Enzymatic defluorination of a terminally monofluorinated pentyl moiety: oxidative or hydrolytic mechanism?

Fluorination of organic compounds plays an important role in the chemical and pharmaceutical industry and is often applied in order to improve physicochemical parameters or modify pharmacological properties. While oxidative and reductive defluorination have been shown to be responsible for the metabolic degradation of organofluorine compounds, the involvement of hydrolytic mechanisms catalyzed by human enzymes has not been reported so far. Here, we investigated the enzymatic defluorination of terminally monofluorinated aliphates with [1-(5-fluoropentyl)-1H-indol-3-yl]-1-naphthalenyl-methanone (AM-2201) as a model substance. We performed in vitro biotransformation using pooled human liver microsomes (pHLM) and human recombinant cytochrome P450 (CYP) assays. In order to elucidate the underlying mechanisms, modified incubation conditions were applied including the use of deuterium labeled AM-2201 (d2 -AM-2201). Identification of the main metabolites and analysis of their isotopic composition was performed by liquid-chromatography coupled to time-of-flight-mass-spectrometry (LC-QToF-MS). Quantification of the metabolites was achieved with a validated method based on liquid-chromatography-tandem-mass-spectrometry (LC-MS/MS). CYP 1A2 mediated defluorination of d2 -AM-2201 revealed an isotopic pattern of the defluorinated 5-hydroxypentyl metabolite (5-HPM) indicating a redox mechanism with an aldehyde as a plausible intermediate. In contrast, formation of 5-HPM by pHLM was observed independently of the presence of atmospheric oxygen or co-factors regenerating the redox system. pHLM incubation of d2 -AM-2201 confirmed the hypothesis of a non-oxidative mechanism involved in the defluorination of the 5-fluoropentyl moiety. So far, enzymatically catalyzed, hydrolytic defluorination was only described in bacteria and other prokaryotes. The presented data prove the involvement of a hydrolytic mechanism catalyzed by human microsomal enzymes other than CYP. Significance Statement Elucidating the mechanisms involved in the enzymatic detoxification of organofluorine compounds is crucial for enhancing our understanding and facilitating the design and development of drugs with improved pharmacokinetic profiles. The carbon-fluorine bond possesses a high binding energy, which suggests that non-activated fluoroalkanes would not undergo hydrolytic cleavage. However, our study provides evidence for the involvement of a non-oxidative mechanism catalyzed by human liver enzymes. It is important to consider CYP-independent, hydrolytic defluorination, when investigating the pharmacokinetic properties of fluorinated xenobiotics.

Intoxications involving methoxyacetylfentanyl and U-47700: a study of 3 polydrug fatalities.

Novel synthetic opioids (NSOs) represent an emerging group of novel psychoactive substances, acting as agonists at the opioid receptors. NSOs include fentanyl-related compounds, e.g. methoxyacetylfentanyl (MeACF), and non-fentanyl analogs, e.g. "U compounds" including U-47700. Here we present three cases of death involving MeACF and U-47700, with particular reference to preliminary data on pharmacokinetics and tissue distribution.After a complete post-mortem examination, general unknown screenings and analysis of drugs of abuse were performed on postmortem samples by immunoassays, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. To quantify the analytes of interest in post-mortem blood and tissues, the standard addition method was used. A toxicological significance score (TSS), weighing the role of the NSO in each death case, was assigned.Case 1 died at the hospital after consumption of U-47700, methadone (serum levels: 2,600 ng/ml and 37 ng/ml), tilidine and benzodiazepines. In case 2, U-47700 (204 ng/ml) together with methadone (290 ng/ml), flubromazepam (480 ng/ml) and diazepam (300 ng/ml) were detected in peripheral blood. In case 3, methoxyacetylfentanyl (266 ng/ml), furanylfentanyl (4.3 ng/ml) 4-ANPP (15 ng/ml) and alprazolam (69 ng/ml) were quantified in femoral blood. In all cases, the NSO likely contributed to the death (TSS = 3).NSOs appear to be often consumed in the setting of polydrug intoxications, especially in combination with other opioids and benzodiazepines, which often exert synergistic effects. The standard addition method remains the most reliable in post-mortem analysis and toxicological results should always be evaluated together with circumstantial and autopsy data.

