JP2009530318A - Lipid-based drug delivery system containing phospholipase A2-degradable lipid that undergoes intramolecular cyclization during hydrolysis - Google Patents

Abstract

The present invention relates to a lipid-based drug delivery system for administration of an anticancer drug in the form of a prodrug, which can further cause an intramolecular reaction by hydrolytic cleavage of an organic group. To the extent it is a substrate for extracellular phospholipase A2, the system includes lipopolymers and / or glycolipids to provide hydrophilic chains on the surface of the system. In addition, lipid prodrugs and drug carriers can be used in combination with incorporated drugs. The pharmaceutical composition comprising the drug delivery system can be used to diagnose various disorders such as cancer, infectious and inflammatory conditions, ie disorders and diseases associated with or caused by elevated levels of extracellular PLA ₂ activity in affected tissues and It can be used in targeted therapy.

Description

The present invention relates to lipid-based pharmaceutical compositions for use in the treatment of various disorders such as cancer, infectious and inflammatory conditions, ie disorders and diseases associated with or resulting from elevated levels of extracellular PLA ₂ activity in the affected tissue About.

Monoether lysophospholipids and alkylphosphocholines are known to be effective anticancer agents. (See, eg, US Pat. No. 3,752,886 and later references). One specific example of monoether alkyl phosphocholine that is under investigation is 1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine (ET18-OCH ₃ ).

  Several mechanisms of ether-lipid toxic effects on cancer cells have been proposed to contribute to the lack of alkyl cleavage lattices in cancer cells. This results in the accumulation of ether-lipids in the cell membrane which induces membrane defects and possibly subsequent cell lysis. Other possible mechanisms of action include effects on intracellular protein phosphorylation and impaired lipid metabolism. Normal cells typically have an alkyl-cleaving enzyme that allows the cells to circumvent the toxic effects of ether-lipid. However, some normal cells, such as red blood cells, for example, do not have a means to avoid the destructive effects of ether lipids like cancer cells. Therefore, therapeutic use of ether-lipids requires an effective drug delivery system that can protect normal cells from toxic effects and deliver ether lipids to affected tissues.

US 5985854, US 6077837, US 6136796 and US 6166089 describe prodrugs with high cell penetration that are particularly useful in treating human conditions or diseases associated with excess intracellular enzyme activity. The prodrug can be a C-2 ester of lysophospholipid. Such agents are designed to be cleaved by intracellular phospholipase A _2.

  In view of the above, there is an increasing need for new drug delivery systems, particularly for targeted delivery of drug substances that can treat or ameliorate conditions such as cancer and inflammation. It is particularly important to inhibit the release of the drug substance or substances in places other than the affected tissue, since cancer treatment drugs can generally be particularly harmful to the tissue.

The present invention relates to drug delivery systems that are particularly useful in the treatment or amelioration of diseases characterized by local activity of extracellular PLA ₂ activity.

The new principle of liposome drug targeting by extracellular PLA ₂ described in this application and shown in FIG. 1 involves lipid-based prodrugs that undergo intramolecular cyclization upon PLA ₂ hydrolysis. In this case, specific lipid analog compounds can be incorporated into polymer or polysaccharide “graft” carrier liposomes, which act as prodrugs that are converted to active agents by hydrolysis through extracellular phospholipases. Possible examples include cyclization after PLA ₂ hydrolysis to form a 5-membered or 6-membered ring, resulting in lipid analogs of the lipids shown to have anticancer activity shown in FIG. It is believed that certain lipid-containing esters can be, but is not limited to.

The principle of drug targeting, release and absorption by extracellular phospholipase A2 (PLA ₂ ) shown in FIG. 1 is the result of hydrolysis by extracellular PLA ₂ where the drug is attached to the lipid and present at high concentrations in the affected target tissue. As well as lipid-based prodrugs that are released after intramolecular cyclization. Possible examples include those shown in FIGS. 3 and 4, but are not limited to these examples. In this way, therapeutically active substances such as prostaglandins, peptides, anticancer ether lipids or retinol derivatives are released at the desired target site. Particularly interesting drugs include, but are not limited to, drugs having free alcohol groups or bioequivalents thereof. Furthermore, some of the hydrolysis products can act as a local permeability enhancer that promotes transport of the generated anticancer drug into cells. Pharmaceutical compositions comprising lipid-based systems can be used therapeutically, for example in the treatment of cancer, infectious and inflammatory conditions.

The present invention relates to alkyl or acyl linkages at the 1-position in the form of lipid-based carriers such as liposomes or micelles and / or from other organic moieties and phospholipid head groups or biological equivalents thereof. Novel lipid bilayer-forming lipids such as glycerophospholipids containing acyl linkages at positions with the correct distance and stereochemistry or another PLA ₂ degradable linkage, eg, a bioequivalent of PLA ₂ hydrolysable ester Such a delivery system is provided. Typically, this is as a phospholipid having a glycerin backbone with or without a backbone substituent at the 1- or 3-position, such as a polymer grafted to a lipid head group or a qualities with a polysaccharide chain. Let's go. In addition, the carrier system can include lipid bilayer stabilizing components such as lipopolymers, glycolipids and sterols that result in increased vascular circulation time and consequent accumulation in the affected target tissue. When the carrier reaches a target site for therapeutic action, eg, cancer cells, acyl-linked PLA ₂ catalyzed release releases therapeutically active ingredients, typically lysoether lipids and ester-linked derivatives that cyclize upon hydrolysis. . Contrary to alkyl-cleaving enzymes which are hardly present in cancer cells, extracellular PLA ₂ activity is high in cancer tissues. Furthermore, extracellular PLA ₂ activity is high in affected areas such as inflamed tissues.

Thus, the present invention provides a lipid for administration of an active drug substance selected from a drug substance capable of binding to a lipid capable of releasing the drug substance during an intramolecular cyclization reaction as a result of lysolipid derivatives or PLA ₂ hydrolysis. A base drug delivery system is provided. Thus, the active drug substance is present in a lipid-based system in the form of a prodrug. With respect to lysolipid derivatives, the corresponding prodrugs are (a) an aliphatic group having a length of at least 2 carbon atoms and an organic group having at least 2 carbon atoms and (b) a lipid derivative having a hydrophilic moiety. And the prodrug further allows the organic group to be hydrolytically cleaved, while the aliphatic group remains substantially unaffected so that the active drug substance is cyclized intramolecularly. Is a substrate for extracellular phospholipase A2 to the extent that it is released in the form of a lysolipid derivative, the system comprising lipopolymers and / or glycolipids to provide a hydrophilic chain on the surface of the system .

  The present invention further provides a lipid-based drug delivery system for administration of at least one second drug substance, wherein said at least one second drug substance is incorporated into said system, said system comprising (a A lipid derivative having an organic group having at least two carbon atoms and (b) a hydrophilic moiety arranged with the correct distance and the correct stereochemistry with respect to each other, said lipid derivative further comprising an organic group hydrolytically A substrate of extracellular phospholipase A2 to the extent that cleavage can produce organic acid fragments or organic alcohol fragments and lysolipid fragments that can undergo intramolecular cyclization, wherein the system is a lipopolymer and / or Alternatively, providing a drug delivery system that includes a glycolipid to provide a hydrophilic chain on the surface of the system.

Thus, the present invention is capable of being specifically and only partially cleaved by extracellular phospholipase, and at the same time, liposomes (and micelles) such as lipopolymers and / or lipid derivatives containing glycolipids are used in mammalian cells. Lipid derivatives of liposomes are not recognized by the reticuloendothelial system and do not penetrate the cell wall and circulate in the bloodstream long enough to reach the target tissue with high extracellular PLA ₂ activity. It takes advantage of the surprising finding that it is specifically cleaved by external PLA ₂ to release the therapeutically active ingredient at the desired location.

  The present invention further provides a class of novel lipid derivatives that are particularly useful as components of the drug delivery systems described herein.

One important feature of the present invention is that certain lipid derivatives have been found to be cleaved by extracellular PLA _{2 in a well-} defined manner at extracellular sites in mammalian affected tissues. Extracellular PLA ₂ can cleave monoether / monoester lipid derivatives as well as lipids with substituents at the glycerin backbone, which yields lipid derivatives, which themselves or in combination with other active compounds, A therapeutic effect was observed.

Lipid derivatives Accordingly, the drug delivery systems (liposomes or micelles) of the present invention may in some cases comprise (a) an aliphatic group having a length of at least 2 carbon atoms and an organic group having at least 2 carbon atoms and ( b) Relying on a lipid derivative having a hydrophilic moiety, the prodrug can further be cleaved organically hydrolytically, resulting in intramolecular cyclization, while the aliphatic group is substantially Is a substrate for extracellular phospholipase A2 to the extent that the active drug substance remains intact and is thus released in the form of a cyclized lysolipid derivative, the system containing lipopolymers and / or glycolipids Inclusion provides a hydrophilic chain on the surface of the system.

The terms “lipid” and “lysolipid” (in the context of phospholipids) are terms known to those skilled in the art, but should be emphasized, within the scope of the description and claims herein, The term “lipid” means a substituted glycerin of the formula

Where
R ^A and R ^B are fatty acid moieties (C _9-30 -alkyl / alkylene / alkyldiene / alkyltriene / alkyltetraene-C (═O) —), where R ^C is phosphatidic acid (PO ₂ —OH) Or a derivative of phosphatidic acid or a bioequivalent of phosphatidic acid. Thus, the groups R ^A and R ^B are linked to the glycerol skeleton via an ester bond. R ^D is an ester moiety ((CH ₂ ) _n C (O) D ¹ )), which promotes intramolecular cyclization during PLA ₂ hydrolysis, where n is an integer of 0-5, preferably 0-2. And D ¹ is an organic moiety, possibly MeOH or EtOH, preferably a biologically active organic moiety. The hydrogen in the CH ₂ group in ^RD may be substituted by an intramolecular cyclization promoting group, for example, fluorine at the α-position with respect to carbonyl. The CH ₂ group in ^RD may be substituted, in particular α-position to the carbonyl group, for example with O, S, NH or their biological equivalents. Alternatively, ^RD is an organic moiety that includes a leaving group such as iodine, ie, an organic moiety that can promote intramolecular cyclization upon PLA ₂ hydrolysis.

The term "lysolipid" is absent R ^B fatty acid group (e.g. hydrolytically cleaved off) lipids, that is, R ^B is hydrogen, the above formula other substituent is not substantially affected Of glycerin derivatives. The conversion of lipids to lysolipids can occur under the action of enzymes, specifically under the action of cellular PLA ₂ as well as extracellular PLA ₂ .

  The terms “lipid derivative” and “lysolipid derivative” are intended to cover possible derivatives of the above-mentioned possible compounds which are included in the group of “lipid” and “lysolipid”, respectively. Examples of bioactive lipid derivatives and lysolipid derivatives are listed in Houlihan et al. (Houlihan, et al., Med. Res. Rev., 15, 3, 157-223). Thus, as will be apparent, the ending “derivative” should be understood in the broadest sense.

