Metabolic pathways of 4-bromo-2,5-dimethoxyphenethylamine (2C-B): analysis of phase I metabolism with hepatocytes of six species including human

Toxicology and Pharmacological Interactions of Classic Psychedelics

As psychedelics are being investigated for more medical indications, it has become important to characterize the adverse effects and pharmacological interactions with these medications. This chapter will summarize what is known about the toxicology and drug-drug interactions for classic psychedelics, such as LSD, psilocybin, DMT, 5-MeO-DMT, mescaline, 2C-B, Bromo-DragonFLY, and 25X-NBOMe.

Metabolic characterization of 25X-NBOH and 25X-NBOMe phenethylamines based on UHPLC-Q-Exactive Orbitrap MS in human liver microsomes

The types and quantities of new psychoactive substances synthesized based on structural modifications have increased rapidly in recent years and pose a great challenge to clinical and forensic laboratories. N-benzyl derivatives of phenethylamines, 25B-NBOH, 25E-NBOH, 25H-NBOH, and 25iP-NBOMe have begun to flow into the black market and have caused several poisoning cases and even fatal cases. The aim of this study was to avoid false negative results by detecting the parent drug and its metabolites to extend the detection window in biological matrices and provide basic data for the simultaneous determination of illegal drugs and metabolites in forensic and emergency cases. To facilitate the comparison of metabolic characteristics, we divided the four compounds into two groups of types, 25X-NBOH and 25X-NBOMe. The in vitro phase I and phase II metabolism of these four compounds was investigated by incubating 10 mg mL-1 pooled human liver microsomes with co-substrates for 180 min at 37 ℃, and then analyzing the reaction mixture using ultrahigh-performance liquid chromatography-quadrupole/electrostatic field orbitrap mass spectrometry. In total, 70 metabolites were obtained for the four compounds. The major biotransformations were O-demethylation, hydroxylation, dehydrogenation, N-dehydroxybenzyl, N-demethoxybenzyl, oxidate transformation to ketone and carboxylate, glucuronidation, and their combination reactions. We recommended the major metabolites with high peak area ratio as biomarkers, B2-1 (56.61%), B2-2 (17.43%) and B6 (17.78%) for 25B-NBOH, E2-1 (42.81%), E2-2 (34.90%) and E8-2 (10.18%) for 25E-NBOH, H5 (49.28%), H2-1 (21.54%), and H1 (18.37%) for 25H-NBOH, P3-1 (10.94%), P3-2 (33.18%), P3-3 (14.85%) and P12-2 (23.00%) for 25iP-NBOMe. This is a study to evaluate their metabolic characteristics in detail. Comparative analysis of the N-benzyl derivatives of phenethylamines provided basic data for elucidating their pharmacology and toxicity. Timely analysis of the metabolic profiles of compounds with abuse potential will facilitate the early development of regulatory measures.

In Vivo and In Vitro Metabolic Fate and Urinary Detectability of Five Deschloroketamine Derivatives Studied by Means of Hyphenated Mass Spectrometry

Ketamine derivatives such as deschloroketamine and deschloro-N-ethyl-ketamine show dissociative and psychoactive properties and their abuse as new psychoactive substances (NPSs) has been reported. Though some information is available on the biotransformation of dissociative NPSs, data on deschloro-N-cyclopropyl-ketamine deschloro-N-isopropyl-ketamine and deschloro-N-propyl-ketamine concerning their biotransformation and, thus, urinary detectability are not available. The aims of the presented work were to study the in vivo phase I and II metabolism; in vitro phase I metabolism, using pooled human liver microsomes (pHLMs); and detectability, within a standard urine screening approach (SUSA), of five deschloroketamine derivatives. Metabolism studies were conducted by collecting urine samples from male Wistar rats over a period of 24 h after their administration at 2 mg/kg body weight. The samples were analyzed using liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS) and gas chromatography-mass spectrometry (GC-MS). The compounds were mainly metabolized by N-dealkylation, hydroxylation, multiple oxidations, and combinations of these metabolic reactions, as well as glucuronidation and N-acetylation. In total, 29 phase I and 10 phase II metabolites were detected. For the LC-HRMS/MS SUSA, compound-specific metabolites were identified, and suitable screening targets could be recommended and confirmed in pHLMs for all derivatives except for deschloro-N-cyclopropyl-ketamine. Using the GC-MS-based SUSA approach, only non-specific acetylated N-dealkylation metabolites could be detected.

