirred for 2 h. After usual aqueous work-up and chromatographic purification, 0.23 g (20 %) of I-A1-NOPD6 was obtained as a reddish-yellow gum. 1H-NMR: (CDCl3, 300 MHz): 2.21 (s, 3H), 2.36 (s, 3H), 2.93- 3.05 (m, 2H), 3.19-3.28 (m, 2H), 3.88 (s, 3H), 3.92 (s, 3H), 4.70-4.87 (m, 6H), 7.10-7.80 (m, 3H), 8.10 (s, IH). MS: ES+ m/z 571 (M+H)+, 593 (M+Na)+. Example 106
Synthesis of NO-releasing prodrug of hydralazine (I-A1-NOPD7): This prodrug was synthesized from hydralazine hydrochloride (0.99g, 5.01mmol) according to the procedure described in Example 109 (see Scheme 13, Method B). After usual workup, the crude product was purified by column chromatography to afford 0.8 g (41%) of prodrug I-A1-NOPD7. 1H-NMR (300 MHz, CDCl3): δ 2.95-3.06 (m, 4H), 4.43 (t, 2H, J = 6.35Hz), 4.69 (t, 2H, J = 6.7 Hz), 7.57 (m, IH), 7.63-7.71(m, 2H), 8.16 (s, IH), 8.29 (d, IH, J = 7.6 Hz). MS (ES+) m/z: 386.05 (M+H)+. Example 107 Synthesis of NO-releasing prodrug of amlodipine (I-A1-NOPD8): This prodrug was synthesized from amlodipine (1.67 g, 4.09 mmol) according to the procedure described in Example 109 (see Scheme 12, Method B). After usual workup, the crude product was purified by column chromatography to afford 1.33 g (61%) of I- A1-NOPD8. 1H-NMR (300 MHz, CDCl3): δ 1.18 (t, 3H, J = 7.1 Hz), 2.36 (s, 3H), 2.93- 2.99 (m, 4H), 3.47 (bs, 2H), 3.61-3.64 (m, 5H), 4.04 (q, 2H, J = 7.1 Hz), 4.35 (bt, 2H), 4.68-4.74 (m, 4H), 5.0 (bs, IH), 7.13-7.36 (m, 4H). MS (ES+) m/z: 634.14 (M+H)+, 656.83 (M+Na)+; (ES") m/z: 631.94 (M-H)+. Example 108
Synthesis of NO-releasing prodrug of levetiracetam (I-A2-NOPDla): This prodrug was synthesized from levetiracetam (1.0 g, 5.87 mmol) according to the procedure generally described in Example 82 (see Scheme 13, Method A). After usual workup and chromatographic purification, the product was further purified by preparative HPLC to afford 728 mg (31%) of prodrug I-A2-NOPDla. 1H-NMR was consistent with the expected structure. MS (ES)+ m/z: 396.1 [M+H]+, 418.1 [M+Na]+, (ES)" m/z: 394.1 [M-H]". Example 109
Synthesis of NO-releasing prodrug of valdecoxib (I-A3-NOPDla): This prodrug was synthesized as shown in Scheme 13, Method B. Thus, to a cold suspension of sodium hydride (271 mg, 6.81 mmol) in THF (7 mL) was added drop-wise a solution of valdecoxib (1.78 g, 5.68 mmol) in THF (15 mL) and stirred at RT for 2 h. A solution of the imidazolide of LI-2b (2.0 g, 6.81 mmol) in THF (15 mL) was added and stirred at room temperature for 18 h. The reaction mixture was concentrated and the residue, after usual aqueous work-up and chromatographic purification, afforded 976 mg (32 %) of prodrug I-A3-NOPDla. 1H-NMR data is consistent with the expected structure. MS (ES)" m/z: 538 [M-H]". Example 110 Synthesis of NO-releasing prodrug of celecoxib (I-A3-NOPD2a):
This prodrug was synthesized from celecoxib (6.62 g, 17.35 mmol) according to the procedure described in Example 109 (see Scheme 13, Method B). After usual workup, the crude product was purified by column chromatography to afford 1.55 g (15%) of prodrug I-A3-NOPD2a. 1H-NMR (300 MHz, CDCl3): δ 2.38 (s, 3H), 2.84-2.98 (m, 4H), 4.34 (t, 2H, J = 6.45 Hz), 4.63-4.71 (m, 2H), 6.74 (s, IH), 7.09-7.25 (m, 4 H), 7.51 (d, 2H, J = 6.8 Hz), 8.02 (d, 2H, J = 6.8 Hz). MS (ES)+ m/z: 606.87 [M + H]+, 628.93 [M + Na]+; (ES)" m/z: 604.88 [M-H]". Example 111 Synthesis of NO-releasing prodrug of paracetamol (I-H1-NOPD1): This prodrug was synthesized as shown in Scheme 14, Method B. Thus, to a solution of paracetamol (2.0 g, 13.24 mmol) in THF (20 mL) was added CDI (2.36 g, 14.57 mmol) and the mixture was stirred at RT for 3 h. To this was added a solution of LI-2b (1.21 g, 6.62 mmol), followed by DMAP (0.802 g, 6.622 mmol) and stirred overnight at RT. The mixture was quenched with water and extracted with EtOAc. After usual aqueous work- up and chromatographic purification, 0.3 g (6%) of prodrug I-H1-NOPD1. 1H-NMR data is consistent with the expected structure. MS (Cl)+ m/z: 376 [M+H]+. Example 112
Synthesis of NO-releasing prodrug of paracetamol (I-Hl-NOPD2a): This prodrug was synthesized as shown in Scheme 14, Method D. Thus, to a solution of chlorocarbonyl isocyanate (0.701g, 6.622 mmol) in benzene (5 mL) at 0 0C was added a solution of paracetamol (1 g, 6.622 mmol) and stirred at 0 0C for 1 h. To this was added a solution of LI-2b (1.21 g, 6.622 mmol) and TEA (1 mL) in THF (5 mL), and stirred overnight at RT. After usual aqueous work-up and chromatographic purification, 90 mg (3%) of prodrug I-Hl-NOPD2a was obtained. 1H-NMR data was consistent with the expected structure. MS: (ES)" m/z: 418 [M-H]". Example 113
Synthesis of NO-releasing prodrug of paracetamol (I-H1-NOPD3): This prodrug was synthesized from paracetamol (2.0 g, 13.24 mmol) according to the procedure described in Example 122 (see Scheme 14, Method C). After usual workup, the crude product was purified by column chromatography to afford 1.0 g (20%) of prodrug I-H1-NOPD3. 1H-NMR (500 MHz, CDCl3): δ 2.11 (s, 3H), 2.91 (t, 2H, J = 6.5 Hz), 3.06 (t, 2H, J = 6.5Hz), 3.49 (t, 2H, J = 6.5 Hz), 4.75 (t, 2H, J = 6.5 Hz), 7.05 (d, 2H, J = 9.0 Hz), 7.54 (d, 2H, J = 9.0 Hz). MS (ES)+ m/z: 376 [M+H]+, 393 [M+NH4]+, 397 [M+K]+. Example 114 Synthesis of NO-releasing prodrug of metronidazole (I-H1-NOPD6) :
This prodrug was synthesized in two steps as shown in Scheme 14, Method C. Step 1 : To a suspension of metronidazole (5 g, 29.22 mmol) in chloroform (100 mL) was added CDI (5.21 g, 32.2 mmol) and stirred overnight at RT. The reaction mixture, after usual aqueous work-up, gave 7.66 g (98 %) of the imidazolide intermediate. 1H-NMR data was consistent with the expected structure. MS (ES)+ m/z: 266.1 [M + H]+.
