Transdermal Kinetics of A Mercurous Chloride Beauty Cream: An In Vitro Human Skin Analysis

Background: Crema de Belleza-Manning is a popular mercurous chloride-containing beauty cream used to smooth and lighten the complexion and treat acne. Hundreds of people in the Southwestern US border states have been identified with elevated (>20 μg/L) urine mercury levels believed to be secondary to using this cream. The kinetic characteristics of percutaneous mercury absorption are incompletely defined. The objective of this study was to determine the transdermal kinetics of two formulations of mercurous chloride from a beauty cream in an in vitro human skin model. Methods: A proprietary formulation and an aqueous formulation of the beauty cream were studied using modified Franz diffusion cells. Mercury content in the skin samples and the underlying diffusion buffer was determined using atomic absorption spectrophotometry. Results: A rapid initial increase in mercury content both in the skin and the buffer was noted for both formulations. Mercury concentrations in the aqueous samples were significantly (p < 0.05) higher in both the skin and the diffusion buffer compared to parallel samples containing glycerol. Conclusions: Mercury was readily absorbed through the skin in this in vitro human skin model. The aqueous preparation had a markedly increased rate and extent of mercury absorption relative to the proprietary formulation.