Low level determination of dorzolamide and its de-ethylated metabolite in human plasma by liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry

Journal of Pharmaceutical and Biomedical Analysis
M L ConstanzerB K Matuszewski

Abstract

A sensitive and specific method for the determination of dorzolamide (I) and its de-ethylated metabolite (II) in human plasma has been developed utilizing high pressure liquid chromatography (HPLC) with tandem mass spectrometric (MS/MS) detection. The analytes and internal standard (III) were isolated from the deproteinized pH 8.0 buffered plasma, using a liquid-liquid extraction with a mixture of ethyl acetate, toluene, and isopropanol. The analytes were then back extracted into 0.085% phosphoric acid (200 microliters) and after washing the acidic extract with hexane, the organic layer was discarded and a fraction (50 microliters) of the acid extract was injected into the LC/MS/MS system. The MS/MS detection was performed on a PE Sciex API III tandem mass spectrometer using a heated nebulizer interface. Multiple reaction monitoring of the parent-->product ion combinations of m/z 325-->199, 297-->199, and 397-->306 were used to quantify I, II, and III, respectively. The assay was validated in the concentration ranges of 0.5-100 and 2.5-100 ng ml-1 of plasma for I and II, respectively. The precision of the assays, expressed as coefficients of variation (C.V.%), were less than 10% over the entire concentration range, with adequat...Continue Reading

Citations

Mar 13, 2014·Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy·Hayam Mahmoud LotfyYasmin Rostom Omran
Apr 4, 2002·Clinical Pharmacokinetics·Jens Martens-Lobenhoffer, Peter Banditt
Apr 18, 2006·Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences·Ruifang FanJiamo Fu
Apr 17, 2016·Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences·Sonia T HassibRawda M Sayed
Jun 25, 2010·Journal of Separation Science·Mojtaba ShamsipurAssem Abdollahpour

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