I Abstract [ A gas chromatography-mass spectrometry method was developed for the analy~s of t]unJtrazepam (FN) and its major metabolite, 7-amino-flunitrazepam (7-amino-FN), in both plasma and whole blood. The method was based on acid hydrolysis of the samples after dilution with HPLC water followed by extraction and derivatization (heptafluorobutyrate) of the resulting benzophenones. Analysis of plasma and whole blood samples from subjects administered 2-mg doses of FN showed that FN was only

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... tected in whole blood (rOD 5 ng/mL) and not in plasma. However, 7-amino-FN was detected in both plasma and whole blood, although the levels were much higher in plasma. 7-Amino-FN was detected for the entire period of specimen collection (12 h), but FN was only detected in whole blood for 4 h after ingestion with peak levels after I h. the time course of detection of the parent drug versus its metabolite in both plasma and blood samples collected at the same time. Experimental Materials 7-Amino-FN-ds was purchased from Lipomed, Inc. (Cambridge, MA). FN, nor-FN, and 7-amino-FN were obtained from Radian Corp. (Austin, TX). 7-Amino-nor-FN was provided by Roche Diagnostics Systems (Somerville, N J). All solvents were high-performance liquid chromatography (HPLC) grade, and the chemicals were American Chemical Society reagent grade.