Physico-chemical characterization of insulin-loaded poly(isobutylcyanoacrylate) nanocapsules obtained by interfacial polymerization

Insulin could be encapsulated very efficiently in oily containing poly(isob utylcyanoacrylate) nanocapsules obtained by interfacial polymerization. In addition, these nanocapsules showed unexpected biological activity after in tragastric administration. The hypoglycemic effect was characterized by a l ag time period of 2 days and a prolonged effect over a period of 20 days. T o explain, the high encapsulation rate of insulin achieved in these nanocap sules and the biological effect, this work was focused on the characterizat ion of the nanocapsules and on the study of the mechanism of nanocapsule fo rmation. Results showed that insulin was found unmodified during the nanoen capsulation process. This was due to the large amount of ethanol used in th e preparation of the nanocapsules that initiated the polymerization of isob utylcyanoacrylate preserving the peptide from a reaction with the monomer. Results also showed that insulin was located inside the core of the nanocap sules and not simply adsorbed onto their surface. (C) 1999 Elsevier Science B.V. All rights reserved.