A new supramolecular gel via host–guest complexation with cucurbit[8]uril and N-(4-diethylaminobenzyl)chitosan

A novel supramolecular gel has been prepared via host–guest interaction between cucurbit[8]uril (Q[8]) and N-(4-diethylaminobenzyl)chitosan (EBCS). The structure of supramolecular gel has been characterized. The spectrum of 1H NMR demonstrated the benzene ring of EBCS is reside inside the hydrophobic cavity of Q[8] and the host–guest interaction between Q[8] and EBCS was the main driving force for the formation of the supramolecular gel. The network structure of the xerogel of Q[8]/EBCS gel was observed by SEM. The Q[8]/EBCS gel system showed thermosensitive and pH-sensitive properties. The physical characterization by SEM, DSC, TG demonstrated the distinguished characters, which proved the formation of supramolecular gel instead of physical blending. The in vitro release study of the 5-fluorouracil-loaded supramolecular gel showed that sustained release profile in acidic condition, suggesting that Q[8]/EBCS gel could be a potential carrier for pH-sensitive drug controlled release system.