Determination of dequalinium chloride and related impurities in cosmetics and pharmaceuticals by reversed-phase HPLC

A rapid, accurate and precise method for the determination of dequalinium chloride and related impurities in pharmaceuticals and cosmetics is described. The method is based on reversed-phase ion-pair HPLC. Different kinds of samples have been considered, but in each case the extracting solvent is methanol-water (1:1,V/V). HPLC is performed on a column packed with Spherisorb ODS-1 (5 mu m) using [GRAPHICS] acetonitrile-aqueous 0.1 M sodium perchlorate, pH 3.0 (10:90) as initial mobile phase (1.5 ml.min(-1)), a linear adient up to 80% acetonitrile in 30 min, and detection at 322 nm. The detection limit is 2 ng for all compounds injected. The method has been applied for the analysis of commercial samples.