Preparation of novel polymeric microspheres for controlled release of finasteride.

The utility of the novel polycarbonate, poly(propylene carbonate maleate) (PPCM) to encapsulate and control the release of finasteride, via microspheres, was investigated. The PPCM microspheres loaded with finasteride were elaborated by a simple oil-in-water (O/W) emulsion-solvent evaporation method. Various manufacturing parameters, including the concentration of polymer in dichloromethane (DCM) and the polymer:finasteride ratios were altered to optimize process variables during the microspheres production. The effects of these changes on the characteristics of the microspheres were examined. The structure and morphology were characterized by wide-angle X-ray diffraction (WXRD) and scanning electron microscopy (SEM). The results showed that the mean diameter of microspheres was approximately 2mum, and had both smooth and spherical surfaces. Greater encapsulation efficiency was obtained by increasing the ratios of polymer:finasteride and the concentration of PPCM in DCM. In vitro drug release of these microcapsules was performed in a pH 7.4 phosphate-buffered solution. The release profiles of finasteride from PPCM microcapsules were found to be biphasic with a burst release followed by a gradual release phase. A prolonged in vitro drug release profile was observed. After an initial burst, a continuous drug release was observed for up to 5-6 weeks.