Step 2: To a mixture of LI-5.TFA (2.68 mmol) and TEA (1.08 g, 10.72 mmol) in DCM (10 mL) at 0 0C was added the imidazolide of metronidazole (0.78 g, 2.95 mmol) and stirred at RT for 48 h. The reaction mixture was quenched with water and extracted with DCM. After usual aqueous work-up and chromatographic purification, 50 mg (4.3%) of I-H1-NOPD6 was obtained. 1H-NMR (500 MHz, CDCl3): δ 2.50 (s, 3H), 2.80 (t, 2H, J = 6.3 Hz), 2.96 (t, 2H , J = 6.6Hz), 3.47-3.50 (m, 2H), 4.41 (t, 2H, J = 5.1Hz), 4.58 (t, 2H, J = 5.1Hz), 4.70 (t, 2H, J = 6.6Hz), 7.96 (s, IH). MS (ES)+ m/z: 395.99 [M+H]+. Example 115 Synthesis of NO-releasing prodrug of budesonide (I-H1-NOPD9): This prodrug was synthesized from budesonide (0.5 g, 1.16 mmol) according to the procedure described in Example 122 (see Scheme 14, Method C). After usual workup, the crude product was purified by column chromatography to afford 0.25 g (33%) of prodrug I-H1-NOPD9. 1H-NMR data was consistent with the expected structure. MS (ES)+ m/z: 655 [M+H]+. Example 116 Synthesis of NO-releasing prodrug of 4-Hydroxy-TEMPO (I-H1-NOPD10):
A solution of LI-2b (0.20 g, 1.20 mmol) and CDI (0.195 g, 1.20 mmol) in chloroform (5 mL) was stirred at RT for 2 h, which was followed by the addition of 4-hydroxy-TEMPO (0.173 g, 1.00 mmol) and DMAP (0.122 g, 1.00 mmol). The mixture was refluxed for 2 d, then purified by column chromatography to afford 110 mg (27 %) of I-H1-NOPD10 as a red oil. MS: EI+ m/z 398 [M+H]+, 420 [MH-Na]+. Example 117
Synthesis of NO-releasing prodrug of edaravone (I-H1-NOPD11): To a solution of edaravone (0.87 g, 5 mmol) in acetonitrile was added KF-Al2O3 (66 g) and, under thorough mixing, LI-3a (2.8 g, 10 mmol) was added. The mixture was agitated for 20 h. After usual aqueous work-up and chromatographic purification, 70 mg (4%) of the intermediate bromide was obtained as a reddish-yellow oil. 1H NMR (CDCl3, 500 MHz): δ 2.28 (s, 3H), 3.00-3.10 (m, 4H), 3.59 (t, 2H, J = 8 Hz), 4.34 (t, 2H, J = 6.5 Hz), 5.5 (s, IH), 7.4 (t, 2H, J = 1 Hz), 7.69 (t, 3H, J = 1 Hz). MS: ES+ m/z 375 [MH-H]+, 397.0 [MH-Na]+. To a solution of the above bromide (0.05 g, 0.134 mmol) in acetonitrile (1.5 mL) was added AgNO3 (0.027 g, 0.160 mmol) and stirred for 20 h. After usual aqueous workup and purification, 0.025 g (53 %) of I-H1-NOPD11 was obtained as a brown gum. 1H NMR (CDCl3, 500 MHz): δ 2.28 (s, 3H), 2.90 (t, 2H, J = 6.5 Hz), 3.10 (t, 2H, J = 6.5 Hz), 4.33 (t, 2H, J = 6.0 Hz), 4.63 (t, 2H, J= 6.5 Hz), 5.5 (s, IH), 7.60-7.63 (bs, 2H), 7.65-7.67 (bs, 3H). MS: ES+ m/z 356 [MH-H]+.
Biological Example 1:
Screening of prodrugs and mutual prodrugs of anticonvulsants:
Most of the prodrugs and mutual prodrugs of anticonvulsants described in this invention were evaluated at National Institute of Neurological Disorders and Stroke (NINDS), National Institute of Health (NIH), under their Antiepileptic Screening Program (ASP).
