壳聚糖/聚N-异丙基丙烯酰胺温敏性珠状小球的药物释放研究

Drug delivery study of temperature-responsive chitosan/poly(N-isopropylacrylamide) semi-interpenetrating-polymer-network beads

以一种天然高分子——壳聚糖和温敏性材料聚N-异丙基丙烯酰胺(PNIPAM)为基材,通过高分子半互穿交联网络技术,制备了一种环保型且具有温度敏感性的珠状小球材料.并以该材料作为药物控制释放载体,在模拟人体胃部pH酸碱环境下,分别在PNIPAM相转变温度以前及以后,研究了该材料对药物的控制释放行为,及其对温度的感应性能.

Recently,considerable attention has been paid to the preparation of smart or intelligent materials for biomedical applications,such as controlled delivery system.Comparison to conventional controlled delivery systems,the release of bioactive agents encapsulated in the smart materials can react according to the change of the environmental conditions.Hydrogels have been extensively studied in the development of the smart delivery systems,by undergoing volume phase transitions or gel-sol phase transitions,as a response to stimuli-responsive characters.In addition,the use of natural biodegradable polymers has shown a continuous increasing in such applications.The motivation lies on the fact that these kinds of polymers have not only biological functionalities,but also lie plentiful in the nature.Chitosan,poly-β-（1→4）-2-amiono-2-deoxy-D-glucose is prepared from deacetylation of natural chitin,and has many useful characteristics such as low toxicity,high biocompatibility and so on,so it has been already widely applied in biomedical field.In this paper,a series of temperature-responsive semi-interpenetrating polymer network（semi-IPN） hydrogel beads,which contained different composites of chitosan and poly（N-isopropylacrylamide）（PNIPAM）,were prepared.The behaviors of drug delivery in the condition of pH value similar to gastric fluid,at below and above the lower critical solution temperature（LCST） of PNIPAM respectively,had been studied.It were found that at below LCST,the drug release behaviors of the beads with different compositions were quite similar;but at above LCST,the amount of the released drug increased with the increase of the content of PNIPAM in the beads,which were ascribed to the temperature-sensitivity of these hydrogel beads.