Background:
Folic acid (vitamin B9) is a water-soluble vitamin that occurs naturally in many kinds of fruit and vegetables, wholemeal cereals and animal source foods. An adequate supply of folic acid is particularly important for expectant mothers during certain phases of pregnancy. It is available on the market in the form of food supplements, enriched foodstuffs and medicinal products. However, folic acid may be contaminated with carcinogenic N-nitroso folic acid under certain circumstances. A strict limit value has therefore already been imposed for pharmaceutical products. Due to the particularly sensitive nature of the target group, the possibility of testing for N-nitroso folic acid should also be considered with respect to the use of folic acid in food supplements.
N-nitroso folic acid in pharmaceutical products
Since carcinogenic N-nitrosamines were detected in the group of angiotensin II receptor blockers (ARBs or sartans) in 2018, N-nitrosamines have been found in numerous other medicinal substances. These include folic acid, from which N-nitroso folic acid can be formed under the influence of sodium nitrite. The European Medicines Agency (EMA) and the U.S. Food and Drug Administration (U.S. FDA) have therefore specified 1,500 ng/day as the maximum permitted daily intake of N-nitroso folic acid (EMA 2025, U.S. FDA 2023)
Determination of N-nitroso folic acid
PhytoLab has developed a method for precise determination of N-nitroso folic acid by means of state-of-the-art technology. The LC-MS/MS method has been comprehensively validated on food supplements containing folic acid in accordance with the ICH guidelines (ICH Q2). It enables determination of N-nitroso folic acid in pharmaceuticals, and in mono- and multivitamin preparations and ingredients with a limit of quantification of 10 μg/kg. Apart from performing routine analyses, we keep a CTD-compliant document package, comprising test method and validation reports available for our pharmaceutical customers. We can also conduct a product-specific verification procedure for your product, if required.
Sources: CMdH 2025 - Heads of Medicines Agencies: Nitrosamine impurities
