CMC & ManufacturingLast reviewed April 2026

Nitrosamine Impurity(Nitrosamine)

A class of genotoxic impurities that can form during drug substance or drug product manufacturing and require risk assessment and control.

Usage Examples

The nitrosamine risk assessment identified three potential formation pathways in the API synthesis route.
NDMA was detected at 0.5 ppm, above the AI limit, triggering a manufacturing process change.
The annual report included the updated nitrosamine risk assessment and revised API specifications.

What is Nitrosamine?

Nitrosamines are a class of potentially carcinogenic impurities that emerged as a major regulatory concern starting in 2018 when N-nitrosodimethylamine (NDMA) was detected in valsartan drug products. Subsequent investigations identified nitrosamines in metformin, ranitidine, and numerous other marketed drugs, triggering large-scale recalls and intense regulatory focus.

FDA, EMA, and other authorities now require a nitrosamine risk assessment for every approved and investigational drug product. The assessment evaluates potential sources (amines in APIs or intermediates, nitrites in excipients, reaction conditions, packaging interactions) and the feasibility of nitrosamine formation. Products with identified risk require confirmatory testing and, where needed, specification limits and control strategies to keep nitrosamine levels below the Acceptable Intake (AI) defined per individual nitrosamine species.

AI limits are highly conservative — often in nanograms per day — and derived from compound-specific carcinogenicity data. Sponsors identifying nitrosamine risk must file CMC changes (manufacturing process changes, specification additions, excipient qualification changes) through appropriate regulatory pathways, sometimes requiring Prior Approval Supplements. The FDA nitrosamine guidance document is frequently updated as new information emerges.

Regulatory Context

This term appears most often in cmc & manufacturing workflows where submission quality, regulatory evidence, and audit readiness depend on consistent language. It is commonly referenced alongside ICH M7, ICH Q3A, ICH Q3B.

FDAICHHealth Canada

When This Matters

The nitrosamine risk assessment identified three potential formation pathways in the API synthesis route.
NDMA was detected at 0.5 ppm, above the AI limit, triggering a manufacturing process change.
The annual report included the updated nitrosamine risk assessment and revised API specifications.

Common Mistakes

Failing to align CMC change narratives with current CFR/ICH expectations.
Submitting incomplete control strategy documentation.
Separating manufacturing and regulatory review cycles too late in execution.

Related Regulations

ICH M7ICH Q3AICH Q3B

How to Conduct a Nitrosamine Risk Assessment

Evaluate potential nitrosamine formation in a drug substance or drug product and determine required controls.

1
Identify potential precursors
Map all secondary and tertiary amines in the drug substance, intermediates, and excipients. Identify nitrite sources including residual nitrites in excipients, packaging materials, and processing water.
2
Evaluate formation conditions
Assess whether pH, temperature, and reaction environment could allow nitrosation of identified amines. Review known nitrosamine formation chemistry in similar product classes.
3
Prioritize identified risks
Classify risks as high, medium, or low based on precursor presence, formation feasibility, and exposure level. High-risk cases require confirmatory testing; low-risk may be controlled by established specifications.
4
Conduct confirmatory testing where indicated
Develop and validate analytical methods (typically LC-MS/MS) sensitive enough to detect nitrosamines at or below the Acceptable Intake (AI) limit. Test representative batches.
5
Define controls
Where nitrosamines are detected: establish drug substance and drug product specifications, review process conditions, consider API or excipient changes, and update the control strategy.
6
File regulatory updates
Annual Report for routine risk assessment documentation. CBE-30 or Prior Approval Supplement for process changes, new specifications, or excipient qualification changes. Submit the risk assessment itself to FDA and EMA per current guidance.

Frequently Asked Questions

Nitrosamines are a class of compounds with demonstrated or probable carcinogenicity in humans. Extended exposure even at low levels presents cancer risk. The AI (Acceptable Intake) limits set by regulators are derived from compound-specific carcinogenicity data and are typically in nanograms per day — very low absolute amounts.

The assessment must identify all potential sources of nitrosamine formation (amine precursors, nitrite sources, reaction conditions, packaging materials), evaluate the likelihood of formation, and — where risk exists — include confirmatory analytical testing and mitigation strategy. FDA and EMA have detailed guidance on assessment methodology.

Depends on mitigation complexity. If existing controls are sufficient and only the risk assessment needs to be documented, an Annual Report may suffice. If manufacturing process changes, new specifications, or significant analytical method additions are needed, a CBE-30 or Prior Approval Supplement may be required.