  Within the scope of the present application, lipid derivatives and lysolipids satisfy, in the above cases, certain functional criteria (see above) and / or structural requirements. Of particular note, one example of a suitable lipid derivative is (a) an aliphatic group with a length of at least 2, 3, 4, 5, 6, 7, 8, preferably at least 9 carbon atoms and Those having an organic group having at least 2, 3, 4, 5, 6, 7, 8, preferably at least 9 carbon atoms and (b) a hydrophilic moiety. It will be clear that aliphatic and organic groups correspond to the two fatty acid moieties in normal lipids, and that the hydrophilic moiety corresponds to the phosphate moiety of (phospho) lipids or their biological equivalents. .

Thus, the idea behind the present invention is to take advantage of the increased level of extracellular PLA ₂ activity in a local region of the mammalian body, particularly in the affected tissue, so that lipids that can be used within the scope of the present invention The derivative should be a substrate for extracellular PLA ₂ , ie the lipid derivative must be capable of undergoing hydrolytic enzymatic cleavage of the organic group corresponding to the fatty acid. In the broadest sense, this means that the organic group and the phospholipid head group or the bioequivalents of the phosphorus head group should be arranged with the correct distance and the correct stereochemistry with respect to each other, for example in phospholipids It means that the organic group is in position 2 and / or the head group is in position 3. Extracellular PLA ₂ is known to belong to the enzyme class (EC) 3.1.1.4. Thus, when referring to (extracellular) PLA ₂ , all extracellular enzymes of this class, such as lipases, which can induce the hydrolytic cleavage of the organic group corresponding to the fatty acid at position 2 in the lipid. Should be understood. One particular advantage of lipid-based drug delivery systems (as liposomes and micelles) is that extracellular PLA ₂ activity is significantly higher towards organized substrates compared to monomeric substrates.

In view of the requirement for hydrolyzability by extracellular PLA ₂ , the organic group (eg aliphatic group) is preferably cleavable by extracellular PLA ₂ , preferably the cleaved group is a carboxylic acid It is clear that they are linked via an ester functional group.

Further, an important feature of the present invention is that the aliphatic group of the lipid derivative, that is, the lysolipid derivative after cleavage with extracellular PLA ₂ (the group corresponding to the 1st fatty acid in the lipid) is caused by the action of extracellular PLA ₂ . It is not substantially affected. “Substantially unaffected” means that the integrity of the aliphatic group is preserved, and that cleavage under the action of extracellular PLA ₂ is less than 1 mol% of the aliphatic group (the aliphatic group at position 1), preferably It means less than 0.1 mol%.

  The drug delivery system (liposomes or micelles) of the present invention, in another example, relies on (a) an organic group having at least 2 carbon atoms and (b) a lipid derivative having a hydrophilic moiety, The drug is further a substrate for extracellular phospholipase A2 to the extent that the organic group can be hydrolytically cleaved to cause intramolecular cyclization, wherein the system comprises a lipopolymer and / or a glycolipid, Provide hydrophilic chains on the surface of the system.

The term “lipid” shall mean a triester of the formula

Where
R ^B is a fatty acid moiety (C _9-30 -alkyl / alkylene / alkyldiene / alkyltriene / alkyltetraene-C (═O) —), R ^C is phosphatidic acid (PO ₂ —OH) or phosphatidic acid A derivative or a bioequivalent of phosphatidic acid. Thus, R ^B is connected to the glycerol backbone via ester bonds. D ² is the drug substance with an organic moiety, i.e. broadest sense having physiological activity. n is an integer of 0-5, preferably 0-2. The hydrogen in the CH ₂ group can be substituted with an intramolecular cyclization promoting group, for example, a? A CH ₂ group that is α to carbonyl can also be substituted with O, S, NH, or a biological equivalent thereof.

In some _{embodiments, (CH 2) n -C (} O) -D 2 may also be equal to ^{R D.}

One preferred type of lipid derivative incorporated into the drug delivery system of the present invention can be represented by the following formula:

Another preferred type of lipid derivative incorporated into the drug delivery system of the present invention can be represented by the following formula:

Where
R ^D is an ester moiety ((CH ₂ ) _n C (O) D ¹ ) that promotes intramolecular cyclization during PLA2 hydrolysis, n is an integer from 0 to 5, preferably 0 to 2; ¹ is an organic moiety, which can be MeOH or EtOH, and is preferably an organic moiety having physiological activity. The hydrogen in the CH ₂ group in ^RD can be substituted with an intramolecular cyclization promoting group, for example, a fluorine with respect to carbonyl. The CH ₂ group in R ^D can be substituted, for example with O, S, NH or their biological equivalents, especially in the α-position to the carbonyl group. Alternatively, R ^D is an organic moiety that includes a leaving group, such as iodine, ie, an organic moiety that can promote intramolecular cyclization upon PLA ₂ hydrolysis.

D ² is the drug substance in the organic moiety, i.e. broadest sense having physiological activity. n is an integer of 0-5, preferably 0-2. The hydrogen in the CH ₂ group can be substituted with an intramolecular cyclization promoting group, for example, a? The CH ₂ group can further be substituted, in particular α-position to the carbonyl group, for example with O, S, NH or their biological equivalents.

X and Z are independently OC (O), O, CH ₂ , NH, NMe, S, S (O), OS (O), S (O) ₂ , OS (O) ₂ , OP (O) ₂ , OP (O) ₂ O, OAs (O) ₂ and OAs (O) ₂ O, preferably selected from O, NH, NMe and CH ₂ , in particular O and CH ₂ ;
Y is selected from OC (O), OC (O) O, OC (O) N, OC (S), SC (O), SC (S), CH ₂ C (O) O, NC (O) O Y is connected to R ² via an oxygen, sulfur, nitrogen or carbonyl carbon atom, preferably via a carbonyl carbon atom;
R ¹ is an aliphatic group of formula Y ¹ Y ² ;
R ² is an organic group having at least 2 carbon atoms, such as an aliphatic group having a length of at least 2, preferably at least 9 carbon atoms, preferably a group of the formula Y ¹ Y ² ;
Y ¹ _{is, - (CH 2) n1 -} (CH = CH) n2 - (CH 2) n3 - (CH = CH) n4 - (CH 2) n5 - (CH = CH) n6 - (CH 2) n7 - _{(CH = CH) n8r - (} CH 2) a _{n9, n1 + 2n2 + n3 +} 2n4 + n5 + 2n6 + n7 + 2n8 + total n9 is an integer from 2 to 29; n1 is an integer of either 0 or 1 to 29, 1 to 20 or is n3 is 0 N5 is 0 or an integer from 1 to 17, n7 is 0 or an integer from 1 to 14, and n9 is 0 or an integer from 1 to 11; n2, n4 , N6 and n8 are each independently 0 or 1; Y ² is CH ₃ , OH, SH, S (O) ₂ OH, P (O) ₂ OH, OP (O) ₂ OH, NH ₂ or CO ₂ is H; each ^Y 1 -Y ² DE Optionally substituted with halogen and aliphatic substituents, but preferably Y ¹ -Y ² is unsubstituted;
R ³ is a biological equivalent to phosphatidic acid (PO ₂ —OH), derivatives of phosphatidic acid and phosphatic acid, such as P (O) O, P (O) ₂ CH ₂ , S (O) O, S (O) CH ₂ , C (O) O, C (O) N, C (S) O, P (S) O ₂ , S (O) ₂ CH ₂ and their derivatives (especially hydrophilic Phosphatidic acid derivatives to which a functional polymer or polysaccharide is covalently bound).

As noted above, preferred embodiments suggest that Y is —OC (O) — and Y is linked to R ² via a carboxyl atom. The most preferred embodiment suggests that X and Z are O, Y is —OC (O) —, and Y is linked to R ² via a carboxyl atom. This means that the lipid derivative is a 1-monoether-2-monoester-phospholipid type compound.

  Another preferred group of lipid derivatives are those in which the group X is S.

In one embodiment, R ¹ and R ² are aliphatic groups of formula Y ¹ Y ² and Y ² is CH ₃ , OH, SH, S (O) ₂ OH, P (O) ₂ OH, OP _(O) 2 OH, it is a NH ₂ or CO ₂ H, preferably CH _3, ^{Y 1} is _{- (CH 2) n1 (CH} = CH) n2 (CH 2) n3 - (CH = CH) n4 _{- (CH 2) n5 - (} CH = CH) n6 - (CH 2) n7 - (CH = CH) n8 - (CH 2) be _{n9; n1 + 2n2 + n3 +} 2n4 + n5 + 2n6 + n7 + 2n8 + total n9 is intended is an integer of 2 to 29, That is, the aliphatic group Y ¹ Y ² is ^one having a length of ² to 29 carbon atoms. n1 is equal to 0 or an integer from 1 to 23; n3 is equal to 0 or an integer from 1 to 20; n5 is equal to 0 or an integer from 1 to 17; n7 is equal to 0 N is an integer from 1 to 14; n is equal to 0 or an integer from 1 to 11; n2, n4, n6 and 8 are each independently equal to 0 or 1.

Aliphatic groups can be unsaturated and _optionally substituted with halogens (fluorine, chlorine, bromine, iodine) and C _1-10 groups (ie, forming branched aliphatic groups), but R ¹ and R The aliphatic groups as ² are preferably saturated and unbranched in one embodiment, i.e. they preferably have no double bonds between adjacent carbon atoms, and n2, n4, n6 and Each of n8 is equal to 0. Accordingly, Y ¹ is preferably (CH ₂ ) _n1 . More preferably (in this embodiment), R ¹ and R ² are each independently (CH ₂ ) _n1 CH ₃ , most preferably (CH ₂ ) ₁₇ CH ₃ or (CH ₂ ) ₁₅ CH ₃ . . In another embodiment, the groups can have one or more double bonds, i.e., they are unsaturated and one or more of n2, n4, n6 and n8 can be 1. For example, when the saturated hydrocarbon has one double bond, n2 is 1, n4, n6 and n8 are each 0, and Y ¹ is (CH ₂ ) _n1 CH═CH (CH ₂ ) _n3 is there. n1 is equal to 0 or an integer of 1 to 21, n3 is also 0 or an integer of 1 to 20, and at least one of n1 and n3 is other than 0.

In certain embodiments, the lipid derivative is selected from (CH ₂ ) _n CH ₃ where X and Z are O, R ¹ and R ² are independently alkyl groups, and n is 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29, preferably 14, 15 or 16, in particular 14; Y is —OC (O)-, wherein Y is a monoether lipid bonded to R ² via a carbonyl carbon atom.

With respect to the hydrophilic moiety corresponding to R ³ (often also referred to as “head group”), phosphatidic acid (PO ₂ —OH), derivatives of phosphatidic acid and biological equivalents to phosphoric acid and their It is believed that a great variety of groups corresponding to derivatives can be used. As is apparent, a very important requirement for R ³ is that the group should allow enzymatic cleavage of the R ² group (eg R ² —C (═O) or R ² —OH) by extracellular PLA _2. It is a point. “Biological equivalents to phosphatidic acid and derivatives thereof” suggest that such groups should be capable of enzymatic cleavage by extracellular PLA ₂ as phosphatidic acid.

