Recent trends in smart and flexible three-dimensional cross-linked polymers: synthesis of chitosan–ZnO nanocomposite hydrogels for insulin drug delivery

drug delivery into the rat nasal cavity. Confocal laser scanning microscopy (CLSM) was used to prove the absorption enhancement of fluorescein isothiocyanate (FITC)-labeled insulin-loaded hydrogels in the rat nasal cavity by this formulation. The formulation of hydrogels apparently decreased the blood glucose concentration (50-65% of initial blood glucose concentration) for at least 4-5.5 h after administration, and no apparent cytotoxicity was found after administration.