Niosomes for oral delivery of peptide drugs

Abstract

One of the great challenges in drug delivery is the administration of peptide and protein drugs by the peroral route [ 11. There are several possibilities by which the bioavailability of these drugs might be increased. In previous investigations intestinal absorption of 9-desglycinamide 8-arginine vasopressin (DGAVP) administered in bioadhesive drug delivery systems was studied in vitro, in situ and in vivo [ 2-41. Bioadhesive drug delivery systems are assumed to stick to the intestinal mucosa which might result in an increase in absorption of the peptide across the mucosa due to the intimate contact between delivery system and absorbing membrane and/or to a prolonged residence time at the site of absorption. The absorption studies were carried out with microspheres consisting of phydroxyethylmethacrylate with or without bioadhesive polycarbophil (weakly crosslinked polyacrylic acid) coating. In vitro the bioadhesive beads resulted in a significantly higher absorption of DGAVP compared to uncoated beads. However, in vivo after direct intraduodenal administration to rat