Quality control of retinoids in commercial cosmetic products.

BACKGROUND Retinoids are widely used in different cosmetic products because of general improvement of skin appearance. However, retinoid concentration in cosmetics is restricted, and one particular form - retinoic acid is banned in cosmetics due to safety reasons. OBJECTIVES Within this study, we aimed to examine the quality of a considerable number of commercial retinoid cosmetic products in terms of their content and labelling, including also screening for the presence of retinoic acid. METHODS An appropriate analytical methodology, based on HPLC-UV for the simultaneous determination of common retinoids, along with a screening method for retinoic acid, was developed and validated. Structural identity confirmation of the newer retinoid - hydroxypinacolone retinoate was performed by LC-MS. RESULTS Retinol and retinyl palmitate were most often found, in concentrations mostly below 0.3%, and up to 1.3% retinol equivalents. Determined contents deviated significantly from the quantitatively declared ones in seven products (0-130%). In more than half of the tested products, inconsistencies between the contained and labelled retinoid were noticed. These products, as well as in 14 additional anti-age cosmetics, were screened for retinoic acid, which was detected in two products. CONCLUSIONS The obtained results from retinoids assay in commercial cosmetic products confirmed that the proposed method is appropriate for their routine analysis. The presence of retinoic acid in two products and determined retinoid contents above the Scientific Committee on Consumer Safety recommendations in 20% of the tested cosmetics reveal the need for their more strict regulation and quality control to ensure their efficacy and safety.