含L-乳酸基的聚丙三醇水凝胶的合成及性能

Synthesis and Properties of Novel Polyglycerol Hydrogels Containing L-Lactic Acid Groups

以L-乳酸和环氧氯丙烷等为原料,设计合成出含L-乳酸基的聚丙三醇水凝胶.用核磁共振碳谱、X射线光电子能谱和扫描电镜表征了其结构和形貌.通过控制反应条件,合成了不同L-乳酸基含量和平衡溶胀率的聚丙三醇水凝胶.化学滴定分析表明,在选定的合成条件下,L-乳酸基的引入率约为87%,其含量可达到17%.溶胀实验结果表明,凝胶具有显著的pH和离子强度敏感性及快速可逆的响应速率.体外释药实验结果显示,载药凝胶具有随溶胀环境pH值变化的释药性能.

Novel pH-sensitive polyglycerol hydrogels were designed and synthesized through the reaction of epichlorohydrin（ECH） with L-lactic acid（LLA） in the presence of sodium hydroxide（NaOH）,and cetyltri-methylammonium bromide（CTAB） as a phase transfer catalyst（PTC） at room temperature,followed by hydrolysis,polymerization and cross-linking reactions.The resultant gel was characterized by 13C NMR and X-ray photoelectron spectroscopy,and it was found that incorporated LLA was bound to polyglycerol network as a pendant acidic substituent by the hydroxyl group of LLA（PGL gel）.The PGL hydrogels with different LLA contents and equilibrium swelling ratios were prepared by changing the feed ratios of materials.The results determined by chemical titration show that under the applied conditions the efficiency of introducing the carboxyl group into polyglycerol network is ca.87% and the amount of LLA in the hydrogel reached to ca.17%.The swelling behavior of the hydrogels in different mediums was investigated.The results show that the hydrogels are pH-,and ionic strength-responsive.The hydrogels also have the reversible swelling/deswelling properties and exhibits modulated release of drug in response to the environment pH.