Abstract: A reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of the contents of adapalene and the preservatives (2-phenoxyethanol and methyl-4-hydroxybenzoate) in adapalene gels. The chromatographic analysis was carried out on a Tigerkin C18 column (150 mm×4.6 mm, 5 μm). The mobile phase was 0.02 mol/L ammonium acetate buffer (pH 3.0) and tetrahydrofuran-acetonitrile with gradient elution, and the detection wavelength was set at 270 nm. The calibration curves were linear over the ranges of 10-100 mg/L (r=0.9999), 4-40 mg/L (r=0.9999) and 4-40 mg/L (r=0.9999) for 2-phenoxyethanol, methyl-4-hydroxybenzoate and adapalene, respectively. The average recoveries of the three substances were within 98.0%-98.6%. The method is simple, reliable and suitable for the simultaneous determination of adapalene, 2-phenoxyethanol and methyl-4-hydroxybenzoate in adapalene gels.

Key words: 2-phenoxyethanol, adapalene, adapalene gels , methyl-4-hydroxybenzoate, high performance liquid chromatography (HPLC)