A simple high-performance liquid chromatographic determination of mexiletine in human plasma at therapeutic levels

Summary A method for the quantitative determination of mexiletine in human plasma by high-performance liquid chromatography has been described. The plasma samples are buffered to pH 12 and extracted on Clin-Elut columns with diethylether-ethylacetate (1:1), after addition of the internal standard, the 2,4,6 methyl analogue of mexiletine. The minimum detectable amount of mexiletine is 50 ng in 0.5 ml plasma. Recovery is between 96–114% and the relative standard deviation at 1.5 ml^–1 level of mexiletine is 2.1% Accurate determinations of human plasma levels were performed after oral or intravenous treatment.Part of the work was presented at the 29. Kongreß der Deutschen Gesellschaft für Laboratoriumsmedizin, Hamburg 1985.