Hair monitoring of chronic ketamine abuse: an innovative analytical approach

Drug abuse is a severe social problem, expecially among young people, which can cause devastating impacts on crime rate and healthcare expenses. Ketamine (2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one) is an emerging drug of abuse often easily accessed in the black market and erroneously perceived by young subjects as a “safe” and “clean” drug. Ketamine was marketed as an anaesthetic drug and at sub-therapeutic doses possesses psychedelic properties including cataleptic state with stupor, sedation and possible amnesia, which can lead to drug-facilitated sexual assaults. This, together with the recent increase in ketamine abuse and ketamine-related death reports, is arousing the attention of the authorities as well as that of the scientific community. Detection and quantitation of residual illicit drugs by the analysis of blood, urine and oral fluid are often employed in forensic and clinical settings; on the other hand, hair monitoring can reveal a retrospective reflection of drug abuse, providing a wider detection window, therefore this strategy can be a useful tool in chronic drug abuse monitoring. The goal of this study is the simultaneous analysis of ketamine and its major active metabolite norketamine (2-amino-2-(2-chlorophenyl)cyclohexan-1-one) in hair samples by means of HPLC separation, using a C18 column as the stationary phase and a mobile phase consisting of an acetonitrile/acidic aqueous buffer mixture. Sample preparation includes an acidic extractive incubation, followed by L/L extraction with organic solvents. Quantitative determination is achieved using detection means such as spectrofluorimetry (F), that exploits the native fluorescence of the analytes, and tandem mass spectrometry (MS/MS). Since the obtained results are promising, after validation the method will be applied for the monitoring in hair of chronic ketamine abusers.