A new class of biodegradable hydrogels stereocomplexed by enantiomeric oligo(lactide) side chains of poly(HEMA‐ <i>g</i> ‐OLA)s

Abstract

Two enantiomeric amphiphilic graft copolymers consisting of water soluble poly(2-hydroxyethyl methacrylate) (HEMA) and biodegradable oligo(L-lactide) (OLLA) or oligo(D-lactide) (ODLA) were synthesized by free radical copolymerization. HEMA-OL(D)LA macromonomers were synthesized by ring opening polymerization of L- or D-lactide. Both HEMA-OLA macromonomers and graft copolymers were characterized by NMR spectroscopy and gel permeation chromatography. Graft copolymers and their stereocomplexes were analyzed by wide angle X-ray diffraction and differential scanning calorimetry (DSC). Due to the formation of stereocomplex crosslinks between poly(HEMA) main chains, amphiphilic, biodegradable hydrogels prepared by blending of two enantiomeric poly(HEMA-g-OLLA) and poly(HEMA-g-ODLA) degraded more slowly in phosphate buffered saline than individual optically pure poly-(HEMA-g-OL(D)LA).