An Update on the Implications of New Psychoactive Substances in Public Health

The emergence of new psychoactive substances has earned a great deal of attention, and several reports of acute poisoning and deaths have been issued involving, for instance, synthetic opiates. In recent years, there have been profound alterations in the legislation concerning consumption, marketing, and synthesis of these compounds; rapid alert systems have also been subject to changes, and new substances and new markets, mainly through the internet, have appeared. Their effects and how they originate in consumers are still mostly unknown, primarily in what concerns chronic toxicity. This review intends to provide a detailed description of these substances from the point of view of consumption, toxicokinetics, and health consequences, including case reports on intoxications in order to help researchers and public health agents working daily in this area.

Novel Phenethylamines and Their Potential Interactions With Prescription Drugs: A Systematic Critical Review

BACKGROUND

The novel phenethylamines 4-fluoroamphetamine (4-FA) and 2,5-dimethoxy-4-bromophenethylamine (2C-B) fall in the top 10 most used new psychoactive substances (NPSs) among high-risk substance users. Various phenethylamines and NPS are also highly used in populations with mental disorders, depression, or attention deficit hyperactivity disorder (ADHD). Moreover, NPS use is highly prevalent among men and women with risky sexual behavior. Considering these specific populations and their frequent concurrent use of drugs, such as antidepressants, ADHD medication, and antiretrovirals, reports on potential interactions between these drugs, and phenethylamines 4-FA and 2C-B, were reviewed.

METHODS

The authors performed a systematic literature review on 4-FA and 2C-B interactions with antidepressants (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, duloxetine, bupropion, venlafaxine, phenelzine, moclobemide, and tranylcypromine), ADHD medications (atomoxetine, dexamphetamine, methylphenidate, and modafinil), and antiretrovirals.

RESULTS

Limited literature exists on the pharmacokinetics and drug-drug interactions of 2C-B and 4-FA. Only one case report indicated a possible interaction between 4-FA and ADHD medication. Although pharmacokinetic interactions between 4-FA and prescription drugs remain speculative, their pharmacodynamic points toward interactions between 4-FA and ADHD medication and antidepressants. The pharmacokinetic and pharmacodynamic profile of 2C-B also points toward such interactions, between 2C-B and prescription drugs such as antidepressants and ADHD medication.

CONCLUSIONS

A drug-drug (phenethylamine-prescription drug) interaction potential is anticipated, mainly involving monoamine oxidases for 2C-B and 4-FA, with monoamine transporters being more specific to 4-FA.

The Clinical Toxicology of 4-Bromo-2,5-dimethoxyphenethylamine (2C-B): The Severity of Poisoning After Exposure to Low to Moderate and High Doses

STUDY OBJECTIVE

We studied the severity of poisoning after exposure to low to moderate and high doses of 4-bromo-2,5-dimethoxyphenethylamine (2C-B).

METHODS

Patients for whom the Dutch Poisons Information Centre was consulted for 2C-B exposure from 2016 to 2018 were included in a prospective cohort study. Data were collected through telephone interviews with the physician or patient. Patients were categorized according to the reported 2C-B dose: low to moderate (up to 20 mg), high (greater than 20 mg), or unknown. Presence of 2C-B was analyzed in leftover drug and biological samples with liquid/gas chromatography-mass spectrometry. The severity of poisoning was graded with the Poisoning Severity Score.

RESULTS

We included 59 patients, of whom 32 could be followed up. Low to moderate 2C-B doses were reported by 9 patients (28%), high doses by 17 (53%), and unknown doses by 6 (19%). Poisoning was moderate in the majority of patients in both the low- to moderate-dose and high-dose groups. Frequently reported symptoms included mydriasis, agitation or aggression, hallucinations, confusion, anxiety, hypertension, and tachycardia. The presence of 2C-B was confirmed in 5 patients in urine (n=3) or drug samples (n=4).

CONCLUSION

In this study, most 2C-B poisonings resulted in moderate toxicity even at high reported doses up to 192 mg. No severe cases were observed. The clinical course was usually short-lived (up to 24 hours) and typically involved hallucinations in addition to mild somatic effects.

