NANOCAPSULES AS CARRIERS FOR ORAL PEPTIDE DELIVERY

Nanocapsules composed of biodegradable spherical polymeric vesicles, less than 300 nm in diameter, were applied for the oral administration of peptides, especially insulin. Nanocapsules were formed by interfacial polymerisation of isobutyl 2-cyanoacrylate around a lipidic phase, the peptide being added to this latter. When administered intragastrically in diabetic rats, insulinloaded nanocapsules reduced markedly glycemia measured after an overnight fast. This effect occurred from the second day up to 20 days depending on the dose of insulin administered. In normal rats or dogs, insulin-loaded nanocapsules reduced the glucose-induced peak of hyperglycemia. Thus, nanocapsules are able to preserve the biological effect of insulin after oral administration. They protect insulin against degradation by proteolytic enzymes; they transport insulin rapidly through the intestinal epithelium; and they change the tissular distribution of iodine-125 after oral administration of labeled insulin-loaded nanocapsules. © 1990.