Levels of Hydroquinone, Selected Heavy Metals (Hg, Pb, As) and Chemical requirements in Some Skin Lightening Creams Sold in Mbarara Municipality

Abstract

In this study, Skin-lightening creams commonly sold in Mbarara municipality were analyzed for chemical parameters (pH, thermal stability and fatty substance content), total hydroquinone, Lead, Mercury, and Arsenic contents. Total heavy metal content was determined by atomic absorption spectrophotometry. The levels of hydroquinone were determined using High Performance liquid chromatography (HPLC). All the creams showed detectable mean levels of mercury, ranging from 0.07±0.01ppm to 0.33±0.01ppm. Only 26.31% of the creams showed detectable levels of lead and 15.79% creams recorded detectable levels of arsenic. The mean levels of hydroquinone ranged from 0.54±0.02% to 4.47±0.02%. All the creams passed the thermal stability and fatty substance content tests. However, all the creams had very low pH values below the recommended 4.5- 8.5 pH ranges by Uganda National Bureau of Standards (UNBS). The levels of mercury, arsenic and lead in the samples were less than the UNBS, European Union and US Food and Drug Administration’s acceptable limits. Only 84.2% of the cream samples analyzed contained hydroquinone levels higher than the recommended WHO limit of 2%. The use of such creams may lead to serious health hazards. While the low concentrations of heavy metals detected in the cream samples analyzed do not pose any potential risk to consumers, repeated application of these creams may cause a cumulative effect over prolonged exposure. The low pH values may cause skin irritations. Therefore, the community needs to be sensitized on the implications of using skin lightening creams and UNBS should conduct periodic analysis to ascertain the levels of hydroquinone, heavy metals, and chemical requirements of skin lightening creams sold in Uganda as well as encourage manufacturers to state the exact bleaching agents in their creams.

Evaluation of the Levels of Hydroquinone and Health Risk Assessment of Toxic Metals in Skin-Whitening Creams

“…The pH of all the samples are acidic, it follows this trend; Sample 3 > Sample 1 > Sample 4 > Sample 2 (Table 2) andall falls below the permissible standard set by WHO except sample 3, the organic locally produced cream. The pH of human skin is acidic and ranges from4.5 to 6.So, application of acidic cream on skin may cause irritation and this can expose the skin to dermal diseases [28]. The pH recorded for creams in this study falls within the range reported by [29,30] Ekpunobi et al, [29], and Oyedeji et al, [30] but, higher than the results of Muloogi et al, [28].and Saleh et al, [31].…”

“…The pH of human skin is acidic and ranges from4.5 to 6.So, application of acidic cream on skin may cause irritation and this can expose the skin to dermal diseases [28]. The pH recorded for creams in this study falls within the range reported by [29,30] Ekpunobi et al, [29], and Oyedeji et al, [30] but, higher than the results of Muloogi et al, [28].and Saleh et al, [31].…”

“…Lead poisoning can occur even at low concentration and may cause neurological damage and adverselyaffects the body systems [6]. Due to the health hazardof Pb in human, its inclusion in cosmetics have been banned by regulatory bodies, yet detectable levels are still found in some skin-whitening creams [28]. The action of melanogenesis a catalyst in melanin production is inhibited Hg, thus affect pigment formation in skin [32].…”

“…Hydroquinone inhibits DNA and RNA synthesis and alters melanosome formation [Briganti et al, 2003]. This exposes the skin to direct ultra violet radiations from sunlight thereby increasing the risk of carcinogenesis [24,28]. Long term application of skin whitening cream containing high level of hydroquinone can lead to exogenous ochronosis [24].…”

Effect of Storage Temperature to Determine Hydroquinone in Face Cream by Spectrophotometry

“…HQ will darken when exposed to light and air because of its nature as a reducing agent. The hydroquinone level in the cream is only allowed to be 2%, if the hydroquinone level is > 2% then it is included in the group of hard drugs that can be used based on a doctor's prescription [8]. Therefore, the use of HQ with high levels in cosmetics has been prohibited [9].…”