[Determination of 7-aminoflunitrazepam, the major metabolite of flunitrazepam in urine by high performance thin-layer chromatography].

A rapid and highly sensitive method, based on high performance thin-layer chromatography, is described for the qualitative and semiquantitative determination of 7-aminoflunitrazepam, the main metabolite of flunitrazepam in human urine. 7-Aminoflunitrazepam in specimen was extracted by solid phase extraction using GDX-403 porous polymer bead as sorbent and ethyl ether as eluant. Fluorescamine was used as a reagent to produce fluorescent product on the plate. The limit of detection was 5 micrograms/L and the limit of quantitation was 15 micrograms/L for 7-aminoflunitrazepam in urine. The method can be successfully used for measuring 7-aminoflunitrazepam in urine samples of the subjects excreted over a 48 h period after receiving 1 mg flunitrazepam orally. The method is applicable to drug examination for the cases of drug-facilitated robbery and rape.