Oral insulin-delivery system for diabetes mellitus.

Current insulin therapy for diabetes mellitus involves frequent dosing of subcutaneous injections, causing local discomfort, patient noncompliance, hypoglycemia and hyperinsulinemia, among others. While noninvasive therapy through oral delivery is greatly desired, there are challenges that include low bioavailability due to rapid enzymatic degradation in the stomach, inactivation and digestion by proteolytic enzymes in the intestinal lumen, poor permeability across the intestinal epithelium and poor stability. This article reviews patents that provide novel approaches for oral insulin delivery to the bloodstream through the GI tract.