Influence of particle size on the degradation of poly(lactide-co-glycolide)-based microspheres

CARLOS BUSATTO; IGNACIO M. HELBLING; NATALIA CASIS; JULIO A. LUNA; DIANA ESTENOZ

Santa Fe

Simposio; XI Simposio Argentino de Polímeros; 2015

Polymer degradation plays a crucial role in drug deliveryfrom sustained release polyester systems, therefore is essential to characterizethe degradation behaviour of these devices. The aim of this study was toinvestigate the effect of particle size on the in vitro degradation ofpoly(lactic-co-glycolic acid) (PLGA)-based microspheres. Microspheres wereprepared by the oil-in-water emulsion solvent evaporation technique.Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), nuclearmagnetic resonance (NMR) and size exclusion chromatography (SEC) were used tostudy polymer degradation and morphological changes of the microparticlesduring degradation process. Higher degradation rates were achieved with largerparticles. For smaller particles, degradation products formed within themicrospheres can readily diffuse to the surface and dissolve into thesurrounding medium. On the other hand, for larger particles, diffusion pathwaysincrease and polymer degradation rate undergoes an autocatalytic effect duringdiffusion of degradation products.