Recent trends in smart and flexible three-dimensional cross-linked polymers: synthesis of chitosan–ZnO nanocomposite hydrogels for insulin drug delivery
One set of major challenges and significant progress is attributed to the discovery of novel pharmaceuticals from the exoskeleton of marine crustacean wastes to minimize the environmental pollutants. In this strategy, high molecular weight chitosan was subsequently used in the synthesis of smart three-dimensional cross-linked network polymers. Super absorbent chitosan–ZnO nanocomposite hydrogels were synthesized via a terminated diisocyanate compound, a chitosan sample (NH2/NCO), and ZnO nanoparticles in different concentrations (1–7%). The discovered intelligent drugs were confirmed by spectral analyses such as FTIR, XRD, DLS, TGA and morphological analyses such as AFM, SEM, and TEM. The unique physical properties of chitosan–ZnO nanocomposite hydrogels towards environmental stimuli and the porosity of their structures have gained particular interest in fluorescence isothiocyanate-labeled insulin-loaded hydrogel nanocomposites for in vivo 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.