Modified screening procedure with fluorescence detection for flunitrazepam and its metabolites via acridine derivatives.

A modified thin-layer chromatographic method with fluorescence detection is described for the screening of flunitrazepam and its major metabolites in urine. The method is based on the hydrolysis and subsequent formation of acridine derivatives by cyclization in dimethyl-formamide. This reliable screening procedure, which has proven its usefulness in many laboratories, provides valid results in the absence of diclofenac, carbamazepine, and tricyclic antidepressants. On the other hand these latter substances are frequently detectable in urine samples taken from addicts especially during therapy. So it was necessary to modify the procedure.