In vitro, in vivo metabolism and quantification of the novel synthetic opioid N-piperidinyl etonitazene (etonitazepipne).

OBJECTIVES: N-piperidinyl etonitazene (etonitazepipne) is a newly synthesized opioid related to the 2-benzylbenzimidazole analog class. Etonitazepipne has been formally notified and placed under intensive monitoring in Europe in January 2022. Nitazenes have high affinity at µ-opioid receptor (MOR). Etonitazepipne, specifically shows a EC50 of 2.49 nM, suggesting about 50 times higher potency combined with higher efficacy compared to morphine. Antinociceptive potency l ('hot plate test' with rats) was 192-fold greater than that of morphine. METHODS: Here we report on a post-mortem case involving etonitazepipne and its quantification using a standard addition method (SAM) through liquid chromatography tandem mass spectrometry (LC-MS/MS). In addition, characterization and identification of phase I human metabolites using in vitro assay based on pooled human liver microsomes (pHLM) was performed along with the analysis of authentic urine samples by means of high-performance liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). RESULTS: The concentration of etonitazepipne in post-mortem blood and urine was 8.3 and 11 ng/mL, respectively. SAM was validated by assessing the following parameters: intraday and interday repeatability, matrix effect and recovery rate in post-mortem blood. A total of 20 and 14 metabolites were identified after pHLM incubation and urine analysis, respectively. Most pronounced in vitro and in vivo transformations were O-deethylation, hydroxylation, ketone reduction, and combinations thereof. CONCLUSIONS: Considering small traces of the parent drug often found in real cases, the identification of metabolic biomarkers is crucial to identify exposure to this drug. O-deethylated, oxidated metabolites, and combination thereof are proposed as urinary biomarkers along with the parent compound.

Interpreting mono- and poly-SCRA intoxications from an activity-based point of view: JWH-018 equivalents in serum as a comparative measure.

Synthetic cannabinoid receptor agonists (SCRAs) are a class of synthetic drugs that mimic and greatly surpass the effect of recreational cannabis. Acute SCRA intoxications are in general difficult to assess due to the large number of compounds involved, differing widely in both chemical structure and pharmacological properties. The rapid pace of emergence of unknown SCRAs hampers on one hand the timely availability of methods for identification and quantification to confirm and estimate the extent of the SCRA intoxication. On the other hand, lack of knowledge about the harm potential of emerging SCRAs hampers adequate interpretation of serum concentrations in intoxication cases. In the present study, a novel comparative measure for SCRA intoxications was evaluated, focusing on the cannabinoid activity (versus serum concentrations), which can be measured in serum extracts with an untargeted bioassay assessing ex vivo CB1 activity. Application of this principle to a series of SCRA intoxication cases (n = 48) allowed for the determination of activity equivalents, practically entailing a conversion from different SCRA serum concentrations to a JWH-018 equivalent. This allowed for the interpretation of both mono- (n = 34) and poly-SCRA (n = 14) intoxications, based on the intrinsic potential of the present serum levels to exert cannabinoid activity (cf. pharmacological/toxicological properties). A non-distinctive toxidrome was confirmed, showing no relation to CB1 activity. The JWH-018 equivalent was partly related to the poison severity score (PSS) and causality of the clinical intoxication elicited by the SCRA. Altogether, this equivalent concept allows to comparatively and timely interpret (poly-)SCRA intoxications based on CB1 activity.

Human metabolism of four synthetic benzimidazole opioids: isotonitazene, metonitazene, etodesnitazene, and metodesnitazene.

