A cell-penetrating peptide mediated chitosan nanocarriers forimproving intestinal insulin delivery

To overcome barriers for oral delivery of insulin, the chitosan(CS)-based nanocarriers with a novel cell penetrating peptide (SAR6EW) have been prepared and evaluated in this study. Characterization measurements showed that SAR6EW/CS/insulin-NPs displayed global particles with smooth surfaces and an average diameter about 150 nm. The entrapment efficiency and loading rates of insulin were 75.36% and 7.58%, respectively. Insulin could be released constantly from SAR6EW/CS/insulin-NPs in vitro. Furthermore, SAR6EW/CS/insulin-NPs could facilitate the uptake of insulin and induce a significantly higher internalization of insulin via adding clathrin and caveolae mediated endocytosis. In addition, in vivo hypoglycemic studies showed that orally administrated SAR6EW/CS/insulin-NPs produced a better hypoglycemic effect as compared with CS/insulin-NPs in diabetic rats. Meanwhile, no significant cytotoxicity of the nanoparticles was observed. In conclusion, SAR6EW-mediated chitosan nanocarriers showed sufficient effectiveness for oral delivery of insulin. This delivery system is also promising for the delivery of other protein drugs by oral administration. (C) 2017 Elsevier Ltd. All rights reserved.