Emergence of new psychoactive substance 2-fluorodeschloroketamine: Toxicology and urinary analysis in a cluster of patients exposed to ketamine and multiple analogues

Monitoring of ketamine-based emerging contaminants in wastewater: a direct-injection method and fragmentation pathway study

The ketamine (KET) and its analogs consumed by humans are becoming emerging contaminants (ECs), as they at present in surface waters after being carried through wastewater systems. Drugs in wastewater can be analyzed using the direct-injection method, a simple wastewater analysis (WWA) method that can provide objective, continuous and nearly to real-time findings. This article describes an ultra-high-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification and confirmation of seven KET-based ECs in wastewater by direct injection. After optimization of the UPLC-MS/MS and sample pretreatment conditions, the method was validated and applied to samples (n = 157) collected from several wastewater treatment plants (WWTPs) in southern China in which KET had the highest detection rate. The established direct-injection method was not only simple to perform but also had better sensitivity, shorter detection times, and analyzed more KET-based ECs than currently published methods, meeting the requirements for the monitoring and high-throughput analysis of common KET-based ECs. We also analyzed the fragmentation pathway of KET-based ECs to obtain product ion information on other unknown substances. Additional studies are needed to establish a comprehensive direct-injection screening method of ECs in wastewater on model-based assessment.

N,N-dimethylpentylone poisoning: Clinical manifestations, analytical detection, and metabolic characterization

INTRODUCTION

The proliferation of new psychoactive substances (NPS) poses a significant challenge to clinical and forensic toxicology laboratories. N,N-dimethylpentylone, a novel synthetic cathinone, has emerged as a public health concern. The aims of this study are to describe the clinical presentation of N,N-dimethylpentylone poisoning, to describe detection methods, and to deduce its metabolic pathways.

METHODS

Clinical data was collected and reviewed retrospectively from patients with confirmed N,N-dimethylpentylone exposure. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify N,N-dimethylpentylone and its metabolites in urine samples. The metabolic pathway was characterised by comparison of the detected substances with reference standards.

RESULTS

Eight cases were included in the case series. Seven different metabolites of N,N-dimethylpentylone were identified in in vivo patient urine samples, where the two major metabolic pathways were proposed to be opening of the 5-membered ring and reduction of carboxide. All patients presented with neuropsychiatric and/or cardiovascular symptoms. Co-ingestion with other substances was reported in all cases. One patient requiring intensive care was described in detail. All patients eventually recovered. The analytical method allowed the simultaneous identification of N,N-dimethylpentylone, pentylone and bisdesmethyl-N,N-dimethylpentylone, as well as other drugs of abuse in patient samples.

CONCLUSION

N,N-dimethylpentylone appears to be less potent than its metabolite pentylone. Co-ingestion with other drugs of abuse is common. Poisoning cases have neuropsychiatric and cardiovascular manifestations. An updated and comprehensive laboratory method is needed for its detection.

Fluorodeschloroketamine found as a street drug in drug seizures and drug driving cases in Hong Kong

BACKGROUND

With the decline of the use of ketamine, one of the common drugs of abuse in Hong Kong, detection of ketamine-related analogues in local laboratories has been encountered.

AIM

A brief account of the occurrence of fluorodeschloroketamine (FDCK) in forensic cases is reported through a retrospective study of all drug seizures and driving under the influence of drugs (DUID) cases since its first appearance.

METHODS

Identification of FDCK in drug seizures was achieved through gas chromatography - mass spectrometry (GC-MS) and/or liquid chromatography - diode array detection (LC-DAD) methods while its quantification was performed using gas chromatography - flame ionization detection (GC-FID). For the analysis of blood samples in DUID cases, identification and quantification were performed using LC-MS/MS by monitoring the respective transitions of FDCK and fluorodeschloronorketamine (FDCNK) using ketamine-d4 and norketamine-d4 respectively as internal standards.

