* Nitrosamines are trace chemical impurities.
* They are classified as probable human carcinogens.
* Global agencies require a strict 3-step risk assessment framework.
* Manufacturers must evaluate, test, and fix any impurity risks.
1. The Global CPCA System
Agencies use the **Carcinogenic Potency Categorization Approach (CPCA)** to set safety limits. This system groups impurities into 5 categories based on their chemical structure.
2. Rules by Country
US FDA (United States)
* The FDA looks closely at active ingredients and excipients.
* Amines can react with trace nitrites in common inactive ingredients.
* The FDA allows antioxidants like Vitamin C to stop this reaction.
#EMA (Europe)
* The EMA fully integrates nitrosamine checks into routine GMP inspections.
* Safety limits apply throughout the entire shelf life of the drug.
* Growth trends during stability tests trigger tighter batch release rules.
#ANVISA (Brazil)
* ANVISA aligns its rules with the EMA and the FDA.
* Testing is optional if impurity levels stay below 10% of the safety limit.
* High levels above 100% trigger immediate market recalls.
#Swissmedic (Switzerland)
* Swissmedic focuses strictly on high-risk Category 1 and Category 2 items.
* They use a strict, risk-based approach for vulnerable active ingredients.
* They allow temporary higher limits for short-term treatments to avoid drug shortages.
#Health Canada (Canada)
* Health Canada keeps a dynamic list of specific limits in Appendix 1.
* They give companies up to 3 years to implement permanent formulation changes.
* Tighter initial batch limits are required if stability data shows impurity growth.
3. Main Quality Control Root Causes
* **Chemical Reactions:**
Secondary amines react easily with nitrous acid.
* **Dirty Materials:** Recycled solvents can carry cross-contamination risks.
* **Excipient Nitrites:** Trace nitrites hide inside standard binding agents.
