Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/10—Dispersions; Emulsions
  • A61K9/127—Liposomes
  • A61K9/1271—Non-conventional liposomes, e.g. PEGylated liposomes, liposomes coated with polymers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • 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
  • A61K47/06—Organic compounds, e.g. natural or synthetic hydrocarbons, polyolefins, mineral oil, petrolatum or ozokerite
  • A61K47/20—Organic compounds, e.g. natural or synthetic hydrocarbons, polyolefins, mineral oil, petrolatum or ozokerite containing sulfur, e.g. dimethyl sulfoxide [DMSO], docusate, sodium lauryl sulfate or aminosulfonic acids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/435—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with one nitrogen as the only ring hetero atom
  • A61K31/47—Quinolines; Isoquinolines
  • A61K31/4738—Quinolines; Isoquinolines ortho- or peri-condensed with heterocyclic ring systems
  • A61K31/4745—Quinolines; Isoquinolines ortho- or peri-condensed with heterocyclic ring systems condensed with ring systems having nitrogen as a ring hetero atom, e.g. phenantrolines
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/70—Carbohydrates; Sugars; Derivatives thereof
  • A61K31/7028—Compounds having saccharide radicals attached to non-saccharide compounds by glycosidic linkages
  • A61K31/7034—Compounds having saccharide radicals attached to non-saccharide compounds by glycosidic linkages attached to a carbocyclic compound, e.g. phloridzin
  • A61K31/704—Compounds having saccharide radicals attached to non-saccharide compounds by glycosidic linkages attached to a carbocyclic compound, e.g. phloridzin attached to a condensed carbocyclic ring system, e.g. sennosides, thiocolchicosides, escin, daunorubicin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K45/00—Medicinal preparations containing active ingredients not provided for in groups A61K31/00 - A61K41/00
  • A61K45/06—Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/10—Dispersions; Emulsions
  • A61K9/127—Liposomes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/10—Dispersions; Emulsions
  • A61K9/127—Liposomes
  • A61K9/1277—Processes for preparing; Proliposomes
  • A61K9/1278—Post-loading, e.g. by ion or pH gradient

Definitions

• the present disclosure is in the field of stable liposomes comprising entrapped amphipathic weak bases and an ammonium alkyl sulfonate.
• Liposomal compositions have been used successfully to deliver entrapped therapeutics.
• Doxil® (Caelyx® in Europe) is a pegylated liposomal formulation including entrapped doxorubicin used for treatment of cancers such as ovarian cancer. Weak amphipathic bases like doxorubicin may be loaded into the liposomes using a transmembrane ion gradient. See, e.g., Nichols et al. (1976) Biochim. Biophys. Acta 455:269-271; Cramer et al (1977) Biochemical and Biophysical Research
• This loading method typically involves a drug having an ionizable amine group which is loaded by adding it to a suspension of liposomes prepared to have a lower inside/higher outside ion gradient, often a pH gradient.
• U.S. Patent Publication No. 20040219201 describes loading of weak amphipathic bases like doxorubicin driven by transmembrane gradient of ammonium glucuronate, which resulted in lack of intra-liposome doxorubicin crystallization and/or precipitation.
• liposomes exhibit enhanced degradation upon long term 40°C storage.
• Doxorubicin extravasated into interstitial tissues' fluids, little is known of the processes determining drug release. It is believed that gradual loss of the ammonium/proton gradients retaining the drug, enzymatic breakdown of liposomal phospholipids by phospholipases and/or endocytosis by scavenger macrophages likely contribute to drug release. Barenholz, (2012) J Control Release. 160(2): 117-34. Doxorubicin when entrapped in the commercially- available liposomal Doxil® forms a salt with the divalent sulfate anion inside the liposome aqueous phase.
• the doxorubicin- sulfate salt precipitate/aggregate in the intraliposome aqueous phase in the form crystal fibers ⁇ see, e.g., Haran et al (1993) Biochim Biophys Acta.
• liposome-encapsulated doxorubicin is less cardio toxic than unencapsulated doxorubicin
• preclinical and clinical data obtained from currently used pegylated liposomal formulations of doxorubicin confirm that there is very low release of drug from circulating liposomes ( ⁇ 5% of the injected dose).
• PPE palmar-plantar erythrodysesthesia
• the major factor which determines remote loading stability as well as kinetic order and rate of drug release from the liposome is the liposome lipid membrane composition (Zucker et al. (2009) J Control Release 139(l):73-80, Zucker et al. (2012) J Controlled Release, in press, Cohen et al (2012) J Controlled Release, in press).
• fine tuning of the release from transmembrane ion gradient driven remotely loaded liposomes can be achieved for example for ammonium sulfate driven loading by altering ammonium counter anion which affects the physical state of drug level and state of aggregation/gelation of precipitation of the amphipathic weak bases which are remote loaded by the transmembrane ammonium gradient (Wasserman et al (2007) Langmuir 23(4): 1937-47; Zucker et al (2009), supra).
• amphipathic weak base-counter ion In cases of remote loading of amphipathic weak bases, the type of the amphipathic weak base-counter ion will affect the level/state of active drug-counter ion salt precipitation and the level of drug intra-liposome precipitation has additional effect to this of liposome membrane composition. For any given amphipathic weak base the higher the precipitation the lower is the release rate
• the present invention relates to liposomes comprising an entrapped (i) amphipathic weak base and (ii) an alkyl- sulfonate salt or ion or aryl- sulfonate salt or ion.
• the invention relates to liposomes comprising an entrapped (i) amphipathic weak base and (ii) an alkyl sulfonate salt or ion.
• the invention relates to liposomes comprising an entrapped (i) amphipathic weak base and (ii) an aryl sulfonate salt or ion.
• the alkyl or aryl sulfonate salt or ion is an ammonium alkyl sulfonate or aryl sulfonate.
• the amphipathic weak base does not form crystals (non-amorphous higher order structures) within the liposomes, for example crystals of more than about 10 to 20 nm in diameter. In certain embodiments, the crystals are less than 20 nm in diameter. In other embodiments, the crystals are less than 20 nm in diameter. Any of the liposomes described herein may include some or no small amorphous precipitates.
• the liposomes are spherical in shape (rather than elliptical). In certain embodiments in which the liposome comprises an aryl sulfonate, magnesium is not present in the liposome.
• the alkyl sulfonate may be, for example, methanesulfonate, ethanesulfonate, 3-HydroxyPropane-l -Sulfonate, 2- HydroxyEthaneSulfonate, l,3-Dihydroxy-2-(hydroxymethyl)-2-propanesulfinic acid, 2- Hydroxy- l-(2-hydroxyethoxy)-2-propanesulfonic acid, 4-Hydroxy-3,3- bis(hydroxymethyl)-l-butanesulfonic acid and the aryl sulfonate may be, for example, 4- HydroxyBenzene Sulfonate, 2,5-DihydroxyBenzeneSulfonate, l,4-Dihydroxy-2- butanesulfonic acid, 2,3,4-Trihydroxybenzenesulfonic acid, 2,4,5- trihydroxybenzenesulfonic acid, 3,4-Dihydroxy-5-methoxybenzen
• the logD value of the alkyl or aryl sulfonate counter-ion (at pH 5.5) is less than -3 (e.g., between -3 and -8), more preferably less than -4.5.
• any of the liposomes described herein may be pegylated.
• the disclosure also provides compositions comprising these liposomes.
• the amphipathic weak base is doxorubicin, vincristine and/or one or more camptothecins such as topotecan.
• methods of making and using these liposomes for example by loading of amphipathic weak bases using a transmembrane ammonium ion gradient having alkyl- or aryl- sulfonate as the ammonium to load an amphipathic weak base drug (e.g., doxorubicin, topotecan, etc.) into the liposomes.
