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Measurement of theophylline metabolites produced by reaction with hepatic microsome by high performance liquid chromatography following solid phase extraction
Author(s) -
Konishi Hiroki,
Yamaji Akira
Publication year - 1994
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.1130080409
Subject(s) - chemistry , chromatography , theophylline , high performance liquid chromatography , extraction (chemistry) , solid phase extraction , acetonitrile , elution , microsome , biotransformation , ethyl acetate , enzyme , biochemistry , pharmacology , medicine
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 C 18 cartridge, followed by high performance liquid chromatography on a reversed‐phase column with isocratic elution using 25 m M acetate buffer containing 4% acetonitrile and 2.5 m M 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 μg/mL, and their analytical recovery was almost 100%. This method can be used to assess drug interactions involving alterations in the biotransformation of theophylline.