Method development for the identification of methoxpropamine, 2-fluoro-deschloroketamine and deschloroketamine and their main metabolites in blood and hair and forensic application.

The constant increase of new psychoactive substances, often available on the illicit drug market as 'research chemicals', poses a concern for public health and a significant analytical and legislative challenge. Β-keto-arylcyclohexamines represent a class of dissociative anesthetics recently introduced on the market of New Psychoactive Substances (NPS). There is still a lack of information about the pharmacological activity of many of such substances, usually depending on the potential chemical modifications introduced to circumvent the law. Furthermore, their intake may not be fully intentional, since consumers do not always have knowledge of the content of online purchases. The present study describes the characterization by liquid chromatography-high resolution mass spectrometry (LC-HRMS), using a benchtop Orbitrap instrument, of the novel ketamine analogues methoxpropamine, 2-fluoro-deschloroketamine and deschloroketamine, found in the post-mortem blood and hair samples from a forensic case of suicide by fall from height, and of some of their metabolites. This allowed the development of analytical methods for the determination of both the β-keto-arylcyclohexamines and the metabolites in LC-HRMS and in LC-MS/MS, providing a starting point for studying their toxicokinetics.