Interaction of CFP with metal ions: complex formation of CFP with metal ion by absorption and fluorescence spectrophotometery

Abstract

Spectrophotometric investigation of the interaction of Cefpodoxime proxetil (CFP) with Ca2+, Mg2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+ in acidic medium showed the formation of 1:1 complex. The absorption spectrum of pure drug exhibits two prominent peaks at 270 and 345 nm. Its spectra scanned at several pH exhibited two isosbestic points (305 and 330 nm) indicating the presence of zwitterionic condition of drug in solution phase. The fluorescence emission spectra of CFP in presence of different concentrations of metal ions showed enhancement in fluorescence intensity which is ascribed to chelating enhancement fluorescence effect (CHEF). The stoichiometry of the complexes was determined by Job's and Benesi-Hildebrand method. The stability of the complexes follow the order Ca2+< Mg2+< Co2+< Ni 2+< Zn2+< Mn2+< Cu2+< Fe3+.