title: Improved high-performance liquid chromatographic method for the routine determination of unconjugated 3-methoxy-4-hydroxyphenylethyleneglycol in human plasma using solid-phase extraction and electrochemical detection.
abstract: An improved semi-automated high-performance liquid chromatographic method is described for the routine determination of unconjugated 3-methoxy-4-hydroxyphenylethyleneglycol in plasma. The 3-ethoxy analogue of the compound is used as an internal standard. The method is based on purification of 0.5-ml plasma samples with phenyl-type reversed-phase extraction columns, reversed-phase separation with an acetate-citrate-methanol mobile phase with an octadecyl-bonded column, and dual-electrode coulometric detection with oxidation at +0.44 V and reduction at -0.25 V. The precision and accuracy of the assay are satisfactory: the lower limit of reliable detection corresponds to a plasma concentration of 1.5 nM. The validity of the determination is demonstrated by an 18% mean increase in plasma levels of 3-methoxy-4-hydroxyphenylethyleneglycol during physical exercise (duration 16 min, n = 13) and a 50% mean reduction in plasma levels induced by a single dose of the monoamine oxidase inhibitor, moclobemide (n = 8). The method is suitable for routine use in pharmacological and physiological experiments.
authors.affiliation: Department of Pharmacology, University of Turku, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Ojala-Karlsson
authors.forename: M
authors.initials: M
authors.lastname: Scheinin
mesh_terms: D001549:Benzamides / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004563:Electrochemistry; D005080:Exercise Test; D006801:Humans; D020912:Moclobemide; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D015238:Sulfotransferases / Q000097:blood*
chemical_list: D001549:Benzamides; D008996:Monoamine Oxidase Inhibitors; C021563:3-methoxy-4-hydroxyphenylethyleneglycol sulfotransferase; D015238:Sulfotransferases; D020912:Moclobemide