Preparation of insulin loaded PLGA-Hp55 nanoparticles for oral delivery

The aim of the present work was to investigate the preparation of PLGA nanoparticles (PNP) and PLGA-Hp55 nanoparticles (PHNP) as potential drug carriers for oral insulin delivery. The nanoparticles were prepared by a modified emulsion solvent diffusion method in water, and their physicochemical characteristics, drug release in vitro and hypoglycemic effects in diabetic rats were evaluated. The particle sizes of the PNP and PHNP were 150 +/- 17 and 169 +/- 16 nm, respectively, and the drug recoveries of the nanoparticles were 50.30 +/- 3.1 and 65.41 +/- 2.3%, respectively. The initial release of insulin from the nanoparticles in simulated gastric fluid over 1 h was 50.46 +/- 6.31 and 19.77 +/- 3.15%, respectively. The relative bioavailability of PNP and PHNP compared with subcutaneous (s.c.) injection (1 IU/kg) in diabetic rats was 3.68 +/- 0.29 and 6.27 +/- 0.42%, respectively. The results show that the use of insulin-loaded PHNP is an effective method of reducing serum glucose levels. (c) 2006 Wiley-Liss, Inc.