Facile preparation and inclusion ability of a chitosan derivative bearing carboxymethyl-beta-cyclodextrin

Coupling carboxymethylated beta-cyclodextrin and partially deacetylated chitin (Mw = 7300) afforded a new type of functional chitosan derivative having an ability to form an inclusion complex. The property to form an inclusion complex was studied using a fluorescent dye, 6-(p-toluidino)-2-naphthalene-6-sulfonate (TNS), as the guest molecule. It was found that the presence of the cyclodextrin bonded to chitosan enhanced the relative intensity of TNS fluorescence significantly (3.6 times as much as that of beta-cyclodextrin). Fluorometric titration revealed that the 1:1 stoichiometrical complex was formed and that the equilibrium constant was 1.13-1.68 x 10(3) M(-1). Ionic interaction between the sulfonic acid moiety of TNS and the amino group of chitosan was suggested from experiments which involved changing the pH and ionic strength of the buffer solution as well as adding a surface-active agent. Copyright (C) 1996 Elsevier Science Ltd