接枝共聚物瓜耳胶-g-丙烯酰胺-丙烯酸的制备及pH敏感性研究

目的制备pH敏感型聚合物瓜耳胶-g-丙烯酰胺-丙烯酸(GG-g-PAAm-AAc,GPAA),并对其结构进行表征。方法采用链引发聚合法制备GPAA;用IR及NMR对GPAA结构进行表征;由元素分析结果计算丙烯酰胺接入率;端基滴定法测定丙烯酸的接入率。以酮洛芬为模型药物,GPAA为骨架材料制备酮洛芬脉冲控释片,采用γ闪烁示踪技术对其体内释药情况进行研究。结果GPAA中丙烯酰胺的接入率为36.4%,丙烯酸的接入率为24.7%;酮洛芬脉冲控释片在胃内基本不释药,进入小肠后,药物逐渐释放,亮点逐渐扩散,7 h药物已释放大部分。结论作者合成的GPAA具有明显的pH敏感性,是一种碱敏感型聚合物,具有广阔的应用前景。

Design and study on the pH sensitive polymer of guar gum-g-polyacrylamide-acrylic acid

Objective to synthesize pH-sensitive polymer guar gum-g-polyacrylamide-acrylic acid, (GG-g-PAAm-AAc, GPAA), and investigate its pH-sensitivity in controlled-release drug. Methods The polymer was synthesized with the method of chain initiation using acrylamide (AAm) and acrylic acid (AAc) as monomers at the presence of Ce6+ as initiator. IR and ¹³C-NMR were applied to characterize the new copolymer; the element-analysis data was used to calculate the mass of AAm grafted in the GPAA; the content of carbonyl group grafted in the GPAA was determined by titration analysis. The properties of ketoprofen release from GPAA hydrogel were studied by Gamma-scintigraphic trace evaluation. Results The grafted polymer was successfully synthesized and characterized by IR and 13CNMR. Element-analysis indicated that the contents of the C, N and H in the GPAA were 44.9%, 7.2% and 5.5%, respectively. The contents of AAm and AAc in the GPAA were 36.4% and 24.7%, respectively. The Gamma-scintigraphic trace evaluation demonstrated that the impulse control released tablets could disintegrate at ileum and release completely in colon. Conclusions GPAA, which is pH-sensitive because of the exist of carbonyl group, can be used as the carrier in the impulse controlled- release drug delivery system and will be widely used in many fields.