RESULTS

Since its first submission in November 2018, a total of 74 drug seizure cases (151 items) and 6 drug driving cases were encountered till December 2019. Drug seizures found with FDCK were physically similar to those of ketamine seizures. The majority of items were detected with FDCK only (103 items, ∼67%) or as a mixture of FDCK with ketamine (42 items, ∼28%). The drug purity detected with either FDCK only or FDCK mixed with ketamine was high which was similar to those purity found in ketamine seizures. The blood drug concentrations of FDCK of the 6 drug driving cases were in the range of <0.002-1.1 μg/mL and other psychoactive drug(s)/metabolite(s) were also identified. Except for one case where the analysis of the metabolite, fluorodeschloronorketamine (FDCNK), was not conducted due to insufficient sample, the FDCK (FDCNK) concentrations in blood found in the 6 cases were <0.002 (0.005), 0.002 (0.002), 0.002 (0.003), 0.02 (0.035), 0.87 (0.44) and 1.1 (not determined) μg/mL.

CONCLUSIONS

With the drug seizures found with FDCK resembled in physical appearance with ketamine seizures, users might likely misuse it as ketamine. Though complicated by other drugs found, it is speculated that the two cases with higher concentration of FDCK found in blood (1.1 and 0.87 μg/mL) might have contributed to the impairment observed.

Determination of Arylcyclohexylamines in Biological Specimens: Sensors and Sample Pre-Treatment Approaches

Arylcyclohexylamine (ACH) compounds represent a predominant faction within new psychoactive substances. Due to their powerful dissociative effects, they are used in recreational contexts but also in situations of drug-facilitated sexual assault, and therefore, they are a constant target of analysis by forensic experts. In recent years, their consumption has been notably high, especially the use of ketamine, presenting daily challenges for laboratories in the determination of this and other ACH analogues. This review comprises the recent strategies that forensic specialists use to identify and quantify ACH compounds in the laboratory with more traditional analytical techniques and technology, and on the point-of-care testing via sensor technology. The study focuses on analogues of phencyclidine (PCP), ketamine, and eticyclidine, highlighting the consistent need for higher sensitivity in the analysis of various samples collected from real cases and simulations of possible matrices. The review also emphasises the ongoing research to develop more sensitive, quicker, and more capable sensors.

A combined toxicokinetic and metabolic approach to investigate deschloro-N-ethylketamine exposure in a multidrug user

The use of new psychoactive substances derived from ketamine is rarely reported in France. A chronic GHB, 3-MMC, and methoxetamine consumer presented a loss of consciousness in a chemsex context and was referred to the intensive care unit with a rapid and favorable outcome. To investigate the chemicals responsible for the intoxication, a comprehensive analysis was conducted on the ten plasma samples collected over a 29.5-hour period, urine obtained upon admission, a 2-cm hair strand sample, and a seized crystal. These analyses were performed using liquid chromatography hyphenated to high resolution tandem mass spectrometry operating in targeted and untargeted modes. Additionally, analyses using gas chromatography coupled to mass spectrometry and nuclear magnetic resonance were conducted to probe the composition of the seized crystal. The molecular network-based approach was employed for data processing in non-targeted analyses. It allowed to confirm a multidrug exposure encompassing GHB, methyl-(aminopropyl)benzofuran (MAPB), (aminopropyl)benzofuran (APB), methylmethcathinone, chloromethcathinone, and a new psychoactive substance belonging to the arylcyclohexylamine family namely deschloro-N-ethyl-ketamine (O-PCE). Molecular network analysis facilitated the annotation of 27 O-PCE metabolites, including phase II compounds not previously reported. Plasma kinetics of O-PCE allowed the estimation of the elimination half-life of ∼5 hours. Kinetics of O-PCE metabolites was additionally characterized, possibly useful as surrogate biomarkers of consumption. We also observed marked alterations in lipid metabolism related to poly consumption of drugs. In conclusion, this case report provides a comprehensive analysis of exposure to O-PCE in a multidrug user including kinetic and metabolism data in human.

Green Analytical Toxicology procedure for determination of ketamine, its metabolites and analogues in oral fluid samples using dispersive liquid-liquid microextraction (DLLME)

