Electrochemical studies on minoxidil and its determination in tablets by differential-pulse polarography

Abstract

A simple differential-pulse polarographic method has been developed for the determination of minoxidil in pharmaceutical dosage forms. The extracting solvent was methanol and the supporting electrolyte was 1.0 N sulphuric acid. An excellent linear relationship was obtained between the concentration and current peak height with a correlation coefficient of 0.9999. Good agreement was obtained between results with the differential-pulse polarography method and those by the manufacturer's method of assay. There was no interference by the tablet excipients. In acid solution, a mechanism for reduction at –1.2 V is proposed, which involves the transfer of four electrons as well as dehydration and deamination steps.