Monitoring of clobetasol propionate and betamethasone dipropionate as undeclared steroids in cosmetic products manufactured in Korea

Abstract Some cosmetic products manufactured in Korea have been suspected to contain anti-inflammatory corticosteroids, such as clobetasol propionate and betamethasone dipropionate, for the treatment of eczema, seborrhea and psoriasis, without any indication on the label of the cosmetic products. Due to their severe side effects, such as permanent skin atopy, these two corticosteroids in cosmetic products need to be monitored from a forensic point of view. Cosmetic product samples (number of samples = 47) of manufacturers charged by consumers have been collected in local and online markets of Korea, and they were validated and analyzed by a simple high performance liquid chromatography (HPLC) method with ultraviolet diode array (UV-DAD). LC–MS/MS and LC–MS were used to confirm these steroids in cosmetic samples with diagnostic ions ( m / z ) and isotope ratio. Linearity was studied with 0.5–10 μg/mL range in both steroids. Good correlation coefficients ( r2 ≥ 0.999) were found, and their limits of quantifications were 0.59 μg/mL and 0.66 μg/mL in clobetasol propionate and betamethasone dipropionate, respectively. At three different concentrations spanning the linear dynamic ranges, mean recoveries were always higher than 93%, and precisions for intra-day and inter-day analyses were both less than 3.5%. The results show 32–96.4 μg/g levels of clobetasol propionate in five different cosmetic products. Also, betamethasone dipropionate in a sample was monitored at the level of 195.1 μg/g. This fact reveals that some manufacturers have added these steroids in their cosmetic products to advertise the treatment effect for skin atopy. Thus, these cosmetic products need to be monitored carefully, and ultimately removed from the market.