New psychoactive substances (NPS) are often synthesized via small changes in the molecular structure, producing drugs whose effect and potency are not yet fully known. Ketamine is one of the oldest NPS, with therapeutic use in human and veterinary medicine authorized in several countries, being metabolized mainly into norketamine and 6-hydroxy-norketamine. Furthermore, two structural analogues of ketamine have recently been identified, deschloroketamine and 2-fluorodeschloroketamine, marketed as drugs of abuse. To comply with Green Analytical Toxicology (GAT) fundamentals, miniaturized techniques such as dispersive liquid-liquid microextraction (DLLME) were employed to determine toxicants in biological fluids. An analytical method for determining ketamine, its metabolites and its analogues in oral fluid was fully developed and validated by using DLLME and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The extraction parameters were optimized by multivariate analysis, obtaining the best conditions with 200 μL of sample, 100 μL of methanol as dispersive solvent and 50 μL of chloroform as extractor solvent. Linearity was obtained from 10 to 1,000 ng/mL, with limit of detection (LOD) and lower limit of quantification (LLOQ) at 10 ng/mL. Imprecision (% relative standard deviation) and bias (%) were less than 8.2% and 9.5%, respectively. The matrix effect did not exceed 10.6%, and the recovery values varied from 24% to 42%. No matrix interference and good selectivity in the evaluation of 10 different sources of oral fluid and 42 drugs at 500 ng/mL, respectively, were observed. The method was applied in the analysis of 29 authentic oral fluid samples and had its green characteristic evaluated by three different tools: the Green Analytical Procedure Index (GAPI), the Analytical Eco-Scale and the Analytical GREEnness (AGREE) metrics.

Metabolism of four novel structural analogs of ketamine, 2-FXE [2-(ethylamino)-2-(2-fluorophenyl) cyclohexan-1-one], 2-MDCK [2-(methylamino)-2-(o-tolyl) cyclohexan-1-one], 3-DMXE [2-(ethylamino)-2-(m-tolyl) cyclohexan-1-one], and 2-DMXE [2-(ethylamino)-2-(o-tolyl) cyclohexan-1-one], in human liver microsomes based on ultra-performance liquid chromatography-high-resolution tandem mass spectrometry

New psychoactive substances are constantly emerging, among which ketamine analogs with the core structure of 2-amino-2-phenylcyclohexanone have attracted global attention due to their continued involvement in acute intoxications. The monitoring of these substances largely relies on the acquisition of metabolic data. However, the lack of in vitro human metabolism information for these emerging structural analogs presents significant challenges to drug control efforts. To address this challenge, we investigated the first-phase metabolism patterns of four novel ketamine structural analogs of 2-FXE [2-(ethylamino)-2-(2-fluorophenyl) cyclohexan-1-one], 2-MDCK [2-(methylamino)-2-(o-tolyl) cyclohexan-1-one], 3-DMXE [2-(ethylamino)-2-(m-tolyl) cyclohexan-1-one], and 2-DMXE [2-(ethylamino)-2-(o-tolyl) cyclohexan-1-one] utilizing human liver microsomes for the first time. Metabolites were identified using ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry. Our findings reveal that N-dealkylation and hydroxylation are the primary metabolic reactions, alongside other notable reactions, including oxidation, reduction, and dehydration. Based on our extensive research, we propose N-dealkylation and hydroxylation metabolites as appropriate analytical markers for monitoring the consumption of these substances.

Study on the Mass Spectrometry Fragmentation Patterns for Rapid Screening and Structure Identification of Ketamine Analogues in Illicit Powders

Ketamine analogues have been emerging in recent years and are causing severe health and social problems worldwide. Ketamine analogues use 2-phenyl-2-aminocyclohexanone as the basic structure and achieve physiological reactions similar to or even more robust than the prototype of ketamine by changing the substituents on the benzene ring (R1 and R2) and amine group (RN1). Therefore, the mass spectrometry (MS) fragmentation pathways and fragments of ketamine analogues have certain regularity. Eight ketamine analogues are systematically investigated by GC-QTOF/MS and LC-Q-Orbitrap MS/MS with the positive mode of electrospray ionization. The MS fragmentation patterns of ketamine analogues are summarized according to high-resolution MS data. The α-cleavage of carbon bond C1-C2 in the cyclohexanone moiety and further losses of CO, methyl radical, ethyl radical and propyl radical are the characteristic fragmentation pathways of ketamine analogues in EI-MS mode. The loss of H2O or the sequential loss of RN1NH2, CO and C4H6 are the distinctive fragmentation pathways of ketamine analogues in ESI-MS/MS mode. Moreover, these MS fragmentation patterns are first introduced for the rapid screening of ketamine analogues in suspicious powder. Furthermore, the structure of the ketamine analogue in suspicious powder is 2-(Methylamino)-2-(o-tolyl)cyclohexan-1-one, which is further confirmed by NMR. This study contributes to the identification of the chemical structure of ketamine analogues, which can be used for the rapid screening of ketamine analogues in seized chemicals.

