Novel sustained release polymer

Abstract

A polymer and a method for its preparation are provided. The polymer comprises poly(lactide), poly(lactide/glycolide) or poly(lactic acid/glycolic acid) segments bonded by ester linkages to both ends of an alkanediol core unit. The polymer is for use in a controlled release formulation for a medicament, preferably leuprolide acetate. The controlled release formulation is administered to a patient as a subcutaneous depot of a flowable composition comprising the polymer, a biocompatible solvent, and the medicament. Controlled release formulations comprising the polymer release leuprolide for treatment of prostate cancer patients over periods of 3-6 months.

1 . A polymer for use in manufacture of a controlled release formulation for leuprolide, comprising a structure of Formula I: 
       
         
           
           
               
               
           
         
       
       wherein:
 R a  is an alkane diradical comprising about 4 to about 8 carbon atoms; 
 R b  is hydrogen or methyl with the proviso that both R b  groups are identical; 
 R c  is hydrogen or methyl with the proviso that both R c  groups are identical; 
 each L/G independently comprises a lactide/glycolide copolymer segment; 
 the polymer has substantially no titratable carboxylic acid groups, and 
 the polymer has a weight average molecular weight of from about 6 kD to about 200 kD.