An UPLC–MS/MS method for the quantitation of vortioxetine in rat plasma: Application to a pharmacokinetic study

Highlights

• First characterize the method of vortioxetine in rat plasma by UPLC–MS/MS.

• The run time was 3 min with no carryover.

• The method is accurate, precise and meets validation requirements by guideline.

• The method could also be used for clinical pharmacokinetic study.

Abstract

In this work, a simple, sensitive and fast ultra performance liquid chromatography with tandem mass spectrometry (UPLC–MS/MS) method was developed and validated for the quantitative determination of vortioxetine in rat plasma. Plasma samples were processed with a protein precipitation. The separation was achieved by an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The validated method had an excellent linearity in the range of 0.05–20 ng/mL (R² > 0.997) with a lower limit of quantification (0.05 ng/mL). The extraction recovery was in the range of 78.3–88.4% for vortioxetine and 80.3% for carbamazepine (internal standard, IS). The intra- and inter-day precision was below 8.5% and accuracy was from −11.2% to 9.5%. No notable matrix effect and astaticism was observed for vortioxetine. The method has been successfully applied to a pharmacokinetic study of vortioxetine in rats for the first time, which provides the basis for the further development and application of vortioxetine.

Introduction

Major depressive disorder (MDD) is a leading cause of disability and is associated with significant reductions in quality of life, impaired productivity, reduced overall health and substantial economic costs [1], [2], [3]. Vortioxetine (1-[2-(2,4-dimethyl-phenylsulfanyl)-phenyl]-piperazine hydrobromide, Fig. 1) is a novel antidepressant with a multi-modal mechanism of action approved in the USA and EU for the treatment of major depressive disorder at doses of 5, 10, 15 and 20 mg [4]. It works through a combination of two pharmacological modes of action: inhibition of the serotonin transporter and direct modulation of receptor activity.

Vortioxetine reaches peak plasma concentrations of 9, 18 and 33 ng/mL within 7–11 h following the doses of 5, 10 and 20 mg/day, respectively. The absolute bioavailability for oral administration of vortioxetine was found to be 75% [5]. Vortioxetine undergoes extensive metabolism, primarily via oxidation and subsequent glucuronic acid conjugation. In vitro data suggest that several CYP isoenzymes are involved in the oxidative metabolism of vortioxetine, including CYP2D6, CYP3A4/5, CYP2C9, CYP2C19, CYP2A6, CYP2C8 and CYP2B6 [6]. Clinical drug–drug interaction studies in healthy individuals have shown that co-administration of omeprazole (a CYP2C19 substrate and inhibitor) had no effect on the pharmacokinetics of vortioxetine, co-administration of bupropion (CYP2D6 inhibitor) increased the exposure of vortioxetine approximately 2-fold and co-administration of rifampicin (a broad CYP inducer) decreased the area under the curve (AUC) of vortioxetine by 72% [7].

Recently, a reliable, stable and predictive pharmacokinetic model was developed to characterise pharmacokinetics of vortioxetine in the healthy population [4], [8], [9]. Pharmacokinetics profile of vortioxetine were researched extensively. There have several analytical methods been published for determination of vortioxetine in human plasma, including LC–MS [10] and LC–MS/MS [11], [12], [13], [14], [15], [16], [17]. However, these methods were not described in enough detail (e.g. plasma extraction procedure, chromatography conditions, parameters of the method, etc.) for duplication in other laboratories. Therefore, to characterize the pharmacokinetic properties of vortioxetine, it is very necessary to develop an accurate and selective bioanalytical method for the determination of vortioxetine in plasma.

With recent advances in analysis techniques, ultra performance liquid chromatography (UPLC) with tandem mass spectrometry (MS/MS) has been used increasingly for biological matrix analyses [18], [19]. In our current study, we developed and validated a rapid, selective, and sensitive UPLC–MS/MS technique for quantifying vortioxetine in rat plasma. The technique was also applied in a pharmacokinetic analysis, and it demonstrated a high level of sensitivity for detecting vortioxetine in as little as 0.1 mL of rat plasma using protein precipitation. To our knowledge, this is the first report of the systematic validation of a UPLC–MS/MS method for quantifying vortioxetine in rat plasma. The UPLC–MS/MS technique is a highly sensitive, practical analytical method for applications in basic and clinical research.