Intranasal insulin delivery and therapy

Intranasal insulin delivery has been widely investigated as an alternative to subcutaneous injection for the treatment of diabetes. The pharmacokineti c profile of intranasal insulin is similar to that obtained by intravenous injection and, in contrast to subcutaneous insulin delivery, bears close re semblance to the 'pulsatile' pattern of endogenous insulin secretion during meal-times. The literature suggests that intranasal insulin therapy has co nsiderable potential for controlling post-prandial hyperglycaemia in the tr eatment of both IDDM and NIDDM. However, effective insulin absorption via t he nasal route is unlikely without employing the help of absorption enhance rs or promoters which are able to modulate nasal epithelial permeability to insulin and/or prolong the residence time of the drug formulation in the n asal cavity. This article discusses the structure and function of the nasal cavity, the barriers which prevent nasal insulin absorption and through th e use of absorption enhancers or promoters methods by which these barriers may be overcome. (C) 1999 Elsevier Science B.V. All rights reserved.