Preparation, spectroscopic and thermal characterization of new metal complexes of verlipride drug. In vitro biological activity studies

Abstract

Metal complexes of the general formula [M(VER)2Cl2(H2O)2]·yH2O and [Cr(VER)2Cl2(H2O)2]Cl·H2O (where VER=verlipride, M=Mn(II) (y=2), Co(II) (y=2), Ni(II) (y=2), Cu(II) (y=1) and Zn(II) (y=0)) are prepared and characterized based on elemental analyses, IR, 1H NMR, magnetic moment, molar conductance, and thermal analyses (TG and DTA) techniques. From the elemental analyses data, the complexes are formed in 1:2 [Metal]:[VER] ratio. The molar conductance data reveal that all the metal chelates are non-electrolytes except Cr(III) complex, it is 1:1 electrolyte. IR spectra show that VER is coordinated to the metal ions in a neutral monodentate manner with O donor site of the carbonyl O atom. On the basis of spectral studies and magnetic moment measurements an octahedral geometry has been assigned for the complexes. The thermal behavior of these chelates is studied using thermogravimetric analysis technique. The results obtained show that the complexes lose hydrated water, HCl and coordinated water molecules followed immediately by decomposition of the ligand molecules in the successive unseparate steps. The VER drug, in comparison to its metal complexes is also screened for its biological activity against Gram positive bacterial (Staphylococcus aureus) and Gram negative bacteria (Escherichia coli) and fungi (Candida albicans and Aspergillus flavus) in vitro. The activity data show that most of the metal complexes have antibacterial activity like or higher than that of the parent VER drug against one or more species.