High throughput and sensitive LC-MS/MS method for the estimation of venlafaxine and its active metabolite O-desmethyl venlafaxine in human plasma and its application to a pharmacokinetic study

摘要

A highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of venlafaxine (VEN) and its active metabolite O-desmethyl venlafaxine (ODV) in human plasma using fluoxetine as an internal standard. The VEN and ODV were extracted by liquid-liquid extraction using MTBE-n Hexane (60:40), and chromatographed on X-terra RP8 (50 mm × 4.6 mm, 5-μm particle size) column eluted with a isocratic mobile phase of 10 mM Ammonium acetate (pH 4.50 ± 0.05) and acetonitrile in 10:90 (v/v). The detection was performed by positive ion electrospray ionization in multiple reactions monitoring mode, monitoring the transitions m/z 278.27→ 121.08 and 264.33 → 57.72 for venlafaxine and O-desmethyl venlafaxine, respectively. The assay was linear over the concentration ranges of 0.100-300.010 ng/mL for VEN and 0.200-600.050 ng/mL for ODV with limits of detection and quantification of 0.050 ng/mL for VEN and 0.100 ng/mL for ODV, respectively. This LC-MS/MS method was validated with Intra-batch and Inter-batch precision 1.65-10.80 for VEN and 1.27-7.08 for ODV, respectively. The Intra-batch and Inter-batch %accuracy was 91.77%-104.39% for VEN and 95.87%-106.28% for ODV, respectively. This method was successfully applied to a pharmacokinetic study of venlafaxine hydrochloride extended release capsules 150 mg steady-state bioequivalence study.