Abstract: In this paper，a pH-sensitive interpenetrating polymer network（IPN）hydrogels designed for colon targeted drug delivery were prepared by using konjac glucomannan（KGM）with different molecular weights（1.070×106（KGM-1），8.272×105（KGM-2），7.329×105（KGM-3），and 6.012×105（KGM-4））and poly（acrylic acid）（PAA）with N,N-methylene-bis-（acrylamide）（MBAAm）as a cross-linker. The structure of the hydrogels was characterized by FTIR and SEM. The swelling ratio of these hydrogels had sensitive respondence to the environmental pH value variation. Hydrogels composed of higher molecular weights KGM had bigger swelling ratio than those hydrogels composed of lower molecular weights KGM. The enzymatic degradation tests showed that the IPN hydrogels retain the enzymatic degradation character of KGM，and hydrogels composed of lower molecular weights KGM can release drug more stably. These results showed that KGM with lower molecular weights could be a more suitable polymeric carrier for controlled release.

Key words: konjac glucomannan, poly(acrylic acid)；weight average molecular weight；drug delivery；β-mannanase

摘要： 对不同分子量的魔芋葡甘聚糖（重均分子量分别为1.070×106，8.272×105，7.329×105和6.012×105）与丙烯酸在引发剂（K2S2O8）和交联剂（MBAAm）的作用下形成的互穿网络（KGM/PAA-IPN）作为缓释药物载体的性能进行了研究。通过红外、扫描电镜、溶胀率、生物降解性和体外释放等对凝胶进行表征。溶胀分析表明KGM/PAA-IPN在pH值7.4时的溶胀率明显大于pH值2.2时的溶胀率，且由分子量较大的KGM组成的KGM/PAA-IPN凝胶的溶胀率、失重速度和失重率都明显大于由分子量较小的KGM组成的KGM/PAA-IPN凝胶。因此，KGM/PAA-IPN凝胶作为药物载体具有生物降解性和pH敏感性，且适当降低KGM的分子量有利于KGM/PAA-IPN凝胶在药物缓释过程中的稳定性。

关键词: 魔芋葡甘聚糖, 聚丙烯酸, 重均分子量, 药物载体, &beta, -甘露聚糖酶