Test 1 is an initial screening for anticonvulsant activity in the Maximal Electroshock Test (MES) and Subcutaneous Metrazol Seizure Threshold Test (scMET) models combined with an initial assessment of toxicity (TOX) in mice via i.p. injection (see further explanation below). The data for each condition is presented as N/F, where N = number of animals protected from seizure and F = number of animals tested. For test of toxicity, N = number of animals displaying toxic effects and F = number of animals tested. Any deaths occurring during the test were recorded. Maximal Electroshock Test (MES): The MES is a model for generalized tonic- clonic seizure and provides an indication of a compound's ability to prevent seizure spread when all neuronal circuits in the brain are maximally active. These seizures are highly reproducible and electro-physiologically consistent with human seizures. For all tests based on MES convulsions, 60 Hz of alternating current (50 mA in mice) is delivered for 2s by corneal electrodes, which have been primed with an electrolyte solution containing an anesthetic agent (0.5% tetracaine hydrochloride). Mice were tested at various intervals following doses of 30, 100 and 300 mg/kg of test compound given by i.p. injection of a volume of 0.01 mL/g. Other doses can be used if indicated by previously known pharmacology. An animal is considered "protected" from MES- induced seizures upon abolition of the hind-limb tonic extensor component of the seizure.
Subcutaneous Metrazol Seizure Threshold Test (scMET): Subcutaneous injection of the convulsant metrazol produces clonic seizures in laboratory animals. The scMET test detects the ability of the test compound to raise the seizure threshold of an animal and thus protect it from exhibiting a clonic seizure. Animals were pretreated with various doses of the test compound given by i.p. injection. At the previously determined Time to Peak Effect (TPE) of the test compound, the dose of metrazol which will produce convulsions in 97% of animals (CDc)7: 85 mg/kg in mice) was injected into a loose fold of skin in the midline of the neck. The animals were placed in isolation cages to minimize stress and observed for the next 30 minutes for the presence or absence of a seizure. An episode of clonic spasms, approximately 305 seconds, of the fore and/or hind limbs, jaws, or vibrissae is taken as the end point. Animals which do not meet this criterion were considered protected.
Acute Toxicity - Minimal Motor Impairment (MMI): To assess a compound's undesirable side effects (toxicity), animals were monitored for overt signs of impaired neurological or muscular function. In mice, the rotorod procedure is used to disclose minimal muscular or neurological impairment. When a mouse is placed on a rod that rotates at a speed of 6 rpm, the animal can maintain its equilibrium for long periods of time. The compound is considered toxic if the animal falls off this rotating rod three times during a 1-min period. In addition to MMI, animals may exhibit a circular or zigzag gait, abnormal body posture and spread of the legs, tremors, hyperactivity, lack of exploratory behavior, somnolence, stupor, catalepsy, loss of placing response and changes in muscle tone.
Compounds that were active in Test 1 (mice i.p.) were further screened in Test 2 (rat p.o.). Compounds retaining activity in Test 2 (rat p.o.) were selected for secondary evaluation (i.e., Test 3, Rat P.O. quantification) as explained below:
Secondary Evaluation: All quantitative in vivo anticonvulsant/toxicity evaluations of the active compounds were conducted at compound's time of peak pharmacodynamic activity (TPE). Groups of at least 8 rats received various doses of the candidate compound until at least two points were established between the limits of 100 percent protection or toxicity and zero percent protection or minimal toxicity. The 95 percent confidence limits, slopes of the regression lines and standard errors of the slopes were calculated for each quantitative determination. Rats received test compounds orally.
Test 1 screening results are presented in Table 1. Compound I-CA-MPD24 was active in both MES and scMET models and was shown to be non-toxic. However, some compounds were active in both MES and scMET models and were also shown to be toxic. The compounds (i.e., I-A1-PD4, 1-AA-MPD12, 1-CA-MPD23, 1-A1-PD5, 1-Al- NOPD3, 1-CA-MPD24, 1-A1-PD15, I-CA-MPD25, and I-AA-MPD11) that are shown to be active in MES but showed no or mild toxicity were selected for Test 2 screening and those results are presented in Table 2.
Three of the compounds (i.e., I-A1-PD4, 1-AA-MPD12, and I-A1-NOPD3) were considered for secondary evaluation, where quantification of their antiepileptic activity and neurotoxicity in rats (p.o.) was carried out. This secondary evaluation determines the time to peak effect (TPE), neurotoxicity, median effective dose (ED50) and biological response. The 95% confidence interval, the slope of the regression line, and the standard error are then calculated. The results of secondary evaluation (Test 3) are presented in Tables 3 A and 3B.
Table 1: Primary Screening (Test 1) data for Anticonvulsant Activity and Neurotoxicity in Mice (test compound administered i.p.)
Figure imgf000193_0001
Figure imgf000194_0001
aKey: +++ = activity or toxicity at 3O.mg/kg, ++ = activity or toxicity at 100 mg/kg, + = activity or toxicity at 300 mg/kg, - = no activity or no toxicity at 300 mg/kg. bMaximal electroshock seizure test. cSubcutaneous pentylenetetrazol seizure test. dNeurological toxicity (number of animals exhibiting toxicity/number of animals tested). e(number of animal protected/number of animal tested), nd = not determined. fLoss of righting reflux. gAt 6 hours after dosing. hAt 2 hours after dosing. 'Unable to grasp rotorod. jDeath. kAt 0.25 hours after dosing. 'Myoclonic jerks. mAt 6 hours after dosing.
Table 2: Screening (Test 2) data for Anticonvulsant Activity and Neurotoxicity in Rats (test compound administered p.o.)
Figure imgf000195_0001
Figure imgf000196_0001
aMaximal electroshock seizure test, (number of animal protected/number of animal tested). cNeurological toxicity. d(number of animals exhibiting toxicity (i.e., atoxia)/number of animals tested).
Table 3A: Screening (Test 3) data for Anticonvulsant Activity (Time to Peak Effect) and Neurotoxicity in Rats (test compound administered p.o.)
Figure imgf000196_0002
Figure imgf000197_0001
aMaximal electroshock seizure test, (number of animal protected/number of animal tested). cSubcutaneous pentylenetetrazole seizure test. dNeurological toxicity. e(number of animals exhibiting toxicity (i.e., atoxia)/number of animals tested). fDeath following continueous seizure. sPopcorn effect and continuous seizure activity. Mild ataxia only.
