Quantitation of NDMA, NMBA, NDEA, NEIPA, NDPA, NDIPA, NMPA and NDBA in 12 different solvents by LC-MS/MS system

Importance of the Topic

Nitrosamines are potent human carcinogens that can contaminate pharmaceutical products via residual amines and recovered solvents. Accurate quantitation of these impurities in solvents is essential for ensuring drug safety and regulatory compliance.

Objectives and Overview

This work presents a single LC-MS/MS method for simultaneous determination of eight nitrosamines (NDMA, NMBA, NDEA, NEIPA, NDPA, NDIPA, NMPA, NDBA) across twelve commonly used solvents. The study addresses contamination risks from API synthesis, solvent recovery, and provides tailored sample preparation approaches.

Applied Methodology and Instrumentation

• Sample Preparation:
  1. Direct injection for water, methanol, ethanol, acetonitrile, isopropanol, DMSO.
  2. Evaporation protocol for dichloromethane, acetone, chloroform, ethyl acetate.
  3. Dilution approach for toluene and dimethylformamide.
• Chromatography:
  • UHPLC (Nexera XS) with Shim-pack GIST C18-AQ (100×4.6 mm, 3 µm).
  • Mobile phase A: 0.1% formic acid/water; B: 0.1% formic acid/methanol.
  • Gradient: 10→85% B (0–7.5 min), flow 0.7 mL/min, temperature 40 °C.
• Mass Spectrometry:
  • Shimadzu LCMS-8045 triple quadrupole with APCI in positive mode.
  • MRM transitions for eight analytes and four deuterated internal standards.
  • Nebulizing gas 3 L/min; drying gas 5 L/min; interface 350 °C; desolvation line 200 °C; block 200 °C.
• Calibration and Validation:
  • Standards 1–100 ppb, 30 ppb internal standard; LOQs determined per solvent.
  • Linearity weighting 1/C², R² > 0.995; injection volumes 4–10 µL.

Key Results and Discussion

• LOQs ranged from 0.001 to 0.01 ppm depending on solvent, with excellent linearity (R² > 0.995).
• Recoveries at LOQ levels were 90–110% for most analyte–solvent combinations.
• DMSO showed enhanced responses for select nitrosamines, requiring matrix-matched standards.
• DMF and toluene exhibited peak-shape issues for certain analytes, resolved by dilution; NDMA in DMF may require head-space GC-MS.
• Evaporation improved sensitivity for volatile solvents; direct injection suited polar media.

Benefits and Practical Applications

• A unified LC-MS/MS method simplifies quality control workflows for nitrosamine screening in diverse solvents.
• Optimized sample preparation strategies ensure sensitivity and reproducibility across solvent chemistries.
• Meets current regulatory expectations for nitrosamine monitoring in pharmaceutical manufacturing.

Future Trends and Opportunities

• Automation and high-throughput workflows to increase laboratory efficiency.
• Extension to additional nitrosamine species and in-process solvent monitoring.
• Integration with high-resolution MS or alternative ionization sources for broader impurity profiling.

Conclusion

This validated LC-MS/MS approach enables reliable, sensitive quantitation of eight nitrosamines in twelve different solvents, supporting pharmaceutical quality assurance and patient safety.

References

• Quantitation of 8 Nitrosamines in 12 different solvents by LC-MS/MS system, Shimadzu LC-040-EN, Mar 2021.