title: An electron-capture dienophile derivatization agent for increasing sensitivity: determination of a vitamin D analog (Ro 24-2090) in plasma samples with liquid chromatography/mass spectrometry.
abstract: A practical analytical method has been developed for the determination of an analog of vitamin D3 (Ro 24-2090) in plasma samples. The method employs liquid-liquid extraction, precolumn derivatization, HPLC separation using an automated column-switching system, and particle-beam negative ionization MS determination. An electron-capture derivatization reagent, 4-pentafluorobenzyl-1,2,4-triazoline-3,5-dione, is utilized to attain high sensitivity through a unique ionization mechanism. The method achieved a lower limit of quantitation of 25 pg (63 fmol) of Ro 24-2090 in plasma aliquots ranging from 0.125 to 1.0 ml. Method validation data were obtained for the quantitation of Ro 24-2090 in plasma from humans and seven animal species. Intraassay precision [mean percent relative standard deviation (%RSD)] ranged from 1.49 to 7.12% among the various species. Interassay precision (mean %RSD) ranged from 4.28 to 17.5%. Mean overall recovery ranged from 71 to 89%. The method has been successfully used to analyze plasma samples from several pharmacokinetic studies. The potential use of this method for determination of vitamin D2, vitamin D3, 1 alpha, 25-dihydroxyvitamin D3, and other drugs containing a diene structural moiety is discussed.
authors.affiliation: Department of Drug Metabolism and Pharmacokinetics, Hoffmann-La Roche, Incorporated, Nutley, New Jersey 07110, USA.
authors.forename: K
authors.initials: K
authors.lastname: Wang
authors.forename: P P
authors.initials: PP
authors.lastname: Davis
authors.forename: T
authors.initials: T
authors.lastname: Crews
authors.forename: L
authors.initials: L
authors.lastname: Gabriel
authors.forename: R W
authors.initials: RW
authors.lastname: Edom
mesh_terms: D000818:Animals; D002762:Cholecalciferol / Q000031:analogs & derivatives* / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006224:Cricetinae; D004285:Dogs; D005464:Fluorobenzenes; D000882:Haplorhini; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D011817:Rabbits; D051381:Rats; D013552:Swine; D014230:Triazoles; D005466:Fluorocarbons
chemical_list: D002762:Cholecalciferol; D005464:Fluorobenzenes; D014230:Triazoles; C104681:4-pentafluorobenzyl-1,2,4-triazolidine-3,5-dione; D005466:Fluorocarbons; C104680:4-pentafluorobenzyl-1,2,4-triazoline-3,5-dione; C104679:Ro 24-2090