Chen Yanmin, Sun Peijian
College of Chemistry and Chemical Engineering, Zhengzhou Normal University, No.6 Yingcai Street, Zhengzhou 450044, China.
Zhengzhou Tobacco Research Institute of CNTC (China National Tobacco Corporation), No. 2 Fengyang Street, Zhengzhou 450001, China.
Polymers (Basel). 2019 Feb 8;11(2):285. doi: 10.3390/polym11020285.
pH-sensitive polyampholyte microgels of poly(acrylic acid--vinylamine) (P(AA--VAm)) were developed as an injectable hydrogel for controlled drug release. The microgels of P(AA--VAm) were prepared via inverse suspension polymerization of acrylic acid and N-vinylformamide followed by hydrolysis of poly(-vinylformamide) (PNVF) chains of the resultant microgels under basic condition. The pH-sensitivity of the P(AA--VAm) microgels in zeta potential and swelling ratio were investigated using a zeta potential analyzer and optical microscope. The results showed that both the zeta potential and the swelling ratio of the microgels were highly affected by the solution pH. By changing the pH of P(AA--VAm) microgel dispersion, the interparticle interaction and the swelling ratio of the microgels could be well adjusted and a colloidal hydrogel could be fabricated at moderate pH, showing a pH-triggered reversible fluid-gel transition. Using the polyampholyte P(AA--VAm) microgels as an injectable hydrogel drug release system, a sustained drug release could be achieved, indicating the great potentials of the pH-sensitive P(AA--VAm) microgels for controlled drug delivery.
聚（丙烯酸-乙烯胺）（P(AA-VAm)）的pH敏感型聚两性电解质微凝胶被开发为一种用于药物控释的可注射水凝胶。P(AA-VAm)微凝胶通过丙烯酸和N-乙烯基甲酰胺的反向悬浮聚合制备，然后在碱性条件下将所得微凝胶的聚（N-乙烯基甲酰胺）（PNVF）链水解。使用zeta电位分析仪和光学显微镜研究了P(AA-VAm)微凝胶在zeta电位和溶胀率方面的pH敏感性。结果表明，微凝胶的zeta电位和溶胀率均受溶液pH的高度影响。通过改变P(AA-VAm)微凝胶分散液的pH值，可以很好地调节微凝胶的颗粒间相互作用和溶胀率，并且可以在中等pH值下制备胶体水凝胶，显示出pH触发的可逆流体-凝胶转变。使用聚两性电解质P(AA-VAm)微凝胶作为可注射水凝胶药物释放系统，可以实现药物的持续释放，表明pH敏感型P(AA-VAm)微凝胶在药物控释方面具有巨大潜力。
