Simultaneous Determination of Hydroquinone, Kojic Acid and L-Ascorbic Acid in Some Cosmetic Emulsions

Abstract

The presence of skin de-pigmenting agents in cosmetic products, have received considerable attention in Nigeria as a possible source of skin abuse. There has been a call by government for cosmetic products manufacturers to comply with regulatory limits of these additives in their products. This study contributes to the pool of data available on levels of skin de-pigmenting agents in cosmetic products. Fifty cosmetic emulsions for skin use were randomly purchased from some sales outlets in Ibadan, South West Nigeria with the aim of determining the level of hydroquinone, kojic acid and l-ascorbic acid in them. Manufacturer claims were determined by examining the cosmetic package labels. The three de-pigmenting additives were determined simultaneously and quantitatively using High Performance Liquid Chromatography (HPLC). Results show that 96% of the emulsions were manufactured in four different continents namely Africa (42%), North America (32%), Europe (20%), Asia (2%) and undetermined origin (4%) by 28 different manufacturers. 36% of the manufacturers indicated % hydroquinone content to be 2% while no manufacturer indicated kojic and ascorbic acid content. 52% of the emulsions were creams, 44% lotions and 4% milks. 34% of the samples did not contain any of the three de-pigmenting agents, while 50% contained just hydroquinone, 2% kojic acid alone and 2% only ascorbic acid. Both hydroquinone and kojic acid were in 8% of the samples and only 4% contained the three additives. Levels of occurrence of the additives were 0.1 – 4.9% hydroquinone, 0.3 – 1.3% kojic acid and ascorbic 0.01 – 3.6%. The emulsions which contained hydroquinone were mostly from Africa (28%) followed by North America (22%) followed by Europe (8%), while only 2% from Asia and unidentified continent. Samples from Cote de Voire contained higher concentrations of hydroquinone which were greater than 3% in all cases except one. In conclusion, this study showed that hydroquinone is the major skin de-pigmenting agent in cosmetics in Nigeria the Nigerian Market. 22% of the manufacturers used hydroquinone at levels higher than the regulatory limit (2%). 64% of these manufacturers (55% Cote de Voire + 9% others) are from Africa. Only one manufacturer from Nigeria included hydroquinone at a level above regulatory limit.