• an amphipathic weak base drug e.g., doxorubicin, topotecan, etc.
• the alkyl or aryl sulfonate counter anions are distinguished from other monovalent counter ions in that they provide a high percentage (e.g., above 80-90%) stable drug loading while concomitantly retaining the chemical stability of the drug.
• the methods described herein also allow production of liposomes without change in the spherical shape of the liposomes from a sphere to an ellipse, where the change to the ellipsoid shape is indicative of the formation of crystals (non-amorphous structured molecules, typically larger than 10 nm in size) within the liposome when the ammonium counter ions is sulfate (e.g., doxorubicin- sulfate crystallization). This effect is suggested to contribute to the very long circulation time of doxorubicin administered as Doxil®.
• liposomes comprising an amphipathic weak base and an alkyl or aryl sulfonate entrapped within the liposome.
• the alkyl or aryl sulfonate is an ammonium alkyl or aryl sulfonate.
• the amphipathic weak base is a chemo therapeutic agent, for example doxorubicin and/or topotecan.
• the liposomes are between about 20 to about 10000 nm in diameter. In other embodiments, the liposomes are between about 60 and 1000 nm in diameter.
• the liposomes comprise phospholipids, cholesterol and/or sphigolipids including ceramides (e.g., comprising any carbon chain from C2 to C22) and pegylated phospholipids in various ratios and concentrations, for example hydrogenated soy phosphatidyl choline (HSPC) in mole ratio of 45 to 70 and cholesterol in mole ratio of 30 to 50 and
• ceramides e.g., comprising any carbon chain from C2 to C22
• pegylated phospholipids in various ratios and concentrations, for example hydrogenated soy phosphatidyl choline (HSPC) in mole ratio of 45 to 70 and cholesterol in mole ratio of 30 to 50 and
• the liposomes comprise HSPC:PEG- DSPE:Ceramide in ratio 69.5:7.5:23.
• Any of the liposomes described herein may be formulated in a composition, for example, a composition comprising liposomes as described herein and further comprising one more pharmaceutically acceptable excipients or carriers.
• the composition comprises alkyl or aryl ammonium sulfonate.
• the liposomes are produced using an ammonium ion gradient, for example, where the amphipathic weak base is loaded into pre-formed liposomes against an ammonium ion gradient provided by an ammonium aryl or alkyl sulfonate (e.g., methanesulfonate) as a monovalent counterion.
• the gradient is capable of active transport of the weak amphipathic compound towards the inside of the liposomes (e.g., transport against the gradient).
• the concentration gradient of alkyl or aryl ammonium across the bilayer lipid membranes can be achieved by (i) preparing a suspension of liposomes, each liposome in the suspension having at least one internal aqueous compartment that contains a sulfonate derivative at a first (high) concentration, the liposomes suspended in an external bulk medium comprising the sulfonate derivative (e.g., ammonium methanesulfonate) at the first concentration; (ii) reducing (e.g., by dilution, dialysis, diafiltration and/or ion exchange) the first concentration of the sulfonate derivate in the external bulk medium (but not in internal aqueous compartment) to a lower, second concentration of the sulfonate derivative, thereby establishing an ammonium ion concentration gradient across lipid bilayers of the liposomes.
• a sulfonate derivative e.g., ammonium methanesulfon
• sulfonate derivative is ammonium methanesulfonate.
• the liposome suspension includes a weak amphipathic base
• the base is transported to the inside of the liposomes by the gradient created after reducing the first concentration in the external medium.
• the preparation does not involve magnesium or calcium ions.
• at least 50% of the amount of the weak amphipathic base (e.g., doxorubicin, topotecan) added to the suspension is transported to the inside of the liposomes.
• approximately 90% of the amount of the weak amphipathic base added to the suspension is transported to the inside of the liposomes.
• the loading efficiency for doxorubicin and for topotecan are greater than 90% and the weak amphipathic base to phospholipid ratio is in the range of about 10-3000 ⁇ / ⁇ respectively.
• liposomes made by the methods described herein as well as compositions comprising the liposomes made by these methods are also described.
• the liposomes and compositions comprising these liposomes as described herein including use in methods of treating a condition susceptible to treatment using a composition comprising one or more liposomes prepared as described herein.
• the weak amphipathic base comprises a chemo therapeutic agent such as doxorubicin, vincristine and/or topotecan and the condition comprises a cancer.
• the compositions further comprise the local anesthetics bupivacaine, and the condition comprises a cancer or pain
• liposomes and compositions comprising the liposomes as described herein can used in the manufacture of medicament for the treatment of any condition susceptible to treatment with liposomes comprising at least one weak amphipathic base.
• methods of reducing the side effects associated with administration of liposomes with entrapped crystallized weak amphipathic bases comprising administering a liposomes (or a composition comprising the liposomes) as described herein to a subject in need thereof.
• the side effect comprises palmar-plantar erythrodysesthesia (PPE, also known as "hand and foot syndrome").
• FIG. 1A shows chromatograms for doxorubicin in the presence of
• FIG. IB shows chromatograms for doxorubicin in the presence of glucuronate at pH 6.03 and 250 mM concentration glucuronate.
• FIG. 1C shows chromatograms for doxorubicin in the presence of ammonium sulfate at pH 5.60 and 500 mM concentration ammonium sulfate. Each chromatogram shows two wavelength of detection, the upper is 254 nm and the lower 480 nm. The concentration loss of Doxorubicin in this short accelerated stability as calculated from the chromatograms is summarized in Table 3.
• FIG. 1 panels A to G, depict cryo-transmission electron micrographs
• FIG. 2A shows Doxil® (Dox -Sulfate, scale bar: 100 nm).
• FIG. 2B shows liposomes loaded with doxorubicin in the presence of ammonium glucuronate ("DOXG,” scale bar: 50 nm).
• FIG. 2C shows liposomes loaded with doxorubicin in the presence of ammonium methanesulfonate ("DOXMS,” scale bar: 100 nm).
• DOXMS ammonium methanesulfonate
• FIG. 2D shows liposomes loaded with doxorubicin in the presence of ammonium ethanesulfonate.
• FIG. 2E shows liposomes loaded with doxorubicin in the presence of ammonium 4-hydroxybenzene sulfonate.
• FIG. 2F shows liposomes loaded with doxorubicin in the presence of ammonium 3-hydroxypropane sulfonate and
• FIG. 2G shows empty (lacking doxorubicin) liposomes ammonium methanesulfonate.
• Figure 3 is a graph depicting a PK comparison of blood levels of doxorubicin 48 hours after administration to mice of either Doxil® ("Doxil”) or ammonium methanesulfonate/doxorubicin liposomes ("DOX-046.2” or “DOXMS-050”).
• Doxil® Doxil®
• DOXMS-050 ammonium methanesulfonate/doxorubicin liposomes
• Figure 4A shows a PK comparison of Doxil® and PLDMS ("DOX- 046.003") blood levels at 24 (left bar) and 48 hours (right bar) in mice.
• DOX-046.003 also referred to as “DOXMS003” was made using a 250 mM methanesulfonate gradient.
• Figure 4B depicts survival of rats (according to humane end points) during as a function of the dose of drug administered.
• DOXMS003 refers to ammonium methanesulfonate doxorubicin liposomes made using a 250 mM methanesulfonate gradient. The event was counted as death when the animal reached a humane end point as described previously.
• Figure 4C is a graph depicting mean Body weight variations of the rats during the study for 1 mg/kg of Doxil® versus ammonium methanesulfonate doxorubicin liposomes ("DOXMS003").
• Figure 4D is a graph depicting average total scoring of rats during the study for 1 mg/kg of Doxil® versus ammonium methanesulfonate doxorubicin liposomes ("DOXMS003").
