European Journal of Mass Spectrometry - Abstract of Study of the metabolites of bencycloquidium bromide racemate, a novel anticholinergic compound, in rat bile by liquid chromatography-tandem mass spectrometry

Qin Xu,^a,b Li Ding,^*,a Wen-Ying Liu,^a Xiao-ping Chen^c and Bu-Ming Liu^d
^aDepartment of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, PR China. E-mail: dinglicpu@sina.com
^bDepartment of Pharmaceutical Analysis, Guilin Medical College, 109 Huan Cheng Bei Er Road, Guilin 541004, PR China
^cBeijing Shiqiao Biological and Pharmaceutical Co. Ltd., Haidian Area, Beijing 100080, PR China
^dGuangxi Institute of Traditional Medical and Pharmaceutical Sciences, Guangxi Nanning 530022, PR China

A sensitive and specific liquid chromatographic-electrospray ionization (ESI) tandem ion trap mass spectrometric method has been developed for identification of bencycloquidium bromide (BCQB) and its metabolites in rat bile. Six healthy rats were administrated a single dose (3.0 mg kg^–1) of BCQB by intraperitoneal (i.p.) injection. The bile were sampled from 0 h to 24 h and purified by using a C₁₈ solid-phase extraction (SPE) cartridge, then the purified bile samples were separated on a reversed-phase C₁₈ column using acetonitrile/40 mM ammonium acetate buffer (containing 0.1% formic acid) as mobile phase at gradient elution and detected by an on-line MSⁿ detector. Identification and structural elucidation of the metabolites were performed by comparing the changes in molecular weight (Δm) and full scan MSⁿ spectra with those of the parent drug. Eight metabolites (such as hydroxylated and oxidized metabolites) and the parent drug were found in rat bile. Eight metabolites of BCQB were identified and hydroxylated metabolites were the major metabolites. The metabolic pathways of BCQB in vivo are proposed for the first time.