Following isotonitazene scheduling in 2019, the availability of alternative 2-benzylbenzimidazole opioids (nitazenes) on the global drug market increased, resulting in many fatalities worldwide. Nitazenes are potent µ-opioid receptor agonists with strong narcotic/analgesic effects, and their concentrations in biological matrices are low, making the detection of metabolite biomarkers of consumption crucial to document use in clinical and forensic settings. However, there is little to no data on the metabolism of the most recently available nitazenes, especially desnitro-analogues. The aim of the research was to assess isotonitazene, metonitazene, etodesnitazene, and metodesnitazene human metabolism and identify specific metabolite biomarkers of consumption. The four analogues were incubated with 10-donor-pooled human hepatocytes, and the incubates were analyzed by liquid chromatography-high-resolution tandem mass spectrometry and data mining with Compound Discoverer (Thermo Scientific); the analysis was supported by in silico metabolite predictions with GLORYx open-access software. Metabolites were identified in postmortem blood and/or urine samples from two metonitazene-positive and three etodesnitazene-positive cases following the same workflow, with and without glucuronide hydrolysis in urine, to confirm in vitro results. Twelve, nine, twenty-two, and ten metabolites were identified for isotonitazene, metonitazene, etodesnitazene, and metodesnitazene, respectively. The main transformations were N-deethylation at the N,N-diethylethanamine side chain, O-dealkylation, and further O-glucuronidation. In vitro and autopsy results were consistent, demonstrating the efficacy of the 10-donor-pooled human hepatocyte model to predict human metabolism. We suggest the parent and the corresponding O-dealkyl- and N-deethyl-O-dealkyl metabolites as biomarkers of exposure in urine after glucuronide hydrolysis, and the corresponding N-deethyl metabolite as additional biomarker in blood.

"Spice"-related deaths in and around Munich, Germany: A retrospective look at the role of synthetic cannabinoid receptor agonists in our post-mortem cases over a seven-year period (2014-2020).

Synthetic cannabinoid receptor agonists (SCRAs, "Spice") are a diverse group of recreational drugs, with their structural and pharmacological variability still evolving. Forensic toxicologists often rely on previous reports to assess their role in intoxication cases. This work provides detailed information on the "Spice"-related fatalities around Munich, Germany, from 2014 to 2020. All cases underwent an autopsy. Pharmaceutical and illicit drugs were detected and quantified in post-mortem peripheral blood or liver by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on circumstantial evidence, only those cases for which a prior consumption was suspected underwent additional analyses for SCRAs and other new psychoactive substances in post-mortem blood, liver or antemortem specimens. Drug concentrations, pathological findings at autopsy and case histories were considered to assess and rank the SCRAs' involvement in each death. Concentration ranges for the individual substances in blood were defined and their distribution patterns over the investigated period were determined and correlated with their legal status and local police seizures. We identified 41 different SCRAs among 98 fatalities. 91.8% were male, at a median age of 36 years. SCRAs played a causative role in 51%, contributory role in 26%, and an insignificant role in 23% of cases. In correlation with local police seizures and legal status, 5F-ADB was the most prevalent in our cases, followed by 5F-MDMB-PICA and AB-CHMINACA. Cumyl-CBMICA and 5F-MDMB-P7AICA were among the least frequently detected SCRAs. "Spice"-related fatalities and SCRAs' causative role have significantly decreased among our cases since the German New Psychoactive Substances Act.

In vitro studies on the dependence of drug deposition in dentin on drug concentration, contact time, and the physicochemical properties of the drugs.

The chemical analysis of dental hard tissues can provide information on previous drug use due to the deposition of drugs into this tissue. For the interpretation of analytical results in, e.g., postmortem toxicology or regarding archeological samples, the influence of drug dosing, consumption frequency, duration of intake and type of drug on analyte concentrations in teeth has to be characterized. To approximate these correlations, in vitro models were applied to investigate the time dependency of drug deposition via and against pulp pressure (perfusion studies) and the concentration dependency of drug deposition via oral cavity (incubation study) as well as the influence of de- and remineralization (pH cycling) on the incorporation of drugs in bovine dentin pellets. Some of the drugs of abuse most relevant in forensic case work (amphetamines, opiates, cocaine and benzoylecgonine) were applied. Concentrations in dentin samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after pulverization and extraction via ultrasonication with methanol. The studies showed that drug deposition in dentin likely depends on the physicochemical properties of the drug molecules as well as on the duration of contact with drugs via the blood stream and on drug concentrations present in the oral cavity. Higher drug concentrations in teeth can result from a more frequent or longer drug use. In addition, intake of higher doses or oral/inhalative consumption can also be expected to lead to higher drug concentrations. These findings can be helpful for the interpretation of postmortem cases.

