Biodegradable comb polyesters. Part II. Erosion and release properties of poly(vinyl alcohol)-g-poly(lactic-co-glycolic acid)

Poly(lactic acid) (PLA) and its random copolymers with glycolide (PLG) were modified by grafting onto hydrophilic macromolecular backbones, such as poly(vinyl alcohol) (PVA), to increase both hydrophilicity and to manipulate the polymer structure. The resulting branched PVA-g-PLG offers the possibility to manipulate physico-chemical properties, such as molecular weight and glass transition temperature. The degradation and erosion rates required for continuous release of hydrophilic macromolecules differs significantly from linear PLG. Microspheres were prepared to investigate the release of hydrophilic dextran as a function of polymer structure.