Determination of Minoxidil in Pharmaceutical Formulations Using Permanganometry

A classic method for determining minoxidil in pharmaceutical formulations was proposed, based on the redox reaction between KMnO4 and minoxidil. The best results in permanganometry were achieved using a concentration of 1.00 x 10^-2 mol L^-1 for permanganate, with minoxidil as the titrant at a concentration of 2.00 x 10^-2 mol L^-1 in a 2.00 mol L^-1 H2SO4 solution. The recovery rates for the proposed method ranged from 94.5% to 95.2%, depending on the commercial sample. This method was applied to commercial samples containing minoxidil and compared with chromatographic procedures, showing relative errors from -1% to -5.26%. The procedure was simple, fast, and could serve as an alternative for determining minoxidil in pharmaceutical samples with relatively high drug concentrations.