磁性壳聚糖-聚丙烯酸载药微球的释放性能研究

The release properties of magnetic chitosan-poly(acrylic acid)(PAA) microspheres

对合成的壳聚糖-聚丙烯酸及磁性壳聚糖-聚丙烯酸微球用扫描电镜进行形貌观察,并测定了磁性壳聚糖-聚丙烯酸微球的热稳定性.以牛血清白蛋白（BSA）为模拟蛋白药物,研究了载有BSA的磁性壳聚糖-聚丙烯酸微球的释放性能.结果表明,壳聚糖-聚丙烯酸共聚物外形呈片层状;而磁性壳聚糖-聚丙烯酸微球为致密微球,粒径约在100～400nm之间,具有较好的分散性,磁性壳聚糖-聚丙烯酸微球在温度区间（0～135℃）内具有良好的热稳定性.载有BSA的磁性微球在模拟肠液中刚开始时有一个突释过程,之后缓慢释放,在6h左右达到了平衡,最终释放率可达到80.5%;而在模拟胃液中几乎没有释放,平衡释放率只有5.8%.

In this study, the shapes of chitosan（CS）-poly（acrylic acid） （PAA） suspension and magnetic chitosan （CS）-poly（acrylic acid）（PAA）microspheres which had been synthesized were investigated by using SEM. The thermal stability of magnetic CS-PAA mirospheres was measured, too. The results showed that the CS-PAA has the shape of flakes, while the magnetic CS-PAA microspheres prepared were well shaped and compact spheres. The size of magnetic CS-PAA mcirospheres is in the range 100nm to 400nm with a rather narrow distribution. As far as the thermal stability concerned, The magnetic CS-PAA microspheres were stable under 135℃. Finally the magnetic chitosan（CS）-poly（acrylic acid）（PAA） microspheres were loaded with Bovine Serum Albumin （BSA） as model drug, and Their release properties were performed in different pH conditions besides both the simulated gastric and intestinal pH conditions. The results showed that the magnetic CS-PAA microspheres was responsive to pH, and the equilibrium release rate reached 80. 5% in simulated intestinal solution, while only 5. 8% in simulated gastric solution.