Novel mixed metal Ag(I)-Sb(III)-metallotherapeutics of the NSAIDs, aspirin and salicylic acid: Enhancement of their solubility and bioactivity by using the surfactant CTAB

Abstract

The already known Ag(I)-Sb(III) compound of the formula {Ag(Ph3Sb)3(NO3)} (1) and two novel mixed metal Ag(I)-Sb(III) metallotherapeutics of the formulae {Ag(Ph3Sb)3(SalH)}(2) and {Ag(Ph3Sb)3(Asp)}(3) (SalH2=salicylic acid, AspH=aspirin or 2-acetylsalicylic acid and Ph3Sb=triphenyl antimony(III)) have been synthesised and characterised by m.p., vibrational spectroscopy (mid-FT-IR), 13C-,1H-NMR, UV-visible (UV-vis) spectroscopic techniques, high resolution mass spectroscopy (HRMS) and X-ray crystallography. Compounds 1,−3 were treated with the surfactant cetyltrimethylammonium bromide (CTAB) in order to enhance their solubility and as a consequence their bioactivity. The resulting micelles a–c were characterised with X-ray powder diffraction (XRPD) analysis, X-ray fluorescence (XRF) spectroscopy, Energy-dispersive X-ray spectroscopy (EDX), conductivity, Thermal gravimetry–differential thermal analysis (TG–DTA), and atomic absorption. Compounds 1–3 and the relevant micelles a–c were evaluated for their in vitro cytotoxic activity against human cancer cell lines: MCF-7 (breast, estrogen receptor (ER) positive), MDA-MB-231 (breast, ER negative) and MRC-5 (normal human fetal lung fibroblast cells) with sulforhodamine B (SRB) colorimetric assay. The results show significant increase in the activity of micelles compared to that of the initial compounds. Moreover, micelles exhibited lower activity against normal cells than tumor cells. The binding affinity of a–c towards the calf thymus (CT)-DNA, lipoxygenase (LOX) and glutathione (GSH) was studied by the fluorescent emission light and UV-vis spectroscopy.