Oral delivery of macromolecules using intestinal patches: applications for insulin delivery

Oral drug delivery, though attractive compared to injections, cannot be utilized for the administration of peptides and proteins due to poor epithelial permeability and proteolytic degradation within the gastrointestinal tract. A novel method is described that utilizes mucoadhesive intestinal patches to deliver therapeutic doses of insulin into systemic circulation. Intestinal patches localize insulin near the mucosa and protect it from proteolytic degradation. In vitro experiments confirmed the secure adhesion of patches to the intestine and the release of insulin from the patches. In vivo experiments performed via jejunal administration showed that intestinal insulin patches with doses in the range of 1-10 U/kg induced dose-dependent hypoglycemia in normal rats with a maximum drop in blood glucose levels of 75% observed at a dose of 10 U/kg. These studies demonstrate that reduction in blood glucose levels comparable to that induced by subcutaneous injections can be achieved via enteral insulin absorption with doses only 2-10-fold higher than subcutaneous doses.