利用超分子接枝聚合物体系制备具有pH响应能力的高分子囊泡及其在药物控制释放方面的应用

pH-Sensitive Vesicles Prepared from Supramolecular Graft Copolymers and the Application in the Controlled Release of Drug

利用自由基聚合的链转移反应,制备了以羧基为端基的聚(N-异丙基丙烯酰胺)(PNIPAM-COOH),然后以该聚合物作为亲水的侧链,利用其羧端基和聚(4-乙烯基吡啶)(PVPy)疏水主链上的吡啶基团间的相互作用,在共溶剂DMF中形成超分子两亲接枝聚合物体系,在上述体系中逐滴加入水可以使其通过自组装形成高分子囊泡.通过控制PVPy与PNIPAM-COOH的质量比在1～3之间,可以控制囊泡尺寸在130～330nm之间.由于囊泡中含有吡啶基团,因而该囊泡具有pH敏感性.以日落黄为药物模型,以这些pH敏感性囊泡作为药物载体,通过调节环境的pH值可以实现对药物的控制释放.

Supramolecular graft copolymers （SGP） were prepared via the ionic interaction between poly（4-vinylpyridine） （PVPy） and poly（N-isopropylacrylamide） with carboxylic end groups （PNI- PAM-COOH）. Hydrophobic PVPy was used as main chains, and hydrophilic PNIPAM-COOH grafted onto the main chains through the ionic interaction between the carboxylic groups and pyridine groups. The SGP could self-assemble to form vesicles in DMF/H2O system. When modulating the mass ratio of PVPy to PNIPAM-COOH from 1 to 3, the size of the vesicles could be controlled from 130 to 330 nm. These vesicles were sensitive to pH, and could be deformed by changing pH. Drug-release studies showed that release rates of the loaded drug （sunset yellow） in the two vesicles could be controlled by the pH of the solution.