title: Metabolites of ephedrines in human urine after administration of a single therapeutic dose.
abstract: Ephedrine (EPH), pseudoephedrine (PEPH), phenylpropanolamine (PPA), methylephedrine (MEPH) and cathine are sympathomimetic amines. These drugs are commonly found in over-the-counter (OTC) cold medicines and some dietary supplements. In Taiwan, the misuse of these drugs has resulted in an increase in athletic violations. Excretion studies of the ephedrine-related drugs have been performed to better understand the metabolic yields of ephedrines in urine. After consuming a single clinical dose of each of these drugs, urine samples from volunteers (n=3 for each drug) were subjected to tert-butyl-methyl-ether (TBME) extraction and trifluoroacetic acid (TFAA) derivatization before gas chromatography-mass spectrometry (GC-MS) analysis. Most ephedrines were excreted unchanged in urine, including EPH (40.9%), PEPH (72.2%), and PPA (59.3%). However, only a relatively small amount of MEPH (15.5%) was excreted unchanged in urine. In addition, a trace amount of PPA (1.6%) and cathine (0.7%) was found to be the metabolites of EPH and PEPH, respectively. Urinary EPH, PEPH, and PPA reached peaks at 2-6h and disappeared in urine at approximately 24-48 h post-administration. For MEPH, the peaks of excretion extended from 4 to 12h post-administration and were undetectable at approximately 48 h. A single clinical dose of EPH (25 mg) may exceed threshold level (10 microg/mL) in sport drug testing if the urine samples are tested within approximately 8h post-administration. However, a single dose of MEPH (20 mg) never reached the threshold value (10 microg/mL).
authors.affiliation: Institute of Pharmacology and Toxicology and Doping Control Center, Tzu Chi University, 701 Section 3, Chung Yan Road, Hualien, Taiwan. ying@mail.tcu.edu.tw
authors.forename: Ying Lung
authors.initials: YL
authors.lastname: Tseng
authors.forename: Min-Hua
authors.initials: MH
authors.lastname: Shieh
authors.forename: Fan-Hsin
authors.initials: FH
authors.lastname: Kuo
mesh_terms: D000322:Adrenergic Agonists / Q000008:administration & dosage / Q000652:urine*; D002849:Chromatography, Gas / Q000379:methods; D004809:Ephedrine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000652:urine*; D005260:Female; D005554:Forensic Medicine; D006801:Humans; D016014:Linear Models; D008297:Male; D010665:Phenylpropanolamine / Q000652:urine*
chemical_list: D000322:Adrenergic Agonists; D010665:Phenylpropanolamine; C041707:N-methylephedrine; D004809:Ephedrine