Diabetes mellitus is a highly prevalent metabolic and chronic disease affecting millions of people in the world. The most common route of insulintherapy is the
subcutaneous injection due to its low bioavailability and enzymatic degradation. The search for effective and high patient compliance insulin delivery systems has been a major challenge over many
decades. The polysaccharide-based nanoparticles as delivery vehicles for insulin oral administration have recently attracted substantial interests. The present review highlights the recent advances
on the development of nanoparticles prepared from polysaccharides,
including chitosan, alginate, dextran and glucan, for oral delivery of insulin, overcoming multiple barriers in
gastrointestinal tract. The aims of this review are first to summarize the strategies that have been applied in the past 5 years to fabricate polysaccharide-based nanoparticles for insulin oral
delivery, and then to provide in-depth understanding on the mechanisms by which such nanoparticles protect insulin against degradation in the digestive tract and provide sustained release to enhance
mucus permeation and transepithelial transport of insulin administered via oral route.