Table 3B: Screening (Test 3) data for Anticonvulsant Activity (ED50 and Biological Response and ED50) in Rats (test compound administered p.o.)
Figure imgf000197_0002
Figure imgf000198_0001
aMaximal electroshock seizure test. . b(number of animal protected/number of animal tested).
I-A1-PD4 is a simple prodrug of lamotrigine. For this prodrug, ED50 for the MES model was determined to be 6.55 mg/kg and the time to peak effect was found to be 4.0 h after drug administration at doses of 10 as well as 30 mg/kg. This compound has shown moderate protection in scMET models where one out of four animals were protected at 0.25 h and 2.0 h period and two out of four animals were protected at 1.0 h after administration of the drug at a dose of 50 mg/kg. For the toxicity analysis, none of the animals given 100 mg/kg showed signs of toxicity.
I-AA-MPD12 is a mutual prodrug of lamotrigine and gabapentin ethyl ester. For this compound, ED50 for the MES model was found to be 17 mg/kg and the time to peak effect was found to be 6.0-8.0 h at a dose of 30 mg/kg and indicated a significant extension protection (2 out of 4 animals were still protected) at 24 h after drug administration. Surprisingly, this compound, although less potent than lamotrigine, has exhibited significant extension in the duration of protection. At 50 mg/kg, none of the animals exhibited toxicity. However, at 100 mg/kg, one of eight animals exhibited mild ataxia. I-A1-NOPD3 is a NO-releasing prodrug of lamotrigine. For this prodrug, ED50 for the MES model was determined to be 10.1 mg/kg and the time to peak effect was found be at 8.0 h at a dose of 30 mg/kg and revealed a significant extension of protection (3 out 4 animals were still protected) even at 24 h after drug administration. Surprisingly, this prodrug, although less potent than its parent drug, has exhibited significant extension in the duration of protection. At 50 mg/kg, this compound has also exhibited significant protection (3 out of 4 animals were protected at 8 h after drug administration) in scMET rat model. For the toxicity analysis, only one in eight animals exhibited toxicity at 6.0 h time point at a dose of 500 mg/kg. At other time points (i.e., 0.25 h, 0.5 h, 1.0 h, 2.0 h, 4.0 h, 8.0 h after drug administration), none of the animals (0/8) exhibited any significant toxicity at the high dose of 500 mg/kg. Biological Example 2:
The pharmacological experiments on NO-releasing aspirin prodrugs were carried out by following the procedures described herein: Animals and Procedures:
Male or female Sprague-Dawley rats weighing 150-200 g were used in the study. The rats were fed normal standard laboratory chow and maintained under standard conditions (room temperature of 22 ± 2 0C; 50 ± 10 % relative humidity; artificial light 06:00 to 18:00). All experimental procedures mentioned below are approved by institutional animal research committees and were performed in accordance with standard guidelines for the treatment of animals. Sample preparation and standard curve:
HPLC: Waters Allience analytical HPLC equipped with 2996 PDA detector and Empower software were used to analyze the samples. HPLC Column: Waters X-Terra RP-18 analytical column, 150 X 3.9 mm, 5 μ.
HPLC Method: Flow: 1 mL/min, detecter set at 210 nm and at Maxplot (210-400 ran range). Solvent A: Acetonitrile; Solvent B: 0.1% TFA in water. Elution method: A linear gradient of 0-100% A.
Plasma samples were processed by transferring 75 μl quantity of blood into a test tube containing 250 μl acetonitrile, vortex-mixed and centrifuged at 1000 g for 5 min. 200 μl of supernatant was then taken and diluted to 2 times with acetonitrile. 100 μl of the sample was injected into HPLC for analysis. Salicylate standard curves were generated using acetonitrile as solvent in the working range of 1-100 μg/ml.
Pharmacokinetic parameters were calculated using WinNonlin software (4.1 version). Cmax, Tmax, AUC 0-24, AUC 0-infmity, and Ty2 characterized and each curve generated following oral treatment. In Vitro Plasma stability:
The rationale is that the prodrugs would be hydrolyzed in-vivo before, during or after absorption to release the corresponding free drugs. Therefore, we tested whether the test compounds (I-C 1 -NOPD6, 1-C 1 -NOPD4, 1-C 1 -NOPD5 A) released parent drug in rat plasma at 37 ° C after 30 minutes incubation. The compounds were extracted back into acetonitrile with rigorous vortex. The results suggested that all prodrugs tested except I- C1-NOPD6 were found to be converting to the expected metabolite (salicylate) of the parent drug (aspirin) as revealed by HPLC analysis. Even aspirin was completely metabolized to salicylate after 30 minutes of incubation with rat plasma indicating that all the test compounds released aspirin, which in turn converted into salicylate. Pharmacokinetic studies:
The oral pharmacokinetics of the test compounds, I-C1-NOPD6, 1-C1-NOPD4, I- C1-NOPD5A and I-C1-NOPD5B was done in rats and the release profiles of salicylate from these compounds were analyzed by HPLC and the results were presented in Figure 1 and Table 4. Overnight fasted rats were fed with 35 mg/kg equivalent doses of aspirin and test compounds. Blood was collected from orbital plexus of test animals at various time points up to 24 hrs. As shown in Figure 1, the test compounds I-C1-NOPD4 and I- C1-NOPD5B indicated unexpected drug release profiles wherein the salicylate is released in a sustained and controlled manner starting from 1 hour through 12 hours. For I-Cl- NOPD5B, the plasma salicylate concentration was maintained between 50 and 75 μg/ml during this extended period of over 11 hours. This kind of plasma concentrations of the drug can result in significant extension of duration of action. For I-C1-NOPD4 also, the plasma salicylate concentration was maintained between 35 and 50 μg/mL during an extended period of over 11 hours. Although aspirin absorption (Figure 1) was highest during 0.5 - 6.0 hrs (during which period much of the damage to the gastrointestinal tract of the subject occurs due to high concentrations of the drug), plasma salicylate concentration for aspirin and I-C1-NOPD4 were comparable during the period from 8 through 24 hours. Such sustained release profile of active drug from the prodrug is expected to cause negligible or insignificant gastrointestinal damage as the plasma concentration of the drug never reaches to the toxic levels. Similar release profile was observed with I-C1-NOPD5A but for a shorter period of time. Unexpectedly, we have also observed as recorded in Table 4, nearly equal drug AUC values for aspirin and I-Cl- NOPD5B (i.e., 923.63 + 182.08 for aspirin vs 951.98 ± 11.58 for I-C1-NOPD5B) which indicates that the prodrug is as bioavailable as its parent drug, but prodrug does not cause gastric damage. Surprisingly, neither the prodrug nor the salicylate was found in the plasma of the animals fed with I-C1-NOPD6 (data not included in the graph) at any point of time tested, the reasons for which are not known.
