Synthesis, characterization, docking and biological studies of M(II) (M= Mg, Ca, Sr) Piroxicam complexes

Abstract

Development of metal complexes of pharmaceutical compounds is an active research area in bioinorganic chemistry because synergistic action of metal and ligand can provide enhanced activity of the drugs. Three new metal complexes of the non-steroidal anti-inflammatory drug (NSAID) piroxicam with Mg(II), Ca(II) and Sr(II) were synthesized and characterized using elemental analyses, UV–Vis, IR, 1H NMR, 13C NMR, conductance, SEM-EDX, XRD and TGA. IR and NMR spectroscopy confirmed that Piroxicam behaves as a bidentate ligand, coordinated to the metal ions via the oxygen and nitrogen atoms of (C―O)carbonyl and (C―N)pyridyl, respectively. The conductance and TGA data showed that metal complexes are non-electrolytes, and have coordinated water molecules respectively. SEM and XRD data are in good agreement confirming the crystalline morphology of all the complexes with the crystalline size of 14.20, 18.29 and 20.42 nm for Mg(II), Ca(II) and Sr(II) complexes respectively. Biological studies evaluated by in vitro antioxidant and in vivo anti-inflammatory, analgesic and anxiolytic activities also indicated that the complexes possess higher biological potential with lower toxicity (LD50 1000 mg/Kg). Ca(II)-complex acts as promising anti-inflammatory and Sr(II) complex along with Ca(II) complex exhibited significant analgesic effects (*P < 0.05) without developing anxiety in experimental rats. Furthermore, in silico docking data showed that the synthesized complexes inhibit COX-2 and PGE-2 more potently than COX-1 which is the main characteristic feature of selective COX-2 inhibitor drugs.