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Fabrication of Poly(D,L-lactide-co-glycolide) Microspheres and Degradation Characteristics in vitro

Poly(D,L-lactide-co-glycolide) (PLGA, 75/25) microspheres were prepared by the emulsion solvent extraction/evaporation technique and their degradation behaviors in vitro at 37°C were investigated. PLGA microspheres with a smooth and nonporous surface were obtained, with a mean particle size of 114.15 μm. It was observed that mass loss and water uptake of PLGA increased with increasing degradation time; however, weight average molecular weight and the pH value of the phosphate buffered saline (PBS) solution decreased. The observed relative rates of mass loss vs. molecular weight decreases were consistent with the explanation that PLGA underwent bulk degradation rather than surface degradation. During the degradation time, the surface of the PLGA microspheres became coarse and there were many micropores that developed upon immersion in the PBS. The microspheres lost their spherical form with increasing degradation time.