Rapid & Efficient Nitroso Drug Substances Related Impurities Analysis in APIs at ppb level

Nitrosamines are a group of organic compounds containing the nitroso functional group. They can be found in water, food, tobacco, pesticides, or plastics, but received public attention in mid-2018, when they were also found in medicinal products.

Nitrosamines are known as possible mutagenic carcinogens for humans. They are referred to as the “cohort of concern” by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guideline on assessment and control of DNA reactive (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risk¹. The two best-known nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have been classified by the International Agency for Research on Cancer (IARC) as possible human (class 2A) carcinogens, but they are also genotoxic² . Once N-nitrosamines are activated by microsomal liver enzymes, they can react with DNA base pairs to form unstable α-hydroxyalkylnitrosamines and produce alkyldiazonium ions, which alkylate DNA bases and induce carcinogenic response³ .

Their presence in active substances may be linked to several factors, such as processing conditions with raw materials impurities like nitrites, accidental introduction due to cross-contamination (due to processes running in parallel on the same production lines), recovery procedures for solvents or also from degradation of the substance.

In addition to a list of nitrosamines classified with their specific maximum daily intake, all other nitrosamines such as Nitroso Drug Substances Related Impurities (NDSRI’s) should be identified and quantified in Active Pharmaceuticals Ingredients and Drug Products based on the risk evaluation. Further to the identification, the toxicological characterization of the Nitroso Drug Substances Related Impurities should be performed.

In this white paper, we review the main analytical techniques that have been investigated, and then we will present our work regarding the development of a UPLC-HRMS (ultra-high-performance liquid chromatography-high resolution mass spectrometry) technique for identifying and quantifying Nitroso Drug Substances Related Impurities, at ppb (parts-per-billion) level in Active Pharmaceutical Ingredients.

References

[1] International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). ICH guideline M7(R1) on assessment and control of DNA reactive (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risk [displayed 7 March 2021]. p. 6. Available at: https://www.ema.europa.eu/en/documents/scientific-guideline/ich-guideline-m7r1-assessment-controldna-reactive-mutagenic-impurities-pharmaceuticals-limit_en.pdf

[2] European Medicines Agency (EMA). Lessons learnt from presence of N-nitrosamine impurities in sartan medicines [displayed 24 September 2020]. Available at https://www.ema.europa.eu/en/documents/report/lessons-learnt-presencen-nitrosamine-impurities-sartan-medicines_en.pdf

[3] Šulc M, Hodek P, Stiborová M. The binding affinity of carcinogenic N-nitrosodimethylamine and N-nitrosomethylaniline to cytochromes P450 2B4, 2E1 and 3A6 does not dictate the rate of their enzymatic N-demethylation. Gen Physiol Biophys 2010;29:175-85. doi:10.4149/gpb_2010_02_175