Windows of detection of lorazepam in urine, oral fluid and hair, with a special focus on drug-facilitated crimes.

摘要

The purported lowering of sex opposition, coupled with a possible abrupt unconsciousness-inducing effect and ease of administration in spiked drinks have resulted in the use of hypnotics in cases of drug-facilitated offense. Among these compounds, lorazepam possesses amnesic properties and can impair an individual rapidly. The chances to detect this substance increase if the most sensitive methods are used and if the biological fluid which allows the longest possible detection time is available. In order to document the window of detection of lorazepam, we have orally administered 2.5mg of the drug to three volunteers and collected oral fluid ( [Formula: see text] ) over 8h, urine ( [Formula: see text] ) over 144h and hair ( [Formula: see text] ) 4 weeks after exposure. Lorazepam was analyzed by LC-MS/MS after alkalinisation (to pH 8.4 with phosphate buffer) and extraction by dichloromethane/diethyl ether in presence of diazepam-d(5), used as internal standard. Reversed-phase separation on a XTerra C18column was achieved in 12min, under gradient conditions. Molecular ions (m/z 321 and 290 for lorazepam and the IS, respectively) were selected in Ql and the corresponding daughter ions (m/z 303 and 275 for lorazepam and m/z 154 and 198 for the IS) were detected in Q3 after collision with argon. Urine tested positive for lorazepam over 144h (2-4ng/ml), with a peak detected after 24h exposure (411-880ng/ml). Oral fluid tested positive for lorazepam over 8h (0.7ng/ml). Despite a limit of quantitation at 1pg/mg, we were unable to detect a single lorazepam dose in hair, contrarily to most other benzodiazepines that are detectable. Therefore, in case of drug-facilitated crimes involving lorazepam, urine appears as the best specimen to document exposure, particularly if LC-MS/MS is used.