Fabrication of starch-based nanoparticles to enhance the stability and in vivo release of insulin.

Oral delivery of insulin could provide a great convenience for the type-1 diabetics and type-2 diabetics when compared to subcutaneous injections. This study aimed to prepare nanoparticle based on starch and explore their potential use in oral delivery of insulin. Nanoparticles with a spherical micromorphology and particle size between 200 and 300 nm were formed based on the electrostatic interactions. The particle size and encapsulation ability could be adjusted by altering the pH. Compared to carboxymethyl starch (CMS) with a substitution degree (DS) of 0.1 (NP1), the nanoparticle (NP2) formed by CMS with high DS 0.2 showed higher stability in a range of pH and better release properties. The results hemolytic activity below 5 % and cell viability above 75 % indicated that the starch-based nanoparticles exhibited good biocompatibility. The cell uptake amount of NP1 and NP2 were approximately 4.78 and 4.35-fold that of the free insulin, respectively. Moreover, NP1 and NP2 exhibited better hypoglycemic response in diabetic mice after oral administration. The nanoparticles prepared using the organic solvent free method and their potential insulin-loading capacity indicated that they may be a potential carrier for oral delivery of insulin.