Highly Sensitive and Robust UPLC-MS/MS Quantification of Nitrosamine Impurities in Sartan and Ranitidine Drug Substances

Importance of the Topic

The presence of nitrosamine impurities in pharmaceutical substances such as sartans and ranitidine poses a significant carcinogenic risk. Regulatory agencies have issued recalls and guidelines, including ICH M7(R1), emphasizing the need for sensitive, reliable analytical methods to detect these genotoxic impurities at trace levels. Robust quantification techniques safeguard patient safety and ensure compliance in drug manufacture and quality control.

Objectives and Study Overview

This work aimed to develop and demonstrate a single, highly sensitive UPLC-MS/MS assay for simultaneous quantification of six nitrosamines—NDMA, NDEA, NEIPA, NDIPA, NDBA, and NMBA—in solutions of ranitidine and three sartan drug substances (irbesartan, losartan, valsartan). The goal was to achieve a lower limit of quantification (LLOQ) of 0.1 ng/mL with full method robustness across a wide dynamic range.

Methodology and Used Instrumentation

The assay employed a Waters ACQUITY UPLC I-Class PLUS system coupled to a Xevo TQ-XS tandem quadrupole mass spectrometer. Chromatographic separation utilized an ACQUITY UPLC HSS T3 column (1.8 µm, 2.1 × 100 mm) and a gradient of 5 mM ammonium formate/0.1% formic acid in water (mobile phase A) and methanol (mobile phase B). Key instrument settings included:

• Injection volume: 30 µL; column temperature: 40 °C; sample tray: 10 °C
• APCI+ source with StepWave ion guide and IonSABRE probe; probe at 400 °C; desolvation gas: 1000 L/hr
• MRM transitions optimized for each nitrosamine; calibration range: 0.05–100 ng/mL

Main Results and Discussion

The method delivered LLOQs of 0.1 ng/mL (3 pg on-column) for all six nitrosamines, with calibration linearity (R2 ≥ 0.99) over 0.1–100 ng/mL. Accuracy and precision results met acceptance criteria, with relative standard deviations ≤15%. Representative chromatograms showed clear separation and high signal-to-noise ratios versus blank injections.

Benefits and Practical Applications

This UPLC-MS/MS approach provides a fast, robust, and sensitive solution for nitrosamine screening in QA/QC laboratories, enabling routine monitoring in pharmaceutical development and manufacturing. Its broad dynamic range and low detection limits support regulatory compliance and risk mitigation.

Future Trends and Applications

Future developments may include expanding analyte panels, coupling with high-resolution MS for non-targeted impurity profiling, and integrating automated sample preparation. Advances in ionization technologies and data processing will further enhance sensitivity and throughput for genotoxic impurity analysis.

Conclusion

A single-run UPLC-MS/MS assay has been established for trace-level quantification of six nitrosamines in sartan and ranitidine substances, achieving high sensitivity, accuracy, and robustness. This method serves as a practical foundation for regulatory-driven impurity control and pharmaceutical quality assurance.

References

1. FDA update on recent voluntary ARB drug recalls. U.S. Pharmacist, 2020.
2. FDA statement on NDMA found in samples of ranitidine. U.S. FDA press announcement, 2019.
3. International Conference on Harmonization. ICH M7(R1): Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals. March 2018.
4. Maziarz M., Naughton S. Use of a proprietary polar column chemistry for the separation of nitrosamines in sartan and ranitidine drug substances. Waters Technology Brief 720006738EN, 2020.