Abstract: Using sodium borohydride as reducing agent, N-mPEG-grafted O-quaternized chitosan was synthesized by grafting mPEG-CHO onto O-quaternized chitosan by the Schiff base reaction. Divinyl sulfone cross-linked N-mPEG grafting O-quaternized chitosan microspheres were prepared by inverse suspension. Using ketoprofen as model drugs, the drug-loading capacity and release behavior of the microsphere was investigated. Experimental results indicated that introduction of quaternary ammonium groups and mPEG increased the drug loading with maximum capacity of 4.31 mg/mg. In vitro release results showed that N-mPEG-O-quaternized chitosan microspheres had better sustained-release performance in simulated intestinal fluid than in simulated gastric fluid, and the microspheres had pH- responsive capability.

Key words: chitosan, PEG, O-quaternized, microsphere, controlled release

摘要： 将聚乙二醇单甲醚（mPEG）醛化改性后，通过西佛碱反应接枝到自制的O-季铵化壳聚糖的NH2上，硼氢化钠还原制得N-mPEG接枝O-季铵化壳聚糖（QACS-mPEG），反相悬浮法制备二乙烯基砜交联QACS-mPEG微球。用FTIR、1 H NMR、EA和SEM对产物进行表征，并且以酮洛芬为模型药物研究微球的载药性能及释放行为。结果表明，mPEG和季铵盐基团的引入提高了N-mPEG-O-季铵化壳聚糖微球的载药量，为4.31mg/mg；载药N-mPEG-O-季铵化壳聚糖微球在模拟肠液的缓释效果优于胃液，微球释药具有pH响应性。

关键词: 壳聚糖, 聚乙二醇接枝, 季铵化改性, 微球, 载药性能