Quantitation of plasma warfarin concentrations by high performance liquid chormatography

Area of Science:

• Analytical Chemistry
• Pharmacokinetics

Background:

• Accurate quantification of warfarin in plasma is crucial for therapeutic drug monitoring.
• Existing analytical methods for warfarin often suffer from limitations in specificity, sensitivity, reproducibility, or convenience.

Observation:

• A novel extraction process involving acidification, removal of basic substances, and reextraction into ether was developed.
• The method utilizes a Bondapak C-18 column for separation and achieves high sensitivity (0.06-9.0 microgram/ml) and precision (CV < 2%).

Findings:

• The described high-performance liquid chromatography (HPLC) method provides specific, accurate, and convenient quantitative analysis of warfarin.
• It demonstrates linearity up to 9 microgram/ml and effectively avoids interference from common co-administered drugs like diazepam.

Implications:

• This validated HPLC method enables precise measurement of low warfarin concentrations, essential for optimizing patient dosing.
• The enhanced specificity and sensitivity offer a reliable alternative to existing methods, improving clinical utility in warfarin therapy management.