Nitroso Impurities in Drug Products: An Overview of Risk Assessment, Regulatory Milieu, and Control Strategy

Many nitrosamines have been recognized to be carcinogenic for many decades. Despite the fact that several nitrosamine precursors are frequently used in the manufacturing of pharmaceutical products, their potential presence in pharmaceutical products has previously been overlooked due to a lack of understanding on how they form during the manufacturing process. From the risk assessment, it is clear that nitrosamines or their precursors may be present in any component of the finished dosage form. As a risk mitigation strategy, components with a high potential to form nitrosamine should be avoided. In the absence of suitable alternatives, sufficient measures to maintain nitrosamines below acceptable intake levels must be applied. Excipient manufacturing pathways must be extensively studied in order to identify probable excipient components that may contribute to nitrosamine formation. The manufacturers must not solely rely on pharmacopeial specifications for APIs and excipients, rather, they should also develop and implement additional strategies to control nitrosamine impurities. The formulation can be supplemented with nitrosating inhibitors, such as vitamin C, to stop the generation of nitrosamine. The purpose of this review is to identify key risk factors with regard to nitrosamine formation in pharmaceutical dosage forms and provide an effective control strategy to contain them below acceptable daily intake limits.