WO2011139343A2

WO2011139343A2 - Amino acid linked peg-lipid conjugates

Info

Publication number: WO2011139343A2
Application number: PCT/US2011/000745
Authority: WO
Inventors: Nian WU; Brian Charles Keller
Original assignee: Wu Nian; Brian Charles Keller
Priority date: 2010-04-28
Filing date: 2011-04-28
Publication date: 2011-11-10
Also published as: WO2011139343A3

Abstract

New lipid-amino acid-polyethylene glycol (L-AA-PEG) conjugates are described. Amino acid are used as a backbone to conjugate lipids and PEG chains. L-AA-PEGs may be selected to optimize formulations of pharmaceuticals and cosmetics, among other uses.

Description

SPECIFICATION TITLE OF INVENTION AMINO ACID LINKED PEG-LIPID CONJUGATES

FIELD OF THE INVENTION

[001] The present invention relates to polyethyleneglycol (PEG)-amino acid-lipid conjugates and to convenient synthetic methods and compositions for preparing such conjugates. More particularly, the present invention relates to new PEG-amino acid-lipid conjugates and their use for drug delivery, cosmetics and other purposes.

PRIORITY CLAIM

[002] This application claims priority to United States provisional patent application no. 61/343,396, entitled "Pure Peg- Amino Acid-Lipid Conjugates for Pharmaceutical Applications" and filed on April 28, 2010; and to United States patent application no. 12/802,197, entitled "Pure PEG-Lipid Conjugates" and filed on June 1, 2010.

BACKGROUND OF INVENTION

[003] Many types of PEG-lipid conjugates are known. When used as a drug delivery vehicle, PEG-lipid conjugates have the capacity to improve the pharmacology profile and solubility of lipophilic drugs. They also provide other potential advantages such as minimizing side effects and toxicities associated with therapeutic treatments.

[004] Simple PEG-lipid conjugates include PEG chains directly linked to lipids. Glycerol backbones are often employed to produce PEG-lipid conjugates for particular purposes. For example, diacyl glycerol PEGs (DAG-PEGs) are used for delivery of bioactive compounds via topical, oral and IV administration. DAG-PEGs may also be used for cleaning up oil spills, among other uses. DAG-PEGs may be used by themselves or in conjunction with other compounds to create microstructures such as liposomes, which have a variety of uses. Distearyl phosphatidylethanolamine PEG may be used in preparation of liposomes for IV use. The wide range of possible structure of PEG-lipid conjugates available provides the potential for a broad range of applications. However, there is a continuing need for additional PEG-lipid conjugates to address problems in many technology areas.

BRIEF SUMMARY OF THE INVENTION

[005] New lipid-amino acid-polyethylene glycol (L-AA-PEG) conjugates are described. Amino acids are used as a backbone to conjugate lipids and PEG chains. L-AA-PEGs may be selected to optimize formulations of pharmaceuticals and cosmetics, among other uses.

ABBREVIATION LIST

[006] The present invention is herein disclosed using the following chemical nomenclature: DAG-PEGs: diacylglycerol- polyethyleneglycols

DAA-PEGs: diacylamino acid- polyethyleneglycols

DSA-PEGs: disteroidamino acid- polyethyleneglycols

DOS- 12: dioleoyl-rac-serinyl-dodecaethylene glycol

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[007] Embodiments of the present invention are described herein in the context of lipid- amino acid-PEG (L-AA-PEG) conjugates for liposomes and drug delivery, among other uses. Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to

implementation of the present invention.

[008] In the interest of clarity, not all of the routine features of the implementations herein are described. It will be appreciated that in the development of such actual implementation, numerous implementation-specific details must be made in order to achieve the developer's specific goals, and that these specific goals will vary. Though such implementation might be complex, it will still be a routine exercise of engineering.

[009] The compounds of the invention comprise an amino acid backbone and three side groups. Lipid-amino acid-PEG compounds of the present invention comprise two basic forms. The first form has two lipid groups and one PEG chain. When the lipids are acyl chains, this form is somewhat similar to a DAG-PEG. The first form is shown in Chemical Structure 1.

[010] Chemical Structure 1

[Oil] In Chemical Struccture 1, PEG is a polyethyleneglycol chain having between 6 and 45 subunits; Ri preferably has a molecular weight of less than about 215; R₂ and R₃ are lipids; and AA represents an amino acid backbone.

[012] The second form comprises one lipid group and two PEG chains, as shown in Chemical Structure 2.

[013] Chemical Structure 2

[014] In Chemical Structure 2, PEG represents polyethyleneglycol chains each having between 6 and 45 subunits; R] and R2 preferably each have a molecular weight of less than about 215; R₃ is a lipid; and AA represents an amino acid backbone.