• FIG 5 A shows results from (l)-DOX-MS (line “1” in the graph); DOX-SHPS (line “2” in the graph); DOX-4HBS (line “3” in the graph); DOX-ES (line “4" in the graph) and DOX-Sulfate (line “5" in the graph).
• Figure 5B shows results using DOX-MS (left panel, labeled “Sample (1)”); DOX-4HBS (middle panel, labeled “Sample (3)”) and DOX-Sulfate (right panel, labeled “Sample (5)”).
• Figure 5C shows scattered intensity of the indicated compositions.
• Figure 5D shows scattered intensity of DOX-MS (labeled “(1)”); DOX-SHPS (labeled “(2)”); DOX-4HBS (labeled "(3)”); DOX-ES (labeled "(4)”); and DOX-Sulfate (labeled "(5)”).
• Figure 6 is a graph showing in vitro release profiles of liposomal doxorubicin in presence of various ammonium sulfonate salts (as indicated).
• FIG. 7 panels A to F, are graphs presenting results of PLDMS /
• Figure 8 is a graph presenting results of a PK study PK003-LC100- 120904 comparing healthy mice PK of PLDMS with Caelyx and free doxorubicin.
• FIG. 9 panels A to D, are graphs presenting chemical results of doxorubicin in presence of various ammonium sulfonate (3HPS, 4HBS, ESA and MSA) and sulfate salts.
• nucleic acid includes a mixture of two or more such nucleic acids, and the like.
• the present disclosure relates to liposomes where an amphipathic ionizable therapeutic agent (amphipathic weak base) is entrapped in the internal liposomal compartment(s) by an ammonium alkyl or aryl sulfonate. Entrapment is driven by a trans-membrane ammonium ion gradient and/or pH gradient.
• the liposomes comprise, in the intra-liposome aqueous phase, a salt of the amphipathic weak base with monovalent sulfonate anions. Some precipitates (e.g., small, amorphous particles) may be present within the liposome.
• the entrapped therapeutic agent retains at 37°C a zero order slow release kinetics which is faster compared to the release rate of the agent entrapped in the liposomes in the form of an ionic salt with divalent sulfate anions, or with monovalent anion which is a derivative of aryl sulfonate.
• non-precipitated doxorubicin in presence of ammonium alkyl sulfonate within a liposomes exhibited a release percentage was 37-46% after three hours of incubation at 37°C.
• the release rate from the liposomes in the presence of mono-valent alkyl sulfonate is faster compared to the release rate of the agent entrapped in the liposomes in the form of an ionic salt with divalent sulfate anions, or with monovalent anion which is a derivative of aryl sulfonate.
• the liposomes described herein exhibit this faster release rate due to remote loading stability based on the monovalent alkyl and aryl ammonium sulfonate counter ions compared with a slower release rate achieved with the divalent sulfate as ammonium counter anions.
• Liposomes suitable for use in the composition of the present invention include those composed primarily of vesicle-forming lipids. Vesicle-forming lipids, exemplified by the phospholipids, form spontaneously into bilayer vesicles in water.
• the liposomes can also include other lipids incorporated into the lipid bilayers, with the hydrophobic moiety in contact with the interior, hydrophobic region of the bilayer membrane, and the head group moiety oriented toward the exterior, polar surface of the bilayer membrane. See, e.g., Israelachvili (1980) Q. Rev Biophys. 13(2): 121-200;
• the liposomes are spherical in shape as they do not contain one or more large crystals that tend to stretch the liposome into an elliptical shape.
• Amphiphiles are defined by a packing parameter (PP), which is the ratio between the cross sectional areas of the hydrophobic and hydrophilic regions.
• Amphiphiles with a packing parameter of 0.74 to 1.0 form a lamellar phase and have the potential to form liposomes.
• Amphiphiles with a larger packing parameter tend to form hexagonal type II (inverted hexagonal) phases.
• micelle forming amphiphiles which self- aggregate include phospholipids with short hydrocarbon chains, or lipids with long hydrocarbon chains ( ⁇ 10 carbon atoms), but with large, bulky polar head-groups (e.g. gangliosides and lipopolymers composed of a lipid to which a polyethylene glycol (PEG) moiety ( ⁇ 750 Da) is covalently attached).
• PEG polyethylene glycol
• the vesicle-forming lipids are preferably ones having two hydrocarbon chains, typically acyl chains, and a head group, either polar or nonpolar. There are a variety of diacyl, dialkyl or one alkyl and one acyl chains, also one shingoid base and one acyl or alkyl chains.
• vesicle-forming lipids such as phospholipids, sphingomyelins, and some dialiphatic glycolipids, and glycosphingolipid which are defined as vesicle-forming lipids.
• phospholipids includes but is not limited to phosphatidylcholine (PC), phosphatidic acid (PA), phosphatidylinositol (PI),
• phosphatidylserine PS
• sphingomyelin PC plasmalogens
• the two hydrocarbon chains are typically between about 14-22 carbon atoms in length, and have varying degrees of unsaturation and having the two of the same hydrocarbon or two different hydrocarbons chains.
• the above-described lipids and phospholipids whose acyl chains have varying degrees of saturation can be obtained commercially or prepared according to published procedures.
• the vesicle-forming lipid can be selected to have the gel to liquid crystalline [solid ordered to liquid disordered (SO to LD)] phase transition at the desired temperature range which allow achieving a specified degree of fluidity or rigidity, to control the stability of the liposome in serum and to control the rate of release of the entrapped agent in the liposome.
• Liposomes having a more rigid lipid bilayer, or a liquid crystalline bilayer are achieved by incorporation of a relatively rigid lipid, e.g., a lipid having a relatively high SO to LD phase transition temperature range, e.g., above room temperature, more preferably above body temperature and up to 80°C.
• the SO to LD phase transition is also defined by Tm value, which is the temperature in which maximal change in the heat capacity during the phase transition occurs (Biltonen and Lichtenberg (1993) Chem.Phys. Lipids 64: 129-142). Rigid, for instance saturated, lipids contribute to greater membrane rigidity in the lipid bilayer and concomitantly lower membrane permeability. Other lipid components, such as cholesterol and/or ceramides, are also known to contribute to membrane rigidity in lipid bilayer , High mole% cholesterol change the membrane lipid physical state to a Liquid Ordered (LO) phase Barenholz, Y. and Cevc, G., Structure and properties of membranes. In Physical Chemistry of Biological Surfaces (Baszkin, A. and Norde, W., eds.), Marcel Dekker, NY (2000) pp. 171-241.
• LO Liquid Ordered
• amphiphiles or lipids which are not liposome-forming lipids such as micelle forming lipids having packing parameter lower than 0.74 (such as lyso-PCs, Lyso- PGs, Lyso-Plas, lyso Pis, gangliosides, PEGylated lipids or detergents such as
• the liposomes may optionally include a vesicle-forming lipid derivatized with a hydrophilic polymer (referred to as a lipopolymer), as has been described, for example in U.S. Patent No. 5,013, 556 and in WO 98/07409, which are hereby
• the lipopolymer comprises a micelle forming lipid having a packing parameter below 0.74.
• pegylated lipids include pegylated diglycerides (Ambegia et al. (2005) Biochimica et Biophysica Acta (BBA) - Biomembranes, 1669(2): 155-163 and PEG- Ceramides (Zhigaltsev et al. (2006) J. of Controlled Release 110:378-386 (2006) and pegylated phosphatidic acid (Tirosh et al (1998) Biophys. J. 74, 1371-1379).
• liposomes having the lipopolymer present only in the external leaflet forming the liposome membrane can also be prepared by insertion of the lipopolymer such as PEGylated lipid to preformed liposomes and will have similar effect of prolongation of liposome circulation time.
