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在具有生物相容性的交联聚乙烯醇(CPVA)微球表面,采用铈盐-羟基氧化还原引发体系,实施了对苯乙烯磺酸钠(SSS)的表面引发接枝聚合,制得了接枝有聚阴离子的接枝微球CPVA-g-PSSS,采用红外光谱(FTIR)、扫描电子显微镜(SEM)及zeta电位测定等法,对接枝微球的化学结构及物理化学特性进行了表征.在此基础上重点考察分析了接枝微球CPVA-g-PSSS对5-氟尿嘧啶(5-FU)的吸附(载药)性能与吸附机理,考察探索了载药微球在不同pH介质中的释放行为.实验结果表明,羟基-铈盐氧化还原引发体系可有效地引发SSS在CPVA微球的表面接枝聚合,在适宜的反应条件下,可制得PSSS接枝度为16.1 g/100g的接枝微球CPVA-g-PSSS.在酸性介质中,受强静电相互作用的驱动,接枝微球CPVA-g-PSSS对5-FU分子表现出很强的吸附能力,吸附容量达105 mg/g,可实现有效载药.载药微球的释药行为具有强烈的pH依赖性,在pH=1的介质中,基本不释药;而在pH=7.4的介质中,则发生突释,表现出良好的结肠定位释放行为.
Surface-initiated graft polymerization of sodium styrenesulfonate (SSS) was carried out on the surface of biocompatible cross-linked polyvinyl alcohol (CPVA) microspheres using a cerium salt-hydroxy redox initiator system The grafted microspheres with polyanion (CPVA-g-PSSS) were characterized by FTIR, SEM and zeta potential measurements. The chemical structure and physico-chemical properties of grafted microspheres were characterized On this basis, the adsorption and drug adsorption mechanism of 5-fluorouracil (5-FU) by grafted microspheres CPVA-g-PSSS were investigated emphatically. The effects of drug loading microspheres in different pH medium The results showed that the redox initiation system of hydroxy-cerium salt could effectively initiate the surface-graft polymerization of SSS on the surface of CPVA microspheres. Under the proper reaction conditions, the graft degree of PSSS was 16.1 g / 100g Grafted microspheres CPVA-g-PSSS.In acidic medium, grafted microspheres CPVA-g-PSSS showed a strong adsorption capacity for 5-FU molecules under the action of strong electrostatic interaction with an adsorption capacity of 105 mg / g, effective drug loading can be achieved.The drug release behavior of drug-loaded microspheres is strongly pH-dependent and in pH = 1 media , The basic release drug; and pH = 7.4 in the media, the burst occurred, showing good colon positioning release behavior.