[015] To be suitable as a backbone in the present invention, amino acids must have at least three reactive groups. Workable amino acids include arginine, aspartic acid, glutamic acid, asparagine, cysteine, histidine, lysine, glutamine, ornithine, tryptophan, tyrosine, serine, threonine, as well as certain synthetic amino acids. For ease of synthesis, aminio acids with exactly three reactive groups are preferable. Also, those without heterocyclic rings or reactive sulfur groups are preferable. Therefore, the most preferable amino acid backbones are aspartic acid, glutamic acid, asparagine, glutamine, ornithine, serine, lysine and threonine.

[016] It will be appreciated that it is possible to link the lipid and PEG side groups to the amino acid backbone in a variety of combinations. Furthermore, since each amino acid has a different structure and since many different side groups may be incorporated as described below, a wide range of compounds are encompassed by the invention.

[017] When employing PEG-lipid conjugates as drug delivery vehicles, it is becoming increasingly important to use well-characterized and highly pure conjugates. For example, US Patent No. 6,610,322, which is incorporated herein by reference, teaches that varying the length of PEG and acyl chains affects the packing parameters of the conjugates which in turn determine whether compositions of PEG-lipid conjugates form liposomes or not. In addition to affecting the physical structure of drug formulations, the choice of lipids and PEG sizes may have significant effects on pharmacokinetics and stability when formulating specific drug compounds with PEG-lipid conjugates. Therefore, uniform batches of conjugates having monodisperse PEG chains of a specific size are often highly preferable over batches having a range of PEG lengths. Preparation of such monodisperse PEG chains is described in co-owned and co-pending United States patent application no. 12/802,197, entitled "Pure PEG-Lipid Conjugates" and filed on June 1, 2010, which is hereby incorporated by reference. [018] Though the terminal group on the PEG chain (e.g., Rl in Chemical Structure 1) is either -OH or -OC¾ in the specific conjugates synthesized and described herein, in practice R₁ (and R2 in Chemical Structue 2) may have effects ranging from negligible to highly important on the overall DAG-PEG molecule. Therefore, the invention includes conjugatess where Ri (and R2 in Chemical Structure 2) is selected from a wide variety of chemical moieties. Such moieties preferably have a molecular weight of less than 215, and more preferably a molecular weight of less than 45. Such moieties include -NH₂, -COOH, - OCH₂CH₃, -OCH₂CH₂OH, -COCH=CH₂, -OC¾CH₂NH₂, -OS0₂C¾, -OCH₂C₆¾, - OCH₂COCH₂CH₂COONC₄H4O₂, -CH₂CH₂=CH₂, and -OCeHe. Also Rj may be a functional group that facilitates linking therapeutic or targeting agents to the surface of lipid vesicle aggregates. Amino acids, amino alkyl esters, maleimide, diglycidyl ether, maleinimido propionate, methylcarbamate, tosylhydrazone salts, azide, propargyl-amine, propargyl alcohol, NHS esters (e.g., propargyl NHS ester, sulfo-NHS-LC-biotin, or NHS carbonate), hydrazide, succinimidyl ester, succinimidyl tartrate, succinimidyl succinate, and

toluenesulfonate salt are useful for such linking. Linked therapeutic and targeting agents may include Fab fragments, cell surface binding agents, and the like. Additionally, Rl may include functional cell-targeting ligands such as folate, transferrin and molecules such as monoclonal antibodies, ligands for cellular receptors or specific peptide sequences can be attached to the liposomal surface to provide specific binding sites. Rl can include either negatively or positively charged head-groups such as decanolamine, octadecylolamine, octanolamine, butanolamine, dodecanolamine, hexanolamine, tetradecanolamine, hexadecanolamine, oleylamine, decanoltrimethylaminium, octadecyloltrimethylaminium, octanoltrimethylaminium, butanoltrimethylaminium, dodecanoltrimethylaminium, hexanoltrimethylaminium, tetradecanoltrimethylaminium, hexadecanoltrimethylaminium, oleyltrimethylaminium, for example.

[019] Presently preferred compounds of the invention have chemically inert terminal groups with a MW of less than 215, as initial applications are expected to be primarily in the formulation of active drug compounds.

[020] The invention can be practiced using a wide variety of fatty acids (acyl chains). Table 1 lists some saturated lipids for use in the invention. Table 2 lists some unsaturated lipids for use in the invention.

