Sensitive and Selective Quantitation of N- Nitroso Dabigatran Etexilate Impurity in Dabigatran Etexilate API using the Agilent 6495C LC/TQ

Significance of the Topic

Quantitation of trace nitrosamines in drug substances is critical due to their potent mutagenic and carcinogenic risks. Regulatory agencies require strict control of NDSRIs to protect patient safety and maintain product quality.

Objectives and Study Overview

This study aimed to develop and validate a highly selective and sensitive LC/TQ method for quantifying N-nitroso dabigatran etexilate impurity in the dabigatran etexilate API at levels down to 0.002 ppm, aligning with regulatory specifications.

Methodology and Instrumentation

The analytical workflow combined reversed-phase liquid chromatography on an Agilent Poroshell HPH-C18 column with multiple reaction monitoring on the Agilent 6495C triple quadrupole mass spectrometer. Sample extraction and pH adjustment were optimized to stabilize the API and improve recovery. Key MRM transitions and ESI positive mode parameters were fine tuned for optimal sensitivity.

Instrumentation

• Agilent 6495C LC/TQ with Agilent Jet Stream ESI source
• Agilent 1290 Infinity II LC
• Agilent InfinityLab Poroshell HPH-C18 column (150 x 3.0 mm, 2.7 µm)
• Mobile phases: aqueous 1 mM ammonium trifluoroacetate with formic acid; organic methanol/acetonitrile
• Gradient elution over 20 minutes at 0.5 mL/min
• Optimized source gases, temperatures, and voltages for enhanced selectivity

Main Results and Discussion

The method demonstrated linearity from 0.01 to 1.0 ng/mL (R2 = 0.9993), with LOD and LOQ at 6 and 10 pg/mL, respectively. Chromatographic separation ensured clear resolution of impurity and API peaks. Precision studies yielded RSD below 5% for repeated injections at the specification level. Recovery experiments across multiple API lots gave results within 90–110%.

Benefits and Practical Applications

• Enables reliable monitoring of nitrosamine impurities to meet regulatory limits
• Supports quality assurance and risk mitigation in pharmaceutical manufacturing
• Applicable to other nitrosamine-related impurities in complex drug matrices

Future Trends and Applications

Advances may include further sensitivity gains through microflow techniques, enhanced automation for high-throughput screening, and integration with data analytics and AI for real-time impurity profiling across diverse pharmaceutical products.

Conclusion

The presented LC/TQ method offers high sensitivity, selectivity, and robustness for quantifying N-nitroso dabigatran etexilate impurity in API, fulfilling stringent regulatory requirements and ensuring patient safety.

References

1. U.S. Food and Drug Administration Center for Drug Evaluation and Research. Recommended Acceptable Intake Limits for Nitrosamine Drug Substance-Related Impurities Guidance for Industry; August 2023.
2. Agilent Technologies. Application Note 5994-7066E. Low-Level Quantitation of N-Nitroso Dabigatran Etexilate Impurity in Dabigatran Etexilate Mesylate API using the Agilent 6495C LC/TQ.