Patent ID: 6743446
Filing Date: 2004-06-01
Classification: A61K

Abstract:
A method of preparing a biodegradable polymeric delivery system for delivering a biologically active agent to a subject, wherein the biodegradable polymeric delivery system maintains a pH of greater than 3 during biodegradation of the polymeric delivery system over a period of 4 weeks, comprising:a) forming a polymer solution comprising a solvent and a poly(lactide-co-glycolide) (PLGA) polymer which comprises from 50% to 100% lactide or lactic acid and from 50% to 0% glycolide or glycolic acid, wherein said lactide or lactic acid is selected from the group consisting of the L isomer, the D isomer, or a D,L racemic mixture; b) optionally blending from 10% to 30% of one or more pore-forming agents with the PLGA polymer solution of step (a); c) dispersing from 0.50% to 20% (w/w) of one or more basic additives wherein the basic additive has a solubility in water of from about 1.24Ã—10âˆ’13 to about 3.16Ã—10âˆ’3 and a pH of about 6.82 to about 9.76 for a saturated aqueous solution, in the polymer solution; d) dispersing from 0.1% to 20% (w/w) of a composition comprising the agent or the agent plus carrier in the polymer solution; and e) solidifying the polymer from the resulting polymer solution to provide a biodegradable polymeric system whose microclimate maintains a pH of greater than 3 during biodegradation of the polymeric system for at least 4 weeks.