Polymeric drug formulations
Polymeric drug formulations containing a non-releasing single-phase dispersion of a water-soluble drug in a water-insoluble tissue-compatible polymer matrix. Polymeric drug formulations are also disclosed containing a single-phase dispersion of a water-soluble drug and a water-insoluble tissue-compatible polymer matrix, and a second, phase-disrupting polymer that is non-miscible with the tissue-compatible polymer and is present in an amount sufficient to form phase-separated microdomains of the second polymer in the tissue-compatible polymer matrix, so that the release rate of the water-soluble drug from the tissue-compatible polymer matrix is related to the amount of the second polymer. Methods of preparing the polymeric drug formulations are also described, as well as methods for site-specific drug delivery utilizing the polymeric drug formulations.
1. A polymeric drug formulation consisting essentially of a single-phase dispersion of a water-soluble drug in a matrix of a water-insoluble tissue-compatible polymer that is miscible in the solid phase with said drug, wherein said single-phase dispersion is essentially free of phase-separated microdomains of drug or polymer on the length scale of visible light, so that less than five percent of the drug loading is released over a thirty day period.
2. The polymeric drug formulation of claim 1 , wherein said tissue-compatible polymer is selected from the group consisting of poly(lactic acid), poly(glycolic acid), and copolymers thereof, poly(ethylene-co-vinyl acetate), poly(caprolactone), poly(orthoesters), poly(carbonates), poly(arylates) poly(imino-carbonates) poly(vinylpyrrolidone), pyran copolymer, poly(hydroxypropyl-methacrylamide-phenol), poly(hydroxy-ethylaspartamide-phenol), poly(ethylene oxide)-poly(lysine) substituted with palmitoyl residues, poly(hydroxybutyric acid), poly(acetals), poly(dihydro-pyran), poly(cyano-acrylates) and cross-linked and amphipathic block copolymers of hydrogels.
3. The polymeric drug formulation of claim 2 , wherein said tissue-compatible polymer is a poly(arylate).
4. The polymeric drug formulation of claim 3 , wherein said poly(arylate) is poly(desaminotyrosyl-tyrosine hexyl ester adipate).
5. The polymeric drug formulation of claim 1 , wherein said water-soluble drug is a non-peptide drug selected from the group consisting of natural and unnatural antibiotics, cytotoxic agents and oligonucleotides.
6. The polymeric drug formulation of claim 1 , wherein said water-soluble drug is a peptide drug selected from the group consisting of immunoglobulins, immunoglobulin fragments and platelet aggregation inhibiting peptides.
7. The polymeric drug formulation of claim 6 , wherein said peptide drug is a platelet aggregation inhibiting peptide.
8. The polymeric drug formulation of claim 1 , containing a drug loading up to about 50 percent by weight.
9. The polymeric drug formulation of claim 8 , containing a drug loading up to about 30 percent by weight.
10. The polymeric drug formulation of claim 9 , containing a drug loading between about 10 and about 20 percent by weight.
11. A method of forming a single-phase dispersion consisting essentially of a water-soluble drug in a water-insoluble tissue-compatible polymer comprising:
blending a water-soluble drug with a water-insoluble tissue-compatible polymer that is miscible in the solid phase with said drug in a solvent system capable of forming a homogenous solution of said drug and said polymer; and
adding said solution to an amount of a non-solvent for said drug and said polymer, so that said drug and said polymer coprecipitate from said solution as a single-phase dispersion of said drug and said polymer;
wherein said single-phase dispersion is essentially free of phase-separated microdomains of drug or polymer on the length scale of visible light, so that less than five percent of the drug loading is released over a thirty day period.
12. The method of claim 11 , wherein said tissue-compatible polymer is selected from the group consisting of poly(lactic acid), poly(glycolic acid) and copolymers thereof, poly(ethylene-co-vinyl acetate), poly(caprolactone), poly(orthoesters), poly(carbonates), poly(iminocarbonates), poly(arylates), poly(vinylpyrrolidone), pyran copolymer, poly(hydroxypropyl-methacrylamide-phenol), poly(hydroxy-ethyl-aspartamide-phenol), poly(ethylene oxide)-poly(lysine) substituted with palmitoyl residues, poly(hydroxybutyric acid), poly(acetals), poly(dihydropyran), poly(cyanoacrylates) and cross-linked and amphipathic block copolymers of hydrogels.
13. The method of claim 12 , wherein said tissue-compatible polymer is a poly(arylate).
14. The method of claim 13 , wherein said poly(arylate) is poly(desaminotyrosyl-tyrosine hexyl ester adipate).
15. The method of claim 11 , wherein said water-soluble drug is a non-peptide drug selected from the group consisting of natural and unnatural antibiotics, cytotoxic agents and oligonucleotides.
16. The method of claim 11 , wherein said water-soluble drug is a peptide drug selected from the group consisting of immunoglobulins, immunoglobulin fragments and platelet aggregation inhibiting peptides.
17. The method of claim 16 , wherein said peptide drug is a platelet aggregation inhibiting peptide.
18. The method of claim 11 , containing a drug loading up to about 50 percent by weight.
19. The method of claim 18 , containing a drug loading up to about 30 percent by weight.
20. The method of claim 19 , containing a drug loading between about 10 and about 20 percent by weight.
21. The method of claim 11 , wherein said blending step comprises dissolving said water-soluble drug in a first solvent in which said drug is soluble, dissolving said tissue-compatible polymer in a second solvent in which said polymer is soluble, and combining said first and second solvent solutions, wherein said first solvent and said second solvent are capable of forming a homogeneous solution with each other and said drug and said polymer.
22. The method of claim 11 , wherein said solvent system comprises at least one solvent selected from the group consisting of methanol, methylene chloride, ethanol, ethylene glycol, glycerol, tetrahydrofuran, ethyl acetate, acetonitrile, acetone, diisopropyl ether, methyl t-butyl ether, chloroform, carbon tetrachloride, dichloroethane and water.
23. The method of claim 11 , wherein said drug and said polymer are each dissolved in said solvent system at a level between about 1 and about 30 percent by weight.
24. The method of claim 11 , wherein said non-solvent is selected from the group consisting of diethyl ether, diisopropyl ether, methyl t-butyl ether, methyl ethyl ketone, acetonitrile, toluene, xylene and carbon tetrachloride.
25. The method of claim 11 , wherein said solution of said drug and said polymer is added to at least 5 to 10 volumes of said non-solvent compared to the volume of said solvent system.
26. The method of claim 11 , wherein said non-solvent is chilled to a temperature as low as the freezing point of said nonsolvent.
27. A polymeric drug formulation, prepared by the method of claim 11 .
28. The polymeric drug formulation of claim 27 , wherein said water-soluble drug is a platelet aggregation inhibiting peptide.
29. A blood-contacting device or implant coated with the polymeric drug formulation of claim 1 , wherein said water-soluble drug is a platelet aggregation inhibiting peptide.