Controlled Release of Ionic Drugs from Complex Micelles with Charged Channels

详细信息    查看全文

• 作者：Xiaojun Liu ; Rujiang Ma ; Junyang Shen ; Yanshuang Xu ; Yingli An ; Linqi Shi
• 刊名：Biomacromolecules
• 出版年：2012
• 出版时间：May 14, 2012
• 年：2012
• 卷：13
• 期：5
• 页码：1307-1314
• 全文大小：477K
• 年卷期：v.13,no.5(May 14, 2012)
• ISSN：1526-4602

文摘

Oral administration of ionic drugs generally encounters with significant fluctuation in plasma concentration due to the large variation of pH value in the gastrointestinal tract and the pH-dependent solubility of ionic drugs. Polymeric complex micelles with charged channels on the surface provided us with an effective way to reduce the difference in the drug release rate upon change in pH value. The complex micelles were prepared by self-assembly of PCL-b-PAsp and PCL-b-PNIPAM in water at room temperature with PCL as the core and PAsp/PNIPAM as the mixed shell. With an increase in temperature, PNIPAM collapsed and enclosed the PCL core, while PAsp penetrated through the PNIPAM shell, leading to the formation of negatively charged PAsp channels on the micelle surface. Release behavior of ionic drugs from the complex micelles was remarkably different from that of usual core鈥搒hell micelles where diffusion and solubility of drugs played a key role. Specifically, it was mainly dependent on the conformation of the PAsp chains and the electrostatic interaction between PAsp and drugs, which could partially counteract the influence of pH-dependent diffusion and solubility of drugs. As a result, the variation of drug release rate with pH value was suppressed, which was favorable for acquiring relatively steady plasma drug concentration.