College of Chemistry and Materials Science, Ludong University, Yantai 264025, China.
Int J Biol Macromol. 2012 May 1;50(4):899-904. doi: 10.1016/j.ijbiomac.2012.02.013.
Thermo-sensitive poly(N-isopropyl acrylamide-co-vinyl pyrrolidone)/chitosan [P(NIPAM-co-NVP)/CS] semi-IPN hydrogels with improved loading capacity and sustained release for anionic drugs NAP were prepared by free-radical polymerization. The LCST of hydrogels was adjusted to the vicinity of body temperature by introducing hydrophilic NVP. The presence of CS in semi-IPN networks improves the swelling behavior and provides a high affinity for anionic drug NAP due to the strong interactions between NAP molecules and CS chains. Release of NAP was suppressed at pH 2.2 and 5.0 and accelerated at pH 7.4 due to the deprotonation of amino groups in CS. Increasing temperature above LCST, hydrogels showed a continuous release of NAP without burst diffusion due to the shrinkage of PNIPAM restraining the drug release.
通过自由基聚合，制备了具有提高的载药量和对阴离子药物 NAP 持续释放性能的温敏性聚（N-异丙基丙烯酰胺-共-乙烯基吡咯烷酮）/壳聚糖[P（NIPAM-co-NVP）/CS]半互穿水凝胶。通过引入亲水性 NVP 将水凝胶的 LCST 调整到接近体温。CS 存在于半互穿网络中，由于 NAP 分子与 CS 链之间的强相互作用，改善了水凝胶的溶胀行为并提供了对阴离子药物 NAP 的高亲和力。在 pH 2.2 和 5.0 时，NAP 的释放受到抑制，而在 pH 7.4 时释放加速，这是由于 CS 中的氨基去质子化所致。当温度升高到 LCST 以上时，由于 PNIPAM 的收缩限制了药物释放，水凝胶表现出连续释放 NAP 而没有突释扩散。
