pH/温度双重敏感微凝胶的制备与药物缓释模拟

Study on Synthesis of Fast Responsive pH-and Thermo-Sensitive Microgels and Vitro Release

通过沉淀聚合法制备了具有pH/温度双重敏感且形态较规则的聚(N-异丙基丙烯酰胺-co-丙烯酸)(P(NIPAAm-co-AAc)微凝胶,考察了交联剂的用量对微凝胶形态的影响。相关测试发现:P(NIPAAm-co-AAc)微凝胶的临界相转变温度(LCST)的大小与丙烯酸(AAc)的用量有关。AAc含量的增大使微凝胶的LCST增大。不含AAc的PNIPAAm,微凝胶溶液的pH敏感性很微弱。在碱性条件下,AAc含量过多的微凝胶溶液已基本丧失温敏性。遴选出合适配方并在模拟人体体温(37℃)和胃肠液pH值(pH值7)的条件下进行了药物(阿司匹林)缓释实验,发现以该微凝胶为药物载体,能更好地达到药物长期有效释放的目的。

The Poly （ N - isopropylacrylamide - co - acrylic acid） （ P （ NIPAAm - co - AAc ） ） microgels with pH - and thermo - sensitive properties are synthesized by the precipitation copolymerization. The effects of cross - linker （ N, N - methylenebisacryamide, Bis） amount to the properties of microgels are studied. It is found that all microgels exhibited reversible phase - transition phenomenon at the lower criti- cal solution temperature （LCST）. Their LCST increases with the amount of AAe. Furthermore, the P （NIPAAm - co - AAc） microgels became more pH - sensitivie with the increasing of AAc. In vitro of drug （Aspirilin） is taken under a condition of gastrointestinal fluid and the body temperature （37 ℃ ）. It is identified that microgel particles as drug matrixes could deliver much longer and more validly.