[021] Table 1: Saturated lipids for use in the invention:

Common name IUPAC name Chemical structure Abbr. Melting point (°C)

Burvric Butanoic acid CH₃(CH₂)₂COOH C4.0 -8

Caproic Hexanoic acid CH₃(CH₂)₄COOH C6.0 -3

Caprvlic Octanoic acid CH₃(CH₂)₆COOH C8:0 16-17

Capric Decanoic acid CH₃(CH₂)₈COOH cio-.o 31

Laurie Dodecanoic acid CH₃(CH₂),oCOOH C12:0 44-46

Mvristic Tetradecanoic acid CH₃(CH₂)₁₂COOH C14:0 58.8 Palmitic Hexadecanoic acid CH₃(CH₂)₁₄COOH C16:0 63-64

Stearic Octadecanoic acid CH₃(CH₂),₆COOH C18:0 69.9

Arachidic Eicosanoic acid CH₃(CH₂)_!8COOH C20:0 75.5

Behenic Docosanoic acid CH₃(CH₂)₂₀COOH C22:0 74-78

[022] Table 2: Unsaturated lipids

[023] Suitable lipids for synthesis of PEG-lipid conjugates include bile acids (steroid acids) as well as alkyl chains. Therefore, the present invention includes a variety of PEG- AA-lipid conjugates and the steroid acid-AA-PEG conjugates can be incorporated into liposomes as a targeting moiety for lipid-based drug delivery to specific cells or as self-emulsifying drug delivery systems (SEDDS). [024] Bile acids (steroid acids) constitute a large family of molecules, composed of a steroid structure with four rings, a five or eight carbon side-chain terminating in a carboxylic acid, and the presence and orientation of different numbers of hydroxyl groups. The four rings are labeled from left to right A, B, C, and D, with the D-ring being smaller by one carbon than the other three. An exemplary bile acid is shown in Chemical Structure 3. All bile acids have side chains. When subtending a carboxyl group that can be amide-linked with taurine or glycine, the nuclear hydroxyl groups can be esterified with glucuronide or sulfate which are essential for the formation of water soluble bile salts from bile alcohols.

Ri and R₂ may be hydroxyl or proton

Chemical Structure 3

[025] Table 3: Bile acid (steroid acid) and its analogues for use in the Invention

[026] The lipid-PEG conjugates of the present invention may be used for many applications. Formulation and delivery of pharmaceutical and cosmetic agents have been described.

Additionally, the conjugates of the present invention may be used in other contexts where water soluble lipids are advantages, for example industrial and/or cleaning processes.

[027] Sample structures of representative PEG-lipid conjugates are listed in Table 4. The structures shown in the Table 4 were mainly named by ChemDraw (version 10). In the event of minor variations of chemical names, the structures shown are meant to be controlling. [028] Table 4: Sample of Lipid- AA-PEG Conjugates

[029] Embodiments of the present invention are described herein in the context of preparation of pharmaceutical compositions including purified PEG-lipid conjugates for increasing the solubility and enhancing the delivery of active agents, among other uses. The approximate preferable compositions for formulated drug products are generally described herein, though different drugs typically have differing optimal formulations. [030] For IV solutions, the preferable concentration of drug is 0.1% to 30%. More preferable is 0.5 to 10%. Most preferable is 0.5 to 5%. The preferable weight ratio of conjugate to the drug (conjugate/drug) is 1 to 20. More preferable is 1 to 10. Most preferable is 1 to 5.

[031] For oral solutions, the preferable concentration of drug is 1% to 40%. More preferable is 2.5 to 30%. Most preferable is 5 to 30%. The preferable ratio of conjugate to the drug (conjugate/drug) is 0.5 to 20. More preferable is 1 to 5. Most preferable is 1 to 3.

[032] For ophthalmic preparations, the preferable concentration of drug is 0.01 to 5%. More preferable is 0.05 to 2%. Most preferable is 0.1 to 2%. The preferable ratio of conjugate to the drug (conjugate/drug) is 1 to 20. More preferable is 3 to 15. Most preferable is 5 to 10.

[033] For topical solutions, the preferable concentration of drug is 0.05 to 5%. More preferable is 0.1 to 5%. Most preferable is 0.1 to 2%. The preferable ratio of conjugate to the drug (conjugate/drug) is 1 to 20. More preferable is 3 to 15. Most preferable is 5 to 10.

[034] For oral capsules, the preferable capsule content of drug is 10 mg to 250 mg. More preferable is 25 mg to 200 mg. Most preferable is 25 mg to 100 mg. The preferable ratio of conjugate to the drug (conjugate/drug) is 1 to 10. More preferable is 1 to 5. Most preferable is 2 to 5.

