Host-guest interaction of cytidine in β-cyclodextrin microcavity: Characterization and docking study

Abstract Cytidine plays key roles in phosphoinositide signaling and the synthesis of lipids. Thus, in this research paper, we describe a study on the inclusion complex formation between cytidine and beta-cyclodextrin (β-CD). The formation of 1:1 a stoichiometry ratio of host-guest inclusion complex of Cytidine (CY) with a nano hydrophobic cavity of Beta-cyclodextrin (β-CD) in the solution phase is studied by a UV–visible spectrophotometer, fluorescence spectroscopy and time-resolved fluorescence. The binding constant and the stoichiometric ratio of inclusion complex have been calculated by using Benesi-Hildebrand plot. And by using the binding constant values, the thermodynamic parameter, (ΔG) is also calculated, which represents the inclusion process is spontaneous at 303 K. A nanosecond time-resolved fluorescence study established that CY exhibits in bi-exponential decay in an aqueous medium and tri-exponential decay in the β-CD medium indicating the formation of a 1:1 inclusion complex. The host–guest solid inclusion complex of Cytidine (CY) with beta-cyclodextrin (β-CD) is prepared by physical mixture, kneading method and co-precipitation method and characterized by using Fourier transform infrared radiation, Thermo gravimetric analyses, differential scanning calorimetry and X-ray diffraction. A part of the CY molecule is entrapped in the β-CD microcavity confirmed by the spectral shifts. The most possible structure of the inclusion complex of CY and β-CD is confirmed by a molecular docking test.