Determination of dexamethasone and dexamethasone sodium phosphate in human plasma and cochlear perilymph by liquid chromatography/tandem mass spectrometry.

Mei Zhang, Grant A Moore, Berit P Jensen, Evan J Begg, Philip A Bird

Department of Medicine, University of Otago-Christchurch, Christchurch, New Zealand. mei.zhang@cdhb.govt.nz

Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 2011 Jan 1

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A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of dexamethasone (Dex) and dexamethasone sodium phosphate (Dex SP) in plasma and human cochlear perilymph. After proteins were precipitated with a mixture of acetonitrile and methanol, Dex, Dex SP and flumethasone, the internal standard, were resolved on a C18 column using gradient elution of 5 mM ammonium acetate and methanol. The three compounds were detected using electrospray ionisation in the positive mode. Standard curves were linear over the concentration range 0.5-500 μg/L (r>0.99), bias was <±10%, intra- and inter-day coefficients of variation (imprecision) were <10%, and the limit of quantification was 0.5 μg/L for both Dex and Dex SP. The assay has been used successfully in a clinical pharmacokinetics study of Dex and Dex SP in cochlear perilymph and plasma. Copyright © 2010 Elsevier B.V. All rights reserved.

Citation

Mei Zhang, Grant A Moore, Berit P Jensen, Evan J Begg, Philip A Bird. Determination of dexamethasone and dexamethasone sodium phosphate in human plasma and cochlear perilymph by liquid chromatography/tandem mass spectrometry. Journal of chromatography. B, Analytical technologies in the biomedical and life sciences. 2011 Jan 1;879(1):17-24