[035] For topical preparations, the preferable concentration of drug is 0.05 to 5%. More preferable is 0.1 to 5%. Most preferable is 0.5 to 2%. The preferable ratio of conjugate to the drug (conjugate/drug) is 1 to 50. More preferable is 3 to 20. Most preferable is 5 to 10. [036] In one aspect, the invention is a compound represented by the formula

where PEG is a polyethyleneglycol chain having between 6 and 45 subunits, where R] has a molecular weight of less than about 215; where R₂ and R₃ are lipids; and where AA represents an amino acid backbone. AA is preferably a single amino acid having three reactive groups. AA may be selected from the group comprising aspartic acid, glutamic acid, asparagine, glutamine, ornithine, serine, lysine and threonine. R2 and R3 may be alkyl (acyl) groups having between 6 and 22 carbons. R₂ and R₃ may be each selected from the group consisting of oleate, myristate, linoleate and palmitate. R2 and R3 may be bile acids. R2 and R3 may preferably be selected from the group comprising cholic acid, desoxycholic acid, dehydrocholic acid, glycochenodeoxycholic acid. R may have a molecular weight of less than about 45. Ri may be either -OH or -OCH₃. The PEG chain may consist of between about 8 and 23 subunits. The PEG chain may consist of between about 12 and 23 subunits. The PEG chain may be monodisperse. The PEG chain may be branched.

[037] In another aspect, the invention is a compound represented by the formula

where PEG represents polyethyleneglycol chains each having between 6 and 45 subunits; Rj and R2 each have a molecular weight of less than about 215; R₃ is a lipid; and AA represents an amino acid backbone. AA may be a single amino acid having three reactive groups. AA may be selected from the group comprising aspartic acid, glutamic acid, asparagine, glutamine, ornithine, serine, lysine and threonine. R3 may be an alkyl groups having between 6 and 22 carbons. R₃ may be selected from the group consisting of oleate, myristate, linoleate and palmitate. R3 may be a bile acid. R3 may be selected from the group comprising cholic acid, desoxycholic acid, dehydrocholic acid, and

glycochenodeoxycholic acid. Ri and R2 may each have a molecular weight of less than about 45. Rj and R2 may each be either -OH or -OCH₃. The PEG chains may consist of between about 8 and 23 subunits. The PEG chains may more preferably consist of between about 12 and 23 subunits. The PEG chains may be monodisperse. The PEG chain may be branched.

[038] In another aspect, the invention comprises a method of solubilizing a water-insoluble agent, i.e., a drug compound that, because of low solubility in water, typically requires formulation with a pharmaceutically acceptable carrier for effective delivery to an intended site of action. In this aspect, the invention comprises selecting a relatively water insoluble drug, selecting a conjugate of the present invention, and combining the drug and the conjugate to form an effective drug delivery formulation. Such delivery may be intravenous, oral, topical, subdermal, sublingual, or any other mode of drug delivery. The invention also includes compositions for such delivery. Both the methods and the compositions related to delivery of water-insoluble agents employ the PEG-lipid conjugates of the present invention and the methods and materials described herein.

EXAMPLES

[039] Chemicals and Reagents: N, N'-dicyclohexylurea, N, N'-dicyclohexylcarbodiimide, DL 1,2 -rac-dioleoylglycerol, and other chemicals were obtained from Sigma- Aldrich (St. Louis, MO, USA). Bulk quantity of DL 1,2 -rac-dioleoylglycerol was supplied by WuXi LipoTech, Ltd (WuXi, China).

[040] Example 1. Preparation of tert-Butyl Carbamates (Boc)-Protected Amino Groups A high yield and effective synthetic method under a catalyst-free and room temperature was reported previously [S. V. Chankeshwara, A. K. Chakraborti, Org. Lett., 8 (2006) 3259] and used with slightly modification. To a solution of starting compound containing amino group in MeOH, di-t-butyl dicarbonate was added as one to one molar ratio. The resulting mixture was stirred overnight at room temperature. When the reaction was done, solvent was removed under Vacuum, the residue was dissolved into EtOAc and washed with saturated NH4CI aqueous solution once, then dried over Na₂SO₄ and condensed to yield the expected product (> 90%). Example of this reaction is demonstrated in Reaction Scheme 1. This method gives N-t-Boc derivatives chemoselectively without any side products (such as isocyanate, urea, NN-di-t-Boc).

