Facile synthesis of chitosan-grafted beta-cyclodextrin for stimuli-responsive drug delivery.

Modification of natural polysaccharides such as chitosan (CS), β‑cyclodextrin (β-CD), and alginic acid offers a promising strategy for the preparation of smart drug carriers, and latest innovations on such carriers are focused on stimuli-responsive biomaterials. In this study, highly hydrophilic three-demensional (3D) porous CS-grafted β-CD (CS-g-β-CD) was prepared through the Williamson ether synthesis reaction with epichlorohydrin (ECH) as the crosslinker and the consequent nucleophilic reaction between the epoxide ring of ECH and the primary amine of CS, which was then characterized by 1H nuclear (1H NMR), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), thermogravimetry (TG), and N2 adsorption/desorption isotherms. When etoposide (VP16), an anti-cancer drug, was encapsulated in the CS-g-β-CD, the encapsulation ratio was up to 73.6%. Finally, the resultant CS-g-β-CD was successfully used as the responsive drug carrier for pH- and thermo-sensitive release of VP16. This work opens a new avenue for the preparation of stimuli-responsive drug carriers with modified natural polysaccharides.