Preparation and characterization of a imipramine-ß-cyclodextrin inclusion complex

This article characterizes the association between imipramine and ss-cyclodextrin. The formation of supramolecular host-guest inclusion complex of imipramine with the nano-hydrophobic cavity of ss-cyclodextrin was prepared by physical mixing and coprecipitation. The inclusion complex of imipramine and ss-cyclodextrin in solution was characterized by ultraviolet-visible and fluorescence spectroscopy. The inclusion complex was characterized by infrared spectroscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. The spectral shifts showed that only a portion of the imipramine molecule was within the ss-cyclodextrin cavity. The binding constant and the 1:1 stoichiometry of the inclusion complex at 303K was obtained using a Benesi-Hildebrand plot. The Gibbs free energy change of the complex formation process was determined and the complex formation was shown to be spontaneous. The changes observed in vibrational frequencies, morphology, diffraction, and thermal stability confirmed the formation of the solid inclusion complex. Molecular docking and semi-empirical studies were used to characterize the ss-cyclodextrin-associated inclusion complexes of imipramine. The results of molecular modeling were systematically analyzed to determine the stability of the complexes.