Author: S. Batna, A. Jha, M. M. Annapurna, A. V. B. Reddy, K. Sulochana

DOI: http://doi.org/10.31788/RJC.2026.1949901

Nitrosamine impurities have received wide attention after their discovery in the valsartan drug in 2018. Studies alsoconfirmed that drug substances can be contaminated with nitrosamines during synthesis and long-termstorage. Hence, validated analytical procedures are in great demand to determine nitrosamine impurities in pharmaceuticalswithin the acceptable threshold limits. The present study reported a sensitive LC-MS/MS method for N-nitrosooxcarbazepine determination in oxcarbazepine drug substance. The impurity was separated on a Zodiac C18 (150x4.6 mm, 5.0 µm) column using two mobile phases (mobile phase A: 0.1% formic acid in water, mobile phase B: 0.1% formic acid in methanol) in gradient elution mode with a flow rate of 0.5 mL/min. A triple quadrupole massspectrometer in positive-ion mode was used for the quantification of impurity. The method achieved an LODof 0.0156 ppm and an LOQ of 0.0312 ppm. The linearity was found excellent through the coefficient of determination(r 2 > 0.99), and the recovery of analyte was found between 87.48 and 97.00% across the tested concentration range. The validation data confirmed the method's reliability for N-nitroso oxcarbazepine impurity analysis inoxcarbazepine following the current regulatory standards. This study contributes to Sustainable Development Goal 9by promoting advanced technologies and quality infrastructure for pharmaceutical manufacturing.

Keywords: Nitrosamines, LC-MS/MS, Method Validation, Quality Assurance, Drug Substances.