title: Determination of (S)-(-)-cathinone and its metabolites (R,S)-(-)-norephedrine and (R,R)-(-)-norpseudoephedrine in urine by high-performance liquid chromatography with photodiode-array detection.
abstract: A high-performance liquid chromatographic (HPLC) procedure with photodiode-array detection (DAD) is described for the determination of (S)-(-)-cathinone (S-CA) and its metabolites (R,S)-(-)-norephedrine (R-NE) and (R,R)-(-)-norpseudoephedrine (R-NPE) in urine. Extraction and clean-up of 1-ml urine samples were performed on a cyano-bonded solid-phase column using (+/-)-amphetamine as internal standard. The concentrated extracts were separated on a 3-microns ODS-1 column with acetonitrile-water-phosphoric acid-hexylamine as the mobile phase. Peak detection was done at 192 nm. The detection limits for S-CA and R-NE/R-NPE in urine were 50 and 25 ng/ml, respectively. The differentiation of the enantiomers of cathinone and norephedrine was achieved by derivatization with (S)-(-)-1-phenylethyl isocyanate to the corresponding diastereomers followed by HPLC-DAD on a 5-microns normal-phase column. The R and S enantiomers of norpseudoephedrine were determined by gas chromatography-mass spectrometry after on-column derivatization with (S)-(-)-N-trifluoroacetylprolyl chloride. Following a single oral dose of 0.5 mg/kg of S-CA, the concentrations found in urine ranged from 0.2 to 3.8 micrograms/ml of S-CA, from 7.2 to 46.0 micrograms/ml of R-NE and from 0.5 to 2.5 micrograms/ml of R-NPE.
authors.affiliation: Institute of Pharmacy, University of Berne, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Mathys
authors.forename: R
authors.initials: R
authors.lastname: Brenneisen
mesh_terms: D000470:Alkaloids / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D010665:Phenylpropanolamine / Q000652:urine*; D011619:Psychotropic Drugs / Q000652:urine*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D011619:Psychotropic Drugs; C005331:norpseudoephedrine; D010665:Phenylpropanolamine; C023665:cathinone