NPAideS: a drug-checking study among 3-methylmethcathinone (3-MMC) users

BACKGROUND

3-methylmethcathinone (3-MMC) has been available on the European drug market for several years, but an increase in its availability seems to have occurred around 2020, associated with reports of harm and death. We aimed to analyze the composition of the supposed 3-MMC samples purchased and its concordance with the assumed composition of the drug.

METHODS

A prospective multicenter (n = 6) study was conducted between February 2021 and September 2021 in Auvergne-Rhone-Alpes, France. The inclusion criteria were: 3-MMC users over 18 years of age in contact with a community-based organization (CBO) called AIDES. Consumption was evaluated with an anonymized questionnaire and samples of 3-MMC powder were analyzed with a combination of qualitative (GC-MS) and quantitative methods (UPLC-MS/MS), to compare the assumed and real compositions of the products purchased.

RESULTS

We studied 45 samples provided by 33 users. The study population was predominantly male (91%), with a median age of 40 years, most were university graduates and regular users of 3-MMC. Intravenous drug use was reported by 15.2% of the population. Most of the users bought their 3-MMC online via the Clear Web. Drug testing was requested by 86% of the users, highlighting the need for this type of harm reduction strategy. The purity of the 3-MMC powder samples tested ranged from 21 to 98%. Other NPS drugs, such as 4-CEC (4-chloroethcathinone), 4-MMC, and 2-fluorodeschloroketamine (2-FDCK), supplied as methoxphenidine (MXP), were also detected.

CONCLUSION

This prospective study shows that 3-MMC purity and dose vary considerably. It also describes the characteristics of 3-MMC users and their expectations of a drug-checking program. Our data suggest that drug-checking services may be useful in this population. Health associations and laboratories should work together to help increase access to such programs.

Screening strategy for ketamine-based new psychoactive substances using fragmentation characteristics from high resolution mass spectrometry

Recreational designer drugs called new psychoactive substances (NPS) are emerging and pose enormous risks to public health. Detection of recently discovered or unreported NPS remains a huge challenge by using traditional targeted mass spectrometry methods. Here a novel screening strategy was developed to detect both known and novel analogs of NPS based on fragmentation characteristics from liquid chromatography-high resolution mass spectrometry (LC-HRMS). The HRMS fragmentation pathway of one selected NPS family was investigated to form a database containing predicted drugs as well as their mass characteristics. During the study, an unexpected substituent effect was found to distinguish geometric isomers. Seventy-eight seized samples were analyzed using this strategy, four ketamine-based NPS were detected and three of them were newly marketed. The substituent effect predicted the position of their phenylic substituent, the results were confirmed by NMR.

Qualitative Screening of Amphetamine- and Ketamine-Type Abuse Drugs in Urine Employing Dual Mode Extraction Column by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS-MS)

This manuscript reported a fast and rapid qualitative screening method for abuse drugs in urine by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The scope of the abuse drugs under investigation included methamphetamine (MA), amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methylenedioxyamphetamine (MDA), paramethoxymethamphetamine (PMMA), ephedrine, pseudoephedrine, ketamine (KET), deschloroketamine (DCK), 2-fluorodeschloroketamine (2 F-DCK) and deschloro-N-ethylketamine (2-oxo-PCE). The method employed a dual mode extraction (DME) column as a novel clean-up method for the urine matrix. To an aliquot of 0.2 mL urine, internal standards (ISTDs) and 0.4 mL of acidified methanol were added. After vortex and centrifugation, the supernatant was passed through a DME column before LC-MS-MS analysis. Chromatographic separation was achieved with a C18 column by gradient elution. The limits of detection (LODs) for MA, AMP, MDMA, MDA and PMMA were 3 ng/mL, whereas those for ephedrine and pseudoephedrine were 10 ng/mL and those for KET, DCK, 2 F-DCK and 2-oxo-PCE were 1 ng/mL. The matrix effects ranged from -12% to 7% (%CV from 4% to 19%). This method is fit for the intended purpose for forensic toxicology, as well as for forensic analysis of drugs facilitating sexual assault and other criminal acts.

