Reliable HPLC/UV Quantification of Nitrosamine Impurities in Valsartan and Ranitidine Drug Substances

Significance of the Topic

Carcinogenic nitrosamine impurities present in valsartan and ranitidine pose significant risks due to their DNA-mutating potential and have led to drug recalls and heightened regulatory scrutiny. Reliable, low-level detection ensures pharmaceutical safety and compliance.

Objectives and Study Overview

This study aimed to develop and demonstrate a robust HPLC-UV method for simultaneous quantification of six nitrosamine impurities (NDMA, NMBA, NDEA, NEIPA, NDIPA, NDBA) in valsartan drug substance and NDMA in ranitidine. The approach integrates UV detection at 245 nm with mass confirmation to ensure accurate peak identification.

Methodology

The separation of nitrosamines was carried out on an XSelect HSS T3 4.6×100 mm, 3.5 μm reversed-phase column at 40 °C, using a gradient of water (0.02% formic acid) and acetonitrile at 1.0 mL/min. A sample injection of 25 μL enabled analysis of spiked drug substances at ~100 μg/mL to establish limits of quantitation (LOQ, S/N ≥10). The method achieved LOQs of 10 ng/mL for NDMA, NDEA, NDIPA and 20 ng/mL for NMBA, NEIPA, NDBA, with linearity over 10–1000 ng/mL (R² ≥0.999). Precision at the LOQ level showed %RSD ≤8.2% across six replicates.

Instrumentation Used

• ACQUITY Arc System with 2998 PDA Detector
• ACQUITY QDa Mass Detector (ESI+ mode, 50–500 m/z)
• XSelect HSS T3 Column, 4.6×100 mm, 3.5 μm
• Empower 3 Chromatography Data System

Main Results and Discussion

The optimized method provided clear separation of six nitrosamines from valsartan and NDMA from ranitidine, as demonstrated by representative chromatograms. UV quantification delivered low ng/mL sensitivity, while the QDa detector offered rapid mass-based confirmation of each impurity. The method showed excellent reproducibility (%RSD ≤7.51%) and strong linearity (R² up to 0.99991), supporting its robustness.

Benefits and Practical Applications

• Single HPLC-UV workflow for multiple nitrosamines
• Low quantitation limits suitable for regulatory monitoring
• Mass detection ensures confident peak identification
• Applicable to quality control of valsartan, ranitidine, and related substances

Future Trends and Potential Applications

Continued advancements may include coupling with tandem mass spectrometry for enhanced sensitivity, automation for high-throughput screening, expansion to other nitrosamine classes, and integration into process analytical technology (PAT) frameworks. Regulatory demands will spur method refinement and broader industry adoption.

Conclusion

A reliable and sensitive HPLC-UV method with mass confirmation has been established for quantification of key nitrosamine impurities in pharmaceutical drug substances. Its low detection limits, reproducibility, and confirmatory capabilities provide a solid foundation for routine QC testing and regulatory compliance.

References

1. US FDA update on recent drug recalls due to nitrosamines.
2. FDA statement on NDMA found in ranitidine.
3. Maziarz M, Naughton S, Rainville P. Waters Technology Brief, December 2019.