R ³ is typically phosphatidic acid (PO ₂ —OH), phosphatidyl choline (PO ₂ —O—CH ₂ CH ₂ N (CH ₃ ) ₃ ), phosphatidylethanolamine (PO ₂ —O—CH ₂ CH ₂ NH). _2), N-methyl - phosphatidylethanolamine _{(PO 2 -O-CH 2 CH} 2 NHCH 3), phosphatidylserine, is selected from phosphatidylinositol, and phosphatidylglycerol _{(PO 2 -O-CH 2 CHOHCH} 2 OH). Other possible phosphatidic acid derivatives are those in which dicarboxylic acids such as glutaric acid, sebacic acid, succinic acid and tartaric acid are coupled to terminal nitrogens such as phosphatidylethanolamines, phosphatidylserine, phosphatidylinositol.

  In certain embodiments where a portion of the lipid derivative is also a lipopolymer or glycolipid, the hydrophilic polymer or polysaccharide is typically covalently linked to the phosphatidyl moiety of the lipid derivative. Another specific lipid derivative comprises an acyl chain attached to the lipid head group.

  Hydrophilic polymers that are suitable and can be incorporated into the lipid derivatives of the present invention to form lipopolymers are readily soluble in water and covalently bound to vesicle-forming lipids. And are tolerated in vivo without toxic effects (ie, are biocompatible). Suitable polymers include polyethylene glycol (PEG), polylactic acid (also referred to as polylactide), polyglycolic acid (also referred to as polyglycolide), polylactic acid-polyglycolic acid copolymer, polyvinyl alcohol, polyvinyl pyrrolidone, polymethoxa There are zoline, polyethyloxazoline, polyhydroxypropylmethacrylamide, polymethacrylamide, polydimethylacrylamide and derivatized celluloses such as hydroxymethylcellulose or hydroxyethylcellulose.

  Preferred polymers are those having a molecular weight of from about 100 daltons to about 10,000 daltons or less, more preferably from about 300 daltons to about 5000 daltons. In a particularly preferred embodiment, the polymer is a polyethylene glycol having a molecular weight of about 100 to about 5000 daltons, more preferably a molecular weight of about 300 to about 5000 daltons. In a particularly preferred embodiment, the polymer is 750 Daltons polyethylene glycol (PEG (750)). The polymer can also be defined by the number of monomers present, and a preferred embodiment of the present invention uses a polymer of at least about 3 monomers, such as a PEG polymer of 3 monomers (about 150 Daltons). It is.

  Where glycolipids or lipopolymers are represented by the proportion of lipid derivatives, such lipid derivatives (polymers or lipid derivatives having a polysaccharide chain) are typically 1-80 mol% of the total dehydrated lipid-based system. For example 2-50 mol% or 3-25 mol%. However, in the case of micelle compositions, the proportion can be higher values of the total dehydrated lipid-based system, for example 1-100 mol%, 10-100 mol%, etc.

  Preferred polymers that are covalently linked to the phosphatidyl moiety (eg, via the terminal nitrogen of phosphatidylethanolamine) include polyethylene glycol (PEG), polyactide, polyglycolic acid, polylactide-polyglycolic acid copolymer, and Polyvinyl alcohol.

Very interesting aspect of the present invention is that it is possible to vary the pharmaceutical effect of the lipid derivative by modifying the group R ^2. It should be understood that R ² must be an organic group having at least 2 carbon atoms (such as an aliphatic group having a certain length (at least 2, preferably 9 carbon atoms)). High variability is possible, for example R ² does not necessarily have to be a long chain residue, but can represent a more complex structure.

In general, R ² is fairly inert to the environment in which it can be released by extracellular PLA ₂ , or R ² is typically an auxiliary drug substance or lysolipid derivative and / or other ( It is believed that it can play an active pharmaceutical role as an efficiency improver for the second) drug substance.

In some embodiments, the R ¹ and R ² groups are long chain residues, such as fatty acid residues (the fatty acid includes a carbonyl from the group Y). This has been described in detail above. Interesting examples of auxiliary drug substances as R ^{2 in} this subgroup include polyunsaturated acids such as oleic acid, linoleic acid, linolenic acid, and arachidonic acid derivatives are prostaglandins, thromboxanes and leukotrienes. (including the carbonyl from Y) derivatives of arachidonic acid from that known to be regulators of hormone action including the action of classes, for example, a prostaglandin such as prostaglandin E _1. Examples of efficiency improvers as R ² include those that increase the permeability of the target cell membrane and further increase the activity of extracellular PLA ₂ or the active drug substance or second drug substance. Examples thereof are short chain ( _C8-12 ) fatty acids.

However, also envisaged that other groups as the organic groups R ² may be useful, for example vitamin D derivative to, steroid derivatives, retinoic acid (all trans - retinoic acid, all cis - retinoic acid, 9-cis-retinoic acid, 13-cis-retinoic acid, etc.), cholecalciferol and tocopherol analogues, branched aliphatic carboxylic acids (eg: valproic acid and those described in WO 99/02485), salicylic acids (eg: acetyl) Salicylic acid), steroidal carboxylic acids (eg lysergic acid and isolysergic acid), monoheterocyclic carboxylic acids (eg nicotinic acid) and polyheterocyclic carboxylic acids (eg penicillins and cephalosporins), diclofenac, Indomethacin, ibuprofen, naproxen, 6-me There are pharmacologically active carboxylic acids such as toxi-2-naphthylacetic acid.

It should be understood that the various examples of possible R ² groups are referred to by the name of the individual species rather than the name of the group. It should be further understood that these possible examples may include a carbonyl group or an oxy group (corresponding to “Y” in the above formula) of an intervening organic group linked to the lipid backbone. This will be understood by those skilled in the art.

Even though not specifically shown in the general formula for preferred examples of lipid derivatives used within the scope of the present invention, the glycol moiety of the lipid derivative is substituted, for example by extracellular PLA ₂ It should be understood that it is possible to change the cleavage rate or simply change the properties of the liposome containing the lipid derivative.

The present invention further relates to such lipid derivatives for use as medicaments, preferably present in pharmaceutical compositions, and further to diseases or conditions associated with local increases in extracellular phospholipase A2 activity in mammalian tissues. The use of lipid derivatives as defined above for the manufacture of a medicament for the treatment of Such diseases or conditions are typically selected from cancers such as brain tumors, breast cancer, lung cancer, colon cancer or ovarian cancer, or leukemia, lymphoma, sarcoma, carcinoma and inflammatory conditions. The compositions and uses of the present invention have an increase in extracellular PLA ₂ activity that is at least 25 compared to normal activity levels in the tissue of interest, which tissue is in a mammal, particularly a human. % Is particularly applicable.

Lipid Derivatives as Prodrugs As noted above, the present invention provides a lipid base for the administration of active drug substances selected from lysolipid derivatives and / or drug substances that can be covalently bound to lipids. A drug delivery system, wherein the active drug substance is present in a lipid-based system in the form of a prodrug, wherein the prodrug is (a) an organic group having at least 2 carbon atoms and (b) a hydrophilic moiety The prodrug can further cleave the organic group hydrolytically to cause an intramolecular cyclization reaction, whereby the active drug substance is released in the form of a lysolipid derivative. To the extent that it is a substrate for extracellular phospholipase A2 and the system contains lipopolymers and / or glycolipids to provide hydrophilic chains on the surface of the system It is to provide a dosage delivery system.

  The term “active drug substance” means a chemical entity that provides a prophylactic or therapeutic effect in the body of a mammal, particularly the human. The present invention thus relates primarily to the therapeutic field.

  The term “prodrug” should be understood in the usual sense, ie for the purpose of converting to the intended drug substance (typically by cleavage but also by in vivo chemical conversion). It should be understood as a mask or a protected drug. One skilled in the art will recognize the scope of the term “prodrug”.

The active drug substance is selected from a lysolipid derivative having a chemical structure capable of binding the drug to a lipid capable of causing intramolecular cyclization upon PLA ₂ hydrolysis and / or a drug having a therapeutic effect, It will be apparent from the description, including the claims.

As will be understood from this description, including the claims, lipid derivatives often constitute the prodrugs referred to above, whereby lysolipid derivatives are active drug substances, often monoether lysolipids. Constitutes a derivative. However, it should be understood that this does not exclude the possibility of containing another drug substance, referred to as the second drug substance, in the drug delivery system of the present invention, but by the action of extracellular PLA ₂ . It does not exclude that hydrolytically cleavable organic groups can have certain pharmacological effects (eg, as an auxiliary drug substance or as an efficiency improver as described elsewhere herein). . Furthermore, the pharmaceutical effect of the “active drug substance”, ie the lysolipid derivative, does not have to be the most dominant when the second drug substance is included; in fact, other major embodiments (see below) (See “Lipid Derivative Liposomes as Drug Delivery Systems”), the effect of the second drug substance is likely to be the most dominant.

Release of the active drug substance (lysolipid derivative) from the prodrug (lipid derivative) is thought to occur as shown in the examples below.

Furthermore, both substituent R ² and / or substituent D can constitute an efficiency improver for the auxiliary drug substance or active drug substance and are simultaneously released under the action of extracellular PLA ₂ .

How the group R ² can have various independent or synergistic effects in the context of the active drug substance, for example as an auxiliary drug substance or an efficiency improver such as, for example, osmotic or cytolytic agents , R ² , as described above. It should be noted, groups corresponding to ^{R 2} (e.g. ^R 2 -OH or ^R 2 -COOH) may have a dominant pharmaceutical effect for the effect of the lysolipid derivative (active drug substance). The above points also apply to D.

Lipid derivatives formulated as liposomes The term “lipid-based drug delivery system” is intended to encompass macromolecular structures comprising lipids or lipid derivatives as a major component. Suitable examples in that regard are liposomes and micelles. At present, liposomes are believed to provide the widest range of uses, and liposomes are described in considerable detail below. Liposomes are currently considered to be the preferred lipid-based system, but micellar systems are also considered to provide interesting embodiments within the scope of the present invention.

  In one important variation that can be advantageously combined with the embodiments described herein, lipid derivatives (eg, prodrugs) are the only component or, more commonly, other components. It is contained in liposomes in combination with (other lipids, sterols, etc.). Accordingly, the lipid-based systems described herein are preferably in the form of liposomes, which constitute a layer containing a lipid derivative (eg, a prodrug).

“Liposomes” are known as self-assembled structures comprising one or more lipid bilayers, each of which surrounds an aqueous compartment and contains two opposed monolayers of amphiphilic lipid molecules. Amphiphilic lipids (ie lipid derivatives) are polar (hydrophilic) covalently linked to one or two non-polar (hydrophobic) aliphatic groups (corresponding to R ¹ and R ² in lipid derivatives). A) a head group region (corresponding to the substituent R ³ in the lipid derivative). The energetically unfavorable contact between the hydrophobic group and the aqueous medium induces rearrangement of the lipid molecules, the polar head group is oriented towards the aqueous medium and the hydrophobic group is directed inward of the bilayer It is thought that it will reorientate. An energetically stable structure is formed in which the hydrophobic groups are effectively blocked from contact with the aqueous medium.

