Determination of the metabolites of mexiletine in human plasma.
A liquid chromatographic method for the determination of mexiletine and unconjugated metabolites in plasma has been developed. A reversed-phase C18 column is used with isocratic elution and either UV or amperometric detection. Sample pretreatment involves double extraction of the metabolites. The method enables the measurement of four mexiletine metabolites at levels as low as 10 ng ml(-1), with both precision and accuracy of about 6%. Forty-nine samples from patients receiving mexiletine were analysed. Metabolite VII was found to be the major metabolite (mean concentration 225 ng ml(-1)), metabolites IX and VI were also found at mean concentrations of 95 and 10 ng ml(-1), respectively, whilst metabolite VIII was not detected.
Selinger
K
K
Division of Clinical Biochemistry, Royal Victoria Hospital and McGill University, 687 Pine Avenue West, Montreal, Quebec, H3A 1A1, Canada.
Crawhall
J C
JC