How to Conduct a Nitrosamine Risk Assessment
Systematically evaluate whether your product could contain nitrosamine impurities.
What a how-to is not
A how-to is SPEQ’s practitioner method, not a procedure. It does not replace your own SOP, it is not a validated approach, and the judgement calls in it belong to your quality unit.
Nitrosamine risk assessment evaluates whether a drug product could contain N-nitrosamine impurities — potent mutagenic carcinogens — from the API synthesis, formulation, packaging, or degradation. Regulators required marketing-authorisation holders to assess all products after nitrosamines were found in sartans and other drugs, following a three-step assess → confirm → mitigate approach.
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Assess the risk (Step 1)
Perform a structured risk assessment across the product and its whole supply chain, examining the route of synthesis, the reagents and solvents, recovered and recycled materials, the excipients, the container-closure and the manufacturing process itself for conditions that could form or introduce nitrosamines. The assessment is only as good as the supply-chain knowledge behind it, so the limits of that knowledge belong in the record.
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Prioritise by risk
Prioritise the products and processes where a risk is identified, using the potency of the potential nitrosamine and the exposure the product represents. Prioritisation is what makes the exercise tractable across a portfolio, and it needs to be recorded as reasoning rather than as a ranking, because an authority will ask why a product was placed where it was.
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Confirm by testing (Step 2)
Confirm by testing where the risk assessment indicates one, with methods sensitive enough for the limits in question and validated for the matrix. A method whose limit of quantitation sits above the acceptable intake cannot confirm absence, and reporting "not detected" from such a method is the error most worth avoiding here.
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Compare against acceptable intake limits
Compare results against the applicable acceptable intake limits for the specific nitrosamine, taking account of the maximum daily dose and, where more than one nitrosamine is present, the combined exposure. The comparison has to use the current limits, since this is an area where the science and the published values have moved repeatedly.
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Mitigate where needed (Step 3)
Mitigate where the result requires it — through changes to the route, the reagents, the suppliers, the process conditions or the specification — and assess the change for its own consequences. Report to the relevant authorities as required, and treat the reporting obligation as part of the mitigation rather than after it.
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Maintain and reassess
Maintain the assessment as a live document and reassess on change: a new supplier, a new route, a new solvent recovery arrangement, or new scientific understanding. Treating nitrosamines as resolved is the characteristic error, because the assessment’s premises are exactly the things that change.
- !Assessing only the API and missing formulation, packaging, and degradation-related sources.
- !Using analytical methods not sensitive enough to detect nitrosamines at the acceptable-intake limits.
- !Treating it as a one-time exercise rather than embedding it into change control.
- !Overlooking nitrite impurities in excipients as a nitrosating source.
How to Conduct a Nitrosamine Risk Assessment: frequently asked questions
Common questions on conduct a nitrosamine risk assessment.
Why are nitrosamines a concern?
N-nitrosamines are potent mutagenic carcinogens. After they were unexpectedly found in sartan blood-pressure medicines (and later others), regulators required all marketing-authorisation holders to assess their products for nitrosamine risk and control any found to safe limits.
What is the three-step approach?
Step 1: risk assessment of all products for potential nitrosamine sources. Step 2: confirmatory testing of at-risk products with sensitive validated methods. Step 3: mitigation (process, supplier, formulation, packaging, or specification changes) and regulatory updates where limits are exceeded.
Where do nitrosamines come from?
From the combination of a nitrosating agent (e.g., nitrite) and an amine, which can arise in API synthesis, from recovered solvents/catalysts, from contaminated raw materials or excipients, from packaging, or from degradation during storage. A thorough assessment covers all of these, not just the synthetic route.
How are acceptable limits set?
Acceptable intake (AI) limits are derived per nitrosamine from carcinogenicity data where available, or via read-across and thresholds consistent with ICH M7 principles for mutagenic impurities. Product results are judged against these AI limits to decide whether mitigation is needed.