由CPVA-g-PSSS功能接枝微球构建pH依赖型5-ASA结肠定位释药体系

采用铈盐-羟基氧化还原引发体系，在交联聚乙烯醇(CPVA)微球表面引发接枝聚合对苯乙烯磺酸钠(SSS)，制备了接枝聚阴离子的功能接枝微球CPVA-g-PSSS，研究了其对5-氨基水杨酸(5-ASA)的吸附(载药)性能、机理和释放行为. 结果表明，在酸性介质中，受强静电相互作用驱动，CPVA-g-PSSS对5-ASA分子表现出很强的吸附能力，吸附容量达39.1 mg/g，可实现有效载药. 载药微球的释药行为具有强烈的pH值依赖性, 在pH=1的介质中基本不释药，而在pH=7.4的介质中发生突释，释放率可达86%，表现出良好的结肠定位释放行为.

Construction of Colon-specific Drug Delivery System with pH-dependency 5-ASA Using Grafted CPVA-g-PSSS Microspheres

The graft-polymerization of sodium 4-styrene sulfonate(SSS) was performed on the surface of crosslinked polyvinyl alcohol(CPVA) microspheres with cerium salt-hydroxyl group redox initiation system,the grafted CPVA-g-PSSS microspheres with strong anionic polyelectrolyte PSSS were obtained.On this basis,the adsorption property of the microspheres for 5-amino salicylic acid(5-ASA),namely drug carrying ability,was investigated and the adsorption mechanism analyzed.The in vitro release behavior of the drug-carried microspheres was also examined.The experimental results show that the grafted CPVA-g-PSSS microspheres exhibit very strong adsorption ability for 5-ASA by driving of electrostatic interaction in the acidic medium.Their adsorption capacity can reach 39.1 mg/g,displaying a high efficiency of drug-loading.Their in vitro release behavior is highly pH-dependent.In the medium of pH=1,the drug is not released,while in that of pH=7.4,the burst release occurs,displaying an excellent colon-specific drug delivery behavior.