Content and stability of B complex vitamins in commercial cosmetic productsTemova Rakuša, Žane (Avtor) Šenk, Anja (Avtor) Roškar, Robert (Avtor) cosmeceuticalscosmetic formulationD-panthenolniacinamidenicotinamidestabilityvitamin B3Background: Individual B vitamins have many favorable effects on the skin and are common cosmetic ingredients. However, their formulation is demanding due to stability issues, which consequently affect the products’ quality. Aims: We aimed to determine the quality (labeling accuracy, content determination, and content-related quality control) and stability under long-term and accelerated storage conditions of a representative sample of commercial cosmetics containing the most common B vitamins – nicotinamide, dexpanthenol, pyridoxine, and cyanocobalamin. Methods: Cyanocobalamin was determined by a previously published stability-indicating HPLC–diode array detector (DAD) method for the simultaneous determination of all hydrophilic vitamins. This method was additionally simplified and adjusted for the time-effective analysis of nicotinamide, dexpanthenol, and pyridoxine. Both methods were properly validated. Results: All labeled B vitamins were present in the 36 tested products, mostly in contents, reported effective on the skin. Thus, a straightforward correlation between vitamin contents and product prices were not observed. The content-related quality control of eight products, which quantitively specify their content, revealed significantly lower nicotinamide contents (47% and 57%) in two products and appropriate or higher nicotinamide (102%–112%) and dexpanthenol (100%–104%) contents than declared in the remaining products. The 6-month long-term and accelerated stability studies demonstrated the products’ physical stability, but also revealed dexpanthenol, pyridoxine, and cyanocobalamin degradation, while nicotinamide was mostly stable in the tested products. Conclusions: The obtained results provide an inside into the quality of commercial vitamin B cosmetics and highlight the importance of stability testing in the formulation of quality, efficient, and safe cosmetics. 20232023-02-13 13:00:05Članek v reviji144304UDK: 665.58ISSN pri članku: 1473-2165DOI: 10.1111/jocd.15321COBISS_ID: 121266691sl