Determination of α-Arbutin, β-Arbutin, Kojic Acid, Nicotinamide, Hydroquinone, Resorcinol, 4-Methoxyphenol, 4-Ethoxyphenol and Vitamin C from Cosmetic Products Using LC-UV Method

Skin lightening products have become increasingly in demand, especially in Asian market. Usually, the topic products include plant extracts reported having skin whitening activity, such as bearberry extracts in which contains β-arbutin and hydroquinone. An HPLC-UV method was developed to determine α-arbutin, β-arbutin, kojic acid, nicotinamide, hydroquinone, resorcinol, 4-methoxyphenol, 4-ethoxyphenol and vitamin C from skin lightening products. Currently there is no analytical method for simultaneously determination of nine analytes in a single injection. The separation of nine compounds was achieved on a reverse phase C-18 column material within 30 minutes. Mobile phase is composed with water, methanol, and acetic acid. Stabilities of analytes at different pH range were estimated, and extraction method was validated. 20 mM NaH₂PO₄ in 10% MeOH (MeOH/water= 10:90, v/v) at pH 2.3 was proved to be the best solvent system for sample preparation. The method was fully validated. The developed HPLC-UV method was successfully applied on quantitative determination of nine entitled analytes from 59 different skin lightening products from United States and India.