Oral insulin delivery by carboxymethyl-β-cyclodextrin-grafted chitosan nanoparticles for improving diabetic treatment

AbstractIn this paper, a new oral insulin formulation, insulin-loaded carboxymethyl-β-cyclodextrin-grafted chitosan nanoparticles (insulin/CMCD-g-CS NPs), was fabricated by ionic crosslinking technique. The therapeutic efficacy of new formulation was investigated in detail. Firstly, the CMCD-g-CS was synthesized by EDC-mediated esterification reaction. The prepared CMCD-g-CS exhibited favourable loading capacity and encapsulation efficiency of drug. The release experiment in vitro showed that the nanocarrier could efficiently protect encapsulated insulin at simulated gastric environment and release drug in the simulated colonic fluid. The insulin/CMCD-g-CS NPs effectively promoted drug internalization into Caco-2 cells and could reversibly open the tight junction between cells. The oral administration of insulin/CMCD-g-CS NPs could lastingly decrease blood sugar level in diabetic mice. The liver function study verified that the insulin/CMCD-g-CS NPs had not obvious toxicity to experimental mice. Therefore...