• Lipids suitable for derivatization with a hydrophilic polymer include any of those lipids having a head group which allows covalent binding of the polymer listed above and, in particular PES, such as distearyl phosphatidylethanolamine (DSPE).
• a preferred hydrophilic polymer chain is polyethyleneglycol (PEG), preferably as a PEG chain having a molecular weight between about 500 and about 15,
• Methoxy or ethoxy-capped analogues of PEG are also preferred hydrophilic polymers, commercially available in a variety of polymer sizes, e.g., 120-20,000 Daltons. Preparation of vesicle-forming lipids derivatized with hydrophilic polymers has been described, for example in U. S. Patent No. 5,395, 619.
• liposomes including such derivatized lipids has also been described; where typically between 1-20 mole percent of such a derivatized lipid is included in the liposome formulation.
• the hydrophilic polymer may be stably covalently coupled to the lipid, or coupled through an unstable linkage which allows the coated liposomes to shed the coating of polymer chains as they circulate in the bloodstream or in response to a stimulus, as has been described, for example, in U. S. Patent No. 6,043, 094, which is incorporated by reference herein.
• the liposomes described herein also include an entrapped alkyl or aryl sulfonate, preferably an ammonium alkyl or aryl sulfonate.
• the alkyl sulfonate may be, for example, methanesulfonate, ethanesulfonate, 3-HydroxyPropane-l-Sulfonate, 2-
• HydroxyEthaneSulfonate, l,3-Dihydroxy-2-(hydroxymethyl)-2-propanesulfinic acid, 2- Hydroxy- l-(2-hydroxyethoxy)-2-propanesulfonic acid, 4-Hydroxy-3,3- bis(hydroxymethyl)-l-butanesulfonic acid and the aryl sulfonate may be, for example, 4- HydroxyBenzene Sulfonate, 2,5-DihydroxyBenzeneSulfonate, l,4-Dihydroxy-2- butanesulfonic acid, 2,3,4-Trihydroxybenzenesulfonic acid, 2,4,5- trihydroxybenzenesulfonic acid, 3,4-Dihydroxy-5-methoxybenzenesulfonic acid, or (3,4- Dihydroxyphenyl)(hydroxy)methanesulfonic acid.
• the logD value of the alkyl or aryl sulfonate counter-ion (at pH 5.5) is less than
• the liposomes described herein may be formulated as pharmaceutical compositions, for example when admixed with an acceptable pharmaceutical diluent, carrier or excipient, such as a sterile aqueous solution, to give a range of final
• the method comprise a remote loading procedure for loading therapeutic agents (e.g., weak amphipathic bases) into pre-formed liposomes driven by an ammonium alkyl sulfonate gradient.
• therapeutic agents e.g., weak amphipathic bases
• the faster rate of release of the therapeutic agent from the liposomes made in this way affords flexibility to adjust dosing schedules without compromising the biological efficacy of the therapeutic agents.
• the instant disclosure therefore provides a beneficial alternative to loading by ammonium sulfate.
• the invention also provides extended shelf life product stability including doxorubicin and lipid chemical stability, doxorubicin encapsulation efficiency and encapsulation stability during storage.
• the remote loading driven by trans membrane ammonium alkyl sulfonate gradient does not require the liposomes to be prepared in acidic pH, nor to alkalinize the extra-liposomal aqueous medium.
• liposomes loaded with lipophilic drugs using an ammonium aryl sulfonate resulted in liposomes including the lipophilic drug-alkyl sulfonate crystallized /precipitates (large, high molecular order structures within the liposome) in order to improve retention of the drug within the liposomes and release the drug more slowly from the liposome (see, e.g., Zhigaltsev et al. (2006) Journal of Controlled Release 110:378 - 386).
• the liposomes described herein include an amphipathic (not lipophilic) drug ⁇ e.g., doxorubicin) and, in addition, include little or no crystallized (or precipitated) drug.
• the logD of the alkyl or aryl sulfonate counter-ion (at pH 5.5) is less than -3 ⁇ e.g., between -3 and -8), more preferably less than -4.5.
• liposomes as described herein made with aryl sulfonates use a trans membrane ammonium gradient for remote loading and do not require the use of a proton gradient, the proton gradient achieved in Zhigaltsev et al.
• the liposomes prepared using an ammonium aryl sulfonate gradient as described herein may not comprise magnesium or calcium ions and are not necessarily made using magnesium and or calcium ions.
• the weak amphipathic drug entrapped within the liposomes described herein does not form crystals ⁇ e.g., crystals of larger than 10 nm in diameter) within the liposome, resulting in liposomes of elliptical shape.
• the liposomes retain their spherical shape ( Figure 2) and, in addition, show significant differences from Doxil® in terms of release rate and reduced adverse effects when administered to a patient. See, Examples.
• Encapsulated refers to an agent entrapped within the aqueous spaces of the liposomes or within the lipid bilayer.
• the increased release rate of the encapsulated compound is a result of using alkyl or aryl sulfonate as the balancing (counter) anion. While not wishing to be bound by one theory, it is hypothesized that the alkyl or aryl sulfonate ion, being monovalent, is less effective compared to a sulfate ion at inducing aggregation and precipitation of the therapeutic agent after being transported inside the liposomes.
• doxorubicin solubility of doxorubicin is approximately 30-fold greater (or more) in a 250 mM ammonium alkyl or aryl sulfonate solution than in a 250 mM ammonium sulfate solution as determined by comparing ammonium alkyl or aryl sulfonate to ammonium sulfate.
• doxorubicin precipitates at less than 2 mM concentration in the presence of sulfate ions, while doxorubicin solubility in ammonium alkyl or aryl sulfonate is similar to the maximal water solubility of doxorubicin HC1 (50 mg/ml, see, Sigma catalog) without precipitating.
• Doxorubicin HC1 at 70 mM did not precipitate in the presence of alkyl or aryl sulfonate ions while in ammonium sulfate precipitation occurs at less than 2mM (namely at least 35 fold higher solubility of the methanesulfonate form). Accordingly, when alkyl sulfonate is the counter anion, most of the therapeutic agent is in a soluble form and therefore it is more available for release from the liposomes. Thus, whereas aryl and alkyl sulfonate liposomes as described herein do not include one or more large crystals (e.g., 10 nm or more) at 37°C, sulfonate precipitation was observed even at 37°C. (see, e.g., FIG. 5B).
• the permeability of alkyl or aryl sulfonate through lipid membranes can be predicted from logP values (see, e.g., Stein D. 1986, Transport and diffusion across cell membranes, Chapter 2. Academic Press, Orlando, FL) and/or logD values.
• the low LogP and LogD values (which determine permeability Coefficients (Stein W.D. et al.
• the LogD values (at pH 5.5) are below about -3 (e.g., between about -3 and -8) and even more preferably less than about -4.5.
• the method of the current invention can be used to remotely load essentially any therapeutic agent which is amphipathic weak base which being proton-able it can exist in a positively charged state, or in charge less state dependent on aqueous medium pH.
• the agent should be amphipathic so that it will partition into the lipid vesicle membranes.
• the therapeutic compound suitable for loading is a weak amphipathic base compound.
• Liposomal suspensions comprised of liposomes having an ion gradient across the liposome bilayer (also referred to as "a trans-membrane ion" and/or "pH gradient") for use in remote loading can be prepared by a variety of techniques, such as those detailed in Szoka et al. (1980) Ann Rev Biophys Bioeng 9:467 and Lichtenberg and Barenholz (1988) in "Methods of Biochemical Analysis” (Click, D., ed.) Wiley, NY, 33, pp. 337-462.
• Multi-lamellar vesicles can be formed by simple lipid-film hydration techniques.
