Mucoadhesive and enzymatic inhibitory nanoparticles for transnasal insulin delivery

Aim: To develop a novel nanocarrier with mucoadhesion and enzymatic inhibition for transnasal insulin delivery. Methods & methods: The physicochemical characterization of the nanoparticles included size and morphology, as well as mucoadhesion and enzymatic inhibition. The in vitro release of insulin from the nanoparticles was evaluated in 3 mg/ml glucose medium. The cytocompatibility of the nanoparticles was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The interactions of the nanoparticles with Caco-2 cells and nasal epithelia, and the effect of the nanoparticles on transnasal insulin delivery were estimated. Results: The nanoparticles were spherical in shape, with an average size of 100 nm, and presented strong enzymatic inhibitory activity and high mucin adsorption ability. The insulin-loaded nanoparticles showed the rapid insulin release in 3 mg/ml glucose medium. The nanoparticles were noncytotoxic to Caco-2 cells. Furthermore, the insulin-loaded nanoparticles overcame mucosal barriers and significantly decreased plasma glucose levels.