摘要:Transition metal complexes are cationic, anionic or neutral species in which transition metal is coordinated by ligands. Metals can play an important role in modifying the pharmacological properties of known drugs after coordinating with it. Stability constants of complexes also have an important role in the design of drugs for alleviation of metal poisoning. In the present study levofloxacin is used as a ligand for complexation. It is a member of fluoroquinolones group of antibiotics which is very active against aerobic Gram negative microorganism. The object of the present work is a physicochemical investigation of the interaction of bivalent metal ion [Mn(II)] with levofloxacin antibiotics and is aimed at understanding the mechanism of inhibitory or lethal effect of antibiotics against fixed types of microorganisms. The stability constants data can also be used for determination of various thermodynamic parameters such free energy (ΔG0), enthalpy (ΔH0), and entropy ΔS0. From these parameters important information about mechanism of interaction can be deduced.