Synthesis, characterization and antimicrobial studies of Fe (ii) and Cu(ii) complexes of acetylated and benzoylated derivatives of ciprofloxacin

Abstract

Derivatization of ciprofloxacin is a promising alternative to the challenge of antibiotic resistance. Incorporation of substituents at the C-7 position (N-piperazine) moiety through acetylation and benzoylation of ciprofloxacin have resulted in its acetylated and benzoylated derivatives (CPCOR) and (CPCOPh) with enhanced biological activities. Copper and iron (II) complexes of the derivatives have been synthesized and characterised by percentage metal analysis, infrared and electronic spectroscopies, room temperature magnetic moments and melting points. The derivatised ligands (CPCOR) and (CPCOPh) act as bidentate ligands through the participation of the carboxy group oxygen and the pyridone carbonyl oxygen. The room temperature magnetic moment and electronic spectra data indicated that the complexes have octahedral geometries which is slightly distorted in the acetylated copper(II) complex.
The in-vitro antimicrobial studies were carried out on the derivatised ligands and their complexes against Bacillus subtilis (ATCC 39090), Escherichia.coli (ATCC 8739), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 7306), Klebsiella pneumonia (ATCC 4592), and Candida albicans (ATCC 10231). It was observed that the ligands as well as their complexes did not exhibit antifungal activity against the tested fungus Candida albicans.The acetylated derivative (CPCOR) showed better activity than the standard drug ciprofloxacin against Bacillus subtilis and Pseudomonas aeruginosa and Klebsiella pneumonia at all the concentrations used while the benzoylated derivative (CPCOPh) exhibited reduced activity in comparison to ciprofloxacin against all the tested organisms, this might be due to the bulkiness of phenyl moiety present in its structure. However, the metal (II) complexes of both the acetylated and benzoylated derivatives showed better activities than ciprofloxacin

Keywords: Antimicrobial, Ciprofloxacin, Benzoylated, Acetylated, N-piperazine