Phase I metabolic profiling of the synthetic cannabinoids THJ-018 and THJ-2201 in human urine in comparison to human liver microsome and cytochrome P450 isoenzyme incubation.

Despite the increasing relevance of synthetic cannabinoids as one of the most important classes within "New Psychoactive Substances", there is still a lack of knowledge concerning their metabolism in humans. Due to the extensive metabolism of synthetic cannabinoids, metabolites are necessarily the best target analytes in urine, posing additional challenges to forensic analysis. The aims of this study were to identify appropriate urinary targets indicating intake of THJ-018 or THJ-2201 as well as to elucidate the most important cytochrome P450 isoenzymes within the metabolism of THJ-018 and THJ-2201 in vitro. For this purpose, the in vitro metabolism of THJ-018 and THJ-2201 was initially established using pooled human liver microsomes. The results obtained were compared to previously published in vitro results as well as to the results of the metabolic profiles from selected recombinant cytochrome P450 isoenzymes and from 23 urine samples from forensic cases. LC-HRMS was used to conduct product ion scans and to examine the metabolite spectra. For THJ-018, 17 different metabolite groups containing 33 different metabolites and isomers were detected after microsomal incubation, with the major metabolic pathways being monohydroxylation at the pentyl chain and of the naphthyl moiety as well as dihydroxylation of both residues. For THJ-2201, 19 different metabolite groups and 46 different metabolites and isomers were observed. The major metabolic pathways were monohydroxylation at the naphthyl moiety and oxidative defluorination. Significant contribution to the in vitro metabolism of THJ-018 and THJ-2201 originated from CYP2B6, CYP2C19, CYP3A4, and CYP3A5. As several cytochrome P450 isoenzymes are involved in the metabolism of these synthetic cannabinoids, a co-consumption with other drugs is unlikely to have an impact on their metabolism.

Activity-Based Detection of Cannabinoids in Serum and Plasma Samples.

BACKGROUND: Synthetic cannabinoids are the largest group of new psychoactive substances monitored by the European Monitoring Centre of Drugs and Drug Addiction. The rapid proliferation of novel analogs makes the detection of these new derivatives challenging and has initiated considerable interest in the development of so-called "untargeted" screening strategies to detect these compounds. METHODS: We developed new, stable bioassays in which cannabinoid receptor activation by cannabinoids led to recruitment of truncated ß-arrestin 2 (ßarr2) to the cannabinoid receptors, resulting in functional complementation of a split luciferase, allowing readout via bioluminescence. Aliquots (500 µL) of authentic serum (n = 45) and plasma (n = 73) samples were used for simple liquid-liquid extraction with hexane:ethyl acetate (99:1 v/v). Following evaporation and reconstitution in 100 µL of Opti-MEM® I/methanol (50/50 v/v), 10 µL of these extracts was analyzed in the bioassays. RESULTS: Truncation of ßarr2 significantly (for both cannabinoid receptors; P = 0.0034 and 0.0427) improved the analytical sensitivity over the previously published bioassays applied on urine samples. The new bioassays detected cannabinoid receptor activation by authentic serum or plasma extracts, in which synthetic cannabinoids were present at low- or sub-nanogram per milliliter concentration or in which Δ9-tetrahydrocannabinol was present at concentrations >12 ng/mL. For synthetic cannabinoid detection, analytical sensitivity was 82%, with an analytical specificity of 100%. CONCLUSIONS: The bioassays have the potential to serve as a first-line screening tool for (synthetic) cannabinoid activity in serum or plasma and may complement conventional analytical assays and/or precede analytical (mass spectrometry based) confirmation.

