title: Measurement of theophylline metabolites produced by reaction with hepatic microsome by high performance liquid chromatography following solid phase extraction.
abstract: An analytical method has been developed with which to measure the microsomal enzyme activities responsible for oxidative theophylline metabolism. Three metabolites: 3-Methylxanthine (3-MX); 1-methylxanthine (1-MX); 1,3-dimethyluric acid (1,3-DMU), with acetaminophen as an internal standard (IS), were separated by solid phase extraction using a Sep-Pak C18 cartridge, followed by high performance liquid chromatography on a reversed-phase column with isocratic elution using 25 mM acetate buffer containing 4% acetonitrile and 2.5 mM tetra-n-butylammonium hydrogen sulphate (pH 5.25) as the mobile phase. The analytes were clearly resolved and no interference with foreign peaks was observed. A linear relationship was obtained for the metabolites over the concentration range of 0.5-5.0 micrograms/mL, and their analytical recovery was almost 100%. This method can be used to assess drug interactions involving alterations in the biotransformation of theophylline.
authors: Department of Hospital Pharmacy, Shiga University of Medical Science, Ohtsu, Japan.
authors: H
authors: H
authors: Konishi
authors: A
authors: A
authors: Yamaji
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D008862:Microsomes, Liver / Q000378:metabolism*; D013806:Theophylline / Q000032:analysis* / Q000378:metabolism*; D014527:Uric Acid / Q000031:analogs & derivatives / Q000032:analysis; D014970:Xanthines / Q000032:analysis
chemical_list: D014970:Xanthines; D014527:Uric Acid; C053085:1-methylxanthine; D013806:Theophylline; C031274:1,3-dimethyluric acid; C029703:3-methylxanthine