A simple and effective method for determination of the antithyroid drugcarbimazole using ruthenium trichloride

Abstract

An accurate, precise, and simple spectrophotometric method is proposed for the determination of theantithyroid drug carbimazole using ruthenium(III) chloride. This method is based on the formation at room temperatureof a stable yellow-colored complex with max370 nm. The method has a Beer's law range of 7.81 to 1.95 102 g mL1,molar absorptivity coefficient"= 1.519 103L mol1cm1, and correlation coefficient of 0.997. The metal:ligand(M:L) ratio of the complex was con rmed by the mole ratio and Job's method of continuous variation, suggesting a 1:2stoichiometry. The formed carbimazole:Ru(III) complex was con rmed by spectral studies, including Fourier transforminfrared, nuclear magnetic resonance, electron spin resonance, magnetic susceptibility, thermal analysis, and powder{X-ray diffraction. Our method could be adopted for routine analysis of carbimazole, due to its ease, affordability, andeffectiveness.