  Liposomes can have a single lipid bilayer (monolamellar liposomes, “ULV”) or multiple lipid bilayers (multilamellar liposomes, “MLV”) and can be produced by various methods (for review). For example, see Deamer and Uster, Liposomes, Marcel Dekker, NY, 1983, 27-52). These methods include Bangham's method for the production of multilamellar liposomes (MLV); MLVs with substantially equal interlamellar solute distribution by Lenk, Fountain and Cullis. (See, for example, US Pat. No. 4,522,803, US Pat. No. 4,588,578, US Pat. No. 5,030,453, US Pat. No. 5,169,637 and US Pat. No. 4,975,282); ULV can be produced from MLV by methods such as sonication (see Papahadjopoulos et al, Biochem, Biophys. Acta, 135, 624 (1968)) or extrusion (US5008050 and US5059421). The liposomes of the present invention can be prepared by any of the methods of these disclosures, the contents of which are hereby incorporated by reference.

  Liposomes of relatively small size can be produced from relatively large liposomes using various methods such as sonication, homogenization, French press pressure and grinding. Using extrusion (see US5008050), liposomes having a predetermined average diameter are produced by reducing the size of the liposomes, that is, by forcibly passing through filter pores of a predetermined selected size under pressure. be able to. Using tangential flow filtration (see WO89 / 08846) to regulate the size of the liposomes, i.e. to produce liposomes having a group of liposomes with a smaller size non-uniformity and a more uniform and defined particle size distribution You can also. The contents of these documents are incorporated herein by reference. The size of the liposomes can also be determined by many methods such as quasielectric light scattering that are within the skill of the art and for example using a Nicomp® particle sorter.

  It is very interesting to mention that even if the system is a liposome system, the lipid derivatives of the present invention can constitute a major part of the lipid-based system. This is due to the structural (non-functional) similarity between the lipid derivatives of the present invention and lipids. Thus, it is believed that the lipid derivatives in the present invention can be the only component of liposomes, i.e. up to 100 mol% of the total dehydrated liposomes can be constituted by lipid derivatives. This is in contrast to known monoether lysolipids such as ET-18-OCH3, which can constitute only a small portion of the liposome.

  Typically, as described in detail below, liposomes may or may not have a medicinal effect, but may make the liposome structure more stable (or more unstable)) , Including other components that protect the liposomes against clearance, prolong the circulation time, and improve the overall efficiency of the medicament containing the liposomes.

  Nevertheless, certain lipid derivatives typically constitute 5-100 mol%, for example 50-100 mol%, preferably 75-100 mol%, especially 90-100 mol%, based on total dehydrated liposomes. I think that.

  Liposomes can be single or multilamellar. Some preferred liposomes are unilamellar and have a diameter of less than about 400 nm, more preferably greater than about 40 nm and less than about 400 nm.

  Liposomes typically, as is known in the art, (a) dissolving the lipid derivative in an organic solvent; (b) removing the organic solvent from the lipid derivative solution of step (a); and ( c) produced by a process comprising the step of forming liposomes by hydrating the product of step (b) with an aqueous solvent.

  The method can further comprise adding at least one second drug substance (see below) to the organic solvent of step (a) or the aqueous phase of step (c).

  Next, the method may include a step of producing a liposome having a certain size, for example, 100 nm, by extruding the liposome produced in step (c) through a filter.

  A wide range of sizes of lipid-based particle systems, ie liposomes as well as micelles, can be produced according to the techniques described above. Depending on the route of administration, suitable particle sizes for pharmaceutical use are usually in the range of 20-10000 nm, in particular in the range of 30-1000 nm. A particle size in the range of 50-200 nm is usually preferred, since liposomes in this particle size range are recognized more rapidly by the mammalian reticuloendothelial system (“RES”) and thus more rapidly from circulation. It is because it is thought that it circulates for a long time in the mammalian circulatory system from the relatively large liposome to be cleared. Prolonged vascular circulation can increase therapeutic efficacy by allowing more liposomes to reach their intended site of action, such as tumors or inflammation.

  In the case of a drug delivery system as defined in the embodiments herein made to be administered by intravenous and intramuscular injection, it is believed that the liposomes should preferably have an average particle size of about 100 nm. Therefore, its particle size should normally be in the range of 40-400 nm.

  Further, for drug delivery systems made to be administered by subcutaneous injection, the liposomes should preferably have an average particle size of 100-5000 nm, and the liposomes can be monolayer or multilayer.

  One of the advantages obtained by including lipid derivatives in liposomes is that the liposome structure has a considerably longer vascular circulation time than the lipid derivatives as individual compounds, especially when stabilized as described below. That is the point. In addition, lipid derivatives may be somewhat inactive or even “invisible” when “packed” into liposomes containing lipopolymers and / or glycolipids. This means that the possibility of adverse effects, for example hemolysis effects, can be reduced.

Liposomes should preferably act as inactive components until they reach the area of interest such as, for example, a cancerous, infected or inflamed area or tissue. As explained below, liposomes can contain many other components. In particular, the drug delivery system according to the present invention may further comprise a second drug substance, an extracellular PLA ₂ activity inhibitor or a permeation enhancer, eg a component that controls the release of short chain lipids and lipopolymer / glycolipids. it can.

Two very important groups of compounds contained in liposomes as improvers are lipopolymers having a PEG molecular weight of 100-10000 daltons (eg, polyethylene oxide-dipalmitoyl phosphatidylethanolamine, DPPE-PEG, polyethylene oxide-di). Lipopolymers and glycolipids which are stabilizing compounds such as stearoylphosphatidylethanolamine, DSPE-PEG). That the lipopolymer functions as a stabilizer for liposomes, ie that the lipopolymer extends circulation time and is very interesting in the context of the present invention, but functions as an activator for extracellular PLA ₂ Has been revealed. The stabilization effect will be described below.

The outer surface of the liposome is thought to become coated with serum proteins such as opsonins in the mammalian circulatory system. Although it is not limited to a specific theory in any form, it is thought that by inhibiting the clearance of the liposome by modifying the outer surface of the liposome, the binding of the serum protein to it is greatly inhibited. A polar head group is derivatized by the attachment of a chemical moiety that can inhibit the binding of serum proteins to the liposomes, altering the pharmacokinetic behavior of the liposomes in the mammalian circulatory system and increasing the activity of extracellular PLA ₂ It is believed that incorporation into liposome bilayer lipids that are enhanced as described for the lipopolymer described above achieves effective surface modification, ie, inhibition of opsonization and RES uptake by changes to the outer surface of the liposome.

  Liposomal formulations have been made that avoid rapid RES uptake, thereby extending the half-life in the bloodstream. STEALTH® liposomes (Liposome Technology Inc., Menlo Park, Calif.) Contain polyethylene glycol (PEG) grafted lipids at about 5 mol% of the total dehydrated liposomes. The presence of the polymer on the external liposome surface reduces liposome uptake by the RES organ. The liposome membrane can be constructed to withstand the destructive effect of the surfactant contained therein. For example, liposome membranes that contain lipids derivatized with hydrophilic (ie, water-soluble) polymers as constituents usually have high stability. The polymer component of the lipid bilayer protects the liposomes from uptake by RES, thus increasing the circulation time of the liposomes in the bloodstream.

  Hydrophilic polymers suitable for use in lipopolymers are readily soluble in water, can be covalently attached to vesicle-forming lipids, and have a toxic effect (ie, are biocompatible).・ Tolerated in vivo. Suitable polymers include polyethylene glycol (PEG), polylactic acid (also referred to as polylactide), polyglycolic acid (also referred to as polyglycolide), polylactic acid-polyglycolic acid copolymer and polyvinyl alcohol. Preferred polymers are those having a molecular weight of from about 100 or 120 daltons to about 5000 or 10,000 daltons, more preferably from about 300 daltons to about 5000 daltons. In a particularly preferred embodiment, the polymer is a polyethylene glycol having a molecular weight of about 100 to about 5000 daltons, more preferably having a molecular weight of about 300 to about 5000 daltons. In a particularly preferred embodiment, the polymer is 750 Daltons polyethylene glycol (PEG (750)). The polymer can also be defined by the number of monomers present, and a preferred embodiment of the present invention uses a polymer of at least about 3 monomers, such as a PEG polymer of 3 monomers (about 150 Daltons). It is. Other hydrophilic polymers that may be suitable for use in the present invention include polyvinylpyrrolidone, polymethoxazoline, polyethyloxazoline, polyhydroxypropylmethacrylamide, polymethacrylamide, polydimethylacrylamide and hydroxymethylcellulose or hydroxy There are derivatized celluloses such as ethyl cellulose.

  A glycolipid is a lipid in which hydrophilic polysaccharide chains are covalently bound. Although it is clear that glycolipids can be used like lipopolymers, at present, lipopolymers give the most promising results.

  The content of lipopolymer is advantageously considered to be in the range of 1-50 mol%, for example 2-25%, in particular 2-15 mol%, based on the total dehydrated liposomes.

  Liposome bilayers or multilayers can also contain other components such as other lipids, sterol-based compounds, polymer-ceramides as stabilizers and targeting compounds.

  Liposomes containing lipid derivatives can (in principle) consist exclusively of lipid derivatives. However, “other lipids” can also be included to modify the liposomes. The ability of other lipids to create a compatible packing conformation with the lipid derivative component of the bilayer so that all lipid components are closely packed and the release of the lipid derivative from the bilayer is prevented. Selected with respect to. Lipid-based elements that contribute to compatible packing conformation are known to those skilled in the art and include, but are not limited to, acyl chain length and unsaturation, and head group size and charge. Absent. Accordingly, those skilled in the art will be able to perform various phosphatidylethanolamines (“PEs”) such as egg phosphatidylethanolamine (“EPE”) or dioleoylphosphatidylethanolamine (“DOPE”) without undue experimentation. Other suitable lipids can be selected, including Lipids can be modified by various methods such as derivatization of head groups with dicarboxylic acids such as glutaric acid, sebacic acid, succinic acid and tartaric acid, preferably the dicarboxylic acid is glutaric acid ("GA") . Accordingly, suitable head group derivatized lipids include dipalmitoyl phosphatidylethanolamine-glutaric acid (“DPPE-GA”), palmitoyloleoylphosphatidylethanolamine-glutaric acid (“POPE-GA”) and dioleoylphosphatidyl. There are phosphatidylethanolamine-dicarboxylic acids such as ethanolamine-glutaric acid ("DOPE-GA"). Most preferably, the derivatized lipid is DOPE-GA.

  The total content of “other lipids” is typically in the range of 0-30 mol%, in particular 1-10 mol%, based on total dehydrated liposomes.

