Related Experiment Video
Updated: Aug 20, 2026

Multi-step Preparation Technique to Recover Multiple Metabolite Compound Classes for In-depth and Informative Metabolomic Analysis
Published on: July 11, 2014
Measurement of theophylline metabolites produced by reaction with hepatic microsome by high performance liquid
1Department of Hospital Pharmacy, Shiga University of Medical Science, Ohtsu, Japan.
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.
More Related Videos
10:44Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
Published on: March 28, 2017
10:17High-throughput and Comprehensive Drug Surveillance Using Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry
Published on: April 23, 2019
Related Concept Videos
Measurement of Bioavailability: Pharmacokinetic Methods
Effect of Hepatic Disease on Pharmacokinetics: Active Drug, Metabolite and Fraction of Metabolized Drug