Development of a Simultaneous Analytical Method for Amines Corresponding to 10 Typical Nitrosamines

Regulatory authorities in various countries have successively issued notices and guidance to pharmaceutical manufacturers and distributors to evaluate the risk of contamination of nitrosamines in pharmaceutical products and to take appropriate measures. Analysis of nitrosamines in pharmaceutical products is not easy due to the large number of foreign substances, and the risk of contamination is determined by first conducting a desk investigation of the manufacturing process of the APIs or pharmaceutical products. However, a desk investigation may miss the risk since this method is not based on actual measurements. Therefore, in addition to conventional desk-based investigation, a new method is required to pick up risks that cannot be covered by a desk investigation. Nitrosamines are known to be formed by the reaction of amines with nitrosating agents such as nitrite. In the case of small alkyl nitrosamines such as NDMA and NDEA, the origin of the amines is mostly residual amines in the APIs. Residual amines in the APIs are a potential nitrosamine contamination risk, although the extent of that risk has rarely been reported. In this study, we developed and validated a simultaneous analytical method for amines corresponding to 10 typical small alkyl nitrosamines. Good linearity was obtained in the range of 0.003 to 10 μg/mL for MPA, 0.003 to 2 μg/mL for DIPA and DBA, 0.003 to 1 μg/mL for MeP, DEA, EIPA, and DPA, and 0.003 to 0.2 μg/mL for DMA, MOR, and MBA. The limits of quantitation and detection were 0.003 and 0.001-0.003 μg/mL, respectively. The recovery rates ranged from 70 to 130% for 121 APIs and were more than 40% for 83 APIs. Repeatability was also good, with %RSD < 15%. Although the correlation between the amount of amines detected in the APIs and the nitrosamines in the pharmaceutical products is under investigation, we expect that this analytical method will be used to determine the residual amine contents in APIs and contribute to the risk assessment of the nitrosamine contamination.