Recent advances in the oral delivery of insulin.

Insulin was discovered over 90 years ago. However oral insulin still remains a challenging and elusive goal. Extensive efforts are being made worldwide for developing noninvasive drug delivery systems, mainly via oral route as it is the most widely accepted means of administration. The main barriers faced in oral protein delivery are the enzymatic degradation and poor permeability across the intestinal wall. The approaches for developing an oral insulin delivery system mainly focus on overcoming these barriers. To overcome the gastro-intestinal barriers various types of formulations such as insulin conjugates, permeation enhancers, micro/nanoparticles, liposomes etc. are investigated. In the recent years a number of advances have taken place in understanding the needs and workable mechanisms of improved oral peptide delivery systems. In this review the recent patents on oral insulin is focused. Emphasis is on the technologies based on permeation enhancers and nanoparticle based carrier systems.