Unexpected Serotonin Syndrome, Epileptic Seizures, and Cerebral Edema Following 2,5-dimethoxy-4-bromophenethylamine Ingestion

4‐bromo‐2,5‐dimethoxyphenethylamine (2C‐B) is a designer drug. In Europe, 2C‐B is easily obtained and used for recreational purposes. It is known for its stimulating effects similar to those of 3,4‐methylenedioxymethamphetamine, although in higher doses it has more hallucinogenic effects. Here, we report a case of 2C‐B ingestion, confirmed by liquid chromatography‐tandem mass spectrometry, in an 18‐year‐old man. The neurological consequences were severe, including the development of serotonin syndrome and severe brain edema. Supportive therapy resulted in a stable condition, although, after several months, the patient still suffered from severe neurological impairment due to the drug‐induced toxicity. This case showed that 2C‐B could not be identified with the drugs of abuse screening routinely used in Dutch hospitals. The use of 2C‐B carries many risks, with potentially profound neurological damage, that both consumers and healthcare physicians are unaware of.

In Vitro Metabolism of 25B-NBF, 2-(4-Bromo-2,5-Dimethoxyphenyl)-N-(2-Fluorobenzyl)ethanamine, in Human Hepatocytes Using Liquid Chromatography⁻Mass Spectrometry

25B-NBF, 2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-fluorobenzyl)ethanamine, is a new psychoactive substance classified as a phenethylamine. It is a potent agonist of the 5-hydroxytryptamine receptor, but little is known about its metabolism and elimination properties since it was discovered. To aid 25B-NBF abuse screening, the metabolic characteristics of 25B-NBF were investigated in human hepatocytes and human cDNA-expressed cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes using liquid chromatography⁻high resolution mass spectrometry. At a hepatic extraction ratio of 0.80, 25B-NBF was extensively metabolized into 33 metabolites via hydroxylation, O-demethylation, bis-O-demethylation, N-debenzylation, glucuronidation, sulfation, and acetylation after incubation with pooled human hepatocytes. The metabolism of 25B-NBF was catalyzed by CYP1A1, CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2J2, CYP3A4, and UGT2B7 enzymes. Based on these results, it is necessary to develop a bioanalytical method for the determination of not only 25B-NBF but also its metabolites in biological samples for the screening of 25B-NBF abuse.

Two immunoassays for the detection of 2C-B and related hallucinogenic phenethylamines

INTRODUCTION

The use of new psychoactive substances as drugs of abuse has dramatically increased over the last years. Hallucinogenic phenethylamines gained particular popularity as they have both stimulating and psychedelic effects. Although generally perceived as safe, these illicit drugs pose a serious health risk; they have been linked to cases of severe poisoning or even deaths. Therefore, simple, cost-effective and reliable methods are needed for rapid determination of abused hallucinogens.

METHODS

For this purpose, two haptens derived from 2C-H were designed, synthesized and subsequently attached to a carrier protein. Polyclonal antibodies obtained from a rabbit immunized with one of the prepared immunogens were used for the development of two immunoassays.

RESULTS

In this study, a lateral flow immunoassay (LFIA) and an enzyme linked immunosorbent assay (ELISA) for the detection of 2C-B and related hallucinogenic phenethylamines in urine were developed. The presented LFIA is primarily suitable for on-site monitoring as it is simple and can provide a visual evidence of 2C-B presence within a few minutes. Its reasonable sensitivity (LOD_LFIA = 15 ± 7 ng mL^-1) allows detection of the drug presence in urine after acute exposure. For greater accuracy, highly sensitive ELISA (LOD_ELISA = 6 ± 3 pg mL^-1) is proposed for toxicological quantitative analyses of positive samples captured by the LFIA.

DISCUSSION

The comparison of the ELISA with the well-established UHPLC-MS-MS method shows excellent agreement of results, which confirms good potential of the ELISA to be used for routine analyses of 2C-B and related hallucinogenic phenethylamines of both main sub-families.

