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Determination of Alprazolam and α‐Hydroxyalprazolam in Human Plasma by Gas Chromatography/Negative‐ion Chemical Ionization Mass Spectrometry
Author(s) -
Höld Karin M.,
Crouch Dennis J.,
Rollins Douglas E.,
Wilkins Diana G.,
Canfield Dennis V.,
Maes Robert A.
Publication year - 1996
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199609)31:9<1033::aid-jms391>3.0.co;2-h
Subject(s) - chemistry , chromatography , mass spectrometry , alprazolam , chemical ionization , gas chromatography , selected ion monitoring , metabolite , gas chromatography–mass spectrometry , ionization , ion , organic chemistry , psychology , anxiety , biochemistry , psychiatry
A sensitive and specific method was developed for the determination of alprazolam and its major metabolite α‐hydroxyalprazolam in plasma. After the addition of deuterium‐labeled internal standards, plasma samples were buffered to pH 9 with 1 ml of saturated sodium borate buffer, extracted with toluene–methylene chloride (7:3) and evaporated to dryness. The residues were treated with N , O ‐bis(trimethylsilyl)trifluoroacetamide containing 1% of trimethylchlorosilane and analyzed on a Finnigan‐MAT mass spectrometer operated in the negative‐ion chemical ionization mode with methane as the reagent gas. Chromatographic separation was achieved on a Restek‐200 capillary column using hydrogen as the carrier gas. The assay was linear from 0.25 to 50 ng ml ‐1 for both compounds. The intra‐assay precision for alprazolam was 16.1% at 0.5 ng ml ‐1 and 4.6% at 50 ng ml ‐1 and that for α‐hydroxyalprazolam was 15.8% at 0.5 ng ml ‐1 and 4.2% at 50 ng ml ‐1 . The method was used to determine alprazolam and α‐hydroxyalprazolam in human plasma samples collected after a single 2 mg oral dose of alprazolam. A peak concentration of 32.9 ng ml ‐1 of alprazolam was detected at 1 h following the dose.