聚-γ-谷氨酸包覆介孔分子筛MCM-41控释体系研究

Study on controlled release ofγ-polyglutamic acid coating MCM-41

用硅酸酯水解法制备了孔径为3nm的MCM-41作为烯效唑载体,采用负压浸渍法载药.用XRD、BET、TEM、SEM、TG等仪器对包覆体系进行了表征分析.用低平均分子量γ-PGA(M.W.≈9180Da)包覆负载药物的纳米粒子,形成控释体系.在不同乙醇-PBSaq溶液中,对不同控释体系的控释效应进行了探究.通过零级释放、一级释放、Higuchi和Rigter-Peppas释放动力学模型的拟合探究控释体系的药物控释机理.分析结果表明:烯效唑在MCM-41外表面及孔道内均有吸附,负压浸渍法能有效促使烯效唑分子进入3nm孔道内部,以单分子层的吸附为主;在聚乙烯亚胺作用下,制得包覆壳层厚度均一、分散性较好的MCM-41@γ-PGA纳米控释体系;未包覆的载药体系的药物释放不满足零级释放、一级释放和Higuchi模型,但满足Rigter-Peppas释放动力学模型,遵循Fick扩散机理.

MCM-41 with pore diameters of 3 nm prepared by hydrolysis of silicate ester was used as the carrier of uniconazole.The pesticide molecules were loaded with impregnation under subatmospheric pressure.The systems were characterized by XRD,BET,TEM,SEM and TG.Subsequently,the formed composite was coated withγ-PGA(M.W.≈9 180 Da)to furnish drug controlled release systems.The controlled release effect of different systems was investigated in various ethanol-PBS aq solutions.The controlled release mechanisms were investigated by fitting the kinetic models of zero-order release,first-order release,Higuchi and Rigter-Peppas.The results showed that uniconazole was adsorbed both on the outer surface and in the holes of MCM-41.The impregnation under subatmospheric pressure enabled incorporation of uniconazole molecules into the holes of 3nm with monolayer adsorption.The appropriate molecular weight was essential to obtain release system of MCM-41@γ-PGA with uniform shell thickness and good dispersity,and polyethyleneimine was used to bridge silica layer andγ-PGA layer.The release of system,including uncoated byγ-PGA was unfitted to zero-order release,first-order release model,or Higuchi models.Rigter-Peppas release kinetics model was fitted well,and the Fick diffusion mechanism was followed.