H

o I

Reaction Scheme 1

[041] Example 2. Deprotection of Boc-Protected Amino Groups

Effective reagents for the deprotection of tert-butyl carbamates or tert-butyl esters include phosphoric acid and tnfluoroacetic acid. The reactions give high yields and very convenient [B. Li, M. Berliner, etc, J. Org. Chem., 71 (2006) 9045]. Equal volumes of Tnfluoroacetic acid was added to a solution of Boc-carbamate (1% of crude product) in CH₂C1₂. The resulting solution was stined at room temperature for overnight and the solvent was evaporated and the residue was re-dissolved into CH₂C1₂, then washed with saturated

NaHC0₃ and dried over gS0₄. Solvent was evaporated and was used in next step without further purification.

[042] Example 3. Preparation of N-oleoyl Serine

[043] Active oleoyl intermediate is prepared by dissolving 0.1 moles of oleic acid in

50 mL of tetrahydrofuran (THF), adding excess triethylamine (0.12 moles) as base and finally by adding isobutyl chloroformate (0.1 moles). After confirming the formation of the active anhydride intermediate by assay of the stable methyl ester, it was added to the N- methyl-2-pynolidinone solution of serine (0.1 moles, 20 mL) and stined for about 4 hours. An assay was performed to verify the yield and then the solution was added to acetone to precipitate the crude product, which was filtered and washed with acetone. The crude wet product was dried in a vacuum oven at about 80 °C and yield (85%) the following product as showed in Chemical Structure 4.

N-Oleoylserine

Chemical Structure 4

[044] Example 3. Preparation of dioleoyl Serine

[045] 0.03 moles of N-oleoylserine was constantly stirred under nitrogen in 100 mL of chloroform. 0.03 mole of oleoyl chloride was dissolved with 100 mL of chloroform and added to this heterogeneous mixture of N-Oleoylserine and followed by adding 10 mL of anhydrous pyridine. The reaction for 30 minutes under constantly stirring at room temperature, the mixture turned to homogeneous and the reaction was completed when no detectable oleoyl chloride was in the mixture. The bulk solvent was removed under vacuum. The residue was wash with water then extracted with ethyl acetate. The aqueous phase was repeatedly extracted with ethyl acetate and the organic layers were combined and washed again with water, dried over sodium sulfate and evaporated. The resulting product (% of yields 75-80) is showed in Chemical Structure 5.

3-((E)-octadec-9-enamido)-2-((E)-octadec-9-enoyloxy)propanoic acid

Chemical Structure 5

[046] Example 4. Preparation of dioleoylserinyldodecaethylene glycol

[047] 0.01 moles of dodecaethylene glycol (0.01 mmol) was dissolved with 50 mL of anhydrous CH2CI2, 0.01 moles of dicyclohexylcarbodiimide and dioleoylserine were added. The resulting mixture was stirred at 0 °C for 2 hours, then allowed to warm up to room temperature and stirred for additional 24 hours. When the reaction was complete, the white precipitate was filtered off over celite. The residue was rinsed with small amount of CH₂C1₂ twice and washed with sutured NH4CI, then dried over MgS0₄. Solvent was evaporated to afford pale yellowish oil as showed in Chemical Structure 6. The crude product's purity was determined by 1H NMR and UPLC-MS, ESI-MS (>90%).

Dioleoylserinyldodecaethylene glycol (DOS- 12)

Chemical Structure 6

[048] Example 5. Preparation of Boc-glycinyldodecaethylene glycol

[049] 0.01 moles of monomethoxyl dodecaethylene glycol ether (0.01 mmol) was dissolved with 50 mL of anhydrous CH₂C1₂, 0.01 moles of dicyclohexylcarbodiimide and N- Boc-glycine (Example 1) were added. The resulting mixture was stirred at 0 °C for 2 hours, then allowed to warm up to room temperature and stirred for additional 24 hours. When the reaction was complete, the white precipitate was filtered off over celite. The residue was rinsed with small amount of CH₂C1₂ twice and washed with sutured NH₄CI, then dried over MgSO₄. Solvent was evaporated to afford pale yellowish oil as showed in Chemical Structure 7. The crude product was used to next step without further purification.

Boc-glycinylmonomethoxyldodecaethylene glycol Chemical Structure 7

[050] Example 6. Preparation of dioleoylglycerolsuccinimide

[051] DL-dioleoylglycerol (0.0 5 mol) was dissolved in 25 mL of dry (molecular sieve) dioxane and warm up in a water batch until the solution was clear then cooled down to room temperatyure. N-N'-disuccinimidyl carbonate (0.5 mol in 100 mL acetone) was added. 0.5 mol of 4-(dimethylamino)pyridine was added dropwise under a constant stirring. The resulting mixture was stirred for 6 hours. When the reaction was complete, the solution was evaporated to afford a sticky colorless liquid (Chemical Structure 8) and was used in next step without further purification.

