Preparation and evaluation of poly (D, L-lactic acid) (PLA) or D, L-lactide/glycolide copolymer (PLGA) microspheres with estradiol.

PLA/PLGA was used for biodegradable and biocompatible carriers to achieve sustained release of estradiol. Microspheres were formed by an emulsification-solvent evaporation method, and then their properties and in vitro drug release behavior were examined including amongst others the effects of the concentration of PVA in the aqueous phase, the concentration of PLA in the organic phase, the stirring speed, the volume ratio of O/W, the weight ratio of E2/PLA fed, and the type and molecular weight of the polymers.