Determination of flunitrazepam in body fluids by means of high-performance liquid chromatography
Vree, T.B.; Lenselink, B.; van der Kleijn, E.; Nijhuis, G.M.
Journal of Chromatography 143(5): 530-534
1977
ISSN/ISBN: 0021-9673 PMID: 19494 Document Number: 121172
Flunitrazepam, a benzodiazepine tranquilizer, is used in anesthesia and in intensive care units in hospitals. Because of its very strong action, only small doses (0.010-0.030 mg/kg) can be administered to man, so the plasma concentration is expected to be very low. The method permits determination of plasma concentrations of flunitrazepam as low as 1 ng/ml. Sensitivity of the method (10-1 ng/ml) is sufficient for most pharmacokinetic studies and routine determinations of plasma concentrations associated with anesthesia. The Spherisorb S-W10 column permits separation of various benzodiazepines that may be used as co-medicants or for induction of anesthesia, e.g., diazepam (Valium), nitrazepam (Mogadon) and clonazepam (Rivotril). Two metabolites of diazepam, oxazepam (Seresta) and oxydiazepam (Temazepam) are not eluted from this column. In those instances, in routine determinations of flunitrazepam when it is not known if co-medication has been applied, a 2nd extraction without internal standard must be made in order to avoid erroneous results.