(8Z,8'Z)-3-((((2,5-dioxopyrrolidin-l-yl)oxy)carbonyl)oxy)propane- 1,2-diyl bis(heptadec-8-enoate)

Chemical Structure 8 [052] Example 7. Preparation of dioleoylglycerolglycinylmonomethoxyldodecaethylene glycol

[053] Deprotection of Boc-glycinylmonomethoxyldodecaethylene glycol was carried out as described in the Example 2. 20 mL of 0.01 moles of dioleoylglycerolsuccinimide in tetrahydrofuran was added to the N-methyl-2-pyrrolidinone solution of

glycinylmonomethoxyldodecaethylene glycol (0.01 moles, 20 mL) and stirred for about 4 hours. An assay is performed to verify the yield and then the solution is added to ether to precipitate the crude product, which is filtered and washed with 50 mL of a mixture of ether and ethyl acetate mixture (v/v, 3/1), and extracted with water (30 mL) three times. The combined aqueous phase was further extracted with ethyl acetate (30mL) three times. The combined ethyl acetate phases were dried over Na₂S04 and yielded pale yellowish oil (~ 65%, Chemical Structure 9). The purity (> 95%) was determined by 1H NMR and HPLC- MS.

CH₂CH2(OCH2CH₂)₁₁OCH3

Dioleoylglycerolglycinylmonomethoxyldodecaethylene glycol

Chemical structure 9

[054] Similar synthetic methods from the examples 1 to 7 can be utilized for the

preparations of other lipid-AA-PEG conjugates, some of these lipid-PEG conjugates are shown in Table 4. [055] Example 8. Solubility of Rapamycin

[056] Solubility experiments were carried out by HPLC assay. Rapamycin was added to selected media and sonicated for 10 minutes. The resulting suspensions were kept in a 55°C water bath for 4 hrs then placed in dark overnight. The samples were centrifuged at lOOOg for 30 minutes. The supematants were filtered through passed through 0.22-um pore-size filter to remove dust particles before the HPLC assay. A Simadzu lOavp chromatography system with a Kinetex Cig (2.6 μπι, 100 ^χ4.6 mm i.d.) column (Phenomenex, Torrance, CA) were used. The mobile phase consisted of a water and acetonitrile mixture (v/v, 20/80) with a flow rate of 1.0 mL/min. The Rapamycin peak was monitored at 220 nm and quantitated using external standard sets of Rapamycin. The drug loading capacity (%DLC) was then calculated from the following equation and the calculated results are summarized in Table 5.

DLC = - °100

w

where C is the concentration measured and W is the sample concentration based on the weight of rapamycin added.

[057] Table 5. Loading capacity of Rapamycin in different PEG-lipids

a averaged number

[057] Example 9. Solubility of Triazoles

[058] Solubility experiments were carried out by HPLC assay. The experiment same as in Example 8. The results are summarized in Table 6. [059] Table 6. Comparison of Solubility of Itraconazole, Voriconazole and Posaconazole in Different PEG-lipids

[060] Example 10. Values of Hydrophilic-lipophilic Balance

[061] Hydrophilic-lipophilic Balance (HLB) is commonly used as a semi-quantitive tool for predicting the drug solubility with a PEG-lipid, which can be calculated by the following equation [Griffin WC, Journal of the Society of Cosmetic Chemists 5 (1954) 259]:

Mw_h

HLB = 20 ·

where Mw_h is the molecular mass of the hydrophilic portion of the Molecule, and MWT is the molecular mass of the whole molecule with a giving arbitrary scale of 0 to 20. While a HLB value of 0 corresponds to a completely hydrophobic molecule, a value of 20 represents a hydrophilic molecule. In the present invention, a preferable PEG-lipid conjugate should have a HLB value in the range of 8 to 14, most preferable 9 to 12.

[062] Example 11 : Solid Dose Compositions

[063] A liquid PEG-lipid conjugate is added to a stainless steel vessel equipped with propeller type mixing blades. The drug substance is added with constant mixing. Mixing continues until the drug is visually dispersed in the lipids at a temperature to 55° - 65 °C. In a separate container, a PEG-lipid conjugate with a melting temperature above about 30 degrees C is melted with heating or dissolved in ethanol and added to the vessel with mixing. Mixing continues until fully a homogenous solution is achieved. If necessary, ethanol is removed by vacuum. The solution is filled into capsule shells or predesigned packaging configurations (molds) when the solution is warm. Filled capsules or molds are placed under refrigeration (2-8 °C) until the cream-like mixture is solidified when cooled. A sample formulation is described in Table 7.

