Effect of citrate spacer on mucoadhesive properties of a novel water-soluble cationic β-cyclodextrin-conjugated chitosan

β-Cyclodextrin (CD) was designed to conjugate with chitosan (CS) through citrate spacer in order to facilitate mucoadhesive properties and CD mobility. To improve their water solubility, the CS backbones were further quaternized with glycidyl trimethylammonium chloride. The mucoadhesive properties of CD-conjugated CS derivatives evaluated by mucin-particle method and surface plasmon resonance sensor were found to be depend on degree of quaternization and citrate amount. The electrostatic attraction between positively charged amino groups of the cationic CS and the negatively charged of the mucin as well as hydrogen bonding between carboxyl and hydroxyl groups of citrate spacers and mucus glycoprotein presumably mediated the mucoadhesion. Moreover, the cytotoxicity test indicated that the CD-conjugated CS derivatives resulted in less toxicity against buccal mucosal cells than the original quaternized CS. Therefore, the CD-conjugated CS derivatives could be useful for mucoadhesive drug delivery systems.