title: Urinary output changes in racemic ethylamphetamine and optical activity discrimination in rat urine by HPLC analysis.
abstract: Characterization of optical activity and simultaneous analysis of racemic ethylamphetamine (EAMP) and its metabolites, as well as the urinary excretion of the optical isomers, were examined in rats by high-performance liquid chromatography (HPLC). Analysis of the optical isomers of EAMP, amphetamine (AMP), para-hydroxy-ethylamphetamine (p-OH-EAMP), and para-hydroxy-amphetamine (p-OH-AMP) was performed within 90 min. The limit of detection was 30 ng for EAMP and AMP, and 60 ng for p-OH-EAMP and p-OH-AMP per 20 microliters injection. After oral administration of racemic EAMP, rat urine specimens were collected at four intervals, 0-4, 4-12, 12-20 and 20-24 h. After administration of 30 mg/kg EAMP, not only each isomer of EAMP, i.e. AMP, p-OH-EAMP and p-OH-AMP, but also an unidentified substance (UI) were detected. The UI was presumed to be 3-hydroxy-4-methoxy-N-EAMP or 3-methoxy-4-hydroxy-N-EAMP by gas chromatographic mass spectrometry (GC-MS) analysis. The d-isomer of EAMP was generally excreted more abundantly than the l-isomer (p < 0.01-0.05). The d-isomer of AMP and p-OH-EAMP was excreted in the first 4 h in a somewhat smaller amount than the l-isomer but thereafter in a greater amount than the l-isomer. The d-isomer of p-OH-AMP was generally excreted in a smaller amount than the l-isomer (p < 0.1-0.05). The total percentages of the dose excreted up to 24 h were 2.65% of the dose of EAMP administered [d: 2.04% and l: 0.61%], AMP 3.15% [d: 1.68% and l: 1.47%], p-OH-EAMP 63.06% [d: 32.68% and l: 30.38%], and p-OH-AMP 2.57% [d: 1.05% and l: 1.52%]. The optical purity ratio (l/d) of EAMP up to 24 h was 0.31, significantly lower than that (1.03) of the original racemic EAMP (p < 0.01). The changes in the excretion of EAMP and AMP indicated a stereoselective disposition, but those of p-OH-EAMP and p-OH-AMP were unremarkable: the d- and the l-isomer of p-OH-EAMP and p-OH-AMP did not differ significantly. The entire amount excreted up to 24 h was about 71.43% of the dose administered; the d-isomer 37.45% and the l-isomer 33.98%. The l/d was 0.91, which was clearly less than that of the original racemic EAMP (p < 0.01). These results suggested stereoselective disposition of EAMP in the rat, and the methods are potentially applicable to identification of the optical activity of EAMP and thereby of methamphetamine abusers.
authors.affiliation: Scientific Crime Detection Laboratory, Tochigi Pref. Police H.Q., Utsunomiya, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Matsushima
authors.forename: T
authors.initials: T
authors.lastname: Nagai
authors.forename: H
authors.initials: H
authors.lastname: Kanaya
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: S
authors.initials: S
authors.lastname: Kamiyama
mesh_terms: D000661:Amphetamine / Q000008:administration & dosage / Q000652:urine; D000662:Amphetamines / Q000008:administration & dosage / Q000652:urine*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism; D013997:Time Factors; D010136:p-Hydroxyamphetamine / Q000008:administration & dosage / Q000652:urine
chemical_list: D000662:Amphetamines; C016434:ethylamphetamine; C060891:4-hydroxyethylamphetamine; D000661:Amphetamine; D010136:p-Hydroxyamphetamine