Limit for Nitroso Ciprofloxacin

[Naiffer_Host]

It seems that regulatory bodies are inquiring manufacturers to demonstrate the absence of Nitroso-Ciprofloxacin.

SMILES: O=NN1CCN(C2=C(F)C=C(C(C(C(O)=O)=CN3C4CC4)=O)C3=C2)CC1

Just for context, I found an article from water research that study the reactivity of Ciprofloxacin under nitrosating conditions and demonstrated the formation of the Nitroso-compound.
https://www.sciencedirect.com/science/article/abs/pii/S0043135420308290

Perhaps the recent post on the FDA structural similarity poster can provide guidance. The authors also refer to the Dobo et al. publication

FDA - A new structural similarity method to ID surrogate compounds of Nitroamines

By Kruhlak, N. L.; Chakravarti, S.; Kumaran, G.; Saiakhov, R. A. FDA poster presented at Society of Toxicology Annual Meeting, San Diego USA 2022 A New Structural Similarity Method to Identify Surrogate Compounds for Assessing the Carcinogenicity of Nitrosamine Impurities A New Structural Similarity Method to Identify Surrogate Compounds for Assessing the Carcinogenicity of Nitrosamine Impurities FDA.pdf (1.3 MB) [image]