Attempts to map the structure and degradation characteristics of aliphatic polyesters derived from lactic and glycolic acids.

During the past 5 years, important advances have been accomplished in the understanding of the fate of aliphatic polyesters derived from lactic acid (LA) and glycolic acid (GA) in aqueous media. Hydrolysis of solid LA/GA polymers is now regarded as dependent upon a diffusion-reaction mechanism. Faster central degradation, degradation-induced composition, and morphology changes are three of the most important findings which appeared to be composition-dependent as deduced from the behavior of different LA/GA polymers. An attempt is made to generalize these findings to the whole family and to elaborate a map which could be used to predict degradation characteristics of LA/GA polymers from their initial composition and morphology.