Heterogeneous hydrolytic degradation of poly(lactic- co -glycolic acid) microspheres: Mathematical modeling

Abstract

A new mathematical model for the prediction of the heterogeneous hydrolytic degradation of poly(D,L-lactide-co-glycolide) (PLGA)-based microspheres was developed. The model takes into account the autocatalytic effect of carboxylic groups and polymer composition on the degradation rate. It is based on mass balances for the different species, considering the kinetic and masstransport phenomena involved. The model estimates the evolution of average molecular weight, mass loss, and morphological change of the particles during degradation, and it was validated with novel experimental data. Theoretical predictions are in agreement with the hydrolysis data of PLGA microspheres (error values less than 5%). The model is able to predict the effect of particle size and molecular weight on the degradation of PLGA-based microspheres and estimates the morphological changes of the particles due to the autocatalytic effect.