Based on the FDA’s current understanding of the chemistry, the guideline discusses potential causes for the formation of nitrosamines and presents a comprehensive risk assessment strategy to detect and prevent their presence. Acceptable intake (AI) limits for the nitrosamine impurities NDMA, NDEA, NMBA, NMPA, NIPEA, and NDIPA are recommended.
Furthermore, circumstances leading to an external introduction of nitrosamines are described as possible sources of contamination. These may origin from catalysts, reagents or recovered solvents. If a contamination is detected in a finished drug, the FDA has to be notified once confirmatory tests have been performed. The guideline provides a step by step instruction.
The document should be understood as a proactive measure on part of the FDA to avoid nitrosamine contamination from the very first step of manufacturing. It enters into force immediately. A public consultation has been dispensed as to provide timely information to manufacturers. However, the guidance remains subject to comment.