• a mixture of liposome-forming lipids (see above) with and without other lipids of the type described above is dissolved in a suitable organic solvent and the solvent is later evaporated off or lyophilized leaving behind a thin film or a dried powder "cake" (respectively).
• the film or dry cake is then hydrated by the desired aqueous medium, containing the solute species, e. g., ammonium alkyl or aryl sulfonate, which forms the aqueous phase in the liposome interior volume and also the extra- liposomal suspending solution.
• the lipid film is hydrates to form LVs, typically with sizes between about 0.1 to 10 microns.
• the lipids used in forming the liposomes of the present invention are preferably present in a mole % of about 50-100 mole percent vesicle-forming lipids, with or without cholesterol and optionally 1-20 mole percent of a lipid derivatized with a hydrophilic polymer chain such as PEG.
• a hydrophilic polymer chain such as PEG.
• One exemplary formulation includes 80-90 mole percent phosphatidylcholine, 1-20 mole percent of PEG-DSPE. Cholesterol may be included in the formulation at between about 1-50 mole %.
• the lipid components are hydrogenated soy phosphatidylcholine (HSPC), cholesterol (Choi) and mono methoxy-capped polyethylene glycol of 2000 Da derivatized distearoyl phosphatidylethanolamine abbreviated as (mPEG (2000) -DSPE, or PEG-DSPE) in a mole % of between about 50 and 60 (HPSC), 35-50 (cholesterol) and 4-10 mole% (PEG- DSPE), for example of the mole ratio of 54.5:41:4.5. for the 3 above components respectively.
• HSPC hydrogenated soy phosphatidylcholine
• Choi cholesterol
• mPEG (2000) -DSPE mono methoxy-capped polyethylene glycol of 2000 Da derivatized distearoyl phosphatidylethanolamine abbreviated as (mPEG (2000) -DSPE, or PEG-DSPE) in a mole % of between about 50 and 60 (HPSC), 35-50 (cholesterol) and 4
• the lipid hydration medium contains ammonium alkyl or aryl sulfonate. It will be apparent that the concentration of ammonium alkyl or aryl sulfonate depends on the amount of therapeutic agent to be loaded. Typically, the concentration is between 50 to 750 mM of alkyl or aryl sulfonate as ammonium salt. In preferred embodiments, the hydration medium contains 250 mM, 350 mM or 500 mM alkyl or aryl sulfonate as ammonium salt.
• the vesicles formed by the thin film or dry cake mechanical dispersion method may be sized to achieve a size distribution within a selected range, according to known methods.
• Small unilamellar vesicles (SUVs) defined as liposomes in the range 20 to 100 nm diameters at a narrow size distribution in this range can be prepared by post- formation ultrasonic irradiation, or homogenization, or extrusion.
• Homogeneously sized liposomes having sizes in a selected range between about 50 nm to 400 nm can be produced, e.
• the sizing is preferably carried out in the original lipid-hydrating buffer, so that the liposome interior spaces retain this medium as an intraliposome aqueous phase throughout the sizing processing steps.
• the therapeutic agent is loaded into the preformed liposomes after their sizing. Remote loading is different from passive loading for the latter the drug is present in the hydration medium and therefore it is encapsulated during the stage of hydration.
• a "remote" or “active” loading process requires firstly creation of an ion (i.e. ammonium ion) gradient by exhaustive dialysis or equivalent approaches such as exhaustive diafiltration, or gel exclusion chromatography (Haran et al. (1993) Biochim. Biophys. Acta 1151:201-215 and U.S. Patent Nos. 5,192,549 and 5,244,574, incorporated in their entireties herein.
• the gradient can be created by four consecutive dialysis exchanges against at least 50 volumes of the dialysis buffer.
• the gradient may be prepared by a three-step tangential flow dialysis, e.
• the dialysis buffer contains electrolytes (e. g., sodium chloride or potassium chloride) or non-electrolytes (glucose or sucrose).
• the dialysis buffer is 15 mM HEPES containing 5% dextrose at approximately pH 7.
• Unprotonated uncharged drug present in the external liposome medium diffuses across the liposomal lipid bilayer into the intra-liposome aqueous phase were it becomes protonated and charged so it can bind the excess of the counter anion of the ammonium (e.g., alkyl or aryl sulfonate) present in the intra-liposome aqueous phase.
• the ammonium e.g., alkyl or aryl sulfonate
• the remote loading results from exchange of the therapeutic agent added to the external or bulk medium in which the preformed sized- liposomes are suspended with the ammonium ions present in the internal liposomal aqueous phase (Haran et al. (1993), supra).
• the efficiency of loading depends, to large extent, on the ammonium ion gradient, where before the remote loading the concentration of the ammonium ion inside the liposomes is much higher than the concentration of ammonium ion in the external, liposomes' medium.
• the magnitude of this gradient determines to a large extent the level of encapsulation; the larger the gradient and the higher is the internal ammonium ion concentration, generally the higher the encapsulation. See, e.g., Clerc and Barenholz (1998) Anal. Biochem. 259: 104-111 ; Zucker et al (2009) J. Controlled Release 139:73-80.
• An ammonium alkyl or aryl sulfonate trans membrane gradient where the ammonium ion concentration is much higher in the intra-liposome aqueous phase than in the external liposome suspension medium (i.e., a higher inside/lower outside ammonium ion gradient) may be formed in a variety of ways, for instant , by (i) controlled dilution of the external medium, (ii) dialysis against the desired final medium, (iii) molecular-sieve gel permeation chromatography, e.g., using Sephadex G-50, and elution medium lacking ammonium ions, or (iv) high-speed centrifugation and re-suspension of pelleted liposomes in the desired final medium (Haran et al. (1993), supra).
• the final external medium selected will depend on the mechanism of gradient formation and the external ion concentration desired.
• the gradient is measured by measuring ammonium in the external liposome medium and the intraliposome ammonium concentration by ammonium or ammonia electrodes (Haran et al. (1993), supra) as the ratio of ammonium alkyl or aryl sulfonate inside to that outside of the liposomes.
• the gradient (the above ratio) is in the range of 10 to 1000 inside/outside.
• the gradient is in the range of 100 - 10000.
• the concentration of ammonium alkyl or aryl sulfonate in an external medium that also contains electrolytes may be measured as ammonia concentration at pH 13- 14 (see, Bolotin et al. (1994) J. Liposome Research 4(i):455-479) by an ion analyzer, e.g., a Coming 250 pH/ion analyzer (Corning Science Products, Corning, NY) equipped with a Corning 476130 ammonia electrode and an automatic temperature compensation (ATC) stainless steel probe.
• ATC automatic temperature compensation
• the external medium is exchanged by a medium lacking ammonium alkyl or aryl sulfonate salt, for example it is replaced by a salt such as NaCl or KC1, or by a sugar such as dextrose or sucrose that gives similar osmolality inside and outside of the liposomes, or osmolality that does not affect liposome physical stability.
• a medium lacking ammonium alkyl or aryl sulfonate salt for example it is replaced by a salt such as NaCl or KC1, or by a sugar such as dextrose or sucrose that gives similar osmolality inside and outside of the liposomes, or osmolality that does not affect liposome physical stability.
• the remote loading is preferably carried out at a temperature above the phase transition temperature of the liposome forming lipids.
• the loading temperature may be as high as 60°C or even higher.
• the loading duration is typically between 15-120 minutes, depending on rate of permeability of the drug to via the liposome bilayer membrane, the temperature, and the relative concentrations of liposome lipid and drug.
• the loading is performed at 60°C and for 60 minutes (for more details see Haran et al. (1993), supra; Zucker et al (2009), supra).
• concentration of added compound, and the ion gradient essentially all of the added compound may be loaded into the liposomes.
