Determination of NDMA Impurity in Ranitidine Using the Agilent 6470 Triple Quadrupole LC/MS

Importance of the Topic

The detection of N-nitrosodimethylamine (NDMA) in ranitidine and related H2 receptor antagonists has become critical following global recalls triggered by carcinogenic nitrosamine contamination. Regulatory bodies such as the US FDA, EMA and China FDA demand highly sensitive, specific analytical techniques to monitor trace nitrosamine impurities in both active pharmaceutical ingredients (API) and finished drug products.

Objectives and Study Overview

This application note presents the development and validation of a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method using the Agilent 6470 triple quadrupole system to quantify NDMA in ranitidine drug substance and drug formulations. The study aims to achieve low detection limits, robust linearity and reliable recovery in the presence of high API concentrations.

Methodology and Instrumentation

Sample Preparation

• Drug substance: 120 mg ranitidine weighed and dissolved in water to 30 mg/mL concentration.
• Drug product: Tablets crushed and extracted in water to yield 30 mg/mL ranitidine solution, shaken and centrifuged with filtration.

Chromatographic Conditions

• UHPLC system: Agilent 1290 Infinity II (pump, autosampler, thermostat, detector).
• Column: Poroshell HPH-C18, 4.6 × 150 mm, 2.7 µm, 40 °C.
• Mobile phases: 0.1% formic acid in water (A) and methanol (B), gradient from 95% A to 5% A over 14 min, 0.3 mL/min.
• Diverter valve: Programmed to waste the ranitidine peak, directing only early NDMA eluent to MS.

Mass Spectrometry

• Instrument: Agilent 6470A triple quadrupole with APCI source in positive MRM mode.
• Source parameters: 300 °C drying gas, 5 L/min; 350 °C APCI heater; 35 psi nebulizer; 4,000 V capillary voltage.
• MRM transitions: NDMA quantifier 75.1→43.1 m/z, qualifier 75.1→58.1 m/z; optimized fragmentor and collision energies.

Data acquisition and analysis performed with Agilent MassHunter software version 10.

Main Results and Discussion

The method exhibited a linear response from 0.1 to 100 ng/mL with R2 > 0.9997 using 1/x weighting. The limit of detection for NDMA was 0.1 ng/mL (S/N > 20) and the limit of quantitation was 0.25 ng/mL (S/N > 45). Accuracy at LOQ was within ±20%. Reproducibility tests at 1 ng/mL produced relative standard deviations below 1%. Recovery in drug substance and product matrices ranged from 86 to 94%. The diverter valve effectively excluded the high-concentration ranitidine, preventing matrix suppression and ensuring MS sensitivity.

Practical Benefits and Applications

This LC–MS/MS approach offers:

• High sensitivity and specificity for trace NDMA detection in pharmaceutical matrices.
• Robust quantitation across regulatory concentration ranges.
• Effective exclusion of high API levels via valve diversion.
• Compatibility with routine QA/QC laboratories for nitrosamine monitoring.

Future Trends and Opportunities

Advances may include automation of sample preparation, expansion to other nitrosamine impurities, integration with high-resolution MS for broader screening, and adaptation to real-time process monitoring in continuous manufacturing.

Conclusion

The Agilent 6470 triple quadrupole LC–MS/MS method provides a validated, sensitive and reproducible platform for NDMA determination in ranitidine APIs and tablets. Its performance meets stringent regulatory requirements and supports effective control of genotoxic impurities in pharmaceutical production.

Reference

• US FDA Updates on Nitrosamine Impurities in ARB Recalls, FDA Drug Safety and Availability.
• FDA Guidance on LC-HRMS Methods for Nitrosamine Impurities Screening.
• Agilent Application Note 5994-1383EN, Determination of Nitrosamine Impurities Using Ultivo Triple Quadrupole LC/MS, 2019.