NDMA Formation Due to Active Ingredient Degradation and Nitrite Traces in Drug Product

N-nitrosamines are genotoxic compounds which can be found as impurities in drug substances and drug products used in the pharmaceutical industry. To date, several possible nitrosamine sources in drug products have been reported and this study aims to illuminate another one. A case of afatinib drug product was investigated, in which up to 50 ppb N-nitrosodimethylamine (NDMA) traces were detected. Afatinib was found to degrade to the secondary amine dimethylamine (DMA), forming NDMA with traces of nitrite in crospovidone. Two series of film-coated tablets were prepared with crospovidone from two different manufacturers, containing different levels of nitrites. Tablets were subjected to an accelerated stability study (40 °C/75% relative humidity) or stored at room temperature and levels of NDMA, DMA and nitrite in tablets were monitored. NDMA and nitrite were found on ppb levels, whereas DMA was detected on ppm levels. NDMA formation in the drug product was found to be time, temperature and nitrite dependent and it was emphasized that DMA and nitrite should be reduced. The accelerated stability study proved to be a useful tool for predicting nitrosamine formation in the drug product.