Alteration of the Binding Strength of Dronedarone with Bovine Serum Albumin by β-Cyclodextrin: A Spectroscopic Study

We report the influence of beta-cyclodextrin on the binding of the drug dronedarone with bovine serum albumin. The stoichiometry, the binding constant, and the mode of binding of the derivative with beta-cyclodextrin are studied by UV-Visible absorption, fluorescence, and 2 Dimensional Rotating Frame Overhauser Effect Spectroscopy (2D ROESY NMR) spectroscopic techniques. The structure of the 1: 1 inclusion complex is proposed. The binding of free dronedarone with bovine serum albumin and beta-cyclodextrin-bound dronedarone are studied by fluorescence quenching and Forster resonance transfer. The decreased magnitude of the Stern-Volmer constant and the binding constant for the interaction of dronedarone with bovine serum albumin in the presence of beta-cyclodextrin are articulated. The donor-to-acceptor distances in the presence and the absence of beta-cyclodextrin are compared. The binding sites of the dronedarone with bovine serum albumin are reported by molecular modeling. Dronedarone binds to the sub-domain III of bovine serum albumin. The 3-(dibutylaminopropoxy)benzoyl moiety of dronedarone binds with bovine serum albumin. Encapsulation with beta-cyclodextrin decreases the binding strength of dronedarone with bovine serum albumin.