含有4,4′-双(甲基丙烯酰胺基)偶氮苯水凝胶的合成及其在结肠位药物释放的动物实验

合成了不同链长的甲基丙烯酸酯、甲基丙烯酰胺及丙烯酸与 4 ,4′ 双 (甲基丙烯酰胺基 )偶氮苯交联共聚的功能凝胶 .三维网络结构通过压缩弹性模量、有效交联密度及聚合物与溶剂间的相互作用参数进行了表征 .主要研究了这类凝胶在pH2 2和pH7 4的缓冲溶液的平衡溶胀特性及其偶氮交联基团在体内的降解行为 ,并讨论了其降解机制 .凝胶在胃部的性能稳定 ,既不发生溶胀 ,亦不发生降解 ;但在盲肠内偶氮交联基因可发生降解 .其降解率与凝胶的平衡溶胀程度有一个很好的关联 :交联程度、疏水基侧链的长度及含量对凝胶溶胀行为的影响结果与这些因素对偶氮交联基团体内降解的影响结果完全一致 .通过调节这些因素不仅可以控制凝胶的溶胀程度 ,而且可以控制偶氮交联基团在体内的降解行为 .

HYDROGELS CONTAINING 4,4′-DI(METHACRYLOYLMINO)AZOBENZENE: SYNTHESIS AND ANIMAL EXPERIMENT FOR COLONIC-SITE DRUG RELEASE

Hydrogels based on n alkyl methacrylate esters( n AMA) of various chain lengths,acrylic acid and acrylamide cross linked with 4,4′ di(methacryloylmino)azobenzene were synthesized.The structure of three dimensional network was characterized by the modulus of elasticity,by the effective network density and by the interaction between polymer and water.The equilibrium swelling behavior of the hydrogels in buffered solutions at pH 2 2 and pH 7 4 and the biodegradability in vivo of their azobenzene cross linking groups as well as the mechanism of degradation by cecal bacteria were studied.The gels neither swelled nor degraded in the stomach broth;but in the medium of cecum their azobenzene cross linking groups were degradable by anaerobes present in the cecum.The rates of degradation were found to be related to the equilibrium degree of swelling.The factors influencing the degree of swelling were also shown to influence the rates of gel degradation.By adjusting these factors including the degree of cross linking,the lengths/content of the n AMA side chains,it is possible to control both the degree of swelling and the degradation in vivo of the azobenzene cross linking groups.Thus these hydrogels have potential for colon specific delivery of drugs.