Concentration Monitoring of Plasma Ribavirin: Validation of a Liquid Chromatography-Mass Spectrometric Method and...

Area of Science:

• Analytical Chemistry
• Pharmacology

Background:

• Development of a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for routine ribavirin measurement in plasma.
• Addressing the need for precise quantification of antiviral drug concentrations.

Purpose of the Study:

• To establish and validate a robust LC-MS/MS assay for quantifying ribavirin in ethylenediaminetetraacetic acid (EDTA)-anticoagulated plasma.
• To investigate the stability of ribavirin in plasma under various storage conditions.
• To apply the developed method for therapeutic drug monitoring in hepatitis C patients.

Main Methods:

• Utilized a hydrophilic interaction chromatography column with a specific mobile phase (0.1 mmol/L ammonium formate pH 3.0) and acetonitrile gradient.
• Employed tandem mass spectrometry for quantitation using specific ion transitions (m/z 245.3 > 113.0 and m/z 245.3 > 96.0).
• Validated the method for linearity, sensitivity (limit of detection and quantitation), imprecision, and bias, and assessed stability in clinical samples.

Main Results:

• Demonstrated a linear relationship up to 10 mg/L with a limit of quantitation of 0.1 mg/L.
• Achieved assay imprecision <10% at 0.1 mg/L and <6% for concentrations >0.4 mg/L, with bias <4%.
• Found ribavirin stable at room temperature for 3 days, but decreased significantly by day 7; stable for 15 weeks at -20 °C. Plasma concentrations showed instability after separation from whole blood at room temperature.

Conclusions:

• A validated hydrophilic interaction LC-MS/MS method is suitable for measuring ribavirin in plasma.
• Recommended optimal sample handling: keep samples at 4 °C, separate within 2 hours, and store at 4 °C for short-term or -20 °C for long-term analysis.
• Successfully applied the method to monitor ribavirin therapy in hepatitis C patients, observing steady-state concentrations after prolonged treatment.