Pharmacokinetic studies, quantitative mass spectrometry liquid chromatography

Macek et al. [120] developed a method to quantitate omeprazole in human plasma using liquid chromatography-tandem mass spectrometry. The method is based on the protein precipitation with acetonitrile and a reversed-phase liquid chromatography performed on an octadecylsilica column (55 x 2 mm, 3 /im). The mobile phase consisted of methanol-10 mM ammonium acetate (60 40). Omeprazole and the internal standard, flunitra-zepam, elute at 0.80 0.1 min with a total rim time 1.35 min. Quantification was through positive-ion made and selected reaction monitoring mode at m/z 346.1 —> 197.9 for omeprazole and m/z 314 —> 268 for flunitrazepam, respectively. The lower limit of quantification was 1.2 ng/ml using 0.25 ml of plasma and linearity was observed from 1.2 to 1200 ng/ml. The method was applied to the analysis of samples from a pharmacokinetic study. 

Segura M, Ortuno J, Farre M et al (2003) Quantitative determination of paroxetine and its 4-hydroxy-3-methoxy metabolite in plasma by high-performance liquid chromatography/elec-trospray ion trap mass spectrometry application to pharmacokinetic studies. Rapid Commun Mass Spectrom 17 1455-1461... 

Recent advances in mass spectrometry have rendered it an attractive and versatile tool in industrial and academic research laboratories. As a part of this rapid growth, a considerable body of hterature has been devoted to the apph-cation of mass spectrometry in clinical studies. In concert with separation techniques such as hquid chromatography, mass spectrometry allows the rapid characterization and quantitative determination of a large array of molecules in complex mixtures. Herein, we present an overview of the above techniques accompanied with several examples of the use of liquid chromatography-tandem mass spectrometry in pharmacokinetics/drug metabohsm assessment during drug development. 

W Muck. Quantitative analysis of pharmacokinetic study samples by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Pharmazie 54 639-644, 1999. 

---