Improving oral hypoglycemic effect of insulin by utilizing of nanoemulsions coated with alginate-chitosan

摘要

Purpose:This study aimed to prepare a new lipidnanoemulsion coated with alginate-chitosan for oral insulin. Methods:Multi-emulsion was prepared by two step method, constituting of Labrafac CC, phospholipid, Span80 and Cremorphor EL. After homogenization of multi-emulsion, 0.067% alginate sodium, 0.1% calcium chloride and 0.06% chitosan were added to coat the nanoemulsion. The coated and uncoated nanoemulsions were characterized by size and TEM. The in vitro and in vivo properties were further studied respectively. Results:The size of coated nanoemulsion was 488nm and the insulin entrapment ratio was 47.3%. In vitro release experiment, insulin was prevented greatly in low pH and released quickly in higher pH (pH6.8 and 7.4), which indicated outstanding protection in gastric fluid. Wonderful hypoglycemic effects were observed in vivo experiment of both normal and diabetic rats. The relative bioavailability of 25IU/Kg and 50IU/Kg dose of coated nanoemulsion were 8.42% and 5.72% in normal rats, 8.19% and 7.84% in diabetic rats respectively. Conclusions: The nanoemulsion coated with alginatechitosan was an potential delivery system for improving oral absorption of polypeptides and peptides.