Introduction:
Sexual abuse of both men and women while under the influence of so-called "date-rape" drugs has been the focus of many investigations. One of these drugs, flunitrazepam (Rohypnol, or "Roofies") has recently been banned in the U.S.A. because of its use in various "date-rape" situations. Unfortunately, the detection of flunitrazepam or two of its metabolites, desmethyl-flunitrazepam and 7-aminoflunitrazepam, (7-AF) in a single specimen such as urine or blood is difficult in criminal situations because of the likelihood of single dose ingestion and the length of time since the alleged incident. Hair provides a solution to the second of these problems, in that drugs tend to incorporate into hair and remain there for longer periods of time than either urine or blood. The objective of this paper was to determine whether a commercially available micro-plate enzyme immunoassay system was sufficiently sensitive for the routine screening of 7-AF in hair.
Sample Preparation:
Drug free hair was powdered and weighed into 50 mg aliquots. 7-AF was added at various concentrations from 0.05 to 1.0 ng/mg of hair. Following standard sample preparation, the samples were extracted using a mixed-mode solid-phase procedure. The specimens were screened using the methodology described in the benzodiazepine urine micro-plate enzyme imunoassay kit (STC Technologies, Inc.). Incubation time and aliquot size were the major variables in optimization of the assay. The final procedure showed a difference between absorbance value produced by the negative hair and that produced by hair containing 0.05 ng/mg, however, a cut-off of 0.1 ng/mg was selected.
Case Studies:
The procedure was run on hair taken from four subjects. Sample A was obtained from an alleged rape victim, sample B was obtained from an emergency room patient whose blood screened positively for benzodiazepines, samples C and D were obtained from corpses whose blood contained flunitrazepam and 7-AF along with other drugs. All the specimens screened positively for benzodiazepines using this assay at 7-AF concentrations approximately equivalent to A:0.2 ng/mg; B: 0.5 ng/mg; C: >1 ng/mg and D: 0.1 ng/mg.
Conclusion:
The micro-plate enzyme immunoassay system was sufficiently sensitive for the screening of 7-AF in hair. Confirmatory procedures are under development. |