Designer Benzodiazepines: Another Class of New Psychoactive Substances.

Benzodiazepines have been introduced as medical drugs in the 1960s. They replaced the more toxic barbiturates, which were commonly used for treatment of anxiety or sleep disorders at the time. However, benzodiazepines show a high potential of misuse and dependence. Although being of great value as medicines, dependence to these drugs is a concern worldwide, in part due to overprescription and easy availability. Therefore, the phenomenon of benzodiazepines sold via Internet shops without restrictions at low prices is alarming and poses a serious threat to public health. Most of these compounds (with the exception of, e.g., phenazepam and etizolam) have never been licensed as medical drugs in any part of the world and are structurally derived from medically used benzodiazepines. Strategies of clandestine producers to generate new compounds include typical structural variations of medically used 1,4-benzodiazepines based on structure-activity relationships as well as synthesis of active metabolites and triazolo analogs of these compounds. As they were obviously designed to circumvent national narcotics laws or international control, they can be referred to as "designer benzodiazepines." The majority of these compounds, such as diclazepam, clonazolam, and nitrazolam, have been described in scientific or patent literature. However, little is known about their pharmacological properties and specific risks related to their use. This chapter describes the phenomenon of designer benzodiazepines and summarizes the available data on pharmacokinetics and pharmacodynamics as well as analytical approaches for their detection.

Activity-Based Detection of Consumption of Synthetic Cannabinoids in Authentic Urine Samples Using a Stable Cannabinoid Reporter System.

Synthetic cannabinoids (SCs) continue to be the largest group of new psychoactive substances (NPS) monitored by the European Monitoring Center of Drugs and Drugs of Abuse (EMCDDA). The identification and subsequent prohibition of single SCs has driven clandestine chemists to produce analogues of increasing structural diversity, intended to evade legislation. That structural diversity, combined with the mostly unknown metabolic profiles of these new SCs, poses a big challenge for the conventional targeted analytical assays, as it is difficult to screen for "unknown" compounds. Therefore, an alternative screening method, not directly based on the structure but on the activity of the SC, may offer a solution for this problem. We generated stable CB1 and CB2 receptor activation assays based on functional complementation of a split NanoLuc luciferase and used these to test an expanded set of recent SCs (UR-144, XLR-11, and their thermal degradation products; AB-CHMINACA and ADB-CHMINACA) and their major phase I metabolites. By doing so, we demonstrate that several major metabolites of these SCs retain their activity at the cannabinoid receptors. These active metabolites may prolong the parent compound's psychotropic and physiological effects and may contribute to the toxicity profile. Utility of the generated stable cell systems as a first-line screening tool for SCs in urine was also demonstrated using a relatively large set of authentic urine samples. Our data indicate that the stable CB reporter assays detect CB receptor activation by extracts of urine in which SCs (or their metabolites) are present at low- or subnanomolar (ng/mL) level. Hence, the developed assays do not only allow activity profiling of SCs and their metabolites, it may also serve as a screening tool, complementing targeted and untargeted analytical assays and preceding analytical (mass spectrometry based) confirmation.

Pregnenolone does not interfere with the effects of cannabinoids on synaptic transmission in the cerebellum and the nucleus accumbens.

