Method Development and Validation for Quantification of N-Nitroso dibutylamine in Simvastatin and Ezetimibe Tablet by LC MS/MS
The detection of nitrosamine-related impurities in pharmaceutical products has emerged as a critical issue for regulatory agencies owing to their potential mutagenic and carcinogenic risks. N-nitrosodibutylamine (NDBA), one of the identified nitrosamine contaminants, is regarded as likely to be carcinogenic to humans and may pose a cancer-related hazard, can be generated during drug synthesis, processing, or storage conditions. Therefore, the identification and quantification of such trace-level impurities are essential to ensure drug safety and compliance with regulatory requirements. The present study aimed to develop and validate a sensitive, selective, and reliable Liquid Chromatography-Tandem Mass Spectrometry (LC–MS/MS) method for the determination of NDBA impurity in Simvastatin and Ezetimibe tablet formulations. Separation was performed on a Zorbax SB-Phenyl column (150 × 4.6mm, 3.5µm) using a gradient system of 0.1% formic acid in water and 0.1% formic acid in methanol, with a flow rate of 0.5mL/min. Detection was achieved using a triple quadrupole mass spectrometer fitted with an APCI source operating in positive ion mode, employing multiple reaction monitoring (MRM). The selected MRM transition for quantification of NDBA was m/z 159 → 103. The proposed analytical method was validated in compliance with International Council for Harmonisation recommendations by evaluating parameters such as specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). The developed LC–MS/MS method was found to be sensitive, accurate, and suitable for routine quality control analysis and regulatory monitoring of NDBA impurity in Simvastatin and Ezetimibe tablet formulations.