Determination of chloral hydrate metabolites in human plasma by gas chromatography mass spectrometry

Chloral hydrate (CH) is a widely used sedative. Its pharmacological and tox icological effects are directly related to its metabolism. Prior investigat ions of CH metabolism have been limited by the lack of analytical technique s sufficiently sensitive to identify and quantify metabolites of CH in biol ogical fluids. In this study a gas chromatography/mass spectrometry (GC/MS) method was developed and validated for determining CH and its metabolites, monochloroacetate (MCA), dichloroacetate (DCA), trichloroacetate (TCA) and total trichloroethanol (free and glucuronidated form, TCE and TCE-Glu) in human plasma. Of these, DCA and MCA are newly identified metabolites in hum ans. The drug, its plasma metabolites and an internal standard, 4-chlorobut yric acid (CBA), were derivatized to their methyl esters by reacting with 1 2% boron trifluoride-methanol complex (12% BF3-MeOH). The reaction mixture was extracted with methylene chloride and analyzed by GC/MS, using a select ed ion monitoring (SIM) mode. The quantitation limits of MCA, DCA, TCA, and TCE were between 0.12 and 7.83 mu M. The coefficients of variation were be tween 0.58 and 14.58% and the bias values ranged between - 10.03 and 14.37% . The coefficients of linear regression were between 0.9970 and 0.9996. (C) 1999 Elsevier Science B.V. All rights reserved.