Figure imgf000201_0001
Time (hr)
Figure 1. Plasma salicylate profile of aspirin and its NO-releasing prodrugs. The data values are expressed as Mean ± S.E.M, n=3-4 animals. The data values at time points 6 and 10 hours is an average from two animals only. Table 4. Comparison of pharmacokinetic parameters of aspirin and its nitro derivatives
Figure imgf000201_0002
AUC0-24 h (h.μg/ml) 905.84 + 173.14 749.36 ± 69.38 557.80 ± 97.65 922.89 ± 12.50
AUCo-α (h.μg/ml) 923. 63 ± 182 .08 772.17 ± 75.68 565.30 ± 96.78 951. 98 ± 11.58
Tin (h) 3.56 ± 0.42 3.98 ± 0.25 3.35 ± 0.32 4.14 ± 0.24
*The data values are mean ± SEM, n = 3-4 Ulcerogenic activity:
Gastrointestinal ulceration is a serious side effect associated with NSAIDs. The clinical uses of potent NSAIDs are greatly limited by its gastrointestinal toxicity. We tested ulcerogenic potential of the test compounds, I-C1-NOPD6, I-C1-NOPD4, I-Cl- NOPD5A, and I-C1-NOPD5B in rats. Overnight fasted rats were given orally 100 mg/kg equivalent doses of aspirin and prodrugs (in the case of I-C1-NOPD5A and I-Cl- NOPD5B, 200 mg/kg equivalent doses were administered). The animals were sacrificed at 3 hours after drug administration. Stomachs of treated rats were separated, perfused with 10 ml of 2 % formalin, and then cut open over the greater curvature. The severity of the mucosal damage was then assessed on the basis of size (area) of the observed ulcers under surgical microscope with a square grid as per the established procedure (Takeuchi et al., J. Pharmacol. Exp. Ther. 1998, 286 (1), 115-121). Interestingly, none of the animals treated with the test compounds showed any signs of development of ulcers. However, severe haemorrhagic lesions (Mean ± S.E.M.: 2.7 ± 0.9 mm2) were seen in aspirin treated rats. Anti-inflammatory activity:
Anti-inflammatory activity of test compounds was measured in carrageenan- induced rat paw edema model (Takeuchi et al., J. Pharmacol. Exp. Ther. 1998, 286 (1), 115-121). The activity of aspirin and test compounds (75 mg/kg equivalent dose of aspirin) is shown in Table 5. Aspirin at 75 mg/kg, p.o. exhibited anti-inflammatory activity from 1 hr through 6 hr with peak maximal activity at 4 hr. I-C1-NOPD4 showed significant activity during the first two hours after drug administration but its activity was not as good as that of aspirin from 2 hr through 6 hr. Surprisingly, I-C1-NOPD5A showed negligible anti-inflammatory activity at any time point tested (data not incorporated). We have not yet evaluated I-Cl-NOPD5Bin this efficacy test. Table 5
Compound Rat paw edema (% inhibition)
Mean ± SEM, n = 6 1 hour 2 hour 4 hour 6 hour
Aspirin 31.0 ± 7.2 52.5 ± 3.4 60.7 ± 6.9 42.8 ± 6.9
I-C1-NOPD4 42.4 ± 13.3 44.9 ± 12.9 24.3 ± 7.7 8.6 ± 5.1
The results indicate the following:
1. Sustained release of the active drug over a period of 10-11 hours, which is good for twice daily dosage regimen, and
2. Exceptional gastrointestinal safety even at high equivalent doses of prodrugs compared to aspirin, which caused severe ulcers at equivalent doses.