Acute Pharmacological Effects of 2C-B in Humans: An Observational Study

2,5-dimethoxy-4-bromophenethylamine (2C-B) is a psychedelic phenylethylamine derivative, structurally similar to mescaline. It is a serotonin 5-hydroxytryptamine-2A (5-HT_2A), 5-hydroxytryptamine-2B (5-HT_2B), and 5-hydroxytryptamine-2C (5-HT_2C) receptor partial agonist used recreationally as a new psychoactive substance. It has been reported that 2C-B induces mild psychedelic effects, although its acute pharmacological effects and pharmacokinetics have not yet been fully studied in humans. An observational study was conducted to assess the acute subjective and physiological effects, as well as pharmacokinetics of 2C-B. Sixteen healthy, experienced drug users self-administered an oral dose of 2C-B (10, 15, or 20 mg). Vital signs (blood pressure and heart rate) were measured at baseline 1, 2, 3, 4, and 6 hours (h). Each participant completed subjective effects using three rating scales: the visual analog scale (VAS), the Addiction Research Centre Inventory (ARCI), and the Evaluation of the Subjective Effects of Substances with Abuse Potential (VESSPA-SSE) at baseline, 2–3 and 6 h after self-administration (maximum effects along 6 h), and the Hallucinogenic Rating Scale (maximum effects along 6 h). Oral fluid (saliva) was collected to assess 2C-B and cortisol concentrations during 24 h. Acute administration of 2C-B increased blood pressure and heart rate. Scores of scales related to euphoria increased (high, liking, and stimulated), and changes in perceptions (distances, colors, shapes, and lights) and different body feelings/surrounding were produced. Mild hallucinating effects were described in five subjects. Maximum concentrations of 2C-B and cortisol were reached at 1 and 3 h after self-administration, respectively. Oral 2C-B at recreational doses induces a constellation of psychedelic/psychostimulant-like effects similar to those associated with serotonin-acting drugs.

The Toxicology of New Psychoactive Substances: Synthetic Cathinones and Phenylethylamines

BACKGROUND

New psychoactive substances (NPSs) are substitutes for classical drugs of abuse and there are now compounds available from all groups of classical drugs of abuse. During 2014, the number of synthetic cathinones increased dramatically and, together with phenylethylamines, they dominate the NPS markets in the European Union. In total, 31 cathinones and 9 phenylethylamines were encountered in 2014. The aim of this article was to summarize the existing knowledge about the basic pharmacology, metabolism, and human toxicology of relevant synthetic cathinones and phenylethylamines. Compared with existing reviews, we have also compiled the existing case reports from both fatal and nonfatal intoxications.

METHODS

We performed a comprehensive literature search using bibliographic databases PubMed and Web of Science, complemented with Google Scholar. The focus of the literature search was on original articles, case reports, and previously published review articles published in 2014 or earlier.

RESULTS

The rapid increase of NPSs is a growing concern and sets new challenges not only for societies in drug prevention and legislation but also in clinical and forensic toxicology. In vivo and in vitro studies have demonstrated that the pharmacodynamic profile of cathinones is similar to that of other psychomotor stimulants. Metabolism studies show that cathinones and phenylethylamines are extensively metabolized; however, the parent compound is usually detectable in human urine. In vitro studies have shown that many cathinones and phenylethylamines are metabolized by CYP2D6 enzymes. This indicates that these drugs may have many possible drug-drug interactions and that genetic polymorphism may influence their toxicity. However, the clinical and toxicological relevance of CYP2D6 in adverse effects of cathinones and phenylethylamines is questionable, because these compounds are metabolized by other enzymes as well. The toxidromes commonly encountered after ingestion of cathinones and phenylethylamines are mainly of sympathomimetic and hallucinogenic character with a risk of excited delirium and life-threatening cardiovascular effects.

CONCLUSIONS

The acute and chronic toxicity of many NPSs is unknown or very sparsely investigated. There is a need for evidence-based-treatment recommendations for acute intoxications and a demand for new strategies to analyze these compounds in clinical and forensic cases.

Identification of Metabolite Biomarkers of the Designer Hallucinogen 25I-NBOMe in Mouse Hepatic Microsomal Preparations and Human Urine Samples Associated with Clinical Intoxication

'NBOMe' (dimethoxyphenyl-N-[(2-methoxyphenyl)methyl]ethanamine) derivatives are a new class of designer hallucinogenic drugs widely available on the Internet. Currently, 2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe) is the most popular abused derivative in the USA. There are little published data on the absorption, