Yuan Hui-yan, Zhang Yuan, Fan Tian-yuan
Department of Pharmaceutics, Peking University School of Pharmaceutical Sciences, Beijing 100191, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2009 Apr 18;41(2):217-20.
To develop and study the properties of ion-exchange polyvinyl alcohol-acrylic acid microspheres (PVA-AA-Ms) for embolization.
The PVA-AA-Ms were produced by the method of inverse suspension polymerization. The morphology and particle size were determined by optical microscope; FT-IR was used to investigate the special functional groups of PVA-AA-Ms; the carboxyl content of PVA-AA-Ms was measured by chemical titration; the compression elasticity was examined by texture analyzer (TA-plus). Pingyangmycin (bleomycin A(5)) was used as model drug to prepare drug-loaded PVA-AA-Ms. Drug loading and entrapment efficiency were measured through UV-spectrophotometer; in vitro drug release characteristic was detected by constant temperature vibration dialysis assay.
The PVA-AA-Ms were round and integrated. The average diameter of PVA-AA-Ms was 500 microm with a range of 150-1 000 microm. The carboxyl vibration was demonstrated by FT-IR and the content of carboxyl was 8.905 mmol/g. PVA-AA-Ms were mechanically stable with appropriate elasticity. Drug loading and entrapment efficiency were 30 g/L and 99.4%, respectively. The drug release rate was slow in phosphate buffer solution (PBS), 88.3% of the drug was released after 24 h and the t(50) was 2.19 h.
PVA-AA-Ms prepared in this study were supposed to be suitable for clinical embolization according to the physicochemical properties. The high carboxyl content of PVA-AA-Ms which allowed them to load cationic drugs (e.g., drug with amino group) through ion-exchange mechanism brought broad prospects for combination of embolization and chemotherapy.
制备并研究用于栓塞的离子交换聚乙烯醇 - 丙烯酸微球（PVA - AA - Ms）的性能。
采用逆相悬浮聚合法制备PVA - AA - Ms。通过光学显微镜测定其形态和粒径；利用傅里叶变换红外光谱（FT - IR）研究PVA - AA - Ms的特殊官能团；采用化学滴定法测定PVA - AA - Ms的羧基含量；通过质构分析仪（TA - plus）检测其压缩弹性。以平阳霉素（博来霉素A5）为模型药物制备载药PVA - AA - Ms。通过紫外分光光度计测定载药量和包封率；采用恒温振动透析法检测体外药物释放特性。
PVA - AA - Ms呈圆形且完整。PVA - AA - Ms的平均直径为500μm，范围为150 - 1000μm。FT - IR证实了羧基振动，羧基含量为8.905 mmol/g。PVA - AA - Ms具有机械稳定性且弹性适宜。载药量和包封率分别为30 g/L和99.4%。在磷酸盐缓冲溶液（PBS）中药物释放缓慢，24 h后88.3%的药物释放，t(50)为2.19 h。
根据理化性质，本研究制备的PVA - AA - Ms适用于临床栓塞。PVA - AA - Ms的高羧基含量使其能够通过离子交换机制负载阳离子药物（如含氨基的药物），为栓塞与化疗联合应用带来广阔前景。
