Novel gelatin-containing polymer hydrogels that can be used as mucoadhesive delivery systems were developed. Poly(acrylic acid) hydrogels were modified by copolymerizing gelatin as adhesion promoter, to improve the adhesion to the mucus layer and the synthesized copolymer of acrylic acid (AA) and methacrylated gelatin (GelMA) were designated as P(AA-co-GelMA). The pH-sensitivity and the mucoadhesive property of the P(AA-co-GelMA) hydrogel were investigated as carries of an oral protein delivery system activated by pH changes of the human GI tract. There was a drastic change in the weight swelling ratio of P(AA-co-GelMA) hydrogels at a pH of around 5, that is, low swelling ratios at a pH below 5, while high swelling ratios at a pH greater than 5. In addition, the swelling ratio increased at a pH above 5, when the AA content in the hydrogel increased. In mucoadhesive experiments using the rheometer, when the GelMA concentration in the P(AA-co-GelMA) hydrogel increased, the maximum force of detachment increased, indicating that the mucoadhesion of the hydrogel was improved. The P(AA-co-GelMA) hydrogels also showed a pH-responsive release behavior. The ratio of the cumulative amounts of Rh-B released from P(AA-co-GelMA) hydrogels at pH 2.6 to pH 7.0 increased, when the AA content in the hydrogel decreased.

中文翻译：

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含明胶的水凝胶在蛋白药物递送应用中的黏膜黏附和pH响应行为

开发了可用作粘膜粘附递送系统的新型含明胶聚合物水凝胶。通过共聚明胶作为助粘剂来改性聚丙烯酸水凝胶，以提高其对粘液层的附着力，并将丙烯酸（AA）和甲基丙烯酸明胶（GelMA）的合成共聚物命名为P（AA-co-GelMA） 。研究了P（AA-co-GelMA）水凝胶的pH敏感性和粘膜黏附特性，该凝胶是通过人类胃肠道的pH改变激活的口服蛋白质递送系统的载体。pH值约为5时，P（AA-co-GelMA）水凝胶的重量溶胀率发生了急剧变化，即pH值低于5时溶胀率低，而pH值大于5时溶胀率高。此外，在pH高于5时，溶胀率增加 当水凝胶中AA含量增加时。在使用流变仪的粘膜粘附实验中，当P（AA-co-GelMA）水凝胶中的GelMA浓度增加时，最大的分离力增加，这表明水凝胶的粘膜粘附性得到了改善。P（AA-co-GelMA）水凝胶也显示出pH响应释放行为。当水凝胶中AA含量降低时，从P（AA-co-GelMA）水凝胶释放的Rh-B累积量在pH 2.6至pH 7.0的比率增加。