title: Direct measurement of salicylphenolic glucuronide in human urine.
abstract: Indirect measurement of salicylphenolic glucuronide (SPG) has suggested that the formation of this metabolite from therapeutic doses of salicyclic acid (SA) is capacity-limited in humans. A direct high performance liquid chromatographic (HPLC) assay for SPG in human urine is described. SPG was prepared by a published method and purified by HPLC. On treatment with beta-glucuronidase, SPG yielded the expected amount of SA. Spectroscopic data, melting point, and optical rotation of the glucuronide and/or its triacetyl dimethyl ester derivative were consistent with the proposed structure. SPG was assayed using a 5-micron C18 column (temperature 55 degrees C) and fluorescence detection. A nonlinear gradient mobile phase at a flow rate of 2 ml/min was used, beginning with 100% 0.1 M pH 2.1 phosphate buffer and finishing with 84% buffer, 16% acetonitrile. Total run time was 25 min. Urine (10 microliter) was injected directly on the column, and quantitation was performed using urine standards. Within-run precision for SPG ranged from 1.2% at 150 mg/L to 2.4% at 5 mg/L. The limit of detection was less than 1 mg/L. A pilot study in two volunteers, each receiving a single 500-mg dose of sodium salicylate, was carried out to validate the usefulness of the assay.
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D005841:Gentisates; D005965:Glucuronates / Q000302:isolation & purification / Q000652:urine*; D006626:Hippurates / Q000652:urine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates / Q000652:urine; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D012459:Salicylates / Q000302:isolation & purification / Q000652:urine*; D020156:Salicylic Acid
chemical_list: D005841:Gentisates; D005965:Glucuronates; D006626:Hippurates; D062385:Hydroxybenzoates; D012459:Salicylates; C000693:salicylurate; C049960:1-salicylate glucuronide; D020156:Salicylic Acid; C010925:2,5-dihydroxybenzoic acid