[Detection of lorazepam and lormetazepam metabolites in urine using thin-layer chromatography].

The determination of benzodiazepine derivatives lorazepam and lormetazepam in urine is based on detection of their metabolites 2-amino-2',5-dichlorobenzophenone and 2-methylamino-2'5-dichlorbenzophenone in hydrolyzed urine. Both substances are structurally very similar to the metabolites of diazepam 2-amino-5-chlorbenzophenone and 2-methylamino-5-chlorbenzophenone and their mobility on thin layer chromatograms is similar as well. This could cause their confusion and misinterpretation of the results. Therefore suitable combination of mobile phases and thin layer plates was sought in this study for the unambiguous identification of respective benzophenones by thin layer chromatography.