Claims

We claim:
1. A compound of formula (I) or pharmaceutically acceptable salts thereof:
Figure imgf000204_0001
Formula (I) wherein, a is 0-2;
B independently represents a bond, (CH2)b, (CH2CH2O)C, S-S, S-S=O, S-SO2 or S-S=NH; b is 1-6; c is 1-1000;
A and A1 independently represent a bond, (CH2)d, 1,2-phenylene, 1,3-phenylene or 1,4- phenylene; d is 1-8;
D1 represents a therapeutic agent comprising one or more of the functional groups selected from the group consisting of -OH, -SH, -NHR1, -CO2H, -CONHR1, - OCC=O)NHR1, -SO2NHR1, -OSO2NHR1, -N(R^CC=O)NHR1 and -N(R^SO2NHR1; D2 independently represents D1, a peptide, protein, monoclonal antibody, vitamin, R2, R3, R4, NO, NO2, NONOate or any other nitric oxide-releasing group or molecule, a group or molecule comprising one or more of water-solubilizing functional groups, a polymer or an amino acid;
E independently represents CH2 or a bond;
L1 and L2 independently represent a bond, O, S, NR1, L, or a linkage selected from the group consisting of:
Figure imgf000205_0001
L is R or a group with bonding in any direction, independently selected from the group consisting of:
Figure imgf000205_0002
and V^v R1 ^N^ ;
X independently represents a bond, C, O, S, or NR1;
Y independently represents a bond, C=O, C=S, S=O, SO2, P(O)XR1, or (CH2)d; wherein d is as defined;
Z independently represents a bond, or (CH2)J; wherein, j is 1-4;
R1 independently represents a bond, H, (d-CsJalkyl, substituted(Ci-Cs)alkyl, (C5-
C]4)aryl, aralkyl or M6+;
R2 independently represents H, NH2, or NHAc;
R3 independently represents H, CO2R5 or CH2CO2R5;
R4 independently represents H, OH, O-(C]-C8)alkyl, OM6+, or a group selected from the group consisting of:
Figure imgf000206_0001
Figure imgf000207_0001
M independently represents Na, K or a pharmaceutically acceptable metal ion; e = 1-3;
R5 independently represents at each occurrence H, Me+, (Ci-Cs)alkyl, (C3-C8)cycloalkyl, substituted (C5-Ci4)aryl, hetero(C2-C14)aryl, C(=O)(CH2)fCHR9CO2R5, CH2C(=O)OR5,
P(=O)(OR5)2 ,
Figure imgf000207_0002
°^Dextran
Figure imgf000207_0003
X2 independently represents O, S, SO, SO2, or NR5;
R6 independently represents H, Na+, K+ any other pharmaceutically acceptable metal ion,
(C1-C8)alkyl, or (C3-C8)cycloalkyl;
R7 independently represents at each occurrence same or different R5;
R8 independently represents CH2, O, NR4, S, S=O or O=S=O;
R9 independently represents H, (Ci-C8)alkyl or an amino acid; f is 0-6; g is 0-1; h is 1-2000; i is 1-4;
Rloand R11 independently represent H, (Ci-C8)alkyl, (C3-C8)cycloalkyl, or a group selected from the group consisting of:
Figure imgf000209_0001
with a proviso that when R10 is selected from the above group, R11 represents H or (C1-
C8)alkyl, and when R11 is selected from the above group, R10 represents H or (C1-
C8)alkyl;
R12 independently represents a group selected from the group consisting of:
Figure imgf000210_0001
Figure imgf000211_0001
X3 is independently 0 or NR7.
2. The compound according to claim 1, wherein a is 0.
3. The compound according to claim 2, wherein D2 is a group or molecule comprising one or more water solubilizing functional groups selected from the group consisting of hydroxyl, amino, acylamino, carboxyl, sulphate, sulfonate, phosphate, phosphonate, N-acylsulfonamide, N-acylsulfamate, N-acylcarbamate, N-acylcarbamate metallic salts, and amino acids to form water-soluble prodrugs.
4. The compound according to claim 2, wherein D2 is selected from the group of amino acids consisting of Alanine, Arginine, Asparagine, Aspartic acid, Cysteine, Glutamine, Glutamic acid, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine, and Valine.
5. The compound according to claim 2 wherein D2 is a polymer.
6. The compound according to claim 5, wherein the polymer is selected from the group consisting of dextran, modified dextran, arabinogalactan, polyamino acids, and polyethylene glycol.
7. The compound according to claim 6, wherein the polymer is a polyaminoacid selected from group consisting of poly(l-glutamic acid), poly(d-glutamic acid), poly(dl- glutamic acid), poly(l-aspartic acid), poly(d-aspartic acid), poly(dl- aspartic acid), copolymers of the polyaminoacids and polyethylene glycol, polycaprolactone, polyglycolic acid, polylactic acid, polyacrylic acid, poly(2-hydroxyethyl 1 -glutamine), dextran aldehyde, carboxymethyl dextran, arabinogalactane aldehyde, carboxymethyl arabinogalactane, and hyaluronic acid.
8. The compound according to Claim 5, wherein the polymer has a molecular weight of about 5000 to about 100,000 Daltons.
9. The compound according to Claim 5, wherein the polymer has a molecular weight of about 10,000 to about 50,000 Daltons.
10. The compound according to claim 2 wherein D2 is a dipeptide.
11. The compound according to claim 2, wherein D2 is a vitamin selected from the group consisting of vitamin A, vitamin C, thiamine, folic acid, biotin, inositol, nicotinic acid, nicotinamide, riboflavin, pyridoxine, pyridoxal 5-phosphate, ergosterol, vitamin D2, vitamin D3, vitamin D4, vitamin E, menadoxime, menadiol, and vitamin K5.
12. The compound according to claim 2, L2 is O; A and A1 are independently (CH2)d, 1,2-phenylene, 1,3-phenylene, or 1,4-phenylene; d is 1-4; B is S-S, S-S=O, S-SO2 or S- S=NH; D2 is NO, NO2 or a NONOate selected from the group consisting of:
Figure imgf000213_0001
Figure imgf000213_0002
and
Figure imgf000213_0003
•
13. The compound according to claim 2, wherein L2 is O; A and A1 are CH2; E is CH2; B is a bond or (CH2)b; b is 1-6; a is O; D2 is NO2 and L1 is a group selected from
Figure imgf000213_0004
wherein,
X is O, S or NR1; and
Y and Z are as defined.
14. The compound according to claim 2, selected from the group consisting of:
Figure imgf000214_0001
Figure imgf000215_0001
Figure imgf000215_0002
I-C1-PD14 I-Cl-PD15a
Figure imgf000216_0001
Figure imgf000217_0001
I-A3-NOPD2a
Figure imgf000218_0001
Figure imgf000219_0001
Figure imgf000220_0001
Figure imgf000221_0001
I-AA-MPD13
Figure imgf000222_0001
Figure imgf000222_0002
Figure imgf000223_0001
Figure imgf000224_0001
Figure imgf000224_0002
PD24
Figure imgf000224_0004
Figure imgf000224_0003
PD25
Figure imgf000225_0001
15. A pharmaceutical composition comprising a therapeutically effective amount of the compound of claim 2, or a pharmaceutical salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
16. A pharmaceutical composition comprising a therapeutically effective amount of the compound of claim 14, or a pharmaceutical salt thereof and one or more pharmaceutically acceptable carriers, vehicles or diluents.
