Khare A R, Peppas N A
School of Chemical Engineering, Purdue University, West Lafayette, IN 47907-1283.
J Biomater Sci Polym Ed. 1993;4(3):275-89. doi: 10.1163/156856293x00564.
Controlled release systems of theophylline, proxyphylline and oxprenolol.HCl exhibiting modulated drug delivery were prepared by using pH-sensitive anionic copolymers of 2-hydroxyethyl methacrylate with acrylic acid or methacrylic acid. Drug release studies were carried out in simulated biological fluids. The initial drug release rates and the drug release mechanisms were dependent upon the pH and ionic strength of the buffer solution as well as its salt composition. Initial drug diffusion coefficients in these swelling-controlled release systems were calculated from the release curves; they were of the order of 10(-7) cm2/s and were dependent upon the degree of swelling. The drug release mechanism was non-Fickian in all the dissolution media studied. Lowest release rates were observed for drug release from nonionized polymer networks in agreement with the relationship between ionization, swelling and drug release.
采用甲基丙烯酸2-羟乙酯与丙烯酸或甲基丙烯酸的pH敏感阴离子共聚物，制备了具有调节药物释放功能的茶碱、丙羟茶碱和盐酸氧烯洛尔控释系统。在模拟生物流体中进行了药物释放研究。初始药物释放速率和药物释放机制取决于缓冲溶液的pH值、离子强度及其盐组成。从释放曲线计算了这些溶胀控释系统中的初始药物扩散系数；其数量级为10(-7) cm2/s，并取决于溶胀程度。在所研究的所有溶解介质中，药物释放机制均为非菲克扩散。与离子化、溶胀和药物释放之间的关系一致，从非离子化聚合物网络中释放药物时观察到最低释放速率。
