Developing LC-MS/MS methods to quantify rivaroxabanin human plasma and urine: Application to therapeutic drug monitoring

Rivaroxaban is an oral anticoagulant directly inhibiting the activity of Factor Xa, which is widely used for the prophylaxis of thromboembolic disorders. Therapeutic drug monitoring (TDM) is required during therapy for individual dosage adjustment. This study aimed at developing a liquid chromatography/tandem mass spectrometry method that was suitable for rivaroxaban TDM in human plasma and urine and exploring the feasibility of urine drug monitoring in medical care. A 3 min run time of the LC-MS/MS methods was established by employing an Acquity UPLC BEH C₁₈ (2.1 × 50 mm, 1.7 μm) column using gradient elution of 10 mmol/L ammonium acetate containing 0.1% formic acid-0.1% formic acid acetonitrile as a mobile phase at a flow rate of 0.4 ml/min with calibration ranges of 0.5-400 and 10-10,000 ng/ml for human plasma and urine, respectively. Rivaroxaban was detected on a triple quadrupole tandem mass spectrometer with an electrospray ionization source in positive ion mode. The methods showed good linearity within the calibration range. The precision and accuracy, matrix effect, extraction recovery and stability in both human matrices were all validated and meet the international guideline requirements. These validated methods were successfully applied to support the TDM of an aged patient receiving rivaroxaban for therapy.