Determination of a Genotoxic NDMA Impurity Using the High-Resolution Agilent 6546 LC/Q-TOF in Ranitidine Drug Substance and Drug Products

Importance of the Topic

Ensuring the safety of pharmaceutical products requires reliable detection of genotoxic impurities. N-nitrosodimethylamine (NDMA) in ranitidine attracted regulatory attention due to its probable carcinogenicity, leading to global product recalls and the need for highly sensitive analytical methods.

Objectives and Overview

This work aimed to develop and validate a high-resolution LC-Q-TOF method using the Agilent 6546 platform for trace-level quantification of NDMA in ranitidine drug substance and finished dosage forms.

Methodology and Instrumentation

Key system configuration and parameters:

• UHPLC: Agilent 1290 Infinity II high-speed pump, multisampler, multicolumn thermostat, and variable-wavelength detector
• Column: Agilent InfinityLab Poroshell HPH-C18 (4.6×150 mm, 2.7 µm) at 40 °C
• Mobile phase A: 0.2% formic acid in water; B: methanol; gradient from 5% to 95% B over 14 min at 0.3–0.5 mL/min
• Injection volume: 20 µL; multisampler at 6 °C; needle wash methanol:water (80:20)
• Mass spectrometry: Agilent 6546 LC/Q-TOF with APCI positive mode, drying gas 6 L/min at 300 °C, nebulizer 45 psi, mass range m/z 70–170
• Data acquisition: MassHunter LC/MS Data Acquisition v10; quantification with MassHunter Quantitative Analysis for TOF v10

Sample preparation involved spiking known NDMA standards into ranitidine API and tablet extracts, with a divert valve protecting the detector from high-concentration matrix components.

Main Results and Discussion

The method exhibited linear calibration from 0.25 to 100 ng/mL (R² > 0.9997). Limit of detection was 0.15 ng/mL (S/N ≈ 19) and limit of quantitation 0.25 ng/mL (S/N ≈ 47). Accuracy across levels remained within ±20%, and reproducibility showed CVs below 15%, with a representative RSD of 2.0% at 1 ng/mL. Recovery studies at 6 ng/mL and 48 ng/mL yielded approximately 94% recovery in both drug substance and product matrices, demonstrating minimal matrix effects.

Benefits and Practical Applications

This validated method provides pharmaceutical laboratories with a robust, sensitive, and specific approach to screen and quantify NDMA. It supports compliance with regulatory guidelines, enhances product safety monitoring, and aids in investigating and preventing nitrosamine contamination.

Future Trends and Possibilities

Emerging developments may include expansion to other nitrosamine species across diverse drug products, integration of automated sample preparation, adoption of data independent acquisition workflows, and application of advanced data analytics or machine learning for real-time impurity screening.

Conclusion

The high-resolution Agilent 6546 LC-Q-TOF platform, combined with optimized chromatographic and APCI-Q-TOF conditions, delivers a sensitive and reliable method for NDMA quantitation in ranitidine. The approach meets stringent regulatory requirements and strengthens pharmaceutical quality control.

References

• USFDA guidance on development and validation of RapidFire-MS/MS methods for nitrosamine screening
• USFDA guidance on LC-HRMS determination of six nitrosamine impurities in ARB drugs
• Determination of nitrosamine impurities using the high-resolution Agilent 6546 LC/Q-TOF; Agilent application note 5994-1372EN, 2019
• FDA guidance on LC-HRMS method for NDMA in ranitidine drug substance and product
• FDA press release on NDMA detection in ranitidine samples