Determination of alprazolam and alpha-hydroxyalprazolam in human plasma by gas chromatography/negative-ion chemical ionization mass spectrometry.
A sensitive and specific method was developed for the determination of alprazolam and its major metabolite alpha-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 alpha-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 alpha-hydroxyalprazolam in human plasma samples collected after a single 2 mg oral does of alprazolam. A peak concentration of 32.9 ng ml-1 of alprazolam was detected at 1 h following the dose.
Höld
K M
KM
Utrecht Institute of Pharmaceutical Sciences (UIPS), Utrecht University, Department of Analysis and Toxicology, The Netherlands.
Crouch
D J
DJ
Rollins
D E
DE
Wilkins
D G
DG
Canfield
D V
DV
Maes
R A
RA
D000328:Adult; D000525:Alprazolam / Q000031:analogs & derivatives* / Q000097:blood; D014151:Anti-Anxiety Agents / Q000097:blood* / Q000493:pharmacokinetics; D002138:Calibration; D005615:Freezing; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D015203:Reproducibility of Results; D012996:Solutions
D014151:Anti-Anxiety Agents; D007202:Indicators and Reagents; D012996:Solutions; C032318:alpha-hydroxyalprazolam; D000525:Alprazolam