Insulin administration: present strategies and future directions for a noninvasive (possibly more physiological) delivery

Abstract

Elena Matteucci,1 Ottavio Giampietro,1 Vera Covolan,2 Daniela Giustarini,3 Paolo Fanti,4 Ranieri Rossi3 1Department of Clinical and Experimental Medicine, 2Department of Chemistry and Industrial Chemistry, University of Pisa, 3Department of Life Sciences, Laboratory of Pharmacology and Toxicology, University of Siena, Siena, Italy; 4Division of Nephrology, University of Texas Health Science Center San Antonio, South Texas Veteran Health Care System, San Antonio, Texas, USA Abstract: Insulin is a life-saving medication for people with type 1 diabetes, but traditional insulin replacement therapy is based on multiple daily subcutaneous injections or continuous subcutaneous pump-regulated infusion. Nonphysiologic delivery of subcutaneous insulin implies a rapid and sustained increase in systemic insulin levels due to the loss of concentration gradient between portal and systemic circulations. In fact, the liver degrades about half of the endogenous insulin secreted by the pancreas into the venous portal system. The reverse insulin distribution has short- and long-term effects on glucose metabolism. Thus, researchers have explored less-invasive administration routes based on innovative pharmaceutical formulations, which preserve hormone stability and ensure the therapeutic effectiveness. This review examines some of the recent proposals from clinical and material chemistry point of view, giving particular attention to patients’ (and diabetologists’) ideal requirements that organic chemistry could meet. Keywords: type 1 diabetes mellitus, drug formulations, drug administration routes, insulin, portal system, nanoparticles, biodegradable polymers