Biodegradable drug delivery compositions

Abstract

A biodegradable drug delivery compositions comprising a triblock copolymer containing a polyester and a polyethylene glycol and a diblock copolymer containing a polyester and an end-capped polyethylene glycol, as well as a pharmaceutically active principle is disclosed.

What is claimed is: 
     
         1 . A biodegradable drug delivery composition comprising:
 (a) a biodegradable triblock copolymer present in an amount of 3.0% to 45% (w %/w %) of the total composition having the formula:
   Poly(lactic acid)v-poly(ethylene glycol)w-poly(lactic acid)x 
   wherein v and x are the number of repeat units ranging from 24 to 682 and w is the number of repeat units ranging from 4 to 273 and v=x or v≠x;   (b) a biodegradable diblock copolymer present in an amount of 8.0% to 50% (w %/w %) of the total composition having the formula:
   methoxy poly(ethylene glycol)y-poly(lactic acid)z 
   wherein y and z are the number of repeat units y ranging from 3 to 45 and z ranging from 7 to 327, wherein the ratio of the biodegradable triblock copolymer of (a) and the biodegradable di block copolymer of (b) is 1:3 to 1:8 or 1:1 to 1:19 or 3:2 to 1:19 in said biodegradable drug composition which is insoluble in water; and   (c) an organic solvent present in an amount of 40%-74% (w %/w %) of the total composition; and   (d) at least one pharmaceutically active principle.