DETERMINATION OF LEUKOTRIENE-B4 IN HUMAN PLASMA BY GAS-CHROMATOGRAPHY USING A MASS SELECTIVE DETECTOR AND A STABLE ISOTOPE LABELED INTERNAL STANDARD - EFFECT OF NE-11740 ON ARACHIDONIC-ACID METABOLISM

A highly selective gas chromatographic method, coupled with selected ion monitoring using a mass selective detector and positive electron ionization, was developed for the determination of leukotriene B4 (LTB4) in human plasma. Plasma was separated from whole human blood via centrifugation, proteins precipitated with acetonitrile and LTB4 recovered (∼82.0%) by ethyl acetate extraction. The methyl ester, bis-t-butyldimethylsilyl ether derivative of LTB4 was formed prior to analysis and determined quantitatively using [18O]2-LTB4 as an internal standard. The limit of detection (S/N = 2) was 425 pg on column (m/z 335/339) using a 1-μl injection. Standard curves were linear over two orders of magnitude with an RSD of <5.0% (n = 10). NE-11740, a new anti-inflammatory drug, was shown to inhibit, in a dose-dependent manner (ED50 = 22 μM) ionophore-stimulated LTB4 biosynthesis by human whole blood in vitro. © 1990.