Abstract
The aim of this paper is to highlight the ideal prerequisites for an oral insulin formulation to exert its maximal effect, by delivering insulin via the portal vein directly to the liver. A description is provided of the resulting differences in the way in which oral and injected insulins act, in order to treat type 2 diabetes. Key among these differences is the ability of the liver to control its activity in accord with the glucose concentration in the bloodstream, as a result of insulin entering the liver via the portal vein, and stimulating generation of glucokinase. The advantages this confers on multiple aspects of treatment of patients (safety, dosing, reproducibility etc) are outlined in detail. Separately, the way in which insulin, administered via the upper intestine, may overcome insulin resistance is discussed. Finally, a case is made for oral insulin to be employed for treatment of type 1 diabetes, gestational diabetes, and for co-administration with certain other anti-diabetes agents.