  The sterol compound contained in the liposome may affect the fluidity of the lipid bilayer. Thus, sterol interaction with surrounding hydrocarbon groups prevents migration of these groups from the bilayer. One example of a sterol compound (sterol) contained in the liposome is cholesterol, but various other sterol compounds are possible. When a sterol compound is present, its content is considered to be in the range of 0 to 25 mol%, in particular 0 to 10 mol%, for example 0 to 5 mol%, based on the total dehydrated liposome.

  Polymer-ceramides are stabilizers that improve vascular circulation time. Examples include polyethylene glycol derivatives of ceramide (PEG-ceramide), especially those having a polyethylene glycol molecular weight of 100-5000. The content of polymer-ceramide is considered to be in the range of 0 to 30 mol%, particularly 0 to 10 mol%, based on the total dehydrated liposome.

  Still other components may constitute 0-2 mol%, in particular 0-1 mol%, based on total dehydrated liposomes.

  According to one embodiment of the present invention, the lipid bilayer of the liposome is derivatized with polyethylene glycol (PEG), so that the PEG chain is encapsulated from the inner surface of the lipid bilayer into the internal cavity. Includes lipids that extend and are adapted to extend from the exterior of the lipid bilayer to the surrounding environment (see, eg, US5882679 and FIG. 1).

  Various coupling methods for producing vesicle-forming lipids derivatized with biocompatible hydrophilic polymers such as polyethylene glycol are known in the art (see for example US Pat. No. 5,213,804; US Pat. No. 5,013,556).

  The derivatized lipid component of the liposomes according to the present invention further includes peptides, esters or disulfide linkages that are cleavable under selective pathophysiological conditions such as in the presence of overexpressed peptidase or esterase enzyme or reducing agent at the affected site. Of labile lipid-polymer linkages. The use of such linkages to link polymers to phospholipids can increase the blood levels of such liposomes for several hours after administration, followed by reversible linkage cleavage and outer liposome assembly. Desorption of the polymer from the overlay occurs. Next, liposomes without polymer undergo rapid uptake by the RES system (see, eg, US Pat. No. 5,356,633).

  Furthermore, the liposomes according to the invention are specific to haptens, enzymes, antibodies or antibody fragments, cytokines and hormones (see eg US Pat. No. 5,527,528) and other small molecule proteins, polypeptides, single glycopolysaccharide moieties or liposomes. Non-polymeric molecules attached to the outside of the liposomes can be included, such as non-protein molecules that provide enzymatic or surface recognition moieties. Reference is made to published PCT application WO94 / 21235. Surface molecules that preferentially target liposomes to specific organs or cell types are referred to herein as “targeting molecules” and include, for example, antibodies and sugar moieties such as gangliosides or (acceptance to sugar moieties). And so on) based on mannose and galactose that direct liposomes to specific cells with specific antigens. Techniques for coupling surface molecules to liposomes are known in the art (see for example US Pat. No. 4,762,915).

  Liposomes can retain a significant portion of their internal contents by dehydration, storage, and regeneration. Liposome dehydration requires the use of hydrophilic dry protection agents such as disaccharides on both the inner and outer surfaces of the liposome bilayer (see US 4880635). This hydrophilic compound is believed to maintain size and content during the drying procedure and subsequent rehydration by preventing lipid rearrangement in the liposomes. Appropriate amounts of such dry protection agents are such that they are strong hydrogen bond acceptors and have stereochemical features that preserve the intramolecular spacing of the liposome bilayer components. Alternatively, when the liposome preparation is not frozen before dehydration and sufficient water remains in the preparation after dehydration, the drying protective agent can be omitted.

Lipid Derivative Liposomes as Drug Carrier System As described above, liposomes containing the lipid derivatives of the present invention can also contain at least one second drug substance. In certain embodiments, the lipid-based drug delivery system is in the form of a liposome incorporating at least one second drug substance. It should be understood that the second drug substance can include pharmaceutically active ingredients that can have individual pharmaceutical effects or synergistic pharmaceutical effects in combination with lipid derivatives and lysolipid derivatives. The term “second” does not necessarily imply that the pharmaceutical effect of at least one second drug substance is inferior with respect to the effect of an active drug substance derived, for example, from a prodrug, only two It is used to distinguish between substances in a group.

  Nevertheless, the present invention also provides a drug delivery system in the form of liposomes and incorporating a second drug substance.

  A possible “second drug substance” is a compound or composition of substances that can be administered to a mammal, preferably a human. Such agents can have physiological activity in mammals. Second drug substances that can be added to the liposome include antiviral drugs such as acyclovir, zidovudine and interferons; antibacterial drugs such as aminoglycosides, cephalosporins and tetracyclines; polyene antibiotics, imidazoles and Antifungal drugs such as triazoles; antimetabolites such as folic acid and purine and pyrimidine analogs; antineoplastic drugs such as anthracycline antibiotics and plant alkaloids; sterols such as cholesterol; for example, sugars and starches Hydrocarbons; amino acids such as cell receptor proteins, immunoglobulins, enzymes, hormones, neurotransmitters and glycoproteins, peptides, proteins; dyes; labeled with radioisotopes and radioisotopes Compound Radiolabels such as; radiopaque compounds; fluorescent compounds; mydriatic compounds; bronchodilators; it is like a local anesthetic, but is not limited thereto.

  The liposomal second drug substance formulation increases the therapeutic index of the second drug substance by reducing the toxicity of the drug. Liposomes can also reduce the rate of clearance of the second drug substance from the mammalian vascular circulation. Thus, a liposomal formulation of the second drug substance can mean that less drug dosage is required to achieve the desired effect.

  Liposomes can be loaded with at least one second drug substance by dissolving the drug in the lipid or aqueous phase used to produce the liposomes. Alternatively, ionization can be accomplished by first forming liposomes, establishing an electrochemical potential across the outermost liposome bilayer, eg, by a pH gradient, and adding an ionizable second drug substance to the aqueous medium outside the liposomes. A possible second drug substance can be loaded onto the liposomes (see, eg, US50777056 and WO86 / 01102).

  Methods for producing lipophilic drug derivatives suitable for liposome or micelle formulations are known in the art (see, eg, US Pat. No. 5,534,499 and US Pat. No. 6,180,111, which describe covalent attachment of therapeutic agents to phospholipid fatty acid chains). . Taxol micelle formulations have been described in the literature (Alkan-Onkyuksel et al., Pharmaceutical Research, 11: 206 (1994)).

Thus, the at least one second drug substance can be any of a wide variety of known and possible pharmaceutically active ingredients, but is preferably a therapeutically and / or prophylactically active substance. Because of the mechanism involved in the degradation of the liposomes of the present invention, it is preferred that at least one second drug substance is associated with a disease and / or condition associated with a local increase in extracellular PLA ₂ activity. .

  Particularly interesting second drug substances are: (i) anthracycline derivatives, cisplatin, paclitaxel, 5-fluorouracil, excislind, cis-retinoic acid, suldinac sulfide, vincristine, interleukins, oligonucleotides, peptides, Selected from anti-tumor drugs such as proteins and cytokines, (ii) antibiotics and antifungals, and (iii) anti-inflammatory drugs such as steroids and non-steroids. In particular, steroids can also have a stabilizing effect on liposomes.

Active agents such as peptides and protein derivatives such as interferons, interleukins and oligonucleotides can also be incorporated into PLA ₂ degradable lipid-based carriers.

  The cytotoxic effect of a wide range of anticancer agents may be improved when encapsulated in the carrier of the present invention. In addition, subsequent hydrolysis products, ie monoether lysolipid and / or ester-linked lysolipid derivatives, along with the released fatty acid derivatives, absorb drug penetration through the target membrane when the carrier is locally disrupted in the affected tissue. It is expected to act as an accelerator.

  At least one second drug substance is distributed in the liposomes according to hydrophilicity, ie, the hydrophilic second drug substance tends to be present in the cavity of the liposome, and the hydrophobic second drug substance is hydrophobic It is conceivable that there is a tendency to exist in the sex bilayer. Methods of incorporating drug substances are well known in the art, as has become clear above.

  As should be understood from the above, lipid derivatives may have pharmaceutical activity as prodrugs or individual components. However, in certain embodiments, the invention further comprises a lipid-based drug delivery system for administration of at least one second drug substance, wherein the at least one second drug substance is incorporated into the system. (For example, the second drug substance is encapsulated in the interior of the liposome or in the membrane portion of the liposome or the core region of the micelle) and the system is (a) an aliphatic group of at least 2 carbon atoms in length And an organic group having at least two carbon atoms and (b) a lipid derivative having a hydrophilic moiety, wherein the lipid derivative is further capable of hydrolytically cleaving the organic group, wherein the aliphatic group is substantially With the substrate of extracellular phospholipase A2 to the extent that it remains unaffected by it, thereby producing organic acid fragments or organic alcohol fragments and lysolipid fragments. Ri, the system is related to lipid-based drug delivery system to provide a hydrophilic group on the surface of the system by including lipopolymer and / or glycolipids.

  As described above for systems according to other embodiments, the hydrolytically cleavable organic group can be an efficiency improver for the auxiliary drug substance or the second drug substance. It should be understood that the lipid derivative is a lipid derivative as further defined above. Typically, the lipid derivative constitutes 5-100 mol%, for example 50-100 mol%, of the total dehydrated (liposome) system.

  As should be understood from the above, the present invention also provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and any of the lipid-based drug delivery systems described above. The composition will be described in detail below.

The invention further relates to the use of any of the lipid-based drug delivery systems described herein as pharmaceuticals, and pharmaceuticals for the treatment of diseases or conditions associated with local elevation of extracellular phospholipase A2 activity in mammalian tissues. It relates to the use of any lipid-based drug delivery system described herein in manufacture. Such diseases or conditions are typically selected from cancers such as brain tumors, breast cancer, lung cancer, colon cancer or ovarian cancer, or leukemia, lymphoma, sarcoma, carcinoma and inflammatory conditions. The compositions and uses of the present invention have an increase in extracellular PLA ₂ activity that is at least 25 compared to normal activity levels in the tissue of interest, which tissue is in a mammal, particularly a human. It is particularly applicable to the case of%.

  It should be noted that the novel and synthetic lipid analogues described above are non-free agents as free drugs that result in increased intracellular cellular uptake making it a preferred substrate for overexpressed intracellular PLA2 in affected target cells. It can be administered in particulate form.

Pharmaceutical Formulations and Therapeutic Uses The present invention also provides pharmaceutical compositions that optionally comprise a pharmaceutically acceptable carrier and a lipid derivative of the present invention, eg, as a liposome.

