Designing of some novel metallo antibiotics tuning biochemical behaviour towards therapeutics: Synthesis, characterisation and pharmacological studies of metal complexes of cefixime

Cefixime is a broad spectrum semi synthetic cephalosporin antibiotic for oral administration. Metal complexes of cefixime with Cu(II), Zn(II), Cd(II), Fe(III) and Ni(II) have been synthesised and characterised by elemental analysis and IR, UV-Vis., NMR and ESR spectra. The electronic spectral behaviour and cyclic voltammetric studies have been carried out on the interaction of metal complexes with calf thymus DNA. The results suggest that the complexes can bind to DNA by intercalation mode. The Cu(II), Zn(II), Cd (II) and Ni(II) complexes exhibit square planar geometry. Fe(III) complex exhibits octahedral geometry. The complexes showed a slightly higher antimicrobial activity than the cefixime drug. Among the metal complexes, Fe(III) was found to be more active than other complexes when tested against bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. SEM analysis provides the morphology of the metal complexes. The DNA binding interaction of metal complexes with CT DNA using the cyclic voltammetry technique and their salient features are discussed.