Comparative thermodynamic study on complex formation of native and hydroxypropylated cyclodextrins with benzoic acid

Complex formation of native and hydroxypropylated α-, β- and γ-cyclodextrins with benzoic acid in water was studied by means of calorimetry of solution at 298.15 K. The 1:1 complexes are formed with α- and β-cyclodextrins, while 1:2 binding stoichiometry was observed for γ-cyclodextrins. Thermodynamic parameters of complex formation of hydroxypropylated cyclodextrins were determined for the first time and analyzed. Comparison of binding affinity of native and modified cyclodextrins was carried out.