  As used herein, a “pharmaceutically acceptable carrier” is an acceptable medium in uses involving administration of lipids and liposomes, such as liposomal drug formulations, to mammals such as humans. The pharmaceutically acceptable carrier is the specific active drug substance used and / or at least one second drug substance, liposomal formulation, its concentration, stability and intended bioavailability; liposomal composition Disease, disorder or condition to be treated with an object; subject, its age, size and general condition; and intended route of administration of the composition, eg nasal, oral, ocular, subcutaneous, intramammary, abdominal cavity It is formulated according to a number of factors that are within the scope of those skilled in the art to be determined and considered, including but not limited to, intramuscular, intravenous or intramuscular administration. Typical pharmaceutically acceptable carriers used for parenteral drug administration include, for example, D5W (aqueous solution containing 5% w / v glucose) and saline. Pharmaceutically acceptable carriers can include additional ingredients, such as those that enhance the stability of the active ingredients included, such as preservatives and antioxidants.

  Liposomes or lipid derivatives are typically formulated in a dispersion medium, such as a pharmaceutically acceptable aqueous medium.

  An anticancerally effective amount of a lipid derivative, typically about 0.1 to about 1000 mg of lipid derivative / kg of mammal body weight, is preferably administered intravenously. In the context of the present invention, an “anticancerally effective amount” of a liposomal lipid derivative inhibits, ameliorates or reduces one or more cancers in a mammal to which a lipid derivative has been administered, or its occurrence, proliferation, metastasis or It is an effective amount for preventing infiltration. An anti-cancerally effective amount is usually selected according to a number of factors such as the subject's age, size and general condition, the cancer being treated and the intended route of administration, and various means such as the subject matter of the present invention. Those of ordinary skill in the art are familiar with and are determined by easily practiced dose range tests. The antineoplastically effective amount of the liposomal drug / prodrug of the present invention is about the same as such an amount of free, non-liposomal drug / prodrug, eg, about 0.1 mg of lipid derivative / treatment mammal The body weight of the animal is about 1000 mg / kg.

  Preferably, the administered liposomes are unilamellar liposomes having an average diameter of about 50 nm to about 200 nm. The anti-cancer therapy can include the administration of at least one second drug substance in addition to the liposomal drug, and these other drugs are contained in the same liposome as the lipid derivative. The second drug substance that can be entrapped in the internal compartment of the liposome or sequestered by its lipid bilayer is preferably an anticancer agent, but need not necessarily be.

  The pharmaceutical composition is preferably injected, infused or implanted (such as veins, muscles, arteries and subcutaneouss) in formulations, formulations or eg suitable delivery devices or implants comprising conventional non-toxic pharmaceutically acceptable carriers and adjuvants ) Parenterally.

  The formulation and preparation of such compositions is known to those skilled in the art of pharmaceutical formulation. Specific formulations are described in textbooks entitled “Remington's Pharmaceutical Sciences”.

  Thus, the pharmaceutical composition according to the invention can contain the active drug substance in the form of a sterile injectable solution. To prepare such compositions, a suitable active drug substance is dispersed in a parenterally acceptable liquid medium, which is conveniently a suspending agent, solubilizer, stabilizer, A pH adjusting agent and / or a dispersing agent may be included. Among the acceptable vehicles that can be used are water, water adjusted to a suitable pH by the addition of an appropriate amount of hydrochloric acid, sodium hydroxide or a suitable buffer, 1,3-butanediol, Ringer's solution, and the like. There is a tonic sodium chloride solution. Aqueous formulations may also contain one or more preservatives, such as methyl, ethyl or n-propyl p-hydroxybenzoate.

  If treatment of a tumor or neoplasm is desired, effective delivery of the liposome-encapsulated drug via the blood stream is a continuous (but “leaking”) way around the blood vessels that supply blood to the tumor. It must be able to penetrate the endothelial layer and the underlying basement membrane. Smaller size liposomes have been found to be more effective in extravasation to the tumor through the endothelial cell barrier and underlying basement membrane that separates capillaries from tumor cells.

  As used herein, a “solid tumor” is one that grows at an anatomical site other than the bloodstream (as opposed to a blood tumor such as leukemia). Solid tumors require the formation of small blood vessels and capillaries to feed nutrients to the growing tumor tissue.

According to the present invention, the selected anti-tumor or anti-neoplastic agent is entrapped within the liposome according to the present invention. Liposomes are formulated in sizes known to cross the endothelial and basement membrane barriers. The resulting liposome preparation can be administered parenterally to a subject in need of such treatment, preferably by intravenous administration. Tumors characterized by an acute increase in vascular permeability in the area of tumor growth are particularly suitable for the treatment according to the invention. Liposomes can eventually degrade due to the action of lipases at the tumor site, or can be rendered permeable by, for example, thermal or ultrasonic irradiation. The drug is then released in a dissolved form that is bioavailable and transportable. Moreover, a slight increase in temperature as often seen in diseased tissue, may further increase the stimulation of extracellular PLA _2.

  When site-specific treatment of inflammation is desired, effective liposome delivery of the drug involves the long half-life of the liposomes, including the continuous endothelial cell layer around the blood vessels adjacent to the site of inflammation and the underlying basement membrane. It must be transmissive. It has been observed that smaller sized liposomes are more effective at extravasation through the endothelial cell barrier and into the associated inflammatory region. However, since the drug delivery capacity of conventional small liposome preparations is limited, the effectiveness for such purposes has been limited.

  According to the invention, selected anti-inflammatory drugs are entrapped within the liposomes according to the invention. Liposomes are formulated in sizes known to cross the endothelial and basement membrane barriers. The resulting liposome preparation can be administered parenterally to a subject in need of such treatment, preferably by intravenous administration. Inflamed areas characterized by an acute increase in vascular permeability in the inflamed area are particularly suitable for the treatment according to the invention.

It is known that the activity of extracellular PLA ₂ is abnormally high in a mammalian body region affected by cancer, inflammation, and the like. The present invention provides a method that takes advantage of this fact, and the extracellular PLA ₂ activity is at least 25% higher in the diseased area of the body compared to the normal area to be compared (measured in the extracellular environment). I think it should be. However, the level of extracellular PLA ₂ activity, such as at least 100%, such as at least 200%, it is often example is considerably high as at least 400% is assumed. This means that treatment of mammals requiring treatment for healing or alleviation can be carried out with negligible impact on tissues where extracellular PLA ₂ activity is at a “normal” level. . This is extremely appropriate for cancer treatment, which often requires a considerably heavy drug (second drug substance).

Thus, with the understanding behind the present invention in mind, the present invention provides the administration of an effective amount of a drug delivery system as defined herein to a mammal in need of treatment, such as an affected area, such as a mammal, Preferably, the agent is selective for a region containing neoplastic cells, such as a region within the human body, that has an extracellular phospholipase A2 (extracellular PLA ₂ ) activity that is at least 25% higher than the normal activity in said region. Provide a method for targeting to

  For example, a method for treating a mammal suffering from cancer such as brain tumor, breast cancer, lung cancer, colon cancer or ovarian cancer or leukemia, lymphoma, sarcoma, carcinoma, wherein the pharmaceutical composition of the present invention is administered to the mammal A method comprising steps is also provided. It is believed that the lipid derivative and / or at least one second drug substance in liposomal form is selectively toxic to tumor cells.

Targeting the affected area in the skin with a lipid-based carrier composed of novel and synthetic lipids A novel targeted liposomal prodrug and drug delivery system is associated with or caused by elevated levels of extracellular PLA ₂ It is useful in the treatment or improvement. In particular, lipid-based prodrug and drug delivery systems, extracellular matrix in which ether PLA ₂ - useful in the administration of the active drug substance selected from fatty acid derivatives of lysolipid and / or lipid prodrug.

Degradation of the flexible liposome carrier by PLA ₂ results in the release of lysolipids and / or fatty acid derivatives designed to be effective in the treatment of various forms of skin diseases such as cancer and inflammation. In addition, novel prodrug liposome carriers may be useful for targeted delivery of conventional drugs to affected areas of the skin associated with elevated PLA ₂ levels.

  There are many skin diseases that are skin-specific, such as cancer, inflammation, psoriasis and eczema, or are signs of systemic disease. Many of these diseases that are confined to the skin or mucous membrane could be cured or ameliorated by topical administration of the pharmaceutical formulation provided that the administration results in efficient uptake of the active ingredient. Many formulations are administered topically to the skin for therapeutic or prophylactic purposes. However, the skin forms one of the body's most effective barriers to foreign bodies, and due to the imperviousness of the skin, many therapeutic drugs are administered either orally or parenterally, even if the skin is the target organ. Must be administered.

  Liposome formulations have been extensively studied as a skin delivery form in many drugs. There is increasing evidence that when applied topically, the new generation of flexible liposomes offers several advantages over other formulations. Such advantages include reduced side effects associated with high systemic absorption of the administered drug, increased accumulation of the administered drug at the desired target, and administration of a wide variety of drugs, both hydrophilic and hydrophobic, to the skin. There are possible points.

  The main physicochemical barrier of the skin is localized in the stratum corneum, the outermost keratinized layer of the skin. The pores in the stratum corneum and the underlying structure are usually very narrow so that only the skin can pass objects smaller than 400 daltons. However, it has been shown that ultra-flexible liposomes can pass through pores of the skin smaller than 30 nm (Cevc et al. (Biochem Biophys Acta (1998) 1368, p 201-215, US Pat. No. 6,180,353)).

An important point when substances are taken up by the skin is the problem of ensuring that the relevant cells are exposed to the pharmaceutically active ingredient. The new targeted prodrug system has the key issue of allowing the relevant cells to be exposed to the drug, as well as the very flexible liposomes that contain “edge actives” that pass through the stratum corneum, Both address the fact that high PLA ₂ levels can penetrate deeply into the affected area of the skin. It is important to understand that prodrug liposomes are not intended for drug administration into the blood through the skin.

It has been observed that the activity of extracellular phospholipase A ₂ (PLA ₂ ) is increased in many skin inflammatory diseases, most notably psoriasis and eczema (Forster et al. (1985) Br J Dermatol 112: 135 -47; Forster et al. (1983) Br J Dermatol 108: 103-5). Furthermore, it has also been recognized that the extracellular PLA ₂ can cleave the prodrug lipid derivative to produce ether-lysolipid derivatives that are effective alone or in combination with other active compounds. Thus, new prodrug liposomes allow specific delivery of pharmaceutically active ether-lysolipids in target cells in the skin using elevated PLA ₂ activity as a site-specific induction mechanism. is there. Furthermore, a specific fatty acid derivative that turns into an active agent by PLA ₂ hydrolysis can be linked to the C-3 position of a lipid-based carrier composed of a novel synthetic lipid. Possible examples include polyunsaturated fatty acids and vitamin D derivatives, steroid derivatives, retinoyl derivatives and tocopherol analogs that can be esterified at the C3 position to make double prodrug lipids substrates for PLA ₂ There are other lipophilic groups such as. Furthermore, conventional drug substances can be specifically incorporated and transported to the affected site by a novel lipid-based carrier.

Thus, the new carrier liposomes provide a solution to both the problem of intact skin permeation and the specific targeting problem of cells, tissues or tissue parts in the skin characterized by elevated PLA ₂ levels. is there.

