Determination of Minoxidil in Hair Care Cosmetics by High Performance Liquid Chromatography

The study developed a method to analyze minoxidil in hair care cosmetics using reverse-phase high performance liquid chromatography (HPLC). The process involved extracting spiked samples with 1% trichloroacetic acid, cleaning them with a MAX solid-phase extraction cartridge, and analyzing them with HPLC-UV. The method demonstrated good precision, repeatability, and spiked recovery, with a detection limit of 1 mg/kg for minoxidil. Calibration curves showed linearity between 0.2 μg/mL and 20 μg/mL. The method was successfully applied to hair care cosmetics, achieving recoveries of 83.1% to 97.7% and relative standard deviations of 2.9% to 6.6%.