Arylcyclohexylamine Derivatives: Pharmacokinetic, Pharmacodynamic, Clinical and Forensic Aspects

Since the 2000s, an increasing number of new psychoactive substances (NPS) have appeared on the drug market. Arylcyclohexylamine (ACH) compounds such as ketamine, phencyclidine and eticyclidine derivatives are of particular concern, given their rapidly increasing use and the absence of detailed toxicity data. First used mainly for their pharmacological properties in anesthesia, their recreational use is increasing. ACH derivatives have an antagonistic activity against the N-methyl-D-aspartate receptor, which leads to dissociative effects (dissociation of body and mind). Synthetic ketamine derivatives produced in Asia are now arriving in Europe, where most are not listed as narcotics and are, thus, legal. These structural derivatives have pharmacokinetic and pharmacodynamic properties that are sometimes very different from ketamine. Here, we describe the pharmacology, epidemiology, chemistry and metabolism of ACH derivatives, and we review the case reports on intoxication.

A comparison of reinforcing effectiveness and drug-seeking reinstatement of 2-fluorodeschloroketamine and ketamine in self-administered rats

2-Fluorodeschloroketamine (2F-DCK), a structural analog of ketamine, has been reported to cause impaired consciousness, agitation, and hallucination in abuse cases. It has similar reinforcing and discriminative effects as ketamine. However, the reinforcing efficacy and drug-seeking reinstatement of this analog have not been clarified to date. In this study, the effectiveness of 2F-DCK and ketamine was compared using a behavioral economics demand curve. The reinstatement of 2F-DCK- and ketamine-seeking behaviors induced by either conditioned cues or self-priming was also analyzed. Rats were intravenously self-administered 2F-DCK and ketamine at a dose of 0.5 mg/kg/infusion under a reinforcing schedule of fixed ratio 1 (FR1) with 4 h of daily training for at least 10 consecutive days. The elasticity coefficient parameter α and the essential value of the demand curve in the two groups were similar. Both groups of rats showed significant drug-seeking behavior induced either by conditional cues or by 2F-DCK and ketamine priming. Moreover, the α parameter was inversely related to the degree of reinstatement induced by cues or drug priming in both groups. In total, the expression levels of brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element-binding protein (p-CREB) in the nucleus accumbens in both extinguished and reinstated rats were significantly lower than those in the control. The expression of total Akt, glycogen synthase kinase (GSK)-3β, mammalian target of rapamycin (mTOR), and extracellular signal-related kinase (ERK) also decreased, but p-Akt, p-GSK-3β, p-mTOR, and p-ERK levels increased in both extinguished and reinstated rats. This is the first study to demonstrate that 2F-DCK has similar reinforcing efficacy, effectiveness, and post-withdrawal cravings as ketamine after repeated use. These data suggest that the downregulation of CREB/BDNF and the upregulation of the Akt/mTOR/GSK-3β signaling pathway in the nucleus accumbens may be involved in ketamine or 2F-DCK relapse.

Reports of Adverse Events Associated with Use of Novel Psychoactive Substances, 2017-2020: A Review

An important role of modern forensic and clinical toxicologists is to monitor the adverse events of novel psychoactive substances (NPS). Following a prior review from 2013 to 2016, this critical literature review analyzes and evaluates published case reports for NPS from January 2017 through December 2020. The primary objective of this study is to assist in the assessment and interpretation of these cases as well as provide references for confirmation methods. Chemistry, pharmacology, adverse events and user profiles (e.g., polypharmacy) for NPS are provided including case history, clinical symptoms, autopsy findings and analytical results. Literature reviews were performed in PubMed and Google Scholar for publications using search terms such as NPS specific names, general terms (e.g., 'designer drugs' and 'novel psychoactive substances'), drug classes (e.g., 'designer stimulants') and outcome-based terms (e.g., 'overdose' and 'death'). Government and website drug surveillance databases and abstracts published by professional forensic science organizations were also searched. Toxicological data and detailed case information were extracted, tabulated, analyzed and organized by drug category. Case reports included overdose fatalities (378 cases), clinical treatment and hospitalization (771 cases) and driving under the influence of drugs (170 cases) for a total of 1,319 cases providing details of adverse events associated with NPS. Confirmed adverse events with associated toxidromes of more than 60 NPS were reported including synthetic cannabinoid, NPS stimulant, NPS hallucinogen, NPS benzodiazepine and NPS opioid cases. Fifty of these NPS were reported for the first time in January 2017 through December 2020 as compared to the previous 4 years surveyed. This study provides insight and context of case findings described in the literature and in digital government surveillance databases and websites during a recent 4-year period. This review will increase the awareness of adverse events associated with NPS use to better characterize international emerging drug threats.

