Objective: Silver complexes of antibacterial quinolones have the potential advantage of combining the antibacterial activity of silver and fluoroquinolones. The objective of our study was the preparation and the preliminary physico-chemical characterization of a silver complex with ofloxacin. Methods: To achieve our goals several spectroscopic methods (ultraviolet spectrophotometry, mass spectrometry, and Fourier transform infrared spectroscopy) and thermal methods (differential scanning calorimetry and thermogravimetric analysis) were used in order to elucidate the chemical structure of the complex. Results: Using mass spectrometry we established the stoichiometric ratio silver:ofloxacin as 1:2. Experimental data suggest a particular coordination for ofloxacin, as a monodentate ligand, in the formation of a complex with silver, through the nitrogen atom from the methyl-piperazine cycle.
IntroductionDue to the excellent chelating properties of quinolone antibacterial several metal complexes of these substances were synthesized and studied for their possible antibacterial and antifungal activities. The silver ion is known for its antibacterial and antifungal properties. Fluoroquinolones are synthetic antibacterial agents, with broad spectrum activity, good oral absorption and bioavailability. The 4-oxo and 3-carboxyl groups of fluoroquinolones offer excellent chelating properties for metal ions. Silver complexes of fluoroquinolone antibacterial have the advantage of combining the antibacterial activity of the silver ion with the one of the fluoroquinolone. There are a large number of studies on the complexation of antibacterial fluoroquinolones with metal ions using different metals [1]. Metal complexes have been synthesized with antimicrobial activity equal to or greater with the corresponding quinolone antibacterial. Research on the fluoroquinolone metal complexes has revealed also other biological effects: antifungal, antiparasitic, anticancer, anti-inflammatory, antioxidant and even insulin mimetic [2][3][4]. In the category of metal complexes with promising therapeutic effects are included those containing silver [5][6][7][8][9][10].Complexation of antibacterial quinolones with silver combines the antibacterial activity of Ag (I) with the one of the quinolone. This complexation presents a particular coordination with the quinolone as the monodentate ligand