Measurement of plasma concentrations of vasodilators and metabolites by the TEA Analyzer.

The determination of therapeutic levels of glyceryl trinitrate (GTN), isosorbide dinitrate (ISDN), pentaerythritol tetranitrate (PETN), and their metabolites in human plasma was conducted using the TEA Analyzer interfaced to a high-performance liquid chromatograph (HPLC-TEA). Chromatographic separation of these compounds was accomplished under isocratic HPLC conditions. The sensitivity of the instrument was established to be 0.1 ng for each of the three nitrate esters. At the 5 ng ml-1 plasma fortification level, the precision of the method gives mean relative standard deviations (RSD) of +/- 10.2 per cent, +/- 6.5 per cent, and +/- 5.9 per cent for GTN, ISDN, and PETN, respectively. The recoveries for the nitrate esters and their metabolites from human plasma over the range 1-50 ng ml-1 are presented. The specific and sensitive HPLC-TEA method developed in this study provides a reliable and rapid assay for the routine analysis for metabolism or bioavailability studies of nitrate esters and their metabolites in plasma of blood, with a detection limit as low as 1 ng ml-1.