Simple method for determination of triazolam in human plasma by high-performance liquid chromatography/tandem mass spectrometry

Triazolam was analyzed from human plasma samples by high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) with an MSpak GFpolymercolumn (50 rnin x 4.6 mm i.d., particle size 6 mu m), which enabled direct injection of crude biological samples. Separation of triazolam, and lorazepam as the internal standard (IS) was carried out using 10 mM ammonium acetate (pH 3.56)-0.1 % formic acid and an acetonitrile gradient elution. Both compounds formed base peaks due to [M + H](+) ions by HPLC/ESI-MS, and product ions were produced from each [M + H](+) ion as seen by HPLC-MS/MS. Quantification of triazolam and the IS in plasma samples was made by selective reaction monitoring using each base peak of product ions of HPLC-MS/MS. The recovery range of triazolam spiked into plasma was 86.4-92.7%. The regression equation for triazolam showed excellent linearity in the range of 0.25-20 ng/mL, and the detection limit was 0.1 ng/mL. Intra- and inter-day precisions for triazolarn in plasma samples were not greater than 12.4%. Accuracy for the drug was in the range of 88.0-101.4%. Data obtained after oral administration of triazolam in male and female subjects are also presented. (c) 2005 Elsevier B.V. All rights reserved.