Liquid chromatography–tandem mass spectrometry (LC–MS–MS) method for simultaneous determination of venlafaxine and its active metabolite O-desmethyl venlafaxine in human plasma

A rapid and sensitive liquid chromatography–tandem mass spectrometry (LC–MS–MS) method has been developed and validated for simultaneous quantification of venlafaxine (VEN) and O-desmethyl venlafaxine (ODV) in human plasma. The analytes were extracted from human plasma by using solid-phase extraction (SPE) technique. Escitalopram (ESC) was used as the internal standard. A Betasil C18 column provided chromatographic separation of analytes followed by detection with mass spectrometry. The mass transition ion-pair has been followed as m/ z 278.27 → 121.11 for VEN, m/ z 264.28 → 107.10 for ODV and m/ z 325.00 → 262.00 for ESC. The method involves a solid phase extraction from plasma, simple isocratic chromatography conditions and mass spectrometric detection that enables detection at nanogram levels. The proposed method has been validated with linear range of 3–300 ng/ml for VEN and 6–600 ng/ml for ODV. The intrarun and interrun precision and accuracy values are within 10%. The overall recoveries for VEN and ODV were 95.9 and 81.7%, respectively. Total elution time as low as 3 min only.