Abstract:

Studying on the adsorption and controlled release behavior for the molecularly imprinted polymers is of great theoretical and applied value. In present work, a thermosensitive diosgenin imprinted silica microsphere (TMIP) was prepared by a surface imprint technology using silylated silica as the carrier, diosgenin as the template, methacrylic acid(MAA) and N-isopropylacrylamide(NIPAm) as common functional monomers, ethylene glycol dimethacrylate as the cross-linker and azodiisobutyronitrile(AIBN) as the initiator. Superficial chemical groups and particle morphology for this TMIP were characterized by using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Loaded capacity and controlled release behavior for this TMIP toward diosgenin under different environmental conditions were tested. Results showed that the imprinted microspheres had higher adsorption capacity toward diosgenin, with a saturated adsorption capacity of 21.6mg/g. It was indicated from drug release dynamics that while the imprinted microspheres emerged a high controlled drug release capability, with a diosgenin-releasing percentage of 81.9% within 12h, the non imprinted silica gel microspheres had no sustained-release property. Environmental conditions also had great influence on the controlled release of thermosensitive imprinted silica microspheres, with the maximum release rate of 99.28% when release was performed at 303K in methanol solution with a NaCl-controlled ionic strength of 1.5×10^-4mol/L.

Key words: molecularly imprinted polymers, thermosensitive imprinted silica microspheres, diosgenin, adsorption, controlled release

摘要：

研究分子印迹聚合物对特定药物的吸附及控制释放具有重要理论和应用价值。本文以硅胶为载体，先对其进行硅烷化修饰，再以薯蓣皂素为模板分子，以甲基丙烯酸（MAA）和N-异丙基丙烯酰胺（NIPAm）为共同功能单体、乙二醇二甲基丙烯酸酯（EGDMA）为交联剂、偶氮二异丁腈（AIBN）为引发剂，通过表面接枝分子印迹聚合物制备了薯蓣皂素温敏印迹硅胶微球。用傅里叶红外光谱及扫描电镜对聚合物表面化学基团及颗粒形貌进行表征。测试了分子印迹硅胶微球的载药性及在不同环境条件下的药物释放行为。结果表明，温敏印迹硅胶微球对薯蓣皂素具有良好吸附性能，其饱和吸附量为21.6mg/g，也具有较高的控制缓释性能。释放动力学表明，其在12h内控制薯蓣皂素释放率为81.9%，而非印迹硅胶微球不具备缓释性。环境条件对温敏印迹硅胶微球的控制释放具有重要影响。当温度为30℃、溶剂为甲醇、NaCl离子强度为1.5×10^-4mol/L时，印迹微球具有最高释放率，达99.28%。

关键词: 分子印迹聚合物, 温敏印迹硅胶微球, 薯蓣皂素, 吸附, 控制释放