Oral Insulin: Myth or Reality

Background: Diabetes Mellitus (DM) is a disorder of glucose metabolism marked by hyperglycemia, glycosuria, hyperlipidemia, negative nitrogen balance and ketonaemia. DM is a major healthcare problems today and its treatment costs billions of dollars worldwide annually. The cases of diabetes have increased rapidly in recent years throughout the world. Currently, for the management of Type-1 Diabetes Mellitus (TIDM), Multiple Daily Insulin (MDI) injections is the most popular treatment. Oral administration of insulin is the most suitable and attractive as compared to subcutaneous route but unfortunately cannot be utilized for the administration of peptides and proteins due to poor epithelial permeability and enzymatic degradation within the gastrointestinal tract. Since many years, extensive research has been carried out to explore the potential ways of insulin administration based on novel methods such as liposome, microsphere, nanoparticle, mouth dissolving strips, sprays exploiting oral and pulmonary route. These next generation efficient therapies for T1DM may help to improve the quality of life of diabetic patients especially in Insulin Dependent Diabetes Mellitus (IDDM). Conclusion: This review emphasizes on the most recent progress made in the development of oral insulin delivery formulations, and focuses on key lessons and implications from studies undertaken till date with the oral insulin formulations. Further, this review analyzes effectiveness of the advancements, applications and limitations of the technologies in delivering insulin to the targeted site through oral administration.