Genotoxic impurity analysis

Importance of the Topic

Genotoxic impurities such as nitrosamines, azido compounds and nitroso drug substance related impurities (NDSRIs) represent critical safety concerns in pharmaceuticals. Regulatory alerts following recalls of sartans, metformin and varenicline have underscored the necessity for ultra-sensitive, selective and compliant methods to detect these carcinogenic contaminants at trace levels in complex drug matrices.

Objectives and Study Overview

This work evaluates a unified LC–MS/MS strategy for simultaneous quantitation of multiple genotoxic impurities in drug substances and formulations. Key aims include achieving sub-nanogram detection limits, high selectivity against chemical interferences, streamlined high-throughput analysis and full compliance with data integrity regulations (21 CFR Part 11, EMA, MHRA).

Used Instrumentation

• Thermo Scientific™ Vanquish™ HPLC/UHPLC system with SmartFlow™ pumping and SmartInject™ dosing
• Thermo Scientific™ TSQ Quantis™ triple quadrupole mass spectrometer with OptaMax™ NG ion source
• Thermo Scientific™ Chromeleon™ Chromatography Data System for method control, data acquisition and audit-ready reporting
• Viper™ Fingertight Fitting system and a range of LC columns (C18, Biphenyl, Mixed Mode WCX-1)

Methodology

A single reversed-phase UHPLC method separates active pharmaceutical ingredients from up to ten targeted nitrosamines and NDSRIs. Segmented quadrupoles and high-resolution Selected Reaction Monitoring (H-SRM at 0.4 Da FWHM) enhanced selectivity, while dual-mode temperature control and high-purity LC/MS solvents minimized background noise and ion suppression.

Main Results and Discussion

Limits of quantitation reached 0.5 ng/mL for most nitrosamines and as low as 0.025 ng/mL for AZBT in sartan drugs. The TSQ Quantis delivered robust linearity and reproducibility across extended sequences. UHPLC separation enabled simultaneous analysis of ten impurities, including N-nitroso-varenicline, within a 55 minute run. Acquisition speeds up to 600 SRMs/s supported high-throughput workflows and facilitated future addition of new targets.

Benefits and Practical Applications

• Exceptional sensitivity and selectivity for trace genotoxic impurities
• Single-method consolidation reduces analysis time and instrument downtime
• Compliance-ready data management with secure audit trails and electronic signatures
• Robust fittings and extended detector lifetime simplify maintenance
• Scalability to incorporate emerging impurities without full method redeployment

Future Trends and Applications

Ultrahigh-resolution mass spectrometry, automated sample preparation and AI-driven data processing will further enhance detection limits, reduce development time and increase laboratory throughput. Innovative stationary phases for polar nitrosamines and real-time impurity risk prediction will enable proactive quality control in drug manufacturing.

Conclusion

Integration of Vanquish HPLC/UHPLC, TSQ Quantis MS and Chromeleon CDS provides a comprehensive, sensitive and compliant platform for genotoxic impurity analysis. Its robustness, speed and regulatory alignment address current pharmaceutical safety mandates and future analytical challenges.