Effects of metal salts on poly(DL-lactide-co-glycolide) polymer hydrolysis

The effects of encapsulated metal salts on poly(DL-lactide-co-glycolide) (PLGA) water uptake and degradation properties were investigated in this work. Salts of varying aqueous solubility characteristics were incorporated into PLGA films either as particles or by codissolution in polymer solutions. Polymer films were characterized with respect to the kinetics of water uptake, morphology changes, degradation, and weight loss after hydration. It was found that these properties are strongly influenced by the presence and nature of encapsulated salts. Effects range from minor changes in water uptake profile with no significant difference in degradation kinetics to major alterations in water uptake kinetics together with a several-fold decrease in the polymer degradation rate. Possible mechanistic explanations for the observed effects are discussed. (C) 1997 John Wiley & Sons, Inc.