Synthesis, characterization, biological activity and voltammetric behavior and determination of cefaclor metal complexes

Cefaclor (CEF), a second generation cephalosporin antibiotic, possesses various donor sites for interaction with transition metal (II) ions such as Cu(II), Co(II) and Ni(II) to form complexes of the type [M(CEF)(H₂O)Cl], with a molar ratio of metal:ligand (M:L) of 1:1. These complexes were prepared and characterized by physicochemical and spectroscopic methods. Their UV-Vis, IR and mass spectra suggest that CEF potentially acts as a bi-dentate ligand. The electrochemical behavior of these synthesized and in solution complexes is studied over glassy carbon electrode in various buffer solutions using cyclic, linear sweep, differential pulse (DP) and square wave (SW) voltammetric techniques. CEF enrichment is observed over Cu(II) complex. The peak current and peak potential of the complex depend on pH, initial potential, and scan rate. DP and SW voltammetric techniques were used for the determination of CEF-Cu(II) complex. For solid synthesis complex, the linear response was within 1×10^-6-3×10^-6 M with a detection limit on one decimal point: 2.26×10^-6 for DPV and 2.30×10^-6 M for SWV techniques in acetate buffer at pH 4.70. The repeatability of the methods was within 0.82-0.78% for peak potentials and 1.16-0.71% for peak currents. All necessary validation parameters were investigated as detailed in all media. The complexes have been screened for antibacterial activity and results were compared with the activity of the uncomplexed antibiotic against Pseudomonas aeruginosa, Kluvyeromyces fragilis, Saccharomyces cerevisiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Bacillus megaterium, Candida albicans, Mycobacterium smegmatis, Bacillus cereus, Enterococcus cloacae and Micrococcus leteus. The copper complex was found to be more potent against two bacterial species than the uncomplexed CEF.