复方左炔诺孕酮阴道避孕环的制备及体外释药研究

报告复方左炔诺孕酮避孕环(CVR)的制备及体外释药研究。CVR以医用硅橡胶作贮药管,内装左炔诺孕酮(LNG)、雌二醇(E_2)和载体制成的混悬剂,在“漏槽状态”下测定CVR药管的体外释药速度。结果表明:不同的硅橡胶、载体和管壁厚度对释药速度有显著影响,温度与释药速度的关系符合Arrhenius关系式,释药速度与厚度的倒数呈线性相关。实验结果提示,LNG为零级释放,其释放机理为膜控制释放;E_2的释放速度与时间的平方根呈线性相关,可能为骨架型释放。本CVR经兔体内释放试验,证明体内外释药相关。

FABRICATION OF A CONTRACEPTIVE VAGINAL RING AND IN VITRO RELEASE OF LEVONORGESTREL COMBINED WITH ESTRAD1OL

This paper reports , the preparation of a contraceptive vaginal ring (CVR) containing levonorgestrel (LNQ) and estradiol (E2) -and their in vitro and in vivo release. The OVR is composed of a rate-limiting silastic elastomer membrane containing a suspension of the drugs in a carrier. The release rates of the drugs from the OVR were measured under"sink" condition.Results indicated that the polymer material, drug carrier and the thickness of the polymer membrane all had statistically significant importances. The relationship between temperature and standardized release rate corresponds to Arrhenius' equation. The release rates of both drugs were linearly dependent on the reciprocal of the membrane thickness. The releasing mechanism of LNG at a constant rate, is of a membrane-controlled nature. However, the cumulative amount of ? released linearly correlated with the square root of elapsed time,this releasing mechanism is probably of a matrix-controlled nature.The vaginal insertion of the OVR in the rabbit resulted in the same release rate profile as in vitro, thus confirming the relative relationship between in "vitro and in vivo studies.