Use of insulin in diabetes: a century of treatment

Insulin is a key player in the control of hyperglycaemia for patients with type 1 diabetes mellitus and selected patients with type 2 diabetes mellitus. There have been many advances in insulin drug delivery from its first administration as a crude pancreatic extract till today. The traditional and most predictable method for administration of insulin is by subcutaneous injection. Currently available insulin delivery systems include insulin syringes, infusion pumps, jet injectors, and pens. The major drawback of insulin therapy is its invasive nature. Non-invasive delivery of insulin has long been a major goal for the treatment of diabetes mellitus. Although there have been improvements in insulin therapy since it was first conceived, it is still far from mimicking the physiological secretion of pancreatic β-cells, and research to find new insulin formulations and new routes of administration continues. This article reviews the emerging technologies, including insulin inhalers, insulin buccal spray, insulin pill, islet cell transplant, and stem cell therapy, as treatment options for diabetes mellitus.