Concentrations of cyclic volatile methylsiloxanes in European cosmetics and personal care products: Prerequisite for human and environmental exposure assessment

Abstract

Low molecular weight cyclic volatile methylsiloxanes (cVMSs) are widely employed as emollients and carrier solvents in personal care formulations in order to acquire desired performance benefits owing to their distinctive physicochemical properties. Under current European legislation cosmetic ingredients such as cVMSs are required to be labeled on the product package only qualitatively, while for the assessment of environmental and consumer exposure quantitative information is needed. The aim of this study was therefore to measure concentrations of three cVMSs, namely octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in 51 cosmetics and personal care products (C&PCPs) that are currently available on the European market. The list of selected articles comprised a variety of hair and sun care products, skin creams and lotions, deodorants including antiperspirants, liquid foundations and a toothpaste. The target compounds were extracted from the products with different organic solvents dependent on the product matrix, followed by gas chromatography analysis with flame ionization detection (GC–FID). D5 was the predominant cVMS with the highest mean and median concentrations in all the C&PCP categories. The median concentrations of D5, D6 and D4 were 142, 2.3 and 0.053mg/g in deodorants/antiperspirants (n=11); 44.6, 30.0mg/g and below the limit of quantification (<LOQ; LOQ for D4=0.00071mg/g) in cosmetics (n=5); 8.4, 0.32mg/g and <LOQ in skin care (n=16); 9.6, 0.18 and 0.0055mg/g in hair care (n=10); and, 34.8, 0.53 and 0.0085mg/g in sun care (n=8) products, respectively. The calculated median aggregate daily dermal exposure to D4 and D5 from multiple C&PCPs was approximately 100 times lower than the current NOAEL derived from chronic inhalation rat studies.