• concentration of added compound, and the ion gradient essentially all of the added compound may be loaded into the liposomes.
• encapsulation of doxorubicin can be greater than 90% and even > 95%. Knowing the calculated internal liposome volume, and the maximum concentration of loaded drug, one can then select an amount of drug in the external medium which leads to substantially complete loading into the liposomes.
• the liposome suspension may be treated, following drug loading, to remove non- encapsulated drug.
• Free drug can be removed, for example, by ion exchange chromatography, molecular sieve chromatography, dialysis, or centrifugation.
• the non-entrapped drug is removed using the cation exchanger Dowex 50WX-4 (Dow Chemical, MI).
• free doxorubicin binds to a cation exchange resin while liposomal doxorubicin when encapsulated in neutral or negatively charged liposomes is not binding to this cation exchanger (Storm et al. (1985) Biochim Biophys Acta 818:343; Amselem et al (1990) J. Pharm. Sci. 79: 1045-1052).
• amphipathic weak base drug can be entrapped within a liposome with ammonium methanesulfonate as described herein.
• therapeutic agents which can be loaded into liposomes by the method of the invention include, but are not limited to, doxorubicin, mitomycin, bleomycin, daunorubicin, streptozocin, vinblastine, vincristine, mechlorethamine hydrochloride, melphalan, cyclophosphamide,
• the weak amphipathic base is doxorubicin, topotecan and the like.
• Doxorubicin loaded in liposomes e.g., liposomes having an external surface coating of hydrophilic polymer [poly ethylene glycol (PEG) chains]
• PEG poly ethylene glycol
• PLD-MS trans membrane ammonium alkyl or aryl sulfonate gradient
• the liposomes and compositions comprising these liposomes as described herein can be administered by any suitable method, including, but not limited to, intravenous, intramuscular, oral, intraperitoneal, intraocular, subcutaneous routes of administration.
• liposomes and compositions comprising these liposomes described herein can be administered alone (in one or more doses) or as part of a combination therapy, for example with other chemotherapeutic agents (e.g., liposomes or other therapeutics). While specific time intervals and courses of treatment will vary depending on the extent of symptoms and the condition of the patient.
• the liposomes and compositions comprising these liposomes as described herein comprise an amphipathic weak base (drug) and ammonium alkyl or aryl -sulfonate. These liposomes do not contain large crystals within their internal compartment (e.g., crystals larger than 10-20 nm in size) and are typically spherical in shape.
• the liposomes load at least 80% of the drug (e.g., at least 80%, more preferably at least 90% and even more preferably at least 95% stable drug loading) and, in addition, the drug maintains its chemical stability within the liposome.
• the liposomes described herein enhance treatment and/or prevention of any of the diseases or conditions treated by the entrapped drug.
• the drug is a chemotherapeutic agent such as doxorubicin and the disease is a cancer (e.g., ovarian, breast, etc.).
• compositions described herein exhibit relatively faster release rates of the entrapped drug in vivo (e.g., as compared to other liposomal formulations such as Doxil®). Therefore, the liposomes described herein reduce the side effects associated with the entrapped drug, as the opportunity for the drug to accumulate in non-targeted tissues (for example, skin when targeting a tumor) is reduced and side effects such as palmar-plantar erythrodysesthesia (PPE), and mucositis or asthenia, sleep disruptions and alimentary tract organs side effects observed in patients and animals treated with liposomal chemotherapeutics (such as Doxil®) are reduced.
• PPE palmar-plantar erythrodysesthesia
• mucositis or asthenia sleep disruptions and alimentary tract organs side effects observed in patients and animals treated with liposomal chemotherapeutics (such as Doxil®) are reduced.
• PPE palmar-plantar erythrodysesthesia
• the screening process for the most suitable counter ion for generation of stable liposome compositions in which the entrapped amphipathic base remains chemically stable included the following steps. First, the relevant physicochemical properties of a large group of ammonium counter ions were compared at pH 5.5 to 6.0 and the ability of these counter ions to induce a precipitation of doxorubicin was studied.
• Liposomes were prepared as described above.
• the liposomes were made in four steps, 1) formation of liposomes containing ammonium counter ion, 2) liposome downsizing, 3) removal of medium ammonium salt for the creation of ammonium salt gradient, and 4) doxorubicin remote loading. All formulations were made from HSPC:Cholesterol:PEG-DSPE mole ratio of 54.5:41:4.5, briefly the lipids were hydrated and suspended in the various ammonium ions to form MLV. The MLV were downsized by extrusion followed by dialysis to remove external ammonium salt and form the gradient, finally drug was remote loaded into the gradient liposomes.
• PLD-MS Ammonium methanesulfonate liposomes
• Table 5 Chemical and encapsulation stability of doxorubicin (2 mg/mL) pegylated liposomal doxorubicin remote loaded via trans-membrane of ammonium salts of various selected sulfonic acids derivatives stored at 5°C
• Dox-G refers to liposomes comprising doxorubicin made with ammonium glucuronate gradient
• Dox026 refers to liposomes comprising doxorubicin made with ammonium sulfate, similar to Doxil®
• CryoTEM was performed in order to study the state of aggregation of the doxorubicin in the liposomes.
• PLD and pegylated nano-liposomes having transmembrane ammonium salts of the desired (alkyl and aryl) sulfonic acid derivatives after remote loading with doxorubicin (prepared as described above) were compared to Doxil® and to doxorubicin liposomes prepared with ammonium glucuronate gradient (see, e.g., WO 2005/046643). All liposomes were of the same size and identical lipid composition.
• cryo-TEM a drop of the solution was placed on a carbon-coated holey polymer film supported on a 300 mesh Cu grid (Ted Pella Ltd), the excess liquid was blotted and the specimen was vitrified via a fast quench in liquid ethane to -170°C.
• the fast cooling preserves the structures present at the bulk solution and therefore provides direct information on the morphology and aggregation state of the objects in the bulk solution without drying.
• the samples were imaged at -180°C using a FEI Tecnai 12 G2 Transmission Electron Microscope, at 120kV with a Gatan cryo-holder maintained at - 180°C.
• the X-ray generator MicroMax-007HF (Rigaku Corporation) is a rotating anode operating at 40 kV and 30 mA and has a copper target producing K a photons with an energy of 8 keV (wavelength of 1.54 A).
• the rotating anode is water-chilled by a refrigerated air-cooled system (Haskris, R075).
• a focused monochromatic beam is obtained using Confocal Max- Flux optics consisting of a CMF-12-100Cu8 focusing unit (Osmic Inc., a Rigaku
• the beam continues into a vacuum flight path (ca. 15 Torr), which contains two slits; fully motorized, scatterless hybrid metal_Ge single-crystal slits (Forvis
• the flight path is closed by a Kapton window; which causes a parasite peak at 4.1nm ⁇ ⁇
• the sample holder is placed immediately after the slits, and a MAR345 image -plate detector (Marresearch GmbH) is stationed at 250 mm of the sample.
• SAXS Small Angle X-rays Scattering experiments
• the scattered beam enters a large He-filled flight path (ca. 36 cm in diameter) before to be collected on the Mar345 image plate detector, placed about 1850 mm after the sample holder.
• WAXS (described above).
• the main difference is that the sample to detector distance is for the SAXS 1850 mm (instead of 250 mm for the WAXS measurements).
• the scattered beam is going through a He flight path to avoid air scattering over such a long distance.
• Lipid mix was dispersed in ammonium alkyl or aryl sulfonate to form MLV (Multi Lamellar large Vesicles) followed by extrusion process for SUV (Small unilamellar Vesicles) to achieve ⁇ 85-90nm liposomes of homogenous uni-modal size distribution.
