Polymeric Nanoparticles (PNPS) For Oral Insulin Delivery:

Successful oral insulin administration can considerably enhance the quality of life (QOL) of diabetes patients who must frequently take insulin injections. However, oral insulin administration is seriously hampered by gastrointestinal enzymes, the wide pH range, and the mucus and mucosal layers, which limit insulin oral bioavailability to ≤2%. Therefore, a large number of technological solutions have been proposed to increase the oral bioavailability of insulin, among which polymeric nanoparticles (PNPs) are highly promising for oral insulin delivery. The search for an effective and reliable oral insulin delivery system has been a major challenge facing pharmaceutical scientists for many decades. Even though innumerable carrier systems that protect insulin from degradation in the gastrointestinal tract with improved membrane permeability and biological activity have been developed, a clinically acceptable device is still not available for human application. Efforts in this direction are continuing at an accelerated speed. One of the preferred systems widely explored is based on polymeric hydrogels that protect insulin from enzymatic degradation in the acidic stomach and deliver it effectively in the intestine. Swelling and deswelling mechanisms of the hydrogel under varying pH conditions control the release of insulin. The micro- and nanoparticle (NP) hydrogel devices based on biopolymers have been widely explored, but their applications in human insulin therapy are still far from satisfactory. The recently published research articles chosen for this review are based on applications of PNPs with strong future potential in oral insulin delivery and do not cover all related work. In this review, we summarize the controlled release mechanisms of oral insulin delivery, the latest oral insulin delivery applications of PNPs nanocarriers, as well as challenges and prospects. This review will serve as a guide to future investigators who wish to engineer and study PNPs and hydrogel-based devices as oral insulin delivery systems.