Abstract: The binding reaction between cefodizime sodium (CDZM) and bovine serum albumin (BSA) in aqueous solution was studied by fluorescence spectra. The binding constant KA was found to be 5.31×104 and the binding sits n to be 0.94 at 299 K by fluorescence quenching method. The quenching mechanism of fluorescence of BSA by cefodizime sodium has been discussed. The thermodynamic parameters of binding reaction were determined as follows： the molar change of enthalpy ΔrHm=－15.8 kJ•mol-1, the molar change of Gibbs function ΔrGm=－27.0 kJ•mol-1 and the molar change of entropy ΔrSm=－90.0 J•K-1•mol-1, and the binding power between cefodizime sodium and bovine serum albumin has been considered. Furthermore, the binding distance (r=3.13 nm) between cefodizime sodium and bovine serum albumin was obtained according to the theory of Föster′s dipile-dipile non-radiation energy transfer mechanism, and the effect of cefodizime sodium on the conformation of bovine serum albumin was analyzed using synchronous fluorescence spectrometry.

Key words: Cefodizime sodium, Bovine serum albumin, Fluorescence quenching