• MLV Multi Lamellar large Vesicles
• SUV Mall unilamellar Vesicles
• SUV's were subjected to dialysis for external Ammonium alkyl or aryl sulfonate followed by Doxorubicin encapsulation into SUV liposomes. Histidine buffer was added.
• Table 7B X-RAY diffraction and CRYO-TEM- physical properties (for the formulation characterization see Table 7A above)
• the lipid tails in the liquid (liquid disordered or liquid ordered) phase contribute to the signal with a weak peak around 15 nm "1 .
• the presence of the drug apparently decreases the level of order of the lipid tails, suggesting that doxorubicin interacts with the membrane lipids.
• this effect is present in all formulations and is not related to the intraliposome drug crystallization.
• Fig. 5B presents the effect of temperature on the WAXS spectra of samples l(Dox-MS), sample 3 (Dox-4HBS) and sample 5 (Dox- sulfate).
• Samples 2 (Dox-3HPS) and 4 (Dox-ES) present exactly the same features than sample 1 (Dox-MS).
• the crystalline doxorubicin phase is present at both 4°C and at 37°C, but not at 60°C and in sample 3, the peak is present only at 4°C. Even at 4°C, samples 1, 2 and 4 don't present the doxorubicin crystalline peak.
• Those results mean that the crystallization temperature of the intra-liposome doxorubicin depends on the ammonium-counter anion salt used for the remote loading. This counter ion also makes the intra-liposome doxorubicin salt.
• Fig. 5C show a small angle X ray scattering (SAXS) in which the doxorubicin crystal peak is observed in both Mimicry of Doxil® and commercial Doxil®, as already presented in Fig. 2A, while for liposomes loaded with DOXMS, doxorubicin does not show any crystallization signs.
• SAXS small angle X ray scattering
• doxorubicin release rate when doxorubicin was remotely loaded into pegylated liposomes to form Dox-MS was equal to Dox-ES and very similar to Dox-3HPS, following three and five hours of incubation as describe above. All these showed faster release rate than liposomes having trans-membrane ammonium sulfate remote loaded Doxil®-like liposomes. However, doxorubicin release rate when doxorubicin was remotely loaded into pegylated liposomes to form Dox-4HBS was unexpectedly even slower than of Doxil®-like liposomes.
• Example 7 In vivo pharmacokinetics (PK) and biodistribution (BD)
• mice of each group were injected intravenously (I.V.) with a single dose of Doxil® or the of various PLDMS shown in Table 8 below. At defined time-points (see Table 8 below, for composition of each formulation see Tables 5 and 6), mice of each group were euthanized with C0 2 and terminal blood was withdrawn from the retro-orbital sinus and collected in labeled K3EDTA tubes.
• Doxorubicin was extracted from the samples as follows. The samples were diluted in acid isopropyl alcohol (A-IPA) and vortexed 30 seconds then centrifuged 14K RPM for 5 minutes for plasma protein precipitation. From the upper phase, ⁇ of the plasma diluted in A-IPA were diluted in 900 ⁇ mobile phase for analysis and the contents of extracted doxorubicin was determined using fluorescence HPLC (as described in Gabizon et al. (1993) Pharm. Research 10(5):703-708).
• A-IPA acid isopropyl alcohol
• PLDMS liposomes show lower drug levels in blood after 24 and 48 hours in comparison to Doxil® demonstrating shorter residence time of doxorubicin in blood and hence likely leading to fewer (or reduced) side effects.
• PK pharmacokinetics
• BD biodistribution
• Ammonium salt Ammonium Methane Ammonium sulfate concentration sulfonate 350mM 250mM
• mice A total of one hundred and ten (110) female Balb/c mice were injected intravenously (I.V.) with a single dose of LClOO or Caelyx ® that was equivalent to 200 ⁇ g DOX (55 mice per tested group). At specified time-points, five mice of each group were sacrificed and blood was immediately collected and subjected to plasma separation procedure. Immediately following blood collection the mouse was perfused with approximately 10-15mL of saline then the following organs were collected separately in labeled CryoTubes and immediately subjected to cryopreservation in liquid nitrogen: liver, heart, spleen, kidneys, lungs, brain and ovaries. The organs were transferred into labeled boxes at -80°C pending analysis.
• doxorubicin was extracted from the plasma samples and the content of extracted DOX was determined using fluorescence-HPLC procedure as described below.
• doxorubicin was extracted from liver and heart according to the procedure described in paragraph 00114 and 0016 below and the content of extracted DOX was quantified fluorometrically ( exc i tat i on 485 nm and
• mice In order to compare the values to the organ biodistribution of free doxorubicin, Balb/c female mice of similar age and body weight to the mice used in this study were injected using exactly the same procedure with 200 ⁇ g of doxorubicin hydrochloride in a separate experiment. The blood and organ collection were performed following the procedures described below. The collected organs of mice treated with doxorubicin hydrochloride were treated and analyzed together with the organs of mice treated with Caelyx® and LClOO. Preparation of blood samples
• mice of each group were sacrificed with C0 2 and terminal blood was immediately withdrawn from the retro-orbital sinus and collected in labeled 0.5 mL K 3 EDTA blood collection tubes (Mini Collect, Greiner-bio-one, Austria). The blood was centrifuged at 4000 rpm (2060 g) for 10 minutes. The plasma was collected in labeled CryoTubes and cryopreserved immediately in liquid nitrogen and then transferred into labeled boxes and stored at -80°C pending analysis.
• mice were perfused with 10 to the mice.
• Plasma samples were delivered by the in vivo pharmacologist to the QC department accompanied with a controlled delivery form ("Collection of blood samples for analysis” and “Collection of organs samples for analysis” forms). Extraction procedure and measurement of DOX content from plasma samples were carried out by QC personnel according to protocol "Analysis protocol for PK study PK003-LC100- 120904." Organ samples
• Table 10 The outcomes of non-compartmental pharmacokinetic analysis of the average doxorubicin plasma concentration vs. time data
• mice treated with LCIOO did not show asthenia (lack or loss of strength and energy; weakness), that mice treated with Doxil® showed.
• asthenia is the most common all-grade adverse reaction (40%) reported by patients with recurrent ovarian cancer treated with Doxil®.
• PLDMS (“DOXMS003”) administered at lmg/kg show much lower PPE score and much better quality of life in term of general physiology (body weight, appearance) and clinical signs when compared with the rats that were injected with commercial Doxil® at the same regimen.
• Example 9 In vivo anti-tumor effects in A549 tumor model in nude mice
• Doxorubicin concentration in Doxil® and PLDMS was identical ⁇ 2mg/ml. Forty eight hours post injection, animals were sacrificed and tumors were excised and sectioned.
• Histopathological studies included staining for mitochondrial enzyme activity by incubating representative tissue sections for 30-45 min in 2% 2,3,5-triphenyl tetrazolium chloride (TTC) at room temperature to identify irreversible nonspecific cellular injury as described in Liszczak et al. (1984) Acta Neuropathol. 65(2): 150- 157). Gross measurements of tumor destruction were performed on both TCC-stained and unstained sections, and photographed. The extent of visible coagulation was measured with the image processing and analysis software ImageJ (NIH, Bethesda, MD).
• TTC 2,3,5-triphenyl tetrazolium chloride
• Coagulation area was measured by precise selection of the white zone in the stained tumor section under high zoom.
