Claims for Patent: 5,324,519

Summary for Patent: 5,324,519

Title:	Biodegradable polymer composition
Abstract:	The invention is directed to a composition composed of a thermoplastic or thermosetting polymer which is capable of forming a biodegradable and/or bioerodible microporous, solid or gelatinous polymer matrix. The matrix is useful as an implant in animals for enhancing regeneration of cells and tissue, such as bone and nerve cells, or for delivery of biologically-active substances to tissue or organs. The composition is administered to an implant site as a liquid. The invention also includes a method of preventing and treating disorders and diseases, such as bone or nerve growth disorders, or of altering body functions such as birth control, using the compositions and implants of the invention.
Inventor(s):	Dunn; Richard L. (Fort Collins, CO), Tipton; Arthur J. (Fort Collins, CO), Southard; George L. (Fort Collins, CO), Rogers; Jack A. (Fort Collins, CO)
Assignee:	Atrix Laboratories, Inc. (Fort Collins, CO)
Application Number:	07/783,512
Patent Claims:	1. A composition suitable for forming an in situ solid implant in an animal, comprising: a liquid formulation of a biodegradable, bioerodible, biocompatible thermoplastic polymer that is insoluble in aqueous or body fluid, and a biocompatible organic solvent that is miscible or dispersible in aqueous or body fluid and dissolves the thermoplastic polymer, the composition being capable of coagulating or solidifying to form a solid or gelatinous microporous matrix upon its contact with aqueous or body fluid, the matrix being a core surrounded by a skin, the core containing pores of diameters from about 1 to about 1000 microns, and the skin containing pores of smaller diameters than those of the core pores. 2. A composition according to claim 1, wherein the skin pores are of a size such that the skin is functionally non-porous in comparison with the core. 3. A method of forming an implant suitable for providing a biological, therapeutic or physiological effect in an animal, comprising: administering to the animal a composition in an amount effective to form in situ a solid implant, the composition being a liquid formulation of a biodegradable, bioerodable, biocompatible thermoplastic polymer that is insoluble in aqueous or body fluid, and a biocompatible organic solvent that is miscible or dispersible in aqueous or body fluid and dissolves the thermoplastic polymer, and the composition undergoing coagulation or solidification of the polymer and dispersion of the solvent into body fluid to form a solid or gelatinous microporous matrix, the matrix being a core surrounded by a skin, the core containing pores of diameters from about 1 to 1000 microns and the skin containing pores of small diameters than those of the core pores. 4. A composition suitable for forming an in situ solid implant in an animal, comprising: a liquid formulation of a biodegradable, bioerodable, biocompatible thermoplastic polymer that is insoluble in aqueous or body fluid, a biocompatible organic solvent that is miscible or dispersible in aqueous or body fluid and dissolves the thermoplastic polymer, and a pore-forming agent, the composition being capable of coagulating or solidifying to form a solid or gelatinous microporous matrix upon its contact with an aqueous or body fluid, the matrix being a core surrounded by a skin, and the skin and core containing pores within the same range of diameters, that range being from about 1 to about 1000 microns. 5. A composition according to claim 4, wherein the pore-forming agent is a sugar, salt, or water-soluble polymer, or water-insoluble substance that degrades to a water soluble substance. 6. A composition according to claim 1, wherein the thermoplastic polymer is selected from the group consisting of polylactides, polyglycolides, polycaprolactones, polyanhydrides, polyamides, polyurethanes, polyesteramides, polyorthoesters, polydioxanones, polyacetals, polyketals, polycarbonates, polyorthocarbonates, polyphosphazenes, polyhydroxybutyrates, polyhydroxyvalerates, polyalkylene oxalates, polyalkylene succinates, polymalic acid, polyamino acids, polymethyl vinyl ether, chitin, chitosan, and copolymers, terpolymers, and any combination thereof. 7. A composition according to claim 1, wherein the solvent is selected from the group consisting of N-methyl-2-pyrrolidone, 2-pyrrolidone, ethanol, propylene glycol, propylene carbonate, acetone, acetic acid, ethyl acetate, ethyl lactate, methyl acetate, methyl ethyl ketone, dimethylformamide, dimethyl sulfoxide, dimethyl sulfone, tetrahydrofuran, caprolactam, decylmethylsulfoxide, oleic acid, N,N-diethyl-m-toluamide, and 1-dodecylazacycloheptan-2-one, and any combination thereof. 8. A composition according to claim 1, further comprising at least one biologically-active agent. 9. A composition according to claim 8, wherein the biologically-active agent is a polypeptide derived from a natural, synthetic, or recombinant DNA source. 