[064] Table 7

Ingredient %

Drug Substance 15

Liquid PEG-lipid Conjugate 40

Solid PEG-lipid Conjugate 45

Ethanol < 1 [065] The liquid conjugate may be selected from DAA-PEG or DS A-PEG including SG- bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS- 2 or GDOG-12. The solid lipid conjugate may be GDO-23, GDO-27, GDM-23, GDM-27, or GDS-23. The drug may be modafinil or nifedapine or esomeprazole or rapamycin or triazole or another active agent.

[066] Example 12: Solid Dose Compositions

[067] A liquid PEG lipid conjugate (having a melting point below about 15 degrees C) was added to a stainless steel vessel equipped with propeller type mixing blades. The drug substance was added with constant mixing. Mixing continued until the drug was visually dispersed in the lipids at a temperature to 55° - 65 °C. In a separate container, TPGS-VE was dissolved in ethanol and added to the vessel with mixing. Mixing continued until fully a homogenous solution was achieved. Ethanol was be removed by vacuum. The solution was filled into capsule shells or predesigned packaging configuration (molds) when the solution was warm. The filled capsules or molds were placed under refrigeration (2-8 °C). The cream-like mixture was solidified when cooled. A sample formulation is described in Table 8.

[068] Table 8

[069] The liquid conjugate may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA- PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS- 12 or GDOG-12. The drug may be modafinil or nifedapine or esomeprazole or rapamycin or another active agent.

[070] Example 13: Oral Solution Compositions

[071] PEG-lipid was added to a vessel equipped with a mixer propeller. The drug substance was added with constant mixing. Mixing continued until the drug was visually dispersed in the lipids. Pre-dissolved excipients were slowly added to the vessel with adequate mixing. Mixing continued until fully a homogenous solution was achieved. A sample formulation is described in Table 9.

[072] Table 9

Ingredient mg/mL

Drug Substance (active) 30.0

PEG Lipid 100

Lactic Acid 50

Sodium Hydroxide See below

Hydrochloric Acid See below

Sodium Benzoate 2.0

Artificial Flavor 5.0

Purified Water qs 1 mL [073] The lipid may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA-PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS-12 or GDOG-12 or any combination thereof. Sodium hydroxide is used to prepare a 10% w/w solution in purified water. The targeted pH is in a range of 4.0 to 7.0. NaOH is used to adjust pH if necessary. The drug may be modafinil or nifedapine or esomeprazole or rapamycin or another active agent.

[074] Example 14: Cyclosporine Ophthalmic Compositions

[075] PEG-lipid was added to a vessel equipped with a mixer propeller. The cyclosporine drug substance was added with constant mixing. Mixing continued until the drug was visually dispersed in the lipids. Pre-dissolved excipients and sterile purified water were slowly added to the vessel with adequate mixing. Mixing continued until fully a

homogenous solution was achieved. A sample formulation is described in Table 10.

[076] Table 10

[077] The lipid may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA-PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS-12 or GDOG-12 or any combination thereof. Sodium hydroxide is used to prepare a 10% w/w solution in purified water. The targeted pH is in a range of 6.0 to 7.4. NaOH is used to adjust pH if necessary.

[078] Example 15: Injection Solution Compositions

[079] The injectable solution was prepared as in Example 13, except that the targeted pH range was between 6.0 and 8.0. A sample formulation is described in Table 11.

[080] Table 1 1

[081] The lipid may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA-PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS-12 or GDOG-12 or any combination thereof. Sodium hydroxide is used to prepare a 10% w/w solution in purified water. The targeted pH is in a range of 6.5 to 7.4. NaOH is used to adjust pH if necessary. The drug may be modafinil or nifedapine or esomeprazole or rapamycin or another active agent.

[082] Example 16: Topical Cream Composition

[083] PEG lipid was added to a stainless steel vessel equipped with propeller type mixing blades. The drug substance was added with constant mixing. Mixing continued until the drug was visually dispersed in the lipids at a temperature to 60° - 65 °C. Organic acid, Cholesterol and glycerin were added with mixing. Ethanol and ethyoxydiglycol were added with mixing. Finally Carbopol ETD 2020, purified water and triethyJamine were added with mixing. Mixing continued until fully a homogenous cream was achieved. The formulation is described in Table 12.

