Preparation, characterization and molecular modelling of inclusion complex between α-naphthylacetic acid with ethylenediamine-β-cyclodextrin

Using ethylenediamine-β-cyclodextrin and α-naphthylacetic acid as raw material, a novel inclusion complex (en-β-CD@NAA) was synthesized. The inclusion complex structures and properties were analyzed by reliable spectroscopic and physicochemical techniques. The stoichiometry of the inclusion complex was 1:1 and the stability constant ( K S ) value was found to be 2511 M −1 at 293 K. Molecular thermodynamic parameters indicated that the spontaneous and exothermic nature of the process. The inclusion form was foreseen by Chem 3D program combined with 1 H-NMR experimental data. The solubilization curves ( K 1  = 2.05) and in-vitro dissolution data demonstrated that the en-β-CD@NAA inclusion complex has satisfactory water solubility.