Simultaneous determination of selegiline- N-oxide, a new indicator for selegiline administration, and other metabolites in urine by high-performance liquid chromatography–electrospray ionization mass spectrometry

• Published in: Journal of chromatography. B, Biomedical sciences and applications Biomedical sciences and applications, 2001-08, Vol.759 (1), p.125-133
• Main Authors: Katagi, Munehiro, Tatsuno, Michiaki, Miki, Akihiro, Nishikawa, Mayumi, Nakajima, Kunio, Tsuchihashi, Hitoshi
• Format: Article
• Language: English
• Subjects: Analysis; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; General pharmacology; Humans; Medical sciences; Monoamine Oxidase Inhibitors - pharmacokinetics; Monoamine Oxidase Inhibitors - urine; Pharmacology. Drug treatments; Reproducibility of Results; Selegiline; Selegiline - analogs & derivatives; Selegiline - pharmacokinetics; Selegiline - urine; Selegiline- N-oxide; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization - methods
• ISSN: 0378-4347; 1387-2273
• DOI: 10.1016/S0378-4347(01)00213-4

In order to discriminate selegiline (SG) use from methamphetamine (MA) use, the urinary metabolites of SG users have been investigated using high-performance liquid chromatography (HPLC)–electrospray ionization mass spectrometry (HPLC–ESI–MS). Selegiline- N-oxide (SGO), a specific metabolite of SG, was for the first time detected in the urine, in addition to other metabolites MA, amphetamine (AP) and desmethylselegiline (DM-SG). A combination of a Sep-pak C 18 cartridge for the solid-phase extraction, a semi-micro SCX column (1.5 mm I.D.×150 mm) for HPLC separation and ESI–MS for detection provided a simple and sensitive procedure for the simultaneous determination of these analytes. Acetonitrile–10 m M ammonium formate buffer adjusted to pH 3.0 (70:30, v/v) at a flow-rate of 0.1 ml/min was found to be the most effective mobile phase. Linear calibration curves were obtained over the concentration range from 0.5 to 100 ng/ml for all the analytes by monitoring each protonated molecular ion in the selected ion monitoring (SIM) mode. The detection limits ranged from 0.1 to 0.5 ng/ml. Upon applying the scan mode, 10–20 ng/ml were the detection limits. Quantitative investigation utilizing this revealed that SGO was about three times more abundant (47 ng/ml, 79 ng/ml) than DM-SG in two SG users’ urine samples tested here. This newly-detected, specific metabolite SGO was found to be an effective indicator for SG administration.