Serum and Urine Concentrations of Flunitrazepam and Metabolites, after a Single Oral Dose, by Immunoassay and GC-MS

Snyder, H.; Schwenzer, K.S.; Pearlman, R.; Mcnally, A.J.; Tsilimidos, M.; Salamone, S.J.; Brenneisen, R.; Elsohly, M.A.; Feng, S. (2001). Serum and Urine Concentrations of Flunitrazepam and Metabolites, after a Single Oral Dose, by Immunoassay and GC-MS. Journal of analytical toxicology, 25(8), pp. 699-704. Oxford University Press 10.1093/jat/25.8.699

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A clinical study was conducted to assess the ability of commercially available immunoassays to detect flunitrazepam (FNP) in plasma and urine samples and to compare the results with those obtained by gas chromatography-mass spectrometry (GC-MS). The clinical study consisted of four individuals (two male and two female) who had taken a single 2-mg dose of FNP. Serum was collected over a 48-h period and urine was collected over a 72-h period. The serum and urine samples were analyzed by the COBAS® INTEGRA Serum Benzodiazepines assay (SBENZ), the TDx serum and urine Benzodiazepines assay, and GC-MS. The GC-MS procedure was developed for analysis of FNP and metabolites in plasma and urine using an acid hydrolysis step resulting in the formation of specific benzophenones corresponding to FNP and its metabolites. The relative sensitivities of the assays for the detection of FNP and metabolites in serum and urine were GC-MS > SBFNZ > TDx. The immunoassay results for serum samples showed peak concentrations of FNP metabolites at 8 h after FNP ingestion for three individuals and at about 1 h for the fourth individual. The GC-MS, SBENZ, and TDx urine immunoassays detected drug above the stated limit of detection (LOD) in 44, 41, and 35 serial FNP urine samples, respectively. FNP metabolites were detected in urine samples with all three assays for up to 72 h after a 2-mg dose. The improved detection rate with the SBENZ assay as compared to the TDx assay is likely explained by its higher cross-reactivity with the major metabolite, 7-amino-flunitrazepam (7-amino-FNP), and its lower LOD.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > DBMR Forschung Mu35 > Forschungsgruppe Phytopharmakologie, Bioanalytik & Pharmakokinetik [discontinued]
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > DBMR Forschung Mu35 > Forschungsgruppe Phytopharmakologie, Bioanalytik & Pharmakokinetik [discontinued]

UniBE Contributor:

Brenneisen, Rudolf Max

ISSN:

0146-4760

Publisher:

Oxford University Press

Language:

English

Submitter:

Marceline Brodmann

Date Deposited:

02 Sep 2020 16:49

Last Modified:

02 Sep 2020 16:59

Publisher DOI:

10.1093/jat/25.8.699

BORIS DOI:

10.7892/boris.115276

URI:

https://boris.unibe.ch/id/eprint/115276

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