A Method for the Determination of Minoxidil in Hair-Regrowth Formulations by Micellar Electrokinetic Capillary Chromatography

In 2005, a method using micellar electrokinetic capillary chromatography (MEKC) was developed to determine the presence of minoxidil in hair-regrowth products. Initially intended to test for illicit imitations of Rogaine, it was later used for generic minoxidil products after the patent expired. The procedure was validated on Dionex CES-1 and PE-ABI 270HT, proving to be simple, quick (with an analysis time of 12 minutes), and selective with respect to known process and degradation impurities. The method yielded slightly higher values than high-performance liquid chromatography (HPLC), but all results met registration specifications and internal targets.