The steroid hormone pregnenolone attenuates several in vivo behavioural and somatic effects of the phytocannabinoid Δ9-tetrahydrocannabinol, and it was suggested that pregnenolone can protect the brain from cannabis intoxication. The primary neuronal cannabinoid action behind most of the behavioural and somatic effects of cannabinoids is presynaptic inhibition of synaptic transmission. Therefore, the hypothesis of the present study was that pregnenolone attenuates the inhibition of synaptic transmission elicited by cannabinoids. Brain slices containing the cerebellum or the nucleus accumbens were prepared from brains of mice and rats. Spontaneous and electrically evoked GABAergic inhibitory postsynaptic currents (sIPSCs and eIPSCs) and evoked glutamatergic excitatory postsynaptic currents (eEPSCs) were recorded in superfused brain slices with patch-clamp electrophysiological techniques. Pregnenolone (10-7M) did not affect the spontaneous GABAergic synaptic input (sIPSCs) to Purkinje cells in mouse cerebellar slices. The synthetic mixed CB1/CB2 receptor agonists JWH-210 (5×10-6M) and JWH-018 (5×10-6M) inhibited the spontaneous GABAergic synaptic input (sIPSCs) to Purkinje cells. This inhibition was not affected by pregnenolone (10-7M). Tetrahydrodeoxycorticosterone (THDOC; 10-7M), an in vivo metabolite of pregnenolone, also did not affect the inhibition of the GABAergic synaptic transmission by JWH-018. The depolarization of the Purkinje cells induced suppression of the GABAergic input to Purkinje cells; pregnenolone (10-7M) did not affect this endocannabinoid-mediated form of synaptic suppression. In rat nucleus accumbens slices, glutamatergic and GABAergic synaptic input to medium spiny neurons was activated by electrical stimulation of axons. Δ9-Tetrahydrocannabinol (2×10-5M), which is a partial agonist of both CB1 and CB2 receptors, suppressed the glutamatergic and GABAergic synaptic transmission in the rat nucleus accumbens. These suppressive effects of Δ9-tetrahydrocannabinol were not changed by pregnenolone (10-7M). The suppression of the GABAergic synaptic transmission by Δ9-tetrahydrocannabinol in the rat nucleus accumbens was also not affected by THDOC (10-7M). The results indicate that pregnenolone, a neurosteroid, does not affect GABAergic synaptic transmission. The inhibition of GABAergic and glutamatergic synaptic transmission elicited by synthetic, endogenous and phyto-cannabinoids is also not changed by pregnenolone. Therefore, it is unlikely that interference with cannabinoid-induced inhibition of synaptic transmission is the mechanism by which pregnenolone attenuates behavioural and somatic effects of Δ9-tetrahydrocannabinol in vivo.

Immunoassay screening in urine for synthetic cannabinoids - an evaluation of the diagnostic efficiency.

BACKGROUND: The abuse of synthetic cannabinoids (SCs) as presumed legal alternative to cannabis poses a great risk to public health. For economic reasons many laboratories use immunoassays (IAs) to screen for these substances in urine. However, the structural diversity and high potency of these designer drugs places high demands on IAs regarding cross-reactivity of the antibodies used and detection limits. METHODS: Two retrospective studies were carried out in order to evaluate the capability of two homogenous enzyme IAs for the detection of currently prevalent SCs in authentic urine samples. Urine samples were analyzed utilizing a 'JWH-018' kit and a 'UR-144' kit. The IA results were confirmed by an up-to-date liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) screening method covering metabolites of 45 SCs. RESULTS: The first study (n=549) showed an 8% prevalence of SCs use (LC-MS/MS analysis) among inpatients of forensic-psychiatric clinics, whereas all samples were tested negative by the IAs. In a second study (n=200) the combined application of both IAs led to a sensitivity of 2% and a diagnostic accuracy of 51% when applying the recommended IA cut-offs. Overall, 10 different currently prevalent SCs were detected in this population. The results can be explained by an insufficient cross-reactivity of the antibodies towards current SCs in combination with relatively high detection limits of the IAs. CONCLUSIONS: In light of the presented study data it is strongly recommended not to rely on the evaluated IA tests for SCs in clinical or forensic settings. For IA kits of other providers similar results can be expected.

Evaluation of CEDIA and DRI Drugs of Abuse Immunoassays for Urine Screening on a Thermo Indiko Plus Analyzer.

BACKGROUND: For analysis of urine samples during abstinence control for driving ability assessment (medical and psychological assessment, MPA), a reliable screening method for ethyl glucuronide and drugs of abuse (cannabinoids, opiates, cocaine, amphetamines, methadone, and benzodiazepines) is needed. METHODS: In this study CEDIA and DRI immunoassays were applied on a Thermo Fisher Scientific Indiko Plus analyzer. Precision and accuracy as well as sensitivity and specificity at the required cut-offs for the MPA were evaluated. RESULTS: The specificity was satisfactory and ranged from 91% for methamphetamine to 100% for opiates, cocaine metabolite, amphetamine, EDDP, and benzodiazepines. Moreover, sensitivity was 100% for all assays except for cannabinoids (91%). CONCLUSION: The presented method can therefore be recommended for abstinence control.

