Simultaneous determination of fluoxetine, venlafaxine, vortioxetine and their active metabolites in human plasma by LC-MS/MS using one-step sample preparation procedure.

The aim of antidepressant therapy is to induce remission and prevent relapses of major depressive disorder with minimum adverse effects during the treatment. Due to high variability in metabolism, therapeutic drug monitoring is recommended as a useful tool for individualisation of the therapy. For this purpose, we have developed simple and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for quantification of fluoxetine (FLX), venlafaxine (VEN), vortioxetine (VTX) and their active metabolites norfluoxetine (NFLX) and O-desmethylvenlafaxine (ODV). After one-step extraction procedure using OSTRO plate, analytes were separated by gradient elution on Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 µm) column with runtime 4.2 min. The detection was done on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode with transitions at m/z 310.23 → 148.20 for FLX, m/z 296.23 → 134.20 for NFLX, m/z 278.31 → 121.13 for VEN, m/z 264.31 → 107.14 for ODV and m/z 299.19 → 150.05 for VTX using a positive electrospray ionisation interface. The method was successfully validated according to the European Medicine Agency guideline for the selectivity, linearity and lower limit of detection, precision and accuracy, matrix effect, extraction recovery, carryover, dilution integrity and stability over a concentration range of 1-300 ng/mL for FLX, NFLX, VEN, ODV and 0.2-100 ng/mL VTX. Extraction recovery for each analyte was > 80 %, and no significant matrix effects were observed. The developed method was employed for quantification of antidepressants in clinical samples from patients treated with either FLX, VEN, or VTX.

Pharmacokinetic and metabolic studies of Vortioxetine in rats using ultra high performance liquid chromatography with tandem mass spectrometry.

Vortioxetine is a multimodal antidepressant that has been recently utilized globally. Vortioxetine hemi-hydrochloride is a novel salt that was previously reported in our research. However, the pharmacokinetics of this salt and the metabolites of Vortioxetine in vivo remain unknown. In this study, the pharmacokinetics of the Vortioxetine hemi-hydrochloride salt is explored in rats through a newly developed ultra-performance liquid chromatography with tandem mass spectrometry method. In addition, ultra-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry was used to identify the metabolites of Vortioxetine in vivo. The results demonstrate that after a single, 3 mg/kg oral dose, the maximum concentration for the Vortioxetine hemi-hydrochloride salt is 14.63 ± 4.00 ng/mL, and is attained in 1.00∼4.00 h. The area under the plasma concentration-time curve from time 0 to 24 h is 67.30 ± 23.78 ng·h·mL-1 . Additionally, 29 metabolites were identified after the oral administration of 10 mg/kg, including 17 metabolites in the plasma, nine in the urine, and 12 in the feces. Eleven metabolites were novel. The major metabolic pathways include methylation, hydroxylation, oxidation, and glucuronidation. In conclusion, this study provides insight for further development of the Vortioxetine hemi-hydrochloride salt.