Study on sustained-release risperidone biodegradable microspheres

Aim: To prepare risperidone biodegradable microspheres whose release could be sustained in half a month. Methods: With PLGA being matrix, risperidone microspheres were prepared by emulsion-solvent evaporation. The essential character, in vitro release and in vivo release of the microspheres were observed. Results: The microspheres was found to be spherical with smooth surface. The diameter ranged in 50 ∼ 70 μm and recovery, entrapment efficient and span of microspheres were estimated to be 71%, 78% and 0.45, respectively. Analyses of in vitro release showed that the release could be best fitted to biexponential equation (r = 0.985 8). In addition, it was found that the microspheres could sustained-release for 16 days and that the initial burst release was well controlled. Conclusion: Risperidone biodegradable microspheres prepared in the proposed method could provide long-term sustained release effect.