Wastewater-based monitoring of 2-fluoro-deschloroketamine abuse from 2019 to 2021 in a southern Chinese province

2-fluoro-deschloroketamine (FDCK) is a ketamine (KET) analog and new psychoactive substance that has appeared on the drug market in Europe and China in the past few years. The substance has been recently listed as a controlled drug by the narcotics control authority of China. In this work, FDCK and its metabolite nor-fluoro-deschloroketmaine (N-FDCK) in wastewater were analyzed for the first time to monitor FDCK abuse in a southern Chinese province that used to be a major producer and consumer of ketamine. For comparison, KET and its metabolite, nor-ketamine (N-KET) were monitored simultaneously. The concentration ratios between FDCK and N-FDCK were not statistically different from those of KET and N-KET. The average FDCK loads in the province in 2019 were higher than KET loads in most major cities in China in 2014 (when KET abuse hit its peak in the country). Rough estimation of FDCK and KET consumption revealed that FDCK was the predominant synthetic drug in the province in 2019, indicating rapid spread of the substance since its first appearance on the market. FDCK consumption decreased dramatically in 2020 and 2021, due to proactive actions by the local drug police before its listing as a controlled drug. Despite the dramatic decrease, FDCK was still the drug with greatest consumption by 2021, indicating that this substance persisted on the market even in the presence of forceful law enforcement. This finding also demonstrates that this substance may indeed have similar or even improved psychoactive effects relative to KET. Quick spread and persistence of FDCK demonstrated here indicates the urgent need to conduct wastewater-based monitoring of the abuse of the substance in other Chinese provinces and other countries.

2-Fluorodeschloroketamine has similar abuse potential as ketamine

2-Fluorodeschloroketamine (2-FDCK) as a substitute for ketamine has emerged among drug abusers in recent years. However, 2-FDCK has not been controlled or regulated in many countries, which may be partly related to the lack of evidence on its abuse potential. In this study, we evaluated the abuse potential of 2-FDCK via the tests of the conditioned place preference (CPP), locomotor sensitization, drug self-administration and drug discrimination using ketamine as a reference. 2-FDCK induced significant CPP at a minimum dose of 3 mg/kg in mice, an effect comparable with that of ketamine (3 mg/kg). Acute injections of 2-FDCK or ketamine at 30 mg/kg enhanced locomotor activity. Repeated treatments with this dose of 2-FDCK and ketamine induced locomotor sensitization after withdrawal. 2-FDCK readily induced self-administration with 0.5 mg/kg/infusion, the same dose for ketamine, and induced the highest seeking response at 1 mg/kg. Drug discrimination test showed that 2-FDCK dose-dependently substitute for ketamine with comparable ED₅₀ to ketamine in substitution testing. Taken together, these results strongly suggested that 2-FDCK has an abuse potential comparable with ketamine.

Structure identification and analysis of the suspected chemical precursor of 2-fluorodeschloroketamine and its decomposition products

In this work, 1-[(2"-fluorophenyl)(methylimino) methyl]cyclopentan-1-ol (2-fluorodeschlorohydroxylimine) was identified as a suspected chemical precursor of 2-fluorodeschloroketamine (2-FDCK) using GC-MS and GC-Q/TOF-MS and comparing the data with those of ketamine and its chemical precursor, hydroxylimine. Furthermore, the entire fragmentation pathway of 2-fluorodeschlorohydroxylimine was theorized from the GC-MS spectrum recorded using an electron ionization (EI) source, and the mechanisms and decomposition pathways of 2-fluorodeschlorohydroxylimine were elucidated. In protic solvents, the nitrogen atom in the C=N group of 2-fluorodeschlorohydroxylimine underwent a protonation reaction. Thereafter, the traces of water present in protic solvents promoted the hydrolysis of the protonated imine, and a carbon cation was obtained following the loss of methylamine. The carbon cation could follow the classical decomposition mechanism of imines and yield an α-hydroxyl ketone, which was the major decomposition product, (2'-fluorophenyl)(1"-hydroxycyclopentyl) methanone. The cation could also undergo a loop expansion rearrangement and yield another α-hydroxyl ketone, 2-(2'-fluorophenyl)-2-hydroxycyclohexan-1-one. The structures of the two aforementioned decomposition products were elucidated using several techniques including theoretical calculation, GC-MS, NMR, the prediction and assistance elucidation functions of ACDLabs-Structure Elucidator Suite, and the virtual separation technology of diffusion-ordered spectroscopy. The aforementioned study revealed important information about the chemical precursor of 2-FDCK and its decomposition. Furthermore, a set of methods for the qualitative analysis of 2-fluorodeschlorohydroxylimine was established, which facilitated accurate analysis of 2-fluorodeschlorohydroxylimine samples following decomposition or destruction.

