Preparation of polyactic-coglycolic acid morphine microspheres and establishment of its in vitro releasing model

Objective: To study the preparation of polyactic-coglycolic acid（PLGA）morphine microspheres and establish its in vitro releasing model. Methods: PLGA morphine microspheres were prepared using the emulsify-solvent evaporation method and observed under a super-microscope.Drug content in morphine microspheres was detected by high performance liquid chromatography（HPLC）.Dialysis method was used to examine the in vitro drug release.The release data fit three model equations. Results: The drug content in morphine microspheres accounted for 11.86%,and the ratio of drug envelopment was 33%.The releasing test in vitro showed that the releasing time of morphine microspheres could last over 10 days and fit the zero-model. Conclusion: PLGA morphine microspheres can obviously prolong the releasing time of morphine.