Nitrosamine impurities analysis using Thermo Scientific™ Orbitrap Exploris™ 120 MS

Significance of Topic

Nitrosamine impurities are recognized genotoxic compounds with probable human carcinogenicity. Their unexpected presence in active pharmaceutical ingredients (APIs) and finished drug products has prompted recalls and heightened regulatory scrutiny. The US FDA has set interim acceptable limits and published guidance requiring risk assessment and control strategies to prevent nitrosamine formation. A robust analytical method is essential to ensure drug safety and compliance with evolving regulations.

Goals and Study Overview

This work aimed to establish a single liquid chromatography–high resolution mass spectrometry (LC-HRMS) method capable of detecting and quantifying nine nitrosamines in pharmaceutical matrices. Key objectives included achieving high selectivity to resolve isobaric interferences, sub-ppm mass accuracy, low limits of quantitation, and robust reproducibility. Integration with compliant software for data acquisition and reporting was also a priority.

Methodology and Instrumentation

The method employed a Thermo Scientific Vanquish UHPLC system equipped with an Acclaim Polar Advantage II column (2.1 × 100 mm, 2.2 µm) to deliver consistent retention times, sharp peak shapes, and negligible carryover (except NDBA). Detection utilized a Thermo Scientific Orbitrap Exploris 120 mass spectrometer operated at up to 120 000 resolution (m/z 200) with EASY-IC internal calibration. Atmospheric pressure chemical ionization (APCI) provided superior sensitivity, achieving a lowest limit of quantitation (LLOQ) of 0.017 ppm for all targets in both neat solutions and excipient matrices. Chromeleon CDS 7.2.10 software governed instrument control, data processing, and reporting, fully compliant with 21 CFR Part 11.

Main Results and Discussion

Retention time reproducibility was better than 0.7 % RSD over 50 injections. Peak area precision remained below 2.5 % RSD. Carryover in excipient matrices was under 0.2 % for all nitrosamines except NDBA. The method resolved NDMA from co-eluting N-methylformamide isotopes at 120 000 resolution, avoiding false positives. Calibration curves were linear across 0.1–50 ng/mL (0.0034–0.017 ppm), with accuracy within ±8 % and precision under 8 % RSD. APCI outperformed HESI by up to 5× in LLOQ for certain analytes. Recovery studies from tablet extracts yielded 93–116 % and RSDs below 13 %.

Benefits and Practical Applications

• Comprehensive detection of nine nitrosamines in a single run.
• High-resolution MS ensures selectivity against isobaric interferences.
• Sub-ppm mass accuracy and low LLOQ support regulatory limits.
• Reproducible retention times and low carryover enable routine screening.
• Fully integrated software streamlines compliance and reporting in QA/QC labs.

Future Trends and Possibilities

Advances may include further automation and high-throughput sample introduction, miniaturized chromatography for reduced solvent consumption, and expanded target panels covering emerging nitrosamine analogues. Integration of machine learning for spectral deconvolution and automated risk assessment could enhance method robustness. Adoption of unified regulatory guidelines worldwide will drive method standardization and broader application across pharmaceutical quality control.

Conclusion

The presented LC-HRMS workflow provides a sensitive, selective, and reproducible solution for nitrosamine impurity analysis in drug products. By leveraging high-resolution Orbitrap technology and compliant data systems, laboratories can meet regulatory demands and protect patient safety through reliable detection and quantitation of genotoxic impurities.

References

No external literature references were provided in the original text.