A Psychonaut's Experience of Intoxication with Multiple Classes of Drugs Including Novel Psychoactive Substance 2-fluorodeschloroketamine: Case Report and Urinary Analysis

Novel psychoactive substances have emerged as drugs of abuse. 2-Fluorodeschloroketamine (2-FDCK) is a ketamine derivative that can be purchased online for as little as $12 per gram. We report the case of a patient with a history of polysubstance use presenting after insufflation of 2-FDCK, with subsequent confirmation of metabolites in the patient's urine. A 28-year-old man presented to the Emergency Department in a dissociated state. He recovered well with supportive care, and described during interview his experience of substance use including the novel psychoactive substance 2-FDCK. A urine sample was sent for analysis and 2-FDCK metabolites were isolated. This case is concerning because 2-FDCK is a relatively new agent that has not yet been reported in the United States. It is easy to obtain over the internet and has significant abuse potential.

Metabolite elucidation of 2-fluoro-deschloroketamine (2F-DCK) using molecular networking across three complementary in vitro and in vivo models

This work first aims to investigate metabolites of 2-fluoro-deschloroketamine (2F-DCK), a new arylcyclohexylamine derivatives (a group of dissociative ketamine-based substances) using two in vitro experimental approaches, and to compare obtained results by means of molecular networking. Metabolites of 2F-DCK were investigated using both human liver microsomes (HLMs) and hepatic (HepaRG) cell line incubates using molecular networking approach: 2F-DCK pure substance was incubated with HLMs for up to 1 h at two concentrations (100 and 500 μM) and with HepaRG cells for two time periods (8 and 24 h) at one concentration (20 μM). In vitro obtained results were subsequently applied to a 2F-DCK-related fatality case. In vitro-produced metabolites were investigated using high-resolution accurate mass spectrometry using Orbitrap mass analyzer technology. Thirteen metabolites were in vitro produced and several metabolic pathways can be postulated. Seven additional metabolites were found in post-mortem samples (bile and urine) of the case, comprising three Phase II metabolites, which appear to be minor in vivo metabolites. HLMs and HepaRG cell models appear to be complementary and obtained data allowed the identification of several specific 2F-DCK metabolites in biological samples. In practical terms, observed metabolic ratios suggested that nor-2F-DCK (208.1137 m/z) and a hydrogenated metabolite (224.1443 m/z) could be proposed as reliable metabolites to be recorded in HRMS libraries in order to improve detection of 2F-DCK use.

Increasing Prevalence of Ketamine in Drivers in New York City Including the Identification of 2-Fluoro-Deschloroketamine

Ketamine is a dissociative anesthetic used in veterinary and human medicine since the 1970s. Its clinical use has expanded to control of seizures, pre-hospital emergency medical services (EMS), and is finding new purpose as an analgesic alternative and antidepressant. Ketamine brings hope for effective management of chronic pain in the absence of opioids, and decreasing suicidal ideations, however, its persistence as a recreational drug for its hallucinogenic properties remains. In the wake of expanding medicinal purposes, the diversity of New York City's population was explored to better understand its misuse. This retrospective study looks at the prevalence of ketamine in driver fatalities over a period of 18 years (2003-2020) and cases involving suspected driving under the influence of drugs (DUID) over a period of 6 years (2015-2020). Ketamine was identified in 6 driver fatalities and in 47 DUID cases. None of the driver fatalities were suspected of ketamine misuse, due to administration either in hospital or EMS administration. In the DUID cases, an increasing trend was observed over the 6-year study period with 100% (N = 47) of the cases confirmed as non-hospital/non-EMS administered ketamine. Of the DUID cases, 94% were male, with the majority between the age of 21-39 years (85%) and were predominantly Hispanic (36%) and Asian (34%). Blood concentrations of ketamine ranged from 27 to > 2000 ng/mL with polydrug use prevalent. The most common drug classes detected in addition to ketamine were cannabinoids (38%), ethanol (32%), benzodiazepines (26%), cocaine (19%), and amphetamines/MDMA (15%). In 2019, 2-fluoro-deschloroketamine (2F-DCK) was identified in two cases for the first time. Despite its increased acceptance for mental health disorders, ketamine's persistence and misuse as a recreational drug remains and should continue to be monitored by relevant toxicological, clinical, and law enforcement communities along with emerging illicit ketamine analogs.

