A study of insulin-chitosan complex nanoparticles used for oral administration

To develop insulin nanoparticles for oral administration, insulin loaded chitosan nanoparticles (ICN), insulin-chitosan complex nanoparticles (ICCN) and enteric coated insulin-chitosan complex nanoparticles (EICCN) were prepared, and their physicochemical characteristics, drug release in vitro and hvpoglycemic effects on normal rats were evaluated. The particle sizes of the ICN, ICCN and EICCN were 265 +/- 14, 284 +/- 19 and 342 +/- 23 nm, respectively, and the zeta potential of the three kinds of nanoparticles were 40.7 +/- 0.7, 31.3 +/- 0.4 and 34.1 +/- 0.9 mv, respectively. The entrapment efficiencies of different nanoparticles were 66.8 +/- 2.1, 81.3 +/- 2.6 and 81.5 +/- 3.1%, respectively. The accumulated percentages of release of insulin from the three kinds of nanoparticles at 2 h were 49, 34.24 and 24.9%, respectively. The bioavailabilities of oral ICN, ICCN and EICCN compared with the SC injection of an insulin solution in Wistar rats were 5.58 +/- 0.7, 7.55 +/- 0.9 and 8.33 +/- 0.5% over 48 h, respectively. These results indicated that the insulin-chitosan complex and the enteric coating were useful to reduce the initial burst of insulin and enhance the bioavailability of oral insulin preparations.