Osváth Zsófia, Tóth Tamás, Iván Béla
Polymer Chemistry Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1117, Budapest, Magyar tudósok krt. 2, Hungary.
Macromol Rapid Commun. 2017 Mar;38(6). doi: 10.1002/marc.201600724. Epub 2017 Feb 6.
Poly(N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate), P(NIPAAm-co-TMSPMA), copolymers with relatively high TMSPMA contents without insoluble fraction are successfully synthesized. Subsequent sol-gel reactions in both the absence and presence of tetraethyl orthosilicate lead to gels with high gel fractions. The resulting gels undergo gel collapse at 28.6-28.7 °C, i.e., below that of poly(N-isopropylacrylamide) homopolymer of 34.3 °C. Unexpectedly, the theophylline-loaded hybrid gels release the drug not only below but also above the gel collapse temperature (GCT) with considerable rates and released amounts of drug. Surprisingly, evaluation of the sustained release profiles by the Korsmeyer-Peppas equation indicates that the release occurs by Fickian diffusion above GCT, which can be attributed to the lack of significant drug-polymer interaction at such temperatures. These results can be widely applied for the design and utilization of TMSPMA-based sol-gel polymer hybrids with desired release profiles of solutes below and above GCT for a variety of applications.
成功合成了具有相对较高甲基丙烯酸3-(三甲氧基硅基)丙酯（TMSPMA）含量且无不溶物的聚（N-异丙基丙烯酰胺-co-甲基丙烯酸3-(三甲氧基硅基)丙酯），即P（NIPAAm-co-TMSPMA）共聚物。在有无原硅酸四乙酯的情况下进行后续的溶胶-凝胶反应，均能得到具有高凝胶分数的凝胶。所得凝胶在28.6 - 28.7℃发生凝胶塌陷，即低于聚（N-异丙基丙烯酰胺）均聚物的34.3℃。出乎意料的是，负载茶碱的杂化凝胶不仅在凝胶塌陷温度（GCT）以下，而且在该温度以上均以相当的速率和释放量释放药物。令人惊讶的是，通过Korsmeyer-Peppas方程对缓释曲线的评估表明，在GCT以上，释放是通过菲克扩散发生的，这可归因于在此温度下药物与聚合物之间缺乏显著的相互作用。这些结果可广泛应用于基于TMSPMA的溶胶-凝胶聚合物杂化材料的设计和利用，以实现各种应用中溶质在GCT以下和以上具有所需释放曲线。