Fatal intoxication related to two new arylcyclohexylamine derivatives (2F-DCK and 3-MeO-PCE)

Continuous development and rapid turnover of drug market of new psychoactive substances (NPS) make it difficult to obtain up-to-date analytical methods for efficient detection of intoxication cases with new substances: no analytical data and no previously published concentration values in biological samples are indeed available. In this context, we aim to report the first fatal case involving two newly emerging arylcyclohexylamine derivatives (a group of dissociative ketamine-based substances): 2-fluoro-deschloroketamine (2F-DCK) and 3-methoxyeticyclidine (3-MeO-PCE). A 42-year-old man was found dead at his home with three plastic bags of "research chemicals" powders near him. Comprehensive screenings of drugs and toxic compounds as well as more selective assays (performed using NMR, HS-GC-FID, LC-MS/MS and LC-HRMS methods) allowed (1) to identify the three unknown powders, 2F-DCK, 3-MeO-PCE, and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT, a hallucinogenic tryptamine-related NPS), with purity above 95%, and (2) to determine peripheral blood (1780, 90, and 52 µg/L), urine (6.1, 6.3, and 2.2 mg/L), bile (12, 3.5, and 1.7 mg/L), and vitreous humour (1500, 66 and 155 µg/L) concentrations of 2F-DCK, 3-MeO-PCE and 5-MeO-DMT, respectively. In addition, toxicological results also revealed recent use of cannabis, cocaine, and amphetamine by the victim, and hair analysis draw pathway of addiction (including experiments with various other NPS) for several months before death. This fatality was considered as the consequence of respiratory depression in a poly-drug user due to a "cocktail effect" of concurrent intakes of 2F-DCK (mainly), 3-MeO-PCE, 5-MeO-DMT, amphetamine, and cocaine. In addition, this case report provides analytical data that could support subsequent toxicological result interpretation in forensic cases involving such arylcyclohexylamine derivatives.

Presence of the ketamine analog of 2-fluorodeschloroketamine residues in wastewater

Ketamine (KET) analogs are increasingly emerging as new psychoactive substances (NPS). The present report describes the first detection of the KET analog, 2-fluorodeschloroketamine (2F-DCK), in influent samples collected from nine wastewater treatment plants in seven major Chinese cities from 2018 to 2020 by wastewater-based epidemiology (WBE). An analytical method based on solid-phase extraction and subsequent gas chromatography-mass spectrometry was developed for the detection of 2F-DCK and KET. The stability experiments showed that 2F-DCK and KET remained stable in wastewater for 15 days at room and frozen temperatures, and at two pH values (pH = 7 and pH = 2), with residue amounts between 90% and 110%. KET was detected in all samples, whereas 2F-DCK was detected in only four samples: from Guangzhou in 2018, Shenzhen in 2019, and Quanzhou and Nanning in 2020, indicating that 2F-DCK has been used as early as 2018 in China. The renal clearance of 2F-DCK was predicted based on the quantitative structure-pharmacokinetic relationship model, which was used to calculate an excretion factor of 3.7. The 2F-DCK consumption in four cities ranged from 3.71 ± 0.05 to 55 ± 0.09 mg/day/1000 inh, and KET ranged from 1.3 ± 0.04 to 76.5 ± 4.63 mg/day/1000 inh. This is the first study to investigate 2F-DCK by WBE, which provides relevant real-time data on the growth of NPS use, as well as useful information for the government to develop new policies.

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.