New silver complexes with levofloxacin: Synthesis, characterization and microbiological studies

• Three new silver complexes of levofloxacin were synthesized.
• Complexes were characterized by FT-IR, ESI-MS, 1H NMR, UV–VIS, and DSC.
• Optimized molecular structures were determined using DFT analysis.
• Activities of the complexes against Gram(+), Gram(−) and Candida spp. are reported.

Levofloxacin is a third generation fluoroquinolone antibiotic with a broad-spectrum including both Gram positive bacteria and Gram negative bacteria, as well atypical bacteria. In order to extend the spectrum of activity and to add new biological effects, several metal complexes of levofloxacin have been obtained and reported recently. The aim of our study was to obtain new silver complexes with levofloxacin with potential broad spectrum antibacterial and antifungal activity. Therefore three new silver complexes of levofloxacin with the proposed chemical structures (levofloxacin)2Ag(NO3), (levofloxacin)2Ag(NO3)(CH3OH) and (levofloxacin)Ag(C6H6O7)·3H2O were synthesized. In order to characterize the obtained complexes elemental analysis, conductivity measurement, spectroscopic, and thermal methods were used. Optimized molecular structures were determined using DFT (density functional theory) analysis. The antibacterial activity against Gram negative and Gram positive bacteria and antifungal activity against Candida spp of the complexes was tested by determination of minimum inhibitory concentration through microtitre broth dilution method.

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