Molecular docking, geometrical structure, potentiometric and thermodynamic studies of moxifloxacin and its metal complexes

Molecular docldng was used to predict the binding between moxifloxacin (H2L) and the receptors of breast cancer mutant (3hb5), prostate cancer mutant (2q7k), crystal structure E. coli (3t88) and crystal structure of S. aureus (3q8u) and it was found that the moxifloxacin shows best interaction with 3hb5 receptor other than receptors. The geometrical structure of moxifloxacin is discussed. The proton-ligand dissociation constant of moxifloxacin (H2L) and metal-ligand stability constants of its complexes with metal ions (Mn2+, Co2+, Ni2+ and Cu2+) have been determined potentiometrically in 0.1 M KCl and 10% (by volume) ethanol-water mixture. At constant temperature, the stability constants of the formed complexes increase in the order of Mn2+ < Co2+ < Ni2+ < Cu2+. The effect of temperature was studied at 298, 308 and 318 K and the corresponding thermodynamic parameters (Delta G, Delta H and Delta S) were derived and discussed. The dissociation process is non-spontaneous, endothermic and entropically unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favorable. The predicted pK(a) obtained by docking measurements for moxifloxacin (H2L) are in agreement with experimental values. (C) 2016 Elsevier B.V. All rights reserved.