17. The compound as in claim 2, wherein D1 and D2 represent known and investigational amino-, hydroxyl-, carboxyl-, and keto- containing drugs compiled in drug databases comprising the Merck Index, IDdb, Prous Science's Integrity®, Prous Science Drugs of the Future™, and The Ensemble®.
18. The composition of claim 15 comprising therapeutically effective amount of pairs of drugs selected from: Paclitaxel and Doxorubicin; Paclitaxel and Mitomycin C; Paclitaxel and 9-aminocamptothecin; 3-Aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP), 3-Ammopyridine-4-methyl-2-carboxaldehyde thiosemicarbazone (3-AMP) and Paclitaxel, Doxorubicin, Mitomycin C; CC-1065 and Paclitaxel, Doxorubicin, Mitomycin C; Trans-Resveratrol [(E)-3,4',5-trihydroxystilbene) and Paclitaxel, Doxorubicin, Mitomycin C; Retinoic acid and Butyric acid; Paclitaxel and Captopril; Doxorubicin and Biotin; 5-Fluorouracil and Cytarabine; Edatrexate and Paclitaxel; Cephalosporanic acid and Paclitaxel; Cephalosporin and Paclitaxel; Paclitaxel and Gemcitabine; Levodopa and Carbidopa; Amoxicillin and Clavulanic acid; Ampicillin and Clavulanic acid; Amoxicillin and Pencillinic acid sulfone; Ampicillin and Pencillinic acid sulfone; Olivanic acid and 3-substituted Z-2-acylaminopropionic acid; Lifibrol and Lovastatin/Pravastatin/Fluvastatin/Atorvastatin/Simvastatin; Ezetimibe and Lovastatin/ Pravastatin/ Fluvastatin/Atorvastatin/Simvastatin; Amlodipine and
Lovastatin/Pravastatin/Fluvastatin/Atorvastatin/Simvastatin; Metformin and
Nateglinide/Glipizide/Glibenclamide (Glyburide); Metformin and
Lovastatin/Pravastatin/Fluvastatin/Atorvastatin/Simvastatin; Pseudoephedrine and Fexofenadine/Cetirizine/Desloratadine/Epinastine; Salbutamol and Ipratropium bromide; Mometasone and Formoterol/Salmeterol; Fluticasone and Formoterol/Salmeterol; Budesonide and Formoterol/Salmeterol; Declofenac and Misoprostol; Declofenac and Omeprazole/Lansoprazol/Rabeprazole/Leminoprazole/Pantoprazole; Naproxen and Prophenazone; Acetaminophen and chlorzoxazone/metaxalone/mephenoxalone; Zidovudine and Lamivudine; Triple prodrug of Zidovudine; Lamivudine and Abacavir (Ziagen); Lopinavir and Ritonavir; Lamivudine and Adefovir/dipivoxil; Amprenavir and Zidovudine; Nelfϊnavir and Zidovudine/Lamivudine; Stavudine and Zidovudine/Lamivudine; Dideoxyinosine and Zidovudine/Lamivudine; Emtricitabine and Penciclovir/Famciclovir; Acyclovir and deoxycholate/chenodeoxycholate and ursodeoxycholate; Triple and Zidovudine; and Lamivudine and Efavirenz;
19. A therapeutically effective amount of the pharmaceutical composition as in claim 15, comprising a two or more drugs, a drug and its own prodrug, a drug and a different prodrug, two different prodrugs, a drug and a mutual prodrug, mutual prodrug and its own drugs or a mutual prodrug and one of its constituent drugs.
20. The compound according to claim 2, wherein D1 and D2 are therapeutic agents selected from the group consisting of: Sedatives, Hypnotics, Antidepressants, Antipsychotics and Antimanics, Analgesics, Antipyretics, Antimigraine agents, Anticonvulsants, Drugs used in parkinsonism and movement disorders, Drug for dementia, Antiemtics, drugs for Vertigo, CNS Stimulants activators; Antiinfective eye preparations; Antiinflammatory; antiallergic preparations, antiglucoma drugs; preparations to cure eye diseases; aural, nasal and oropharyngeal preparation, Antiarrhythemic drugs, Antihypertensives, alfa/beta-blockers, channel blockers, ACE inhibitors, Angiotensin II receptor antagonists, diuretics, Antianginals, nitrates, calcium channel blockers, Drugs for cardiac failure and shock, Vasodilators, Coagulants, Anticoagulants, Thrombolytics, antiplatelet drugs, Respiratory stimulants, Antitissives, Expectorants, Mucolytics, Decongestants, Antihistamine agents, antiasthmatics; Antiulcer, Antisecretory drugs, H2 receptor antagonists, Proton Pump Iinhibitors, Prostaglandin analogues, Antacids, Antispasmodics, drugs modifying intestinal motility, Antidiarrhoeals, antimotility drugs, antimicrobial drugs, drugs acting on gall bladder, Urinary antiinfectives, Diuretics, Urinary analgesics, Antispasmodics, Antiinfective drugs acting on urethra and vagina, drugs acting on uterus, Drugs for prostatic hypertrophy, alfa blockers, antiandrogens, Drugs for erectile dysfunction, Spermicidals, nonhormonal contraceptives, Emollients, keratolytics, topical antiinfectives, topical antifungals, topical parasiticidals, topical steroids, topical drugs for acne vulgaris, drugs for psoriasis, pigmentation disorders, and Antiseborrhoeics, Non Steroidal Anti Inflammatory Drugs (NSAIDs), COX-2 inhibitors, Antiarthritic agents, Immunosuppressants, Topical analgesics, Muscle relaxants, Neuromuscular Drugs, Penicillin antibiotics, Cephalosporin antibiotics, Quinolone, Fluoroquinolone antibiotics, Macrolide antibiotics, Chloramphenicol, Tetracyline antibiotics, Sulfonamides, Antianaerobics, Metronidazole, Antitubercular drugs, Antileprosy drugs, Antifungals, Antiprotozoals, Anthelminthics, Antiinfestive Drugs, Antimalarials, Antivirals, Anabolics, androgenic steroids, Corticosteroids, Oestrogens, Progestogens and Hormonal contraceptives, Fertility Agents, Trophic hormones and related drugs, Thyroid and antithyroid drugs, Antidiabetics and hyperglycaemics, Vitamins, Amino acids, Anti- obesity drugs, Hypolipidaemic drugs, fibric acid derivatives, statins, HMG CoA reductase inhibitors, nicotinic acid group, drugs used for Gout, drugs affecting bone metabolism, bisphosphonates, Anticancer drugs, alkylating agents, cytotoxic antibiotics, antimetabolites, cytarbine, Fludarbine, 5-Fluorouracil, Mercaptopurine, Thioguanine, Vinca alkaloids, Etoposide, Taxanes, Topoisomerase 1 inhibitors, Cytotoxic immunosuppressants, Immunostmulants, Cytoprotectives, Amifostine, Oestrogens, Progestogens, hormon antagonists, antineoplastic drugs, Antiallurgics, non-sedative antihistamins, Cetirizine, Desloratadine, Terfenadine, Fexofenadine, sedative histamines, histamine receptor blockers, Local anaesthetics, intravenous anaesthetics, inhalation anaesthetics, and muscle relaxants.
