左炔诺孕酮宫内节育器的研制

DEVELOPMENT OF LEVONORGESTREL-RELEASING INTRAUTERINE DEVICE

制备一种每天释放１０μｇ左炔诺孕酮（ＬＮＧ）的宫内节育器（ＩＵＤ）。在硅橡胶制成的控制释药管中填入ＬＮＧ和硫酸钡混合细粉，并与乙烯－醋酸乙烯共聚物（ＥＶＡ）铸成的横臂粘接成钥匙形ＩＵＤ，体外释药速度测定表明本品释放符合零级动力学。测得的标化速度为１．６７μｇ·ｍｍ／ｃｍ￣２·ｄ。其释药速度（ｑ）与药管壁厚度（ｈ）的倒数呈良好线性关系，并表明本品释药过程符合骨架控制释放机理。

A noval key-shaped levonorgestrel (LNG)-releasing intrauterine device(IUD) was developed with a release rate of 10μg/d of LNG, which was considered clinically to be appropriate to Chinese women for contraception. Silicone eiastomer was selected as the rate-controlling membrane material by its greater diffusion coefficient and permeability of LNG than that of ethylene-vinyl acetate copolymer employed before. The reservoir contained a mixture of LNG and barium sulfate which served as an X-ray contrast medium.The in vitro release investigation showed its constant rate for more than 50 days and a normalized flux of 1.67±0.12μg·mm/cm￣2·d.In addition,the release rate(q)was founded to be a linear function of the reciprocal thickness(1/h) of silicone elastomer tube.