[084] Table 12

Ingredient %

Drug Substance (Active) 1.0

PEG Lipid 5.0

Carbopol ETD 2020 0.5

Ethyoxydiglycol 1.0

Ethanol 5.0

Glycerin 1.0

Cholesterol 0.4

Triethylamine 0.20

Organic acid 10

Sodium hydroxide See below

Purified water qs 100 [085] The lipid may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA-PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS-12 or GDOG-12 or any combination thereof. Organic acid may be lactic acid or pyruvic acid or glycolic acid. Sodium hydroxide is used to adjust pH if necessary. The targeted pH range was between 3.5 and 7.0. The drug may be itraconazole, posaconazole, voriconazole or equaconazole, Terbinafine , Amorolfine, Naftifine, Butenafine, Benzoic acid, Ciclopirox, Tolnaftate, Undecylenic acid, Flucytosine , Griseofulvin , Haloprogin, Sodium bicarbonate or Fluocinolone acetonide.

[086] Example 17: Topical Solution Composition

[087] The topical solution was prepared as in Example 11, a sample formulation is described in Table 13.

[088] Table 13

Ingredient %

Drug Substance (Active) 1.0

PEG Lipid 5.0

a-Tocopherol 0.5

Organic acid 10.0

Ethanol 5.0

Sodium Benzoate 0.2

Sodium Hydroxide 1 See Below

Purified Water qs 100 [089] The lipid may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA-PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS- 12 or GDOG-12 or any combination thereof. Organic acid may be lactic acid or pyruvic acid or glycolic acid. Sodium hydroxide is used to adjust pH if necessary. The targeted pH range was between 3.5 and 7.0. The drug may be itraconazole, posaconazole, voriconazole or equaconazole, Terbinafine , Amorolfine, Naftifine, Butenafine, Benzoic acid, Ciclopirox, Tolnaftate, Undecylenic acid, Flucytosine , Griseofulvin , Haloprogin, Sodium bicarbonate or Fluocinolone acetonide.

[090] Example 18: Anti-infective Ophthalmic Compositions

[091] PEG-lipid was added to a vessel equipped with a mixer propeller. The azithromycin drug substance was added with constant mixing. Mixing continued until the drug was visually dispersed in the lipids. Pre-dissolved excipients and sterile purified water were slowly added to the vessel with adequate mixing. Mixing continued until fully a

homogenous solution was achieved. A sample formulation is described in Table 14.

[092] Table 14

[093] The lipid may be DAA-PEG or DAG-AA-PEG or DSG-PEG or DSA-PEG including SG-bisPEG-12, SG-AA-bisPEG-12, GDOG-12 or DOS- 12 or GDOG-12 or any combination thereof. Sodium hydroxide is used to prepare a 10% w/w solution in purified water. The targeted pH is in a range of 7.0 to 7.8. NaOH is used to adjust pH if necessary. The active may be azithromycin or itraconazole or posaconazole or voriconazole or another active agent.

[094] Preferable concentration of active is 0.5 to 3%, more preferable is 0.5 to 2%, most preferable is 1 to 2%. The preferable ratio of PEG-lipid to the drug (PEG-Lipid/drug) is 1 to 20, more preferable is 3 to 15, most preferable is 5 to 10.

[095] While preferred embodiments of the present invention have been described, those skilled in the art will recognize that other and further changes and modifications can be made without departing from the spirit of the invention, and all such changes and modifications should be understood to fall within the scope of the invention.

Claims

CLAIMS We claim:

1. A compound represented by the formula

where PEG is a polyethyleneglycol chain having between 6 and 45 subunits;

where Ri has a molecular weight of less than about 215;

where R₂ and R₃ are lipids; and

where AA represents an amino acid backbone.

2. The compound of claim 1 , where AA is a single amino acid having three reactive groups.

3. The compound of claim 2, where AA is selected from the group comprising aspartic acid, glutamic acid, asparagine, glutamine, ornithine, serine, lysine and threonine.

4. The compound of claim 1, where R2 and R3 are alkyl groups having between 6 and 22 carbons.

5. The compound of claim 4, where R₂ and R₃ are each selected from the group consisting of oleate, myristate, linoleate and palmitate.

6. The compound of claim 1, where R2 and R3 are bile acids.

7. The compound of claim 6, where R2 and R3 are selected from the group comprising cholic acid, desoxycholic acid, dehydrocholic acid, glycochenodeoxycholic acid.

8. The compound of claim 1 where Ri has a molecular weight of less than about 45.

9. The compound of claim 8 where Ri is either -OH or -OCH₃.

10. The compound of claim 5 where the PEG chain consists of between about 8 and 23 subunits.

11. The compound of claim 5 where the PEG chain consists of between about 12 and 23 subunits.

12. The compound of claim 1 where the PEG chain is monodisperse.

13. The compound of claim 1 where the PEG chain is branched.