ISSN:
1052-9306
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A sensitive and selective assay has been developed for the identification and quantitation of 3-amino-1-phenylbutane (3-APB), a metabolite of labetalol, in biological fluids using electron impact gas chromatography/mass-selective detection. Samples were extracted with n-hexane, derivatized with heptafluorobutyric anhydride and chromato-graphed on a cross-linked fused-silica capillary column. A positive EI spectrum was obtained using a mass-selective detector. Identification of the metabolite was accomplished using an authentic standard; quantitation was performed in the selected ion monitoring mode using ions m/z 345 (M+) and 132. The assay was linear over the calibration range of 0.5-1000 ng of the analyte and the intra-sample coefficients of variation were less than 12% in all cases. The absolute recovery of 3-APB following extracton from urine and bile was found to be 102.9 ± 4.9% and 98.3 ± 1.45% (mean ± SEM) respectively. The minimum quantitation limit of the assay was 0.5 ng ml-1 (≈ 2 pg injected). Application of the assay in a pharmacokinetic-pharmacodynamic study of labetalol in sheep is demonstrated. The metabolite was detected in urine and bile samples obtained from adult non-pregnant sheep following labetalol administration. The cumulative amount of 3-APB excreted in urine over 24 h was found to be 71.55 μg in one animal following a 100 mg dose of labetalol. Evidence for biliary excretion, glucuronidation and sulfation of 3-APB was also found.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bms.1200211103
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