Development and validation of an ultra-high-performance liquid chromatography-tandem mass spectrometry method to determine the bioavailability of warfarin and its major metabolite 7-hydroxy warfarin in rats dosed with oral formulations containing different polymorphic forms

Advancements in electrochemical sensor technology for warfarin detection: a comprehensive review

Warfarin (WA), the most prescribed oral anticoagulant in patients with atrial fibrillation, is widely utilized for the treatment of various diseases, such as vascular disorders, venous thrombosis, and atrial fibrillation. However, its abnormal concentration is linked to a variety of disorders and diseases, namely bleeding while brushing teeth, skin tissue issues, hair loss, and chest pain. Therefore, WA monitoring in blood serum is vital due to its narrow therapeutic window. Accordingly, WA determination has been conducted using various methods, such as high-performance liquid chromatography, fluorescent, surface-enhanced Raman scattering, and electrochemical methods. Electrochemical methods have received considerable attention due to their outstanding selectivity, remarkable sensitivity, great time efficiency, and cost-effectiveness. Herein, a comprehensive literature survey on electrochemical methods for determining WA is presented. This review discusses the development of various chemically modified electrodes (CMEs). These CMEs, such as multi-wall carbon nanotubes, molecularly imprinted polymers, metal oxide nanoparticles, and polymer nanocomposites, owing to their morphology and structure, high selectivity, high conductivity, and high volume/area ratio, are designed to overcome the limitations of bare electrodes, which include reduced electrocatalytic activity, slower electron transfer rates, and poor sensitivity. Also, this review presents the advantages and disadvantages of various modified electrodes applied in WA detection.

Quantitative determination of plasma free and total concentrations of antivitamin K drugs using a new sensitive and rapid LC-MS/MS method: Application in hemodialysis patients

BACKGROUND AND AIMS

Vitamin K antagonists (VKAs) are the first-line anticoagulants used in end stage renal disease. This population experiences a significant variability in their International Normalized Ratio (INR) over time. There is a need for methods allowing the study of the pharmacokinetics of free and total concentrations of VKAs to explain INR variability.

MATERIALS AND METHODS

We developed and validated a high-performance liquid chromatography-tandem mass spectrometry method allowing the quantification of warfarin and fluindione free and total plasma concentrations. Chromatographic separation was achieved in a raptor biphenyl column and the spectrometry acquisition was set in multiple reaction monitoring mode after negative electrospray ionization. We then applied it in describing the plasma free and total concentrations of VKAs in samples from 50 hemodialysis patients.

RESULTS

The developed method is rapid, sensitive and specific. Our cohort results showed a correlation between free and total VKA concentrations. The free VKA concentrations tended to be higher in patients with higher INR. Although VKAs are highly albumin-bound drugs, albumin concentration did not totally explain the high inter-individual total VKA concentrations variability.

CONCLUSION

This opens the door to further studies to understand the factors involved in their variability.

Simultaneous Characterization and Determination of Warfarin and Its Hydroxylation Metabolites in Rat Plasma by Chiral Liquid Chromatography-Tandem Mass Spectrometry

Warfarin is extensively used for venous thromboembolism and other coagulopathies. In clinical settings, warfarin is administered as a mixture of S- and R-warfarin, and both enantiomers are metabolized by multiple cytochrome P450 enzymes into many hydroxylation metabolites. Due to the high degree of structural similarity of hydroxylation metabolites, their profile possesses significant challenges. The previous methods generally suffer from lacking baseline resolution and/or involving complex analysis processes. To overcome this limitation, a sensitive and specific chiral liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously identify warfarin and hydroxywarfarins enantiomers. Chromatographic separation was achieved on a HYPERSIL CHIRAL-OT column. The mass spectrometric detection was carried out in negative ion MRM mode with electrospray ionization source. The optimized method exhibited satisfactory within-run and between-run accuracy and precision with lower limit of quantification (LLOQ) of 10.0 ng/mL and 1.0 ng/mL for warfarin and 7-, 10(R)-OH-warfarin enantiomers, respectively. Linear responses of warfarin enantiomers and 7-, and 10(R)-OH-warfarin enantiomers in rat plasma were observed over the range of 10.0–8000 ng/mL, and 1.00–800 ng/mL, respectively. The analytes were shown to be stable in various experimental conditions in rat plasma. Protein precipitation was used in sample preparation without a matrix effect. This method was successfully applied to pharmacokinetic study for quantitating the concentrations of S/R-warfarin, S/R-7-OH-warfarin, and S/R-10(R)-OH-warfarin and relatively quantitating 3′-, 4-, 6-, and 8-OH warfarin enantiomers in rat plasma.

A novel, rapid and simple UHPLC-MS/MS method for quantification of warfarin in dried blood spots

Warfarin is a common first line anticoagulant with a narrow therapeutic window. Because of the large blood volume needed, previous warfarin determination methods were not applicable to small animals, such as mice. To reduce the number of small animals used needed, we developed and validated a sensitive rapid assay for the simultaneous detection of warfarin enantiomers in mouse dried blood spot (DBS) samples. Analytes were extracted by tert-butyl methyl ether and then separated by a chiral Cellulose-1 column with a mobile phase of 75% acetonitrile (containing 0.1% formic acid). The total chromatographic run time was 3 min. Negative mode electrospray ionization was used for MS/MS detection, where the monitored ion transitions were m/z 307.1 → 161.0 and 341.1 → 284.0 for warfarin and coumachlor (internal standard) respectively. The calibration curves were linear with a correlation coefficient of ≥0.994 for both enantiomers over a concentration range of 10-1000 ng/mL. The satisfactory accuracy and adequate reproducibility of both warfarin enantiomers were validated in terms of intra- and interday precision with mouse DBS cards. The samples were stable at room temperature for at least 14 days. The validated method was applied to a pharmacokinetic study in mice.