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Quantitation of iptakalim in human plasma by high-performance liquid chromatography-tandem mass spectrometry.

Teng G, Wang Y, Tang Y, Wang R, Fang Y, Fawcett JP, Gu J

Research Center for Drug Metabolism, College of Life Science, Jilin University, Changchun 130023, China.

This paper describes a rapid and sensitive analytical method for the quantitation of iptakalim, a novel antihypertensive drug, in human plasma. The method is based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) using sildenafil as internal standard. Sample preparation involved liquid-liquid extraction with dichloromethane-diethyl ether (2:3, v/v) in a basic environment. Chromatography was carried out on an amino column with a mobile phase consisting of acetonitrile-water (55:45, v/v, water containing 0.5% formic acid). Detection employed electrospray ionization (ESI) tandem mass spectrometry in the multiple-reaction-monitoring (MRM) mode. The assay was linear in the concentration range of 0.5-100 ng/ml with a lower limit of quantitation (LLOQ) of 0.5 ng/ml. Intra- and inter-day precision (R.S.D.) were <4.5% and <12.0%, respectively and the accuracy (R.E.) was in the range +/-5%. The method was successfully applied to a single oral dose pharmacokinetic study in human volunteers.

Published 12 November 2007 in J Chromatogr B Analyt Technol Biomed Life Sci, 859(2): 256-60.
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