title: Determination of eflornithine enantiomers in plasma by precolumn derivatization with o-phthalaldehyde-N-acetyl-L-cysteine and liquid chromatography with UV detection.
abstract: A bioanalytical method for indirect determination of eflornithine enantiomers in 75 microL human plasma has been developed and validated. L- and D-eflornithine were derivatized with o-phthalaldehyde and N-acetyl-L-cysteine to generate diastereomers which were separated on two serially connected Chromolith Performance columns (RP-18e 100 x 4.6 mm i.d.) by a isocratic flow followed by a gradient flow for elution of endogenous compounds. The diastereomers were detected with UV (340 nm). The between-day precisions for L- and D-eflornithine in plasma were 8.4 and 2.3% at 3 microm, 4.0 and 5.1% at 400 microm, and 2.0 and 3.7% at 1000 microm. The lower limit of quantification was determined to be 1.5 microm, at which precision was 14.9 and 9.9% for L- and D-eflornithine, respectively.
authors.affiliation: Unit for Pharmacokinetics and Drug Metabolism, Department of Pharmacology, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Jansson-Löfmark
authors.forename: S
authors.initials: S
authors.lastname: Römsing
authors.forename: E
authors.initials: E
authors.lastname: Albers
authors.forename: M
authors.initials: M
authors.lastname: Ashton
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D003545:Cysteine / Q000737:chemistry; D000518:Eflornithine / Q000097:blood* / Q000737:chemistry; D013237:Stereoisomerism; D009764:o-Phthalaldehyde / Q000737:chemistry
chemical_list: D009764:o-Phthalaldehyde; D003545:Cysteine; D000518:Eflornithine