Detection and Activity Profiling of Synthetic Cannabinoids and Their Metabolites with a Newly Developed Bioassay.

Synthetic cannabinoids (SCs) are the largest group of compounds currently monitored in Europe by the EU Early Warning System on new psychoactive substances. Emerging recreational use of these products has led to multiple cases of adverse health effects and even death. In contrast to marijuana, where Δ9-tetrahydrocannabinol (Δ9THC) is metabolized to only one major active metabolite, it has been reported that several major phase I metabolites of SCs remain biologically active, exerting cannabinoid (CB) receptor affinity, potency, and efficacy greater than those of Δ9THC. It is therefore reasonable that more SCs can also be biotransformed into molecules with various levels of CB activity. Here, we developed and applied a new G-protein coupled receptor (GPCR) activation assay based on NanoLuc binary technology (Promega). More specifically, by demonstrating CB1 and CB2 receptor activation by JWH-018 and a selection of its metabolites, we are the first to show the suitability of the newly developed bioassay for monitoring GPCR-mediated activity. We also successfully applied this reporter system to evaluate the in vitro activity of JWH-122, JWH-210, and PB-22, their 5-fluoro analogues (MAM-2201, EAM-2201, and 5F-PB-22, respectively), and their main phase I metabolites. By doing so, we demonstrate that several major metabolites of these SCs retain their activity at cannabinoid receptors. All of these active metabolites may prolong the parent compound's psychotropic and physiological effects and may contribute to its toxicity profile. We also demonstrate a proof of concept of the applicability of the newly developed bioassay for screening urine for CB receptor activity exerted by SCs.

Detection of the ethanol consumption markers ethyl glucuronide and ethyl sulfate in urine samples from inmates of two German prisons.

INTRODUCTION: Abstinence from ethanol is necessary in various situations. Among these are jail terms. Nevertheless, it is a matter of fact that ethanol is illegally produced and ingested in prisons. So far, data regarding drug prevalence in jail have mainly been collected by questionnaires. To get an objective database for the prevalence of ethanol consumption in jail, a cross-sectional study was performed. METHODS: Inmates of two German prisons (Offenburg and Freiburg) were asked to give a urine sample at an unknown and random point of time. Participation was voluntary and did lead to neither negative consequences nor benefits. All samples were anonymized. Using the consumption markers ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urine samples were tested for previous ethanol consumption. Analyses were performed by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. RESULTS: In total 676 male inmates participated in this study. The participation rate was 70-75% of all permanent inmates in Offenburg and 30.6% in Freiburg. Ten of the 555 (1.8%) samples from Offenburg and 1 of the 121 (0.8%) samples from Freiburg were positive for ethanol consumption markers with concentrations ranging from trace amounts to 1400 ng/mL for EtG and up to 510 ng/mL for EtS, respectively. CONCLUSIONS: The number of participants in this study was rather high, so that the results represent a good cross section, at least for Offenburg, the jail with the higher number of positive samples.

Metabolites of synthetic cannabinoids in hair--proof of consumption or false friends for interpretation?

