Identification of metabolites of lobeline in the rat urine by liquid chromatography-tandem mass spectrometry

This is a report about the analysis of lobeline and its metabolites in rat urine by using high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometric method (LU/MSn). The urine of healthy rat were sampled from 0 to 24 h after administered a single dose of lobeline Q mg/kg) by oral gavage, then centrifuged at 10,000 rpm for 10 min to get the supernatants. The supernatants were purified by solid-phase extraction (SPE) with a C 18 cartridge. After the above purified process, the purified urine were injected into a reversed-phase C-18 column with mobile phase of methanol/water (70:30, v/v, adjusted to pH 3.5 with formic acid) and detected by an on-line MSn system. The identification and structural elucidation of the metabolites were performed by comparing their changes in molecular mass (Delta M), full-scan MSn spectra with those of the parent drug. Ten metabolites of lobeline were found in rat urine. All the metabolites were reported for the first time. (c) 2007 Elsevier B.V All rights reserved.