Spectroscopic and cytotoxic studies of losartan complexes

Abstract

Use of drug-metal complexes for the treatment of several human diseases has resulted in significant progress in the field of medicinal inorganic chemistry. The current study describes the synthesis and characterization of Cu (II) and Ni (II) complexes of Losartan, an antihypertensive drug. These complexes were evaluated for their cytotoxic activity against four human cancer cell lines; SNB-19, HCT-15, COLO-205 and KB-3-1. Spectroscopic characterization revealed that during complex formation, the metal was bound through the nitrogen atoms of the tetrazole moiety of the losartan molecule. The molecular formulas of copper ([Cu (LS)2 Cl2].6H2O) and nickel ([Ni (LS)2Cl2]. H2O) complexes were found to be in agreement with the analytical data obtained through elemental analysis. For both the complexes, metal to ligand ratios of 1:2 were calculated. As revealed by FTIR, UV-Visible, and 1 H-NMR studies, both the complexes displayed octahedral geometries. Scanning electron microscopy (SEM) revealed marked changes in the morphology of the complexes, compared to the pure drug. From XRD studies, characteristic crystalline peaks of pure losartan were observed whereas no prominent peaks were observed for its complexes. Complexes were found to be inactive in the cytotoxic activity test performed using SNB-19, HCT-15, COLO-205 and KB-3-1 cell lines.