Analysis of benzphetamine and its metabolites in rat urine by liquid chromatography-electrospray ionization mass spectrometry

An analytical method to identify and determine benzphetamine (BMA) and its five metabolites in urine was developed by liquid chromatography-electrospr ay ionization mass spectrometry (LC-ESI-MS) using the solid-phase extractio n column]Bond Elut SCX, Deuterium-labeled compounds, used as internal stand ards, were separated chromatographically from each corresponding unlabeled compound in the alkaline mobile phase with an alkaline-resistant ODS column . This method was applied to the identification and determination of BMA an d its metabolites in rat urine collected after oral administration of BMA. Under the selected ion monitoring mode, the limit of quantitation (signal-t o-noise ratio LO) for BMA, N-benzylamphetamine (BAM), p-hydroxybenzphetamin e (p-HBMA), p-hydroxy-N-benzylamphetamine (p-HBAM), methamphetamine (MA) an d amphetamine (AM) was 700 pg, 300 pg, 500 pg, 1.4 ng, 6 ng and 10 ng in 1 mi of urine, respectively. This analytical method for p-HBMA, structurally closer to the unchanged drug of all the metabolites, was very sensitive, ma king this a viable metabolite for discriminating the ingestion of BMA longe r than the parent drug or other metabolites in rat. (C) 2001 Elsevier Scien ce B.V. All rights reserved.