Ultra-Sensitive Dynamic Headspace GC-MS/MS Method for Trace Level Quantitation of Nitrosamines in Deferiprone API

Significance of the Topic

The presence of nitrosamines in pharmaceutical ingredients poses a significant health concern due to their genotoxic potential and stringent regulatory limits. Deferiprone, a long-term therapy for thalassemia patients, requires highly sensitive analytical methods to detect trace-level impurities below acceptable intake thresholds to ensure patient safety and compliance.

Study Objectives and Overview

This work aimed to develop and partially validate an ultra-sensitive dynamic headspace GC-MS/MS method for simultaneous quantitation of six nitrosamines (NDMA, NDEA, NEIPA, NDIPA, NDPA, NDBA) in Deferiprone API. The study compares dynamic headspace sampling with static headspace approaches and aligns with global guidelines for controlling mutagenic impurities.

Methodology and Instrumentation

A Shimadzu GCMS-TQ8050 NX mass spectrometer coupled with an HS-20 NX dynamic headspace sampler was used, featuring a SH-PolarD capillary column (0.32 mm×60 m, 0.5 μm). Helium was the carrier gas under linear velocity control. The dynamic headspace sequence included optimized trap equilibration, desorption steps, and multi-injection cycles to maximize analyte capture. MRM transitions and collision energies were established via scan-mode tuning. Validation followed ICH Q2(R2) guidelines, assessing system precision, LOQ precision, linearity (0.03–0.54 ppb), accuracy across four spike levels, and method repeatability.

Results and Discussion

The dynamic headspace GC-MS/MS method achieved LOQs between 0.03 and 0.11 ppb for all six nitrosamines, with signal-to-noise ratios above 10. Calibration curves exhibited excellent linearity (r2 > 0.99). System precision at LOQ (%RSD area) remained below 11%, and method repeatability (%RSD content) was under 12%. Spiked recoveries ranged from 86% to 117%, meeting acceptance criteria. Compared to static headspace, dynamic sampling demonstrated enhanced sensitivity and flexibility, enabling reliable quantitation at regulatory thresholds.

Benefits and Practical Applications

• Provides enhanced sensitivity for trace nitrosamine detection to meet strict intake limits.
• Dynamic headspace flexibility accelerates method development through adjustable injection counts.
• Robust MRM configuration ensures high precision and accuracy for routine quality control.

Future Trends and Opportunities

Emerging directions include automated sample preparation integration, extension to other APIs, coupling with high-resolution mass spectrometry, and advanced data analytics for impurity profiling. Miniaturized headspace systems and online sampling could further reduce analysis time and resource consumption.

Conclusion

The validated dynamic headspace GC-MS/MS method on the Shimadzu GCMS-TQ8050 NX platform offers a sensitive, precise, and accurate solution for nitrosamine quantitation in Deferiprone API, supporting drug safety and regulatory compliance.

References

1. ICH Q2(R2) Validation of Analytical Procedures: Text and Methodology.
2. ICH M7(R1) Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals.
3. USP <1469> Nitrosamine Impurities General Chapter.