An Overview and Discussion of Azido Impurities and their Risk Assessments in Drug Substances and Drug Products

Azido impurities are known to be mutagenic and carcinogenic. A small exposure to these impurities may lead to cancer. These impurities may be formed and get incorporated into drug substances or drug products through reagents, catalysts, solvents, or raw materials used in the process of manufacturing drug substances. Various regulatory authorities have published press releases and notices regarding the control of these impurities with the interim limit. Azido impurities can be avoided by taking precautions during the manufacturing of drug substances and products. The methods used to identify and quantify these impurities require highly sensitive instruments such as LCMS/MS or GCMS, which can detect these impurities to a trace level within the given interim limit. These methods are validated according to various regulatory guidelines. Liquid chromatography, along with a mass detector, is mostly used for their determination.