Determination of Nitrosamine Impurities and NDSRI in Anti-diabetic Drugs on Shimadzu LCMS-8060NX

Importance of the topic

Nitrosamine impurities are recognized carcinogens found in various drugs, including anti-diabetic medications. Regulatory agencies impose strict limits to protect patients. Developing reliable analytical methods for trace-level detection is crucial for pharmaceutical quality control and regulatory compliance.

Objectives and Study Overview

The study aims to establish a straightforward, sensitive LC-MS/MS method using atmospheric-pressure chemical ionization (APCI) for simultaneous quantification of ten nitrosamines, including nitroso-sitagliptin as an NDSRI, in anti-diabetic drug products. Method validation and real-sample analysis demonstrate the method’s applicability.

Methodology

• Calibration standards were prepared by serial dilution of concentrated nitrosamine stocks in LCMS-grade methanol to cover 0.1–10 ng/mL (API equivalent to 1–100 ppb).
• Drug samples (100 mg API equivalent) were extracted with 1 mL ultrapure water, sonicated, centrifuged, and filtered (0.22 µm) prior to analysis.
• Detection was carried out on Shimadzu LCMS-8060NX operating in MRM mode with APCI for enhanced sensitivity.

Instrumentation Used

• Shimadzu LCMS-8060NX triple quadrupole mass spectrometer
• Atmospheric-pressure chemical ionization (APCI) source
• Analytical HPLC system with optimized chromatographic column for nitrosamine separation

Key Results and Discussion

• Calibration curves for ten nitrosamines exhibited excellent linearity (R2 > 0.999) over 0.1–10 ng/mL.
• Limits of quantitation were below 10% of regulatory thresholds.
• Accuracy fell within ±20% and precision (RSD) remained <10% at LOQs (n=6).
• Recovery studies at LOQs in two drug matrices showed satisfactory recoveries.
• Application to commercial anti-diabetic samples revealed detectable levels of certain nitrosamines, highlighting practical relevance.

Benefits and Practical Applications of the Method

• Simplified sample preparation with minimal solvent and a 10 µL injection volume
• High sensitivity reaching 0.1 ng/mL quantitation, suitable for strict regulatory limits
• Adaptable chromatographic conditions permit extension to various drug products
• Supports routine pharmaceutical safety testing and quality assurance

Future Trends and Potential Applications

• Broader screening panels covering additional nitrosamines and related impurities
• Integration with high-throughput, automated sample processing workflows
• Real-time in-process monitoring during drug manufacturing
• Use in risk assessment, process optimization, and regulatory submission support

Conclusion

The developed APCI-based LC-MS/MS method on Shimadzu LCMS-8060NX provides a robust, sensitive, and efficient solution for quantifying nitrosamine impurities at trace levels in anti-diabetic drugs, ensuring compliance with regulatory standards and safeguarding patient health.

Reference

1. Nitrosamines as Impurities in Drugs – Health Risk Assessment and Mitigation Public Workshop, Food and Drug Administration, 2021.
2. Nitrosamine impurities, European Medicines Agency, accessed 2024-02-01.
3. Control of Nitrosamine Impurities in Human Drugs, U.S. Food and Drug Administration, 2020.
4. Nitrosamine impurities in medicines, Health Sciences Authority, accessed 2024-02-01.