Nitrosamines in Focus – Meeting Regulatory Requirements with Confidence

What are nitrosamines and why do they matter?

Nitrosamines are genotoxic and carcinogenic substances that can form under certain conditions from secondary or tertiary amines in the presence of nitrosating agents – including nitrous acid and its salts, nitrites and nitrogen oxides. How readily and to what extent this reaction occurs depends not only on the concentration of the starting materials but also significantly on pH, temperature and exposure time. Nitrosamines are relevant not only as reaction products, however: they can also be present as impurities directly in pharmaceutical active substances (APIs), excipients and primary packaging materials.

What the EMA requires

Triggered by the discovery of nitrosamine impurities in sartans, the EMA introduced far-reaching requirements: marketing authorisation holders of chemically synthesised medicines and all applicants for new marketing authorisations have since been obliged to systematically assess their products for a possible nitrosamine risk and, where a risk is identified, to carry out targeted analyses.

The end of the Call for Review for chemically defined medicines and biologics in 2021 did not close the matter. Marketing authorisation holders and applicants for all human medicines are permanently obliged to control the presence of nitrosamines and reduce them to a minimum, regardless of marketing status or product type.

Limits for API-specific nitrosamines: staying up to date

For many active substances, substance-specific nitrosamines have now been identified, for which general or specific limits for the maximum daily intake apply depending on the available data. The associated reference list – Appendix 1 (EMA/CHMP/42189/2026/Rev. 12) – is updated regularly: the current version of 1 March 2026 includes 13 new substances and updated AI values for 8 existing entries. Newly added substances include N-nitrosoadrenaline, N-nitroso-desmethyl-cidoxepin and N-nitroso-desmethyl-diltiazem.

More than just the active substance: the extended scope of testing

The risk assessment is not limited to active substances – it must equally cover excipients, packaging materials and other process-related substances such as extraction solvents. With the ICH Q3E Guideline for Extractables and Leachables (EMA/CHMP/ICH/236669/2025), currently available in draft form, primary packaging materials and product-contact materials will receive greater attention in future. Where a risk is identified, analytical evidence is required; where necessary, appropriate risk mitigation measures must be defined.

Support from PhytoLab

Risk assessment

The product-specific risk assessment covers the examination of all relevant components as required by the EMA: active substances and excipients, the manufacturing process and primary packaging. In addition, a comprehensive database search is carried out using our own library. We perform nitrosamine assessments for your chemically defined medicines as well as for herbal medicinal products.

Nitrosamine analytics

For analytical verification, we use a highly sensitive and selective LC-MS/MS method for the determination of the nitrosamines required by Ph. Eur. monograph 2.5.42 “N-nitrosamines in active substances and medicinal products” as well as further nitrosamines classified as carcinogenic in accordance with the EFSA Opinion “Risk assessment of N-nitrosamines in food” (EFSA Journal 2023;21(3):7884). The determination of API-specific nitrosamines is available on request.