USP Standard for Nitrosamine Impurities Becomes Official

Rockville, MD, December 1, 2021 – USP announced that its new General Chapter <1469> Nitrosamines Impurities became official today in the United States Pharmacopeia—National Formulary. This new standard supports manufacturers and regulators by providing guidance on assessing materials for nitrosamine presence, establishing control strategies for these impurities and ensuring the performance of analytical procedures to monitor nitrosamine levels in drug products.

Starting in 2018, nitrosamine impurities were found to be present in some angiotensin II receptor blockers used to treat high blood pressure and heart failure. Depending on the levels and extent of exposure to this class of chemical compounds, nitrosamines have the potential to cause cancer. Nitrosamine impurities have since been found in ranitidine and metformin, leading to major recalls and efforts by regulators and industry worldwide to reduce or eliminate the presence of these impurities in the drug supply.

To protect patients and strengthen the global medicines supply chain, USP has been developing tools and solutions to analyze and monitor emerging impurities in the drug supply. In addition to the documentary standard that became official today, USP has produced educational events on the topic and has also developed eight reference standards for various nitrosamine impurities. These reference standards are highly characterized specimens of the impurities which can be used by manufacturers to detect the presence of nitrosamines in their products.

For additional information on USP’s solutions related to nitrosamines, visit