Determination of esomeprazole and its two main metabolites in human, rat and dog plasma by liquid chromatography with tandem mass spectrometry.

A LC-MS/MS method was developed for quantitative determination of esomeprazole, and its two main metabolites 5-hydroxyesomeprazole and omeprazole sulphone in 25 microL human, rat or dog plasma. The analytes and their internal standards were extracted from plasma into methyl tert-butyl ether - dichloromethane (3:2, v/v). After evaporation and reconstitution of the organic extract the analytes were separated on a reversed-phase LC column and measured by atmospheric-pressure positive ionisation MS.

No effect of encapsulation on the pharmacokinetics of warfarin.

Background: In double-blind comparator studies with the oral direct thrombin inhibitor (oral DTI) ximelagatran, warfarin (Coumadin) was administered in encapsulated form in order to maintain patient and investigator blinding. This open, randomized, two-way crossover study was conducted to determine whether the encapsulated warfarin tablets (Coumadin) used in the ximelagatran studies are bioequivalent to nonencapsulated, commercially available warfarin (Coumadin) tablets.

Methods And Results: Eighteen healthy men received two 2.

Factorial design for the development of automated solid-phase extraction in the 96-well format for determination of tesaglitazar, in plasma, by liquid chromatography-mass spectrometry.

An analytical method was developed for the determination, in blood plasma, of a novel peroxisome proliferator-activated receptor (PPAR) agonist drug, tesaglitazar. The drug and the isotope labelled internal standard were isolated by solid-phase extraction (SPE) on hexylsilica, separated by reversed-phase liquid chromatography and quantified by tandem mass spectrometry. Factorial design and a robotic sample processor were employed in the exploration and optimisation of the SPE procedure in the 96-well format.