羧甲基壳聚糖-聚乙二醇作为胰岛素载体的研究

目的：制备胰岛素-羧甲基壳聚糖-聚乙二醇纳米粒。方法：利用红外光谱（FTIR）和核磁共振氢谱（¹H-NMR）对羧甲基壳聚糖-聚乙二醇的结构进行表征，用粒度分析仪测定纳米粒的粒径分布及电位，采用动态透析法考察纳米粒的释药性能，用CCK-8试剂盒检测纳米粒细胞毒性，以糖尿病小鼠为模型，研究纳米粒的降血糖作用。结果：聚乙二醇成功接枝到羧甲基壳聚糖上，包埋胰岛素的纳米粒的平均粒径为（257.5±12.1）nm，Zeta电位为（-15.2±0.3）mV，负载胰岛素的羧甲基壳聚糖-聚乙二醇纳米粒在中性释放介质中，5 h内胰岛素的释放速度较快，之后8 h趋于平稳，胰岛素的累计释放量可达到80%，CCK-8试剂盒显示纳米粒对L929细胞基本无细胞毒性，50 U·kg^-1的纳米粒溶液经灌胃给药后，血糖浓度明显降低。结论：胰岛素-羧甲基壳聚糖-聚乙二醇纳米粒基本无毒性，具有良好的生物相容性，对糖尿病小鼠有效发挥降血糖作用。

Preparation and characterization of PEG coupled carboxymethyl chitosan carrier for insulin

OBJECTIVE To prepare insulin loaded polyethylene glycol-carboxymethyl chitosan nanoparticles (CMCS-mPEG/insulin NPs).METHODS The structure of CMCS-mPEG was confirmed by FTIR and ¹H-NMR spectroscopy.The size distribution and zeta potential of CMCS-mPEG/insulin NPs were evaluated by laser particle size determination,drug-loading rate was determined by dynamic dialysis method,the cytotoxicity of nanoparticles was detected by CCK-8 kit,hypoglycemic activity was evaluated by montoring the blood sugar level of alloxan-induced diabetic mice.RESULTS PEG was successfully grafted to carboxymethyl chitosan.The average diameter of the nanoparticles was (257.5±12.1) nm,the mean electric potential was (-15.2±0.3) mV.Insulin realease in vitro exhibitted a rapid release in neutral medium in the frist five hours,and then became slow in the next eight hours,and the cumulative release rate of insulin was up to 80%.CCK-8 assay demonstrated that nanoparticles showed almost no toxicity to L929 cells.The blood glucose concentration was significantly decreased after intragastric administration of nanoparticles.CONCLUSION CMCS-mPEG/insulin nanoparticles with good biocompatibility and very low toxicity show effective hypoglycemic activity after oral administration in diabetic mice.