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Enantiomeric separation of tramadol and its active metabolite in human plasma by chiral high‐performance liquid chromatography: Application to pharmacokinetic studies
Author(s) -
Campanero M.A.,
Calahorra B.,
Valle M.,
Troconiz I.F.,
Honorato J.
Publication year - 1999
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(1999)11:4<272::aid-chir3>3.0.co;2-i
Subject(s) - chemistry , chromatography , enantiomer , metabolite , tramadol , pharmacokinetics , active metabolite , high performance liquid chromatography , detection limit , coefficient of variation , quantitative analysis (chemistry) , analgesic , stereochemistry , pharmacology , medicine , biochemistry
A sensitive and stereoselective high‐performance liquid chromatographic assay for the quantitative determination of the analgesic tramadol and O ‐demethyltramadol, an active metabolite, is described in this work. Ketamine was used as internal standard. The assay involved a single tert ‐butymethylether extraction and liquid chromatography analysis with fluorescence detection. Chromatography was performed at 20°C on a Chiracel OD‐R column containing cellulose tris‐(3,5‐dimethylphenyl‐carbamate) as stationary phase, preceded by an achiral end‐capped C 18 column. The mobile phase was a mixture of phosphate buffer (containing sodium perchlorate (0.2 M ) and triethylamine (0.09 M ) adjusted to pH 6) and acetonitrile (80:20). The method developed was validated. The limit of quantitation of each enantiomer of tramadol and its active metabolite by this method was 0.5 ng/mL; only 0.5 mL of the plasma sample was required for the determination. The calibration curve was linear from 0.5 to 750 ng/mL for tramadol enantiomers, and from 0.5 to 500 ng/mL for O ‐demethyltramadol enantiomers. Intra and interday precision [coefficient of variation (CV)] did not exceed 10%. Mean recoveries of 95.95 and 97.87% for (+)R,R‐ and (−)S,S‐tramadol and 97.70 and 98.79% for (+)R,R‐ and (−)S,S‐ O ‐demethyltramadol with CVs <2.15% were obtained. Applicability of the method was demonstrated by a pharmacokinetic study in normal volunteers who received 100 mg of tramadol by the intravenous route. Chirality 11:272–279, 1999. © 1999 Wiley‐Liss, Inc.