Development and Validation of a Highly Sensitive Liquid Chromatography Coupled With Tandem Mass Spectrometry Method for Trace‐Level Determination of N‐Nitroso‐Dabigatran Etexilate in Dabigatran Etexilate Mesylate Drug Substance

ABSTRACT

Nitrosamine drug substance‐related impurities have attracted increased regulatory attention because their occurrence at trace concentrations may affect pharmaceutical quality. Dabigatran Etexilate Mesylate contains nitrogen‐containing functional groups that may be susceptible to nitrosation under certain conditions, resulting in the formation of N‐nitroso‐dabigatran etexilate. Therefore, a sensitive liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) procedure was developed and validated for determination of N‐nitroso‐dabigatran etexilate in Dabigatran Etexilate Mesylate drug substance. Chromatographic separation was achieved on a Shim‐pack Scepter C18 column (150 × 4.6 mm, 3.0 µm) using gradient elution with 20 mM ammonium formate buffer (pH ∼5.0) and acetonitrile: water (90:10, v/v) as mobile phases. Quantitative analysis was performed in positive electrospray ionization mode using multiple reaction monitoring with the transition m/z 658.10 → 365.10. The method was evaluated for specificity, linearity, precision (including intermediate precision), accuracy, and sensitivity. A linear response was obtained across the studied concentration range with a correlation coefficient ( r ² ) of 0.9979. The limit of detection and limit of quantification were established at 0.0173 and 0.0525 ppm, respectively. Accuracy studies demonstrated satisfactory recovery across the evaluated concentration levels, while precision results confirmed reproducible analytical performance. The developed LC‐MS/MS method provides a sensitive approach for the determination of N‐nitroso‐dabigatran etexilate in Dabigatran Etexilate Mesylate drug substance.