The landscape of impurity control in pharmaceutical manufacturing has been profoundly reshaped by the emergence of N-nitrosamines as potent mutagenic impurities. Since the initial discovery of NDMA in sartan-based products in 2018, regulatory bodies have continuously refined their expectations to safeguard public health.
Recent updates introduced by the European Medicines Agency (EMA), particularly revisions linked to acceptable intakes and broader regulatory implementation measures, represent a significant step in refining acceptable intake limits and harmonizing risk assessment expectations across the pharmaceutical lifecycle. These nitrosamine guidelines reinforce the need for proactive impurity management supported by robust analytical science.
EMA’s Appendix 1 update: New acceptable intake limits for nitrosamines
One of the most consequential developments within the EMA’s nitrosamine updated guidelines is the refinement of acceptable intake (AI) limits published through the Appendix 1 framework. These limits define maximum daily exposure thresholds designed to keep lifetime cancer risk below 1 in 100,000 patients, aligning with international risk-based impurity principles derived from the International Council for Harmonisation (ICH) M7 guideline.
This revision adds new acceptable intake limits linked to newly identified nitrosamine drug substance-related impurities (NDSRIs) associated with the manufacturing processes of several active pharmaceutical ingredients, including levodropropizine, cytisine, lumefantrine, mifepristone, tapentadol, and selumetinib. In parallel, regulators have defined an acceptable intake for a nitrosamine impurity formed from the fragrance ingredient methyl N-methylanthranilate, reflecting increased regulatory attention to less traditional impurity sources beyond core Active Pharmaceutical Ingredient (API) synthesis.
The establishment of new acceptable intake values signals that risk evaluations must remain dynamic and data-driven throughout the product lifecycle.
Regulatory comparison: EMA and FDA approaches to nitrosamine control
The European Medicines Agency (EMA) and the Food and Drug Administration (FDA) largely align on controlling nitrosamine impurities in pharmaceuticals, relying on shared scientific principles derived from nitrosamine impurities ICH guidelines, particularly ICH M7(R2). Their regulatory expectations largely converge around three core actions:
- Conduct risk assessments evaluating potential nitrosamine formation pathways.
- Perform confirmatory testing using sensitive and validated analytical methods.
- Implement manufacturing or formulation changes to maintain impurities below acceptable limits.
Despite being based on the same principles, some differences can be found between them. Key distinctions remain in implementation. While the European framework focuses on lifecycle reassessment and coordinated portfolio-wide evaluations, the FDA nitrosamine guidance places more emphasis on predictive toxicological assessment, particularly for nitrosamines without sufficient carcinogenicity data (NDSRIs), using structure-activity relationships to estimate acceptable intake limits.
As global harmonization advances through initiatives such as the ICH M7 addendum on nitrosamines, pharmaceutical companies increasingly need analytical and compliance strategies capable of satisfying both EMA lifecycle expectations and FDA predictive safety assessment requirements.
Analytical strategies to quantify nitrosamines at trace levels
Increasingly stringent limits defined in current nitrosamines guidelines require analytical methods capable of detecting impurities at extremely low concentrations. Because acceptable intake thresholds are often in the low parts-per-billion range, pharmaceutical testing relies on highly sensitive chromatographic and mass spectrometric techniques to ensure accurate quantification and regulatory compliance.
The most widely applied platforms combine chromatographic separation with mass spectrometry, particularly UPLC-MS/MS and GC-MS/MS, which provide the selectivity and sensitivity necessary to quantify multiple compounds simultaneously while meeting modern nitrosamine standards. Analytical performance, however, depends not only on instrumentation but also on optimized sample preparation designed to minimize matrix interference.
Key preparation strategies typically include:
- Solid phase extraction (SPE) to concentrate analytes and reduce background noise.
- Hydrophilic interaction chromatography (HILIC)-based clean-up approaches to improve selectivity in complex formulations.
- Matrix-specific workflows adapted to APIs and finished drug products.
A critical challenge is avoiding artefactual nitrosamine formation during sample handling, which may produce false positives. Careful solvent selection and the use of scavengers help prevent unintended nitrosation reactions, an aspect increasingly emphasized in nitrosamine updated guidelines.
Recent developments also prioritize faster and more robust analytical workflows suitable for routine quality control across diverse pharmaceutical matrices. Together, sensitive detection technologies and optimized preparation strategies enable reliable trace-level monitoring aligned with global expectations, supporting ongoing product safety and compliance.
Risk assessment and compliance actions for pharmaceutical companies
Risk assessment is a mandatory multi-step regulatory process established by global nitrosamine guidelines for pharmaceutical manufacturers to identify, evaluate, and mitigate potential carcinogenic nitrosamine impurities in drug products.
Risk mitigation actions extend beyond testing alone and require coordinated manufacturing and quality improvements. Common compliance strategies include:
- Reformulation or process modification to eliminate nitrosating conditions.
- Strengthened supplier and raw material oversight.
- Enhanced quality systems and lifecycle monitoring programs.
- Real-time monitoring and avoidance of nitrosating agents during manufacturing.
Establishing acceptable intake thresholds through structural grouping allows companies to prioritize analytical resources and regulatory actions, particularly for complex nitrosamines lacking direct toxicological datasets. In practice, implementing these measures demands integrated expertise across analytical development, regulatory interpretation, and impurity investigation.
Analytical partners such as AMSbiopharma support pharmaceutical companies by combining high-quality detection capabilities with risk-based method development and regulatory-aligned testing strategies, helping translate evolving requirements into practical and sustainable compliance solutions.
Our laboratory is equipped with advanced instrumentation, such as UPLC-MS/MS equipment, designed to achieve the ultra-low detection limits required by the updated Appendix 1 of EMA nitrosamine guidance. We help you transform complex trace analysis into a streamlined regulatory submission, ensuring the continued safety and availability of your therapeutic pipeline.
References
European Medicines Agency. Nitrosamine impurities in human medicines [Internet]. Amsterdam: EMA; [cited 2026 Feb 12]. Available from: https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/referral-procedures-human-medicines/nitrosamine-impurities
European Medicines Agency. ICH M7 assessment and control of DNA reactive (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risk – Scientific guideline [Internet]. Amsterdam: EMA; 2023 [cited 2026 Feb 12]. Available from: https://www.ema.europa.eu/en/ich-m7-assessment-control-dna-reactive-mutagenic-impurities-pharmaceuticals-limit-potential-carcinogenic-risk-scientific-guideline
U.S. Food and Drug Administration. CDER nitrosamine impurity acceptable intake limits [Internet]. Silver Spring, MD: FDA; [cited 2026 Feb 12]. Available from: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cder-nitrosamine-impurity-acceptable-intake-limits