Assessment of levels of some active skin lightening compounds in selected facial creams and soaps in the Kenyan market
Abere, Grace Kwamboka
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Cosmetics are generally used to improve the appearance by the removal or correction of blemishes and to treat diseases of the human skin and hair. Skin-lighteners which include hydroquinone, mercury, arbutin, kojic acid, ascorbyl glucoside, magnesium ascorbyl phosphate have been frequently used in skin lightening creams and soaps. However chronic exposure to mercury compounds in skin lightening creams and soaps may lead to various disorders such as nephritic, peripheral neuropathy, anxiety, depression and damage the developing foetus. Mercury may also cause skin rashes, skin discoloration and scarring, as well as a reduction in the skin’s resistance to bacterial and fungal infections. Similarly when hydroquinone is applied at levels higher than the allowed, it can result in ochronosis, dermatitis, exonogenous ochronosis, macular hyperchromia, fingernail discolouration, hydroquinone neuropathy and damage of the nervous system. On the other hand if arbutin, kojic acid, ascorbyl glucoside, or magnesium ascorbyl phosphate are used above the permissible levels they cause pigmentation increasing to the joints at the finger, toes, buttocks and ears. Although there are allowed levels of the skin lighteners, some producers use levels above the set limits. There is scanty information reported on the levels of skin lighteners in creams and soaps that contain them. The labels on the market products do not indicate levels of active compounds among the ingredient list. Some of the active compounds have been banned but yet they are in continue use. The aim of this study therefore was to assess the levels of these compounds in some skin lightening facial creams and soaps in the Kenyan market. Samples of cosmetics were obtained from small outlets in Nairobi and Kisii. Cold Vapour Atomic Absorption Spectrometry (CV-AAS) was used to determine mercury and High Performance Liquid Chromatography (HPLC) was used to determine hydroquinone, arbutin, ascorbyl glucoside, kojic acid and magnesium ascorbyl phosphate. The mean levels in of skin lighteners in creams ranged as follows; mercury 47.87 ± 0.00 to 513.06 ± 26.74 ppm, hydroquinone 0.002 ± 0.00 % to 0.05 ± 0.00 %, arbutin 0.95 ± 0.02 to 107 ± 0.06 %, kojic acid 0.06 ± 0.00 to 15 ± 0.65 %, ascorbyl glucoside 5.83 ± 0.00 to 61. 47 ± 0.00 % and magnesium ascorbyl phosphate 1.68 ± 0.01 to 40.48 ± 4.5 %. In soaps the levels were as follows; ascorbyl glucoside 5.83 ± 0.00 to 5.84 ± 0.00 %, kojic acid 1.12 ± 0.086 to 3.50 ± 0.44 %, and mercury 578.25 ± 77.63 to 1108.754 ± 1.32 ppm. In most cases, there were significant differences (p<0.05) in the levels of skin lighteners among creams and between the creams and soaps. The mean levels of most skin lighteners were found to be above the maximum permissible limits set by WHO except for hydroquinone. These findings indicate that the use of skin lightening creams and soaps may potentially not be safe as far as toxicity is concerned. Although hydroquinone was not above the set limit, continuous use of cosmetics containing it may lead to bioaccumulation hence the need to have it monitored.