Claims for Patent: 6,479,065

Summary for Patent: 6,479,065

Title:	Process for the preparation of polymer-based sustained release compositions
Abstract:	The invention relates to a sustained release composition and methods of forming and using said composition for the sustained release of biologically active agent. The sustained release compositions of the invention comprise a biocompatible polymer and a biologically active agent characterized by a porous center and a less porous outer layer wherein the center and outer layer consist of essentially the same materials. The sustained release compositions can be prepared by annealing at least a substantial portion of the exterior surface of a polymer/active agent matrix. The compositions which have been annealed exhibit a decrease in the release of agent over the first 24 hours following administration (i.e., reduced burst) and as a result can show an increase in the duration of sustained release thereby providing increased therapeutic benefits.
Inventor(s):	Jaworowicz; Warren E. (Boxboro, MA), Wright; James I. (Lexington, MA)
Assignee:	Alkermes Controlled Therapeutics, Inc. (Cambridge, MA)
Application Number:	09/801,272
Patent Claims:	1. A sustained release composition comprising microparticles of a biocompatible polymer and a biologically active protein characterized by a porous center and a less porous outer layer, wherein the center and the outer layer consist of essentially the same materials. 2. The sustained release composition of claim 1 wherein the biocompatible polymer is biodegradable. 3. The sustained release composition of claim 2 wherein the biodegradable polymer is selected from the group consisting of poly(lactide)s, poly(glycolide)s, poly(lactide-coglycolide)s, poly(lactic acid)s, poly(glycolic acid)s, poly(lactic acid-co-glycolic acid)s, poly(caprolactone), polycarbonates, polyesteramides, polyanhydrides, poly(amino acid)s, poly(ortho ester)s, polycyanoacrylates, polyamides, polyacetals, poly(ether ester)s, copolymers of poly(ethylene glycol) and poly(ortho ester)s, poly(dioxanone)s, poly(alkylene alkylate)s, biodegradable polyurethanes, blends and copolymers thereof. 4. The sustained release composition of claim 3 wherein said polymer is poly(lactide-co-glycolide). 5. The sustained release composition of claim 1 wherein the biocompatible polymer is non-biodegradable. 6. A method of providing a therapeutically effective level of an active agent in a subject for a sustained period comprising administering to the subject a dose of the sustained release composition of claim 1. 7. The microparticles of claim 1, wherein the porous outer layer comprises from about 5% to about 30% by weight of the microparticles.