title: Gas chromatography-mass spectrometry assay for determination of ketamine in brain.
abstract: A sensitive and precise gas chromatography-mass spectrometry method with selected ion monitoring has been developed for determination of ketamine in the brain using chlorpheniramine as an internal standard. The assay is based on the acid extraction of brain homogenate with hexane and ethyl ether with subsequent alkaline ethyl ether extraction. The analytical procedure has a coefficient of variation of 3.0-5.3% and from 3.8 to 6.1% for extraction from water or spiked brain samples, respectively. The lowest detectable level of ketamine was 1 ng in any brain region. This level of detection was used to measure the ketamine concentrations in cerebellum, brain stem, midbrain, hypothalamus, and cortex of C57B1/6 mice at awakening following intraperitoneal injection of a hypnotic dose. The ketamine concentrations in mouse brain were in the range from 41.6 to 48.6 ng/mg of tissue.
authors.affiliation: Department of Anesthesiology, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: Y A
authors.initials: YA
authors.lastname: Blednov
authors.forename: V J
authors.initials: VJ
authors.lastname: Simpson
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002744:Chlorpheniramine / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007649:Ketamine / Q000032:analysis* / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D012680:Sensitivity and Specificity; D012890:Sleep / Q000187:drug effects; D013997:Time Factors
chemical_list: D002744:Chlorpheniramine; D007649:Ketamine