口服胰岛素纳米脂质体的制备及其降血糖作用

Preparation of Oral Insulin Nano-liposomes and Its Hypogly-cemic Effect

目的 :改进胰岛素纳米脂质体的制备方法 ,考察脂质体经正常大鼠小肠给药和灌胃给药的降血糖效果。方法 :通过改变油相容积及油 /水相比例 ,采用逆相蒸发 -超声法制备了胰岛素纳米脂质体 ;测定了纳米脂质体的包封率 ;通过灌胃和小肠途径 ,给正常大鼠以 350 IU/ kg的剂量 ,用酶 -苯酚法测定大鼠血糖 ,并与空白纳米脂质体、胰岛素溶液及生理盐水相比较。结果 :胰岛素纳米脂质体的平均粒径为 83.3nm,多分散系数为 0 .4 45,包封率为 78.5% ;大鼠灌胃给药后未能显示降血糖作用 ,但小肠给药后 0 .2 5h血糖下降 37.6%± 1 3.9% ,0 .5h血糖下降了 89.3%± 9.5% ,维持 50 %左右降血糖水平 2 h,而同法给予的胰岛素溶液、生理盐水和空白纳米脂质体组均无降血糖作用。结论 :实验初步证实制备的纳米脂质体可以保护胰岛素在小肠中的活性并促进胰岛素吸收。

AIM: The present reseach was developed to prepare lecithin nano liposomes encapsulating insulin and evaluate the enhancing effect of these vesicles on the absorption of hydrophilic proteins in the intestine. METHODS: Insulin nano liposomes were prepared by reverse phase evaporation and treated further by sonication. The content and entrapment efficiency of nano liposomes were analyzed by HPLC. When liposomes were applied to the rats at a dose of 350IU/kg through both directly into the intestine and i.g. \%in vivo\%, the hypoglycemic effect was investigated. RESULTS: The particle size of nano liposomes was 83.3nm with polydispersity index of 0.445. The entrapment efficiencies of nano liposomes were 78.5%. In vivo hypoglycemic study showed the level of blood glucose reduced by nano liposomes was 37.6%±13.9% at 0.25 h, reached 89.3%±9.5% at 0.5 h and remained less than 50% within 2 h. Blank nano liposomes, insulin solution and saline had no hypoglycemic effect. CONCLUSION: Nano liposomes may become a promising carrier for enhancing absorption of hydrophilic proteins in intestine.