【摘要】 以壳聚糖和甲基丙烯酸为原料,硝酸铈铵为引发剂,合成了不同接枝率的壳聚糖-g-聚甲基丙烯酸(CS-g-PMAA),用FTIR、1H NMR和元素分析表征了产物的结构,以柠檬酸三钠和戊二醛为交联剂制备了具有核壳结构的CS-g-PMAA载药体系。用UV/Vis检测了CS-g-PMAA粒子对模型药物的释放行为。结果表明,CS-g-PMAA接枝率为12.21%时药物释放速率最慢,其在pH=1.8介质中药物累积释放量(11 h)为44.18%,而壳聚糖粒子的累积释放量高达65.24%,即接枝改性壳聚糖粒子对药物的缓慢控制释放性能较好;CS-g-PMAA粒子的释药行为还依赖于介质的pH值和盐浓度,在低pH值和低盐浓度下,药物释放速率较快;酶环境下由于载体材料的降解使药物释放速率加快。分析了不同条件下CS-g-PMAA载药粒子中药物的释放机理。更多还原

【Abstract】 Chitosan grafted poly(methacrylic acid)(CS-g-PMAA) was synthesized using methacrylic acid and chitosan as precursors and cerium ammonium nitrate as initiator.Products with different grafting degree were characterized by means of FTIR,1H NMR and elemental analysis.Drug-loaded beads made from the as-prepared copolymers were fabricated by combining ionic-crosslink with chemical-crosslink using trisodium citrate and glutaraldehyde as crosslinking agent,respectively.The beads have a core-shell structure as revealed from scanning electron microscopy.The release behaviors of model drug incorporated in the beads were monitored using UV/Vis spectrophotometer and found to be dependent on pH and NaCl content.The results show that the drug release rate is slowest for CS-g-PMAA beads with grafting fraction(Gg) of 12.21%.The total drug release fraction for the CS-g-PMAA beads is 44.18% at pH=1.8 and is less than that of CS beads,which is 65.24%.Therefore,the grafting of CS could improve the drug release behavior.In addition,CS-g-PMAA beads have higher enzymatic stability than that of CS beads.更多还原