Determination of Alprazolam and α-Hydroxyalprazolam in Human Plasma by Gas Chromatography/Negative-ion Chemical Ionization Mass Spectrometry

✍ Scribed by Höld, Karin M.; Crouch, Dennis J.; Rollins, Douglas E.; Wilkins, Diana G.; Canfield, Dennis V.; Maes, Robert A.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 567 KB
• Volume: 31
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199609)31:9<1033::aid-jms391>3.0.co;2-h

✦ Synopsis

A sensitive and specific method was developed for the determination of alprazolam and its major metabolite a-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 toluen+methylene chloride (7 : 3) and evaporated to dryness. The residues were treated with N,O-bis(trimethylsily1)tnfluoroacetamide 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 m1-I for both compounds. The intra-assay precision for alprazolam was 16.1% at 0.5 ng ml-' and 4.6% at 50 ng ml-' and that for a-hydroxyalprazolam was 15.8% at 0.5 ng ml-I and 4.2% at 50 ng m1-l. The method was used to determine alprazolam and a-hydroxyalprazolam in human plasma samples collected after a single 2 mg oral dose of alprazolam. A peak concentration of 32.9 ng ml-' of alprazolam was detected at 1 h following the dose.