双亲水性超支化接枝共聚物的pH响应性药物释放

Drug release property of a pH-responsive double-hydrophilic hyperbranched graft copolymer

首先利用阳离子开环聚合合成了超支化聚缩水甘油醚(HPG),然后通过酯化反应制备了低接枝率的大分子引发剂HPG-Br,并进一步引发甲基丙烯酸-2-(N,N-二甲氨基)乙酯(DMAEMA)单体的原子转移自由基聚合,合成了低接枝率的双亲水性超支化接枝共聚物HPG-g-PDMAEMA,用1HNMR和GPC对聚合物结构进行了表征.并采用芘荧光探针法,HNMR和DLS研究了HPG-g-PDMAEMA在不同pH水溶液中的组装行为.以1香豆素102为模型药物研究了HPG-g-PDMAEMA聚合物在不同pH条件下的药物释放行为,发现在pH连续振荡刺激下HPG-g-PDMAEMA聚合物胶束对药物分子能实现部分"可逆"的释放和再包载.

The work reports the synthesis and self-assembly of double-hydrophilic hyperbranched graft copolymers of HPG-g-PDMAEMA, which consist of a hyperbranched polyglycerol （HPG） core and several grafted poly （2-（Dimethylamino）ethyl methacrylate） （PDMAEMA） arms. HPG was synthesized by cationic polymerization. Then HPG-Br macroinitiator was obtained by esterification of HPG with 2-bromoisobutyryl bromide, which was subsequently used in the preparation of HPG-g-PDMAEMA graft copolymer through atom transfer radical polymerization （ATRP） of DMAEMA monomers. The molecular structures were studied by ^1H NMR and GPC. The pyrene-based fluorescent probe method, ^1H NMR and DLS were used to study the self-assembly behavior of HPG-g-PDMAEMA. The drug loading and pH-responsive release properties of HPG-g-PDMAEMA were also investigated by using coumarin 102 as a model drug. The results show that the HPG-g-PDMAEMA micelles can continuously release and re-ncapsulate coumarin 102 as the pH continuously changes from 11.5 to 2.5; however, this process is not totally reversible.