Simultaneous determination of a novel thrombin inhibitor and its two metabolites in human plasma by liquid chromatography/tandem mass spectrometry

Determination of ximelagatran, an oral direct thrombin inhibitor, its active metabolite melagatran, and the intermediate metabolites, in biological samples by liquid chromatography-mass spectrometry

Analytical methods for the determination of ximelagatran, an oral direct thrombin inhibitor, its active metabolite melagatran, and intermediate metabolites, melagatran hydroxyamidine and melagatran ethyl ester, in biological samples by liquid chromatography (LC) positive electrospray ionization mass spectrometry (MS) using selected reaction monitoring are described. Isolation from human plasma was achieved by solid-phase extraction on octylsilica. Analytes and isotope-labelled internal standards were separated by LC utilising a C(18) analytical column and a mobile phase comprising acetonitrile-4 mmol/l ammonium acetate (35:65, v/v) containing 0.1% formic acid, at a flow-rate of 0.75 ml/min. Absolute recovery was approximately 80% for ximelagatran, approximately 60% for melagatran ethyl ester and >90% for melagatran and melagatran hydroxyamidine. Limit of quantification was 10 nmol/l, with a relative standard deviation <20% for each analyte and <5% above 100 nmol/l. Procedures for determination of these analytes in human urine and breast milk, plus whole blood from rat and mouse are also described.

Determination of melagatran, a novel, direct thrombin inhibitor, in human plasma and urine by liquid chromatography-mass spectrometry

Analytical methods for the determination of melagatran (H 319/68) in biological samples by liquid chromatography (LC)-positive electrospray ionization mass spectrometry using multiple reaction monitoring are described. Melagatran in plasma was isolated by solid-phase extraction on octylsilica, either in separate extraction tubes or in 96-well plates. Absolute recovery of melagatran from plasma was >92%. Melagatran and the internal standard, H 319/68 D2 13C2, were separated from other sample components by LC utilizing a C18 stationary phase and a mobile phase comprising 35% acetonitrile and 0.08% formic acid in 0.0013 mol/l ammonium acetate solution. After dilution, urine was injected directly onto the LC column and subjected to gradient LC. The relative standard deviation was 1-5% for concentrations above the limit of quantification, which was estimated for plasma at 10 or 25 nmol/l for sample volumes of 500 or 200 microl, respectively, and 100 nmol/l for urine.