AI, acceptable intake; APIs, active pharmaceutical ingredients; ARBs, angiotensin II receptor blockers; AZBC, 4'-(azidomethyl)-[1.1'-biphenyl]-2-carbonitile; AZBT, 5-(4'-(azidomethyl)-[1,1'-biphenyl]-2-yl)-1H-tetrazole; AZTT, 5-(4'-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl) methyl)-[1,1'-biphenyl]-2-yl)-1H-tetrazole; CDER, center for drug evaluation and research; CPNP, 1-cyclopentyl-4-nitrosopiperazine; Control limits; DBA, N,N-dibutylamine; DEA, N,N-diethylamine; DIPEA, N,N-diisopropylethylamine; DMA, dimethylamine; DMF, N,N-dimethyl formamide; DPA, N,N-dipropylamine; EMA, European Medicines Agency; EPA, Environmental Protection Agency; FDA, Food and Drug Administration; HSA, Health Sciences Authority; IARC, International Agency for Research on Cancer; ICH, International Council for Harmonisation; LD50, median lethal dose; MBA, N-methylamino-N-butyric acid; MDD, maximum daily dose; MNP, 1-methyl-4-nitrosopiperazine; NAP, nitrosation assay procedure; NDBA, N-nitrosodibutylamine; NDEA, N-nitrosodiethylamine; NDIPA, N-nitrosodiisopropylamine; NDMA, N-nitrosodimethylamine; NDSRIs, Nitrosamine drug substance-related impurities; NEIPA, N-nitroso ethylisopropylamine; NMBA, N-nitroso-N-methyl-4-aminobutyric acid; NMP, N-methyl pyrrolidinone; NOCs, N-nitroso compounds; Nitrosamines; Nitrosation; PPRs, proportionate reporting ratios; Ranitidine; SARs, structure­activity relationships; Sartans; TD50, median toxic dose; TEA, triethylamine; TMA, trimethylamine; TTC, threshold of toxicological concern; USFDA, United States Food Drug and Administration; USP, United States Pharmacopoeia; WHO, World Health Organization