Determination of Methimazole by Potassium Permanganate Spectrophotometry

Abstract

In H2SO4 medium, oxidation-reduction reaction can be happened between methimazole and potassium permanganate, which results in the fading of potassium permanganate solution. The Beer's law is obeyed between the concentration of methimazoletea and the decrease value of absorbance, and the content of methimazoletea can be indirectly measured by measuring the decrease value of absorbance. A new method for the determination of methimazoletea by potassium permanganate spectrophotometry is established. The optimum conditions for the determination of methimazoletea is confirmed. The maximum absorption wavelength of the discoloring system is 525 nm. In the range of 0.001600-0.009600 mg/mL, the linear regression equation is ΔA=-0.0061+34.518C (mg/mL), and the linear correlation coefficient of 0.9992. This method is applied to the determination of methimazole in drugs, and the results are satisfactory.