21. The compound according to claim 2, wherein D1 and D2 are from same or different therapeutic class and exhibit either the same or different mechanisms of action or work on same or different biological targets or work on same or different disease conditions.
22. A method of treating a mammal or human in need thereof comprising administering a therapeutically effective amount of the composition according to claim 15.
23. A method of treating a mammal or human in need thereof comprising administering a therapeutically effective amount of the composition according to claim 16.
24. A method of use of the compound according to claim 2, for prevention or treatment of diseases where a chronic, sustained and selective release of the constituent drug or nitric oxide is beneficial.
25. A method of use of the compound according to claim 2, in a subject in need there of for prevention or treatment of diseases of Central Nervous System, Eye, Ear, Nose and Oropharynx, Cardiovascular System, Respiratory System, Gastrointestinal tract system, Genito-urinary system, skin, musculo-skeletal system, Endocrine system, metabolism and neoplastic disorders, infectious diseases, allergy and immunology, and for anaesthetic, analgesic and surgical needs.
26. A method of treating a mammal or human in need thereof comprising administering a therapeutically effective amount of two or more compositions according to claim 15, wherein compositions used in combination to treat a patient in need of a combination therapy.
27. A method of use of composition as claimed in claim 15, for prevention and/or treatment of diseases where a chronic, sustained and selective release of the constituent drug(s) and/or nitric oxide is beneficial.
28. The novel intermediates obtained in the preparation of compounds of claim 1, wherein the intermediates are selected from:
Figure imgf000230_0001
Figure imgf000231_0001
2-((2-(te^Butoxycarbonylamino)ethyl)- 2-((2-Aminoethyl)disulfanyl)- disulfanyl)ethyl carbonochloridate (LI-7) ethanol (SL-2)
Figure imgf000231_0002
Methyl 2-((2-hydroxyethyl)- Methyl 2-((2-(chlorocarbonyloxy)- disulfanyl)acetate (L3I2a) ethyl)disulfanyl)acetate (L3I3a)
Figure imgf000231_0003
2-((2-((2,5-Dioxopyrrolidin- 1 -yloxy)carbonyloxy)ethyl)- disulfanyl)ethyl 2-(dimethylamino)ethylcarbamate (LI-10)
29. The use of the novel intermediates of claim 26, in the preparation of compounds of formula I or pharmaceutically acceptable salts thereof.
30. The process for the preparation of the compound as in claim 1, or a pharmaceutically acceptable salts thereof, wherein the process is selected from:
Process 1: A ) Monoprotection of Bis-(2-hydroxyethyl)disulphide (SL-I) with an appropriate hydroxyl protecting group to give the corresponding monoprotected intermediate LI-Ix,
B) Converting LI-Ix, obtained in step A to an activated formyl intermediate LI- lxy by treating with phosgene or its equivalent, and C) Reacting LI- lxy obtained in the step B with an appropriate amino- or hydroxyl containing drug (D1) to give the corresponding compound of formula I; Process 2: A) Converting carboxyl containing drug (D1) into its activated acyl halide or imidazolide or isocyanate by known methods, and
B) Reacting the intermediate obtained in the step A with the linker intermediate LI-Ix to obtain the compound of formula I;
Process 3: Mixing a selectively protected and activated drug with a solution of 2-((2- hydroxyethyl)dithio)ethyl nitrate (LI-2b) in a suitable solvent in presence of a suitable coupling agent to obtain the compound of formula I and pharmaceutically acceptable salt thereof, wherein D2 is NO2;
Process 4: Converting 2-((2-hydroxyethyl)dithio)ethyl nitrate (LI-2b) into its formyl halide or imidazolide (LI-4x) by using a phosgene or its equivalent reagent and mixing/reacting the resulting reactive intermediate with a suitable amino- or hydroxy- containing drug in suitable solvent in presence of a suitable base to obtain the compound of formula I and pharmaceutically acceptable salt thereof , wherein D is NO2; Process 5: Mixing/reacting a an appropriately protected and activated drug with a solution of 2-((2-aminoethyl)dithio)ethyl nitrate (LI-5) in a suitable solvent in presence of a suitable coupling agent and/or base to obtain the compound of formula I and pharmaceutically acceptable salt thereof , wherein D2 is NO2 ; and Process 6: A ) Monoprotection of Bis-(2-hydroxyethyl)disulphide (SL-I) with an appropriate hydroxyl protecting group to give the corresponding monoprotected intermediate LI-Ix,
B) Reacting formyl linker intermediate LI- lxy with amino or hydroxyl containing drug (D1) to obtain the prodrug of formula I with free hydroxyl group on the linker,
C) Converting the intermediate obtained in the step B into activated formyl halide or imidazolide derivative, and
D) Reacting the intermediate obtained in the step C with the drug D2 to obtain the mutual prodrug of formula I.
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