The detection of drug metabolites in hair is widely accepted as a proof for systemic uptake of the drug, unless the metabolites can be formed as artefacts. However, regarding synthetic cannabinoids, not much is known about mechanisms of incorporation into hair. For a correct interpretation concerning hair findings of these compounds and their metabolites, it is necessary to identify the different routes of incorporation and to assess their contribution to analytical findings. This study presents the results of the LC-ESI-MS/MS analysis of an authentic hair sample taken from a patient with a known history of heavy consumption of synthetic cannabinoids. In the authentic hair sample, 5F-PB-22 and AB-CHMINACA as well as their main metabolites 5F-PB-22 3-carboxyindole, PB-22 5-OH-pentyl, and AB-CHMINACA valine were detected in all segments, comprising segments grown in a time period where the substances had not been distributed on the 'legal high' market. To enable interpretation of the results regarding the distribution of the detected analytes along the hair shaft, the stability of 5F-PB-22 and AB-CHMINACA in hair matrix and under thermal stress was assessed. The stability tests revealed that the three 'metabolites' are also formed in externally contaminated hair after storage of the samples under different conditions. In addition, 5F-PB-22 3-carboxyindole and AB-CHMINACA valine were identified as degradation products in smoke condensate. Therefore, interpretation of 'metabolite' findings of compounds comprising chemically labile amide/ester bonds or 5-fluoro-pentyl side chains should be carried out with utmost care, taking into account the different mechanisms of formation and incorporation into hair.

Impact of a synthetic cannabinoid (CP-47,497-C8) on protein expression in human cells: evidence for induction of inflammation and DNA damage.

Synthetic cannabinoids (SCs) are marketed worldwide as legal surrogates for marihuana. In order to predict potential health effects in consumers and to elucidate the underlying mechanisms of action, we investigated the impact of a representative of the cyclohexylphenols, CP47,497-C8, which binds to both cannabinoid receptors, on protein expression patterns, genomic stability and on induction of inflammatory cytokines in human lymphocytes. After treatment of the cells with the drug, we found pronounced up-regulation of a variety of enzymes in nuclear extracts which are involved in lipid metabolism and inflammatory signaling; some of the identified proteins are also involved in the endogenous synthesis of endocannabinoids. The assumption that the drug causes inflammation is further supported by results obtained in additional experiments with cytosols of LPS-stimulated lymphocytes which showed that the SC induces pro-inflammatory cytokines (IL12p40 and IL-6) as well as TNF-α. Furthermore, the proteome analyses revealed that the drug causes down-regulation of proteins which are involved in DNA repair. This observation provides an explanation for the formation of comets which was seen in single-cell gel electrophoresis assays and for the induction of micronuclei (which reflect structural and numerical chromosomal aberrations) by the drug. These effects were seen in experiments with human lymphocytes which were conducted under identical conditions as the proteome analysis. Taken together, the present findings indicate that the drug (and possibly other structurally related SCs) may cause DNA damage and inflammation in directly exposed cells of consumers.

Genotoxic properties of XLR-11, a widely consumed synthetic cannabinoid, and of the benzoyl indole RCS-4.

Aim of this study was the investigation of the genotoxic properties of XLR-11 [1-(5-fluoropentyl)-1H-indol-3-yl](2,2,3,3-tetramethylcyclopropyl)methanone, a widely consumed synthetic cannabinoid (SC), and of the benzoyl indole RCS-4 (4-methoxyphenyl)(1-pentyl-1H-indol-3-yl)methanone). We characterized the DNA-damaging properties of these drugs in different experimental systems. No evidence for induction of gene mutations was detected in bacterial (Salmonella/microsome) tests, but clear dose-dependent effects were found in in vitro single cell gel electrophoresis (SCGE) assays with human lymphocytes and with buccal- and lung-derived human cell lines (TR-146 and A-549). These experiments are based on the determination of DNA migration in an electric field and enable the detection of single- and double-strand breaks and apurinic sites. Furthermore, we found that both drugs induce micronuclei which are formed as a consequence of chromosomal aberrations. The lack of effects in SCGE experiments with lesion-specific enzymes (FPG, Endo III) shows that the DNA damage is not caused by formation of oxidatively damaged bases; experiments with liver enzyme homogenates and bovine serum albumin indicate that the drugs are not converted enzymatically to DNA-reactive intermediates. Furthermore, results with buccal- and lung-derived human cells show that gaseous treatment of the cells under conditions which reflect the exposure situation in drug users may cause damage of the genetic material in epithelia of the respiratory tract. Since DNA instability is involved in the etiology of cancer, these findings can be taken as an indication that consumption of the SCs may cause tumors in the respiratory tract of consumers.