生物降解型左炔诺孕酮微球的体内外释药特性研究

 目的对左炔诺孕酮(LNG)微球的体内释药特性进行研究和评价。方法用放射免疫法测定生物降解型PLGA(9∶1)LNG微球在大鼠的药代动力学，进行了体内外释药试验。结果该微球具有相似的体内外释药特性：存在双峰现象，双峰之间有一较为平稳的释药区域，约占整个释药过程的70%。LNG微球在大鼠的MRT约为对照组LNG微晶的6.6倍。结论该微球有比较好的控释作用。依据微球体内外释药的两个特点可对该生物降解型控释微球的质量进行初步控制。

Investigation on the invitro and in vivo release of biodegradable PLGA(9

OBJECTIVE To evaluate the release of PLGA (9:1)microspheres containing levonorgestrel in vitro and in vivo.METHODS The pharmacokinetics of levonorgestrel(LNG) in the form of injectable biodegradable PLGA (9∶1) microspheres containing LNG were tested in rats by means of RIA method.The drug release in vitro was determined by means of UV spectrophotometry. RESULTS The release profiles of microspheres showed a similar pattern in vitro and in vivo.A similar two peak release was observed:the first peak of the release was diffusion controlled,and a secondary rise in the drug level related to the onset of degradation of the PLGA.Between the first peak and the second,there was about 70% steady release in vitro and in vivo.The first peak of plasma LNG of the microspheres was significantly lower than that of LNG microcrystal,but MRT of the microspheres was about 6 times as long as that of LNG microcrystal.CONCLUTION The drug release from PLGA (9∶1) microspheres in vitro correlated well with that in vivo.The microspheres have remarkablely long control release action.