• Example 10 Therapeutic efficacy studies: OVCAR-3 ovarian adenocarcinoma xenograft model of athymic nude mice
• doxorubicin HCl G6 animals were treated with 8 mg/kg doxorubicin HCl, LC3-PLDMS-2 (PLMDS-2 are liposomes containing 250mM ammonium methanesulfonate (MS) and remote loaded with doxorubicin (group 5 in the experiment), LC4_PLDMS-5 are liposomes containing 500 mM ammonium methanesulfonate (MS) and remote loaded with doxorubicin (group 6in the experiment) (respectively, given intravenously (5 ml/kg dose volume) once weekly for 2 consecutive weeks. Body weight, general clinical observations and tumor size were monitored throughout the experimental period. Experimental groups were terminated when median tumor volume reached 2500mm .
• Endpoint parameters such as body weight change, %ILS, Median tumor volume, TGI, %T/C, RTV, LCK, Tumor growth delay, TVDT and TVDTD were calculated.
• MST median survival time
• %ILS percentage increased life span
• TV median tumor volume
• TGI median tumor growth inhibition
• %T/C relative tumor volume
• RTV relative tumor volume
• LCK log cell kill
• TVDT tumor volume doubling time
• TVDTC tumor volume doubling time delay
• LC3-PLDMS-2 and LC4-PLDMS-5 both exhibited improved survival benefit compared to doxorubicin HC1 (%ILS values of 26.9, 26.9 days for the 2 PLDMS formulations compared with 21.2, day for doxorubicin as is respectively), reflecting their increased median life span (66 days in each group compared to 63 days in the doxorubicin HC1 group).
• Median TV was decreased relative to the saline control, with volumes of 895.1 and 1123.4 in the mm 3 the LC4-PLDMS-5 and LC3-PLDMS-2 groups, respectively on day 52, when the saline control group was terminated due to tumor size.
• the doxorubicin HC1 treatment group at this time point was 1430.3 mm .
• Other anti-tumor efficacy measures listed above, all derived from median tumor volume, consistently showed the improved anti-tumor activity of the two liposomal formulations compared to doxorubicin HC1 as well as their relative activity. Tumor growth delay was evident at all the predetermined time points, e.g., at tumor volumes of 250, 500 and 1000mm in the treatment groups.
• both the LC3-PLDMS-2 and LC4-PLDMS-5 formulations showed promising anti-tumor therapeutic efficacy which are higher than equivalent dose of doxorubicin as is in all measured parameters of activity as well as better tolerability.
• mice bearing growing tumor were selected and randomized into 4 groups containing 8 animals in each based on a mean tumor size of ⁇ 100mm3.
• Gl animals served as vehicle control and received 5 ml/kg saline whereas G2, G5 and G6 animals received Doxorubicin HC1, LC3-PLDMS-2 or LC4-PLDMS-5, respectively, at a dose of 8 mg/kg. All the animals were dosed intravenously at the dose volume of 5ml/kg weekly once for two weeks. Body weight, general clinical observations and tumor volume parameters were recorded during the experimental period. Groups reaching median tumor volume of 2500mm were terminated.
• test formulation For preparation and administration of reference and test item, all the test items are ready to use formulations.
• the strength of test formulation is 2mg/ml of doxorubicin HC1 in sterile 5ml vial. 2 ml of reference or test item formulation (i.e.
• Doxorubicin HC1, LC3-PLDMS-2 and LC4-PLDMS-5) was diluted to 0.5 ml normal saline to achieve 1.6mg/ml. ⁇ . of final test formulation was injected intravenously to 20g of mouse to achieve the 8mg/kg dose. Group Gl animals received normal saline at the dose volume of 5ml/kg.
• Body weight parameters were statistically analyzed using one-way
• Log cell kill defines the change in tumor size that is directly (linearly) related to the logarithm of the number of cells killed.
• the maximum log cell kill value of 0.66 was observed in LC4-PLDMS-5 (G6), followed by LC3-PLDMS-2 (G5) with an LCK value of 0.56 and doxorubicin HCL group (G2) with an LCK value of 0.40.
• Data on Log Cell Kill are presented in Table 14 and Figure 7E.
• Tumor volume doubling time refers to time taken by tumor to double its volume; it is widely used for quantification of tumor growth rate.
• the vehicle control tumor doubled its volume in shortest time, 6 days.
• tumor doubling times were 11, 9.5 and 7 days in the LC4-PLDMS-5 (G6), LC3-PLDMS-2(G5) and doxorubicin HC1 groups, respectively.
• the primary objective of this study is to evaluate safety, maximum tolerated dose (MTD), dose limiting toxicities (DLT) and basic pharmacokinetic properties for PLDMS in client-owned dogs (weighing > 10 kg), with spontaneous tumors.
• a secondary objective of the study will be to characterize the frequency and intensity of palmar-plantar erythrodysesthesia (PPE) in dogs with spontaneous tumors treated with PLDMS using standard criteria and comparison to a group of published historical controls receiving pegylated liposomal doxorubicin (Doxil®).
• Specific Aim 1 Determine the MTD, DLT and adverse event (AE) profile of PLDMS in client-owned dogs with spontaneous tumors.
• Dogs in the expanded cohort will be phlebotomized at time intervals following treatment to establish tl/2 (h), Cmax (nmol/L), Tmax (h), AUC(0- ⁇ ) (nmol/L h).
• Specific Aim 3 Determine the frequency, intensity and characteristics ofPPE in all treatment cohorts, in particular the expanded cohort, and compare to a group of historical client-own dogs treated with the MTD of Doxil®.
• Dogs with histologically confirmed measurable tumors of any histology with a likelihood of being responsive to doxorubicin based on the current literature e.g., lymphoma, carcinoma, soft tissue sarcoma and osteosarcoma.
• Dogs must have a Modified Performance Status of 0 (fully active, able to perform at pre-disease level) or 1 (activity less than pre-disease level, but able to function as an acceptable pet).
• dogs will receive q3wk dosing of PLDMS according to a standard 3+3 phase I design, beginning with an initial cohort at 0.25 mg/kg i.v (Cohort 1), every 3 weeks for a total of 5 cycles. Dose escalations will be made with 3 dogs per dose level at an escalation level of 0.25 mg/kg per cohort.
• a DLT is defined as > Grade 3 toxicity (VCOG-CTCAE v 1.1) in any AE category except for neutropenia, where a Grade 4 toxicity is dose-limiting.
• the cohort will be expanded to 6 dogs at that dose level.
• Escalation to the next higher dose cohort will occur if 0/3 dogs in a cohort experience a DLT or if only 1/6 dogs in an expanded cohort experiences a DLT. If a DLT attributable to treatment is observed in more than 1 dog at a dose level, then the MTD has been exceeded, accrual to that dose level will cease, and dose-escalation will be terminated. The prior dosing cohort will then be expanded to a minimum of 6 dogs and the MTD will be defined as the highest dose level in which no more than 1/6 dogs develops a DLT.
• All dogs in a cohort must be observed for at least 3 weeks following initiation of treatment before beginning accrual to the next higher dose level.
• Five dosing cohorts are planned (cohort 1, 0.25 mg/kg; cohort 2, 0.5 mg/kg; cohort 3, 0.75 mg/kg; cohort 4, 1.0 mg/kg; and cohort 5, 1.25 mg/kg) up to a final dosing cohort of 1.25 mg/kg (the MTD previously established for Doxil® in tumor bearing dogs from previous trials was 1.0 mg/kg). This translates into a likely total of 18 - 21 dogs, allowing for 2 cohort expansions.
• PLDMS MTD (established in Aim 1) will be phlebotomized at 6 time intervals following treatment to establish tl/2 (h), Cmax (nmol/L), Tmax (h), and AUC(0- ⁇ ) (nmol/L h). Dogs in the expanded cohort will also receive 5 total cycles of PLDMS. Specific Aim 3
• Antitumor activity While not a primary endpoint of phase I trials, tumor measurements will be performed prior to initiation of therapy and at each subsequent recheck. Standard RECIST vl.l criteria for the assessment of solid tumors will be applied.

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