Published Paper Details:

Diabetes mellitus is a metabolic disorder, caused by dysfunction of insulin secretion or insulin function or both, leading to persistent hyperglycemia and other vascular complications as the disease progresses. Several factors contribute to the progression of the disease, such as family history or genetics, environmental factors, and various genetic disorders. A sedentary lifestyle, unhealthy diet, physical inactivity, and obesity are the major responsible factors. Treatment of diabetes is started with the use of drugs such as metformin, Sulfonylureas, thiazolidinediones, SGLT-2 inhibitors, DPP-4 antagonists, etc. Moreover, cell-based treatments such as the pancreas or pancreatic cell transplantations are being explored broadly for the treatment of type-1 diabetes mellitus. Whereas, insulin is the major player in the treatment of diabetes mellitus. For several decades, insulin has been administered as a subcutaneous injection, several times a day. However, the subcutaneous route has several limitations, such as pain at the injection site, infections due to improper administration/self-administration, hypertrophy due to deposition of insulin at the site of injection, patient discomfort; fail to achieve blood glucose control in several patients. This led to the exploration of alternative routes for insulin delivery, soon after its discovery. Various non-invasive and novel routes have been studied, including oral route, nasal route, pulmonary, transdermal route, and buccal, ocular, intrauterine, and rectal routes. These routes have proven successful up to some extent and several complications are also associated with these novel delivery systems. Toxicity associated with long-term use, safety and efficacy studies, feasible formulation of these delivery systems for efficient human use, still need to be explored deeply. In this review, we will study diabetes mellitus, alternative insulin delivery routes, and various advantages and disadvantages associated with formulations of these routes.