制备工艺对石杉碱甲微球体外释药机制的影响

目的考察制备工艺对石杉碱甲(Hup)乳酸-羟基乙酸共聚物(PLGA)微球体外释药机制的影响。方法 采用两种O/O型乳化溶剂挥发法工艺(A法和B法)制备Hup微球。考察微球的体外释药曲线，结合微球在释放介质中的降解速度和溶胀速度曲线以及微球的形态和微球中药物的分布情况阐述微球的释药机制。结果采用A法制备的微球包封率为47.60%，体外无明显突释现象，可缓释35 d，符合零级动力学方程，通过扩散和降解两种机制释药。采用B法制备的微球包封率为83.50%，体外可缓释21 d，整体释药曲线符合Higuchi方程，主要以扩散机制释药。结论采用A法制备的微球具有更理想的缓释效果。

Effect of preparation technique on In vitro release mechanism of huperzine A microspheres

Aim To investigate the effect of preparation technique on in vitro release mechanism of huperzine A-PLGA microspheres.Methods Huperzine A-PLGA microspheres were prepared by two kinds of O/O emulsion solvent evaporation method(method A and B).In vitro release mechanism was explained by release profile,degradation rate and swelling rate of microspheres in vitro.The microspheres morphology and drug distribution within microspheres were observed in order to explain further the drug release mechanism.Results The encapsulation efficiency of huperzine A microspheres prepared by method A and B was 47.60% and 83.50% respectively.Microspheres prepared by method A could sustain release for 35 days with nearly no initial burst release.The release profile fitted well to zero order equation and drug release mainly through degradation and diffusion mechanism.Huperzine A microspheres prepared by method B could sustain release for 21 days with some evidence of initial burst release.The release profile fitted well to the Higuchi equation and drug release was mainly through diffusion mechanism.Conclusion Huperzine A microspheres prepared by method A had more desirable release profile.