10. A composition according to claim 8, wherein the biologically-active agent is selected from a group consisting of anti-inflammatory agents, antibacterial agents, antiparasitic agents, antifungal agents, antiviral agents, anti-neoplastic agents, analgesic agents, anaesthetics, vaccines, central nervous system agents, growth factors, hormones, antihistamines, osteoinductive agents, cardiovascular agents, anti-ulcer agents, bronchodilators, vasodilators, birth control agents, and fertility enhancing agents. 11. A composition suitable for forming an in situ solid implant in an animal, comprising: a liquid formulation of a biodegradable, bioerodable, biocompatible thermoset polymer that is insoluble in aqueous or body fluid, and an agent selected from the group consisting of a pore-forming agent, a biocompatible organic solvent that is miscible or dispersible in aqueous or body fluid and a releasible, pore-forming moiety within the thermoset polymer; the composition being capable of forming a solid microporous matrix, the matrix being a core surrounded by a skin and the core containing pores of diameters from about 1 to about 1000 microns. 12. A composition according to claim 11, wherein the skin contains pores of smaller diameters than those of the core pores such that the skin is functionally non-porous in comparison with the core. 13. A composition according to claim 11, wherein the core and skin contain pores within the same range of diameters. 14. A method of forming an implant suitable for providing a biological, therapeutic or physiological effect in an animal, comprising: administering to the animal a composition in an amount effective to form in situ a solid implant, the composition being a liquid formulation of a biodegradable, bioerodable, biocompatible thermoset polymer that is insoluble in aqueous or body fluid, and an agent selected from the group consisting of a pore-forming agent, a biocompatible organic solvent that is miscible or dispersible in aqueous or body fluid and a releasible, pore-forming moiety within the thermoset polymer; and the composition undergoing curing to form a microporous matrix, the matrix being a core surrounded by a skin and the core containing pores of diameters from about 1 to 1000 microns. 15. A composition according to claim 11 wherein the pore-forming agent is a sugar, salt, water-soluble polymer, or water-miscible organic solvent. 16. A composition according to claim 11, wherein the polymer is an acrylic ester-terminated biodegradable prepolymer capable of cross-linking to form a polymer matrix. 17. A composition according to claim 16, wherein the acrylic ester-terminated biodegradable prepolymer is selected from the group consisting essentially of polylactides, polyglycolides, polycaprolactones, polyanhydrides, polyamides, polyurethanes, polyesteramides, polyorthoesters, polydioxanones, polyacetals, polyketals, polycarbonates, polyorthocarbonates, polyphosphazenes, polyhydroxybutyrates, polyhydroxyvalerates, polyalkylene oxalates, polyalkylene succinates, polymalic acid, polyamino acids, polymethyl vinyl ether, chitin, chitosan, and copolymers, terpolymers, and any combination thereof. 18. A composition according to claim 11, further comprising a curing agent. 19. A composition according to claim 11, further comprising at least one biologically-active agent that is free of functional groups that would interfere with the thermosetting reaction of the thermoset polymer. 20. A composition according to claim 19, wherein the biologically-active agent is a polypeptide derived from a natural, synthetic, or recombinant DNA source. 21. A composition according to claim 19, wherein the biologically-active agent is selected from a group consisting of anti-inflammatory agents, antibacterial agents, antiparasitic agents, antifungal agents, antiviral agents, anti-neoplastic agents, analgesic agents, anaesthetics, vaccines, central nervous system agents, growth factors, hormones, antihistamines, osteoinductive agents, cardiovascular agents, anti-ulcer agents, bronchodilators, vasodilators, birth control agents and fertility enhancing agents. 22. A method according to claim 3, wherein the implant is capable of enhancing tissue regeneration. 23. A method according to claim 3, wherein the implant is capable of filling in defects in tissue. 24. A method according to claim 3, wherein the composition further comprises at least one biologically-active agent. 25. A method according to claim 24, wherein the biologically active agent is selected from the group consisting of anti-inflammatory agents, antibacterial agents, antiparasitic agents, antifungal agents, antiviral agents, anti-neoplastic agents, analgesic agents, anaesthetics, vaccines, central nervous system agents, growth factors, hormones, antihistamines, osteoinductive agents, cardiovascular agents, anti-ulcer agents, vasodilators, bronchodilators, birth control agents, and fertility enhancing agents. 26. A method of claim 24, wherein the biologically-active agent has a biological or physiological therapeutic effect of the reproductive system.