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目的利用酰化反应合成维生素E-琥珀酰聚赖氨酸接枝共聚物(N-tocopheryl-N’-succinyl-ε-polylysine,TOS-SA-PLL)作为载体材料,胰岛素作为模型药物,制备p H敏感接枝共聚物囊泡。方法采用核磁共振扫描和红外光谱对接枝共聚物TOS-SA-PLL结构进行表征;利用2,4,6-三硝基苯磺酸法对接枝共聚物的取代度进行测定;利用动态光散射法对囊泡的粒径,多分散性和Zeta电位进行测定;采用超滤离心法测定囊泡的包封率和载药量以及载药囊泡在不同p H条件下的体外释药行为。结果接枝共聚物自组装形成的囊泡平均粒径为165.7~232.3 nm,Zeta电位为-32.2~-20.1 m V;载胰岛素共聚物囊泡的包封率最高可达70.15%,载药量(w)为6.55%;体外释放结果表明该接枝共聚物囊泡的释放行为具有p H敏感性的特征。结论 TOS-SA-PLL接枝共聚物囊泡具有p H敏感的特点,其作为水溶性生物大分子药物的载体,在胃肠道传递领域具有较好的应用前景。
OBJECTIVE To synthesize p-vitamin-E-succinyl poly-lysine (TOS-SA-PLL) as a carrier by acylation and insulin as a model drug to prepare p H-sensitive graft copolymer vesicles. Methods The structure of graft copolymer TOS-SA-PLL was characterized by 1H-NMR and FT-IR spectroscopy. The degree of substitution of graft copolymer was measured by 2,4,6-trinitrobenzenesulfonic acid method. The particle size, polydispersity and Zeta potential of the vesicles were determined by the scattering method. The entrapment efficiency and drug loading of the vesicles were determined by ultrafiltration centrifugation and the drug release behavior of vesicles in vitro under different p H . Results The average diameter of vesicles formed by self-assembly of graft copolymer was 165.7 ~ 232.3 nm and Zeta potential was -32.2 ~ -20.1 mV. The entrapment efficiency of vesicles containing insulin copolymer was up to 70.15% (w) was 6.55%. The in vitro release results showed that the release behavior of the graft copolymer vesicles was p H-sensitive. Conclusions TOS-SA-PLL grafted copolymer vesicles have p H-sensitive characteristics. As a carrier of water-soluble biopolymer drugs, TOS-SA-PLL graft copolymer has good application prospect in the field of gastrointestinal tract transmission.