The simultaneous determination of diazepam and its three metabolites in dog plasma by high-performance liquid chromatography with mass spectroscopy detection

A fast, sensitive and specific LC/MS/MS method for the simultaneous determi nation of diazepam and its three metabolites, oxazepam, temazepam and desme thyldiazepam. in dog plasma is described. The method consists of an automat ed 96-well solid phase extraction procedure and electrospray LC/MS/MS analy sis. D-5-Diazepam is used as the internal standard for all the compounds. I ntra-day and inter-day assay coefficients of variations are less than 12.7% . The lower limit of quantitation (LLOQ) is 1 nM for each analyte, based on 0.1 ml aliquots of dog plasma. The analytical run time was 5 min, Linearit y is observed over the range of 1-500 nM. This method has been used to supp ort the discovery of pharmacokinetic studies. (C) 2001 Elsevier Science B.V . All rights reserved.