Abstract
Block copolymers were synthesized by ring opening polymerization of L-lactide or D-lactide in the presence of mono- or dihydroxyl poly(ethylene glycol) (PEG), using zinc metal as catalyst. The composition of the copolymers was designed such that they were water soluble. Novel bioresorbable hydrogels were prepared from aqueous solutions containing both poly(L-lactide)/PEG and poly(D-lactide)/PEG block copolymers. In fact, stereocomplexation occurred between poly(L-lactide) and poly(D-lactide) blocks, leading to the formation of a hydrogel. A model protein drug, bovine serum albumin, was incorporated into the hydrogel for drug delivery studies. Data showed that the protein was released at a relatively constant rate over two weeks.