Imaging of affected tissue with contrast carriers composed of novel and synthetic lipids A novel lipid-based carrier system is a targeted diagnosis of diseases such as cancer, infection and inflammation characterized by local and high activity of extracellular PLA ₂ Is useful. Increased PLA ₂ activity combined with the finding that microparticles accumulate in diseased tissue via extravasation through leaky capillaries provides the basis for using contrast agent microcarriers for enhanced imaging.

Thus, a novel diagnostic system would allow liposomes (and micelles) that can be specifically degraded by extracellular PLA ₂ to circulate in the bloodstream for as long as they reach the target tissue where PLA ₂ activity is elevated. It takes advantage of the fact that it can be designed. At the affected area, the lipid derivative of the liposome is cleaved by PLA ₂ to release the image enhancing agent.

  Diagnostic imaging is widely used in medicine. In that case, it is necessary to obtain an appropriate strength of the signal from the target region and to distinguish the affected tissue from normal surrounding tissue. Imaging involves the relationship between the three spatial dimensions of the region of interest, the pharmacokinetics of the diagnostic agent, and time, which is the fourth dimension related to both the period required for image acquisition. Physical properties that can be used to obtain an image signal include, for example, radiation emission or absorption, nuclear magnetic moments and relaxation, and ultrasonic transmission or reflection. Usually, imaging of various organs and tissues for early detection and location identification of many diseases cannot be performed well without using an appropriate contrast medium.

  Imaging contrast agents refer to substances that can absorb certain signals that are significantly stronger than the surrounding tissue. Contrast agents are unique to each imaging technique, and can be seen with the naked eye by using appropriate imaging techniques by accumulating them at certain affected sites. The tissue concentration at which imaging can be reliably performed varies between diagnostic techniques.

  In order to promote the accumulation of contrast medium in the affected area, various fine particles have been proposed as a carrier for contrast medium. Among microcarriers, liposomes are particularly noteworthy because of easy property control. For almost 20 years, liposomes have (1) been fully biocompatible with liposomes; (2) it can actually carry any drug or diagnostic agent, depending on the physicochemical properties of the compound, Can be entrapped in the membrane itself; (3) compounds entrapped in liposomes are protected from inactivation effects in the body, but at the same time do not cause undesirable side reactions; It has been recognized as a promising carrier for drugs and diagnostic agents because it provides a custom-made opportunity to deliver drugs or diagnostic agents within the cell compartment. To achieve various in vivo delivery objectives, the size, charge and surface properties of the liposomes can be easily altered by simply incorporating various lipids and / or changing the manufacturing method.

One important area of application of the new contrast-loaded liposomes is tumor imaging. PLA ₂ has been shown to be secreted by malignant tumor cells, and immunohistochemical staining of various cancers such as pancreatic cancer, breast cancer and gastric cancer show elevated levels of PLA ₂ . Increased PLA ₂ expression and secretion is also observed in several cancer cell lines stimulated by interleukins such as IL-6. Furthermore, increased extracellular PLA ₂ activity has been reported in inflamed and infected tissues.

  The main mechanism of liposome accumulation in tumors is via extravasation from leaking tumor capillaries into the interstitial space. Tumor accumulation can be significantly increased by using long-circulating polymer-coated liposomes.

Lipid-based microcarriers can also be used for visualization of inflammatory and infected sites. Similar to what is known about cancerous tissue, the use of microparticulate contrast agents for the visualization of infected and inflammatory sites characterized by increased PLA ₂ activity is associated with the extravasation of microparticles from leaking capillaries. Is based on the ability to accumulate.

One of the important features of the novel diagnostic system is that it is a well-known form of extracellular PLA in a specific extracellular site of the affected mammalian tissue where certain lipid derivatives are characterized by increased PLA ₂ activity. It is that it is cleaved by ₂ . It has been recognized that extracellular PLA ₂ can cleave monoether / monoester lipid derivatives to target diagnostic agent labeling in relevant affected tissues. Degradation of lipid derivatives and liposomes by PLA ₂ results in site-specific release of diagnostic contrast agent in the affected tissue.

One of the key features of the targeted targeted delivery system of infected tissue by lipid-based carriers composed of novel synthetic lipids is the rapid in vivo liposomes by cells of the mononuclear phagocyte system (MPS) It is uptake. MPS contains macrophages, one of the most important components of the immune system involved in clearance of foreign particles such as liposomes. Macrophages are found in various organs and tissues, such as in the spleen and liver (Kupffer cells), and exist as free and immobilized macrophages in the bone marrow and lymph nodes.

Novel lipid-based systems composed of prodrug lipids can be found in various affected livers or spleens containing parasites due to liposome accumulation and increased levels of prodrug-cleavable PLA ₂ enzyme in infected tissues. Of lipid prodrugs and encapsulated drugs can be delivered directly. Furthermore, one particular advantage of lipid-based drug delivery systems is that extracellular PLA ₂ activity is significantly higher for ordered lipid substrates such as prodrug liposomes compared to monomeric lipid substrates. is there.

The released ether-lipid analogs generated by the action of PLA ₂ have been shown to cause very important regulatory enzyme disturbances in parasites such as Leishmania and trypanosoma (Lux et al. Biochem. Parasitology 111 (2000) 1-14), toxic to parasites when administered in sufficient doses. Because the liver, spleen, and bone marrow are organs and tissues where multivalent macrophages can be found, targeted delivery of toxic drugs to parasites that have entered these organs can be achieved. In addition, parasitic infections characterized by elevated PLA ₂ levels such as parasites that cause malaria are also targets for treatment with novel prodrug liposomes. Regarding the increase in PLA ₂ levels in malaria infections caused by the parasite, Plasmodium falciparum, see, for example, the report (Vadas et al., Infection and Immunity, 60 (1992) 3928-3931 and Am. J Trop. Hyg. 49 (1993) 455-459).

  Normal cells typically have an ether-cleaving enzyme that makes it possible to avoid the toxic effects of ether-lipids. However, some normal cells, such as erythrocytes, do not have the means to circumvent the ether-lipid destructive effects like cancer cells. Thus, therapeutic use of ether-lipids requires an effective drug delivery system that protects normal cells from toxic effects and can deliver ether-lipid directly to the affected tissue.

Thus, novel targeted prodrug delivery systems can be used to treat parasitic infections characterized by elevated PLA ₂ levels in infected tissues. This is done by administering the liposomes of an effective amount is present active drug substance in the form of a lipid prodrug which is a substrate for extracellular PLA ₂ (about 1000 mg / kg or less). Furthermore, prodrug liposomes can enhance the effectiveness of conventional drugs in combination with lysolipids and / or fatty acid derivatives by PLA ₂ generation, which is thought to be able to enhance the targeted transport of encapsulated conventional anthelmintic drugs. Is a candidate for.

The toxicity of liposomes containing toxic lipid derivatives can be assessed by determining the therapeutic window “TW”, which is a numerical value derived from the relationship between the compound's ability to induce hemolysis and inhibit tumor cell growth. The TW value is HI ₅ / GI ₅₀ (“HI ₅ ” is equal to the compound concentration that induces 5% hemolysis of red blood cells in the medium, and “GI ₅₀ ” represents 50% growth inhibition in the cell population exposed to the drug. Equivalent to the compound dose to induce). The higher HI ₅ value of the drug, low hemolytic agents. A relatively high HI ₅ value means that the compound concentration that must be present for the compound to elicit a 5% solution is relatively high. Therefore, since it is possible to provide a greater amount until the HI ₅ induces the same amount of hemolysis relatively low drug, the higher the HI _5, a high therapeutic utility of the compounds. In contrast, a relatively low GI ₅₀ value indicates a relatively good therapeutic agent. A relatively low GI ₅₀ value indicates that the drug concentration required to effect 50% growth inhibition is relatively low. Therefore, the higher the HI ₅ value and the lower the GI ₅₀ value, the better the therapeutic properties of the compound's drug.

In general, if the TW of a drug is less than 1, it cannot be used effectively as a therapeutic agent. In other words, without causing the level of hemolysis unacceptable, to the extent it is not possible to administer enough drug to achieve an adequate level of tumor growth inhibition, HI ₅ value of the drug is low, a high its GI ₅₀ value. Since the lipid derivative liposome utilizes the fact that the extracellular PLA ₂ activity in the bloodstream is lower than the activity in the affected tissue, it is considered that the TW is considerably higher than that of normal monoether lysolipid. The TW of the liposomes of the present invention is greater than about 3, more preferably greater than about 5, since the variation in activity is orders of magnitude and the liposomes are “trapped” by tissues with high extracellular PLA ₂ activity. It is considered large, even more preferably greater than about 8.

Schematic diagram of a liposome drug carrier accumulation and subsequent drug release and extracellular PLA lipid-based drug targeting and drug-induced principle transport is involved in through the target membrane via the ₂ activity in porous diseased tissue (I) pathological tissue with leaking capillaries, (II) liposomes containing prodrugs and drugs, (III) target cells and cell membranes, (IV) eg prodrugs (lipids), proenhancers (lipids), Novel analogs such as proactivators (lipids), (V) drugs (lysolipids and fatty acid derivatives), enhancers (lysolipids + fatty acids), PLA2 activators (lysolipids + fatty acids) (lysolipids are then molecules Internal cyclization). FIG. 3 is a diagram showing an example of a specific prodrug that forms lysolipid generated by PLA ₂ hydrolysis undergoes intramolecular cyclization to generate cyclic anticancer lipid. FIG. 2 shows an example of a specific prodrug that results in lysolipids that cyclize to form cyclic anticancer lipids by PLA ₂ hydrolysis (and drug auxiliary substances are released as a result of intramolecular cyclization). ). FIG. 2 shows an example of a specific prodrug that results in release of a drug auxiliary substance as a result of intramolecular cyclization by PLA ₂ hydrolysis.

Claims (34)

A lipid-based drug delivery system for drug substance administration, wherein the drug substance is incorporated into the system, the system comprising (I) (a) an organic group having at least two carbon atoms and (b) hydrophilic a lipid derivative comprising the sexual portion, said to the extent that the organic groups are formed hydrolytically cleaved by intramolecular cyclization reaction, the lipid derivative is a substrate for extracellular phospholipase a _2, and (II) the system Lipid-based drug delivery system comprising lipopolymers and / or glycolipids to provide hydrophilic chains on the surface of. The lipid derivative is further by remaining substantially unaffected by the hydrolytic activity phospholipase A _2, according to an aliphatic group to produce organic acid fragment or an organic alcohol fragment and a lysolipid fragment performing intramolecular cyclization reaction Item 2. A lipid-based drug delivery system according to Item 1.   The lipid-based drug delivery system according to claim 1, wherein the lipid derivative is a prodrug, whereby the drug substance is incorporated into the system as a prodrug.   4. A lipid-based drug delivery system according to any one of claims 1 to 3, wherein the system further comprises at least one second drug substance.   The lipid-based drug delivery system according to claim 1, wherein the lipopolymer and / or glycolipid is represented by a part of the lipid derivative.   The polymer of the lipopolymer is polyethylene glycol, poly (lactic acid), poly (glycolic acid), poly (lactic acid) -poly (glycolic acid) copolymer, polyvinyl alcohol, polyvinyl pyrrolidone, polymethoxazoline, polyethyloxazoline, polyhydroxypropyl 6. A lipid-based drug delivery system according to any one of claims 1 to 5 selected from methacrylamide, polymethacrylamide, polydimethylacrylamide and derivatized celluloses.   7. The organic group that is hydrolytically cleavable is an auxiliary drug substance or an efficiency improver for the at least one second drug substance. A lipid-based drug delivery system according to claim 1.   7. The organic moiety released during the intramolecular cyclization is an auxiliary drug substance or an efficiency improver for the at least one second drug substance. The lipid-based drug delivery system according to Item. The lipid-based drug delivery system according to any one of claims 1 to 8, wherein the lipid derivative is a lipid derivative represented by the following formula.

[Where:
R ^D is an ester moiety ((CH ₂ ) _n C (O) D ¹ ) that promotes intramolecular cyclization during PLA ₂ hydrolysis, n is an integer of 0-5, preferably 0-2, D ¹ is an organic moiety, which can be MeOH or EtOH, and is preferably an organic moiety having bioactivity. The hydrogen in the CH ₂ group in ^RD can be substituted with an intramolecular cyclization promoting group, for example, a fluorine with respect to carbonyl. The CH ₂ group in ^RD can be substituted, for example with O, S, NH or their biological equivalents, in particular in the α-position to the carbonyl group. Alternatively, ^RD is an organic moiety that contains a leaving group, such as iodine, ie, an organic moiety that can promote intramolecular cyclization upon PLA ₂ hydrolysis;
X and Z are independently O, CH ₂ , NH, NMe, S, S (O), OS (O), S (O) ₂ , OS (O) ₂ , OP (O) ₂ , OP (O) Selected from ₂ O, OAs (O) ₂ and OAs (O) ₂ O;
Y is selected from OC (O), OC (O) O, OC (O) N, OC (S), SC (O), SC (S), CH ₂ C (O) O, NC (O) O Y is connected to R ² via an oxygen, sulfur, nitrogen or carbonyl carbon atom;
R ¹ is an aliphatic group of formula Y ¹ Y ² , and Y ¹ is — (CH ₂ ) _n1 — (CH═CH) _n2 — (CH ₂ ) _n3 — (CH═CH) _n4 — (CH _{2 ) n5 - (CH = CH)} n6 - (CH 2) n7 - (CH = CH) n8r - (CH 2) a _{n9, n1 + 2n2 + n3 +} 2n4 + n5 + 2n6 + n7 + 2n8 + total n9 is an integer from 2 to 29; or is n1 is 0 1 N3 is 0 or an integer of 1 to 20, n5 is 0 or an integer of 1 to 17, n7 is 0 or an integer of 1 to 14, and n9 is an integer or a 0 1~11; n2, n4, n6 and n8 are each independently 0 or ^1; Y ₂ is _{CH 3, CO 2 H, SH} , S (O) 2 OH, P (O) ₂ OH, OP (O) ₂ OH, OH NH ₂ ; each carbon of Y ¹ -Y ² may be independently substituted with halogen and aliphatic substituents;
R ² is an organic group having at least 2 carbon atoms;
R ³ is selected from phosphatidic acid (PO ₂ —OH), derivatives of phosphatidic acid and biological equivalents to phosphoric acid and derivatives thereof. ] The lipid-based drug delivery system according to any one of claims 1 to 8, wherein the lipid derivative is a lipid derivative represented by the following formula.

[Where:
D ² is a biologically active organic moiety, that is, the drug substance in the broadest sense, n is an integer of 0-5, preferably 0-2, and hydrogen in the CH ₂ group promotes intramolecular cyclization. Can be substituted by a fluorine such as α on a group, eg carbonyl;
Z represents O, CH ₂ , NH, NMe, S, S (O), OS (O), S (O) ₂ , OS (O) ₂ , OP (O) ₂ , OP (O) ₂ O, OAs Selected from (O) ₂ and OAs (O) ₂ O;
Y is selected from OC (O), OC (O) O, OC (O) N, OC (S), SC (O), SC (S), CH ₂ C (O) O, NC (O) O , Y is linked to R ² via an oxygen, sulfur, nitrogen or carbonyl carbon atom;
R ² is an organic group having at least 2 carbon atoms;
R ³ is selected from phosphatidic acid (PO ₂ —OH), derivatives of phosphatidic acid and biological equivalents to phosphoric acid and derivatives thereof. ] Lipid-based drug delivery system according to claim 9 or 10 R ² is at least two aliphatic groups of the length of the carbon atoms. Lipid-based drug delivery system according to claim 11 R ² is a group of formula ^Y 1 ^{Y 2.} At least a portion of the lipid is of the formula defined in claim 9 and R ³ is a derivative of phosphatidic acid, against which polyethylene glycol, poly (lactic acid), poly (glycolic acid), poly (lactic acid) A polymer selected from poly (glycolic acid) copolymers, polyvinyl alcohol, polyvinylpyrrolidone, polymethoxazoline, polyethyloxazoline, polyhydroxypropylmethacrylamide, polymethacrylamide, polydimethylacrylamide and derivatized celluloses covalently 13. A lipid-based drug delivery system according to any one of claims 1 to 12 which is bound.   The lipid-based drug delivery system according to any one of claims 1 to 13, wherein the lipid derivative constitutes 5 to 100 mol% of the total dehydrated system.   15. A lipid-based drug delivery system according to any one of claims 1 to 14, wherein the lipopolymer constitutes 2-50 mol% of the total dehydrated system.   The lipid-based drug delivery system according to any one of claims 1 to 15, wherein the system is in the form of a liposome.   The at least one second drug substance is a therapeutically and / or prophylactically active substance selected from (i) an anti-tumor agent, (ii) an antibiotic and an antifungal agent or (iii) an anti-inflammatory agent. Item 17. The lipid-based drug delivery system according to any one of Items 1 to 16.   A pharmaceutical composition comprising a drug delivery system according to any one of claims 1 to 17 and an appropriately pharmaceutically acceptable carrier.   18. A lipid-based drug delivery system according to any one of claims 1 to 17 for use as a medicament. For the manufacture of a medicament for the treatment of diseases or conditions associated with localized increase in extracellular phospholipase A ₂ activity in mammalian tissue, lipid-based drug delivery according to any one of claims 1 17 Use of the system.   21. Use according to claim 20, wherein the disease or condition is selected from the group consisting of inflammatory conditions and cancer.   The use according to claim 21, wherein the type of cancer is selected from the group consisting of brain tumor, breast cancer, lung cancer, colon cancer, ovarian cancer, leukemia, lymphoma, sarcoma and carcinoma. Use according to any one of the extracellular phospholipase A ₂ the increase in activity as compared to a normal level of activity in the target tissue claim 21 is at least 25% 22. The lipid-based drug delivery system according to any one of claims 1 to 8, wherein the lipid derivative is a lipid derivative represented by the following formula.

[Where:
R ^D is an ester moiety ((CH ₂ ) _n C (O) D ¹ ) that promotes intramolecular cyclization during PLA ₂ hydrolysis, n is an integer of 0-5, preferably 0-2, D ¹ is an organic moiety, which can be MeOH or EtOH, and is preferably an organic moiety having bioactivity. The hydrogen in the CH ₂ group in ^RD can be replaced by an intramolecular cyclization promoting group, for example, a? The CH ₂ group in R ^D can be substituted, for example with O, S, NH or their biological equivalents, especially in the α-position to the carbonyl group. Alternatively, ^RD is an organic moiety that contains a leaving group, such as iodine, ie, an organic moiety that can promote intramolecular cyclization upon PLA ₂ hydrolysis;
X = Y;
Y is selected from OC (O), OC (O) O, OC (O) N, OC (S), SC (O), SC (S), CH ₂ C (O) O, NC (O) O Y is connected to R ² via an oxygen, sulfur, nitrogen or carbonyl carbon atom;
Z represents O, CH ₂ , NH, NMe, S, S (O), OS (O), S (O) ₂ , OS (O) ₂ , OP (O) ₂ , OP (O) ₂ O, OAs Selected from (O) ₂ and OAs (O) ₂ O;
R ¹ is an aliphatic group of formula Y ¹ Y ² , and Y ¹ is — (CH ₂ ) _n1 — (CH═CH) _n2 — (CH ₂ ) _n3 — (CH═CH) _n4 — (CH _{2 ) n5 - (CH = CH)} n6 - (CH 2) n7 - (CH = CH) n8r - (CH 2) a _{n9, n1 + 2n2 + n3 +} 2n4 + n5 + 2n6 + n7 + 2n8 + total n9 is an integer from 2 to 29; or is n1 is 0 1 N3 is 0 or an integer of 1 to 20, n5 is 0 or an integer of 1 to 17, n7 is 0 or an integer of 1 to 14, and n9 is an integer or a 0 1~11; n2, n4, n6 and n8 are each independently 0 or ^1; Y ₂ is _{CH 3, CO 2 H, SH} , S (O) 2 OH, P (O) ₂ OH, OP (O) ₂ OH, OH NH ₂ ; each carbon of Y ¹ -Y ² may be independently substituted with halogen and aliphatic substituents;
R ² is an organic group having at least 2 carbon atoms;
R ³ is selected from phosphatidic acid (PO ₂ —OH), derivatives of phosphatidic acid and biological equivalents to phosphoric acid and derivatives thereof. ] Lipid-based drug delivery system according to claim 23 R ² is at least 7 aliphatic groups of the length of the carbon atoms. Lipid-based drug delivery system according to claim 11 R ² is a group of formula ^Y 1 ^{Y 2.}   27. A lipid-based drug delivery system according to claims 1 and 26, wherein the system is in the form of a liposome.   1 to 8, wherein the drug substance is a therapeutically and / or prophylactically active substance selected from (i) an anti-tumor agent, (ii) an antibiotic and an antifungal agent or (iii) an anti-inflammatory agent. 28. A lipid-based drug delivery system according to any one of 24-27.   A pharmaceutical composition comprising a drug delivery system according to any one of claims 1 to 8 and 24 to 28 and optionally a pharmaceutically acceptable carrier.   29. A lipid based drug delivery system according to any one of claims 1 to 8 and 24 to 28 for use as a medicament. For the manufacture of a medicament for the treatment of diseases or conditions associated with localized increase in extracellular phospholipase A ₂ activity in mammalian tissue, according to any one of claims 1 to 8 and 24 to 28 Use of lipid-based drug delivery systems.   32. Use according to claim 31, wherein the disease or condition is selected from the group consisting of inflammatory conditions and cancer.   The use according to claim 32, wherein the type of cancer is selected from the group consisting of brain tumor, breast cancer, lung cancer, colon cancer, ovarian cancer, leukemia, lymphoma, sarcoma and carcinoma. Use according to any one of the extracellular phospholipase A ₂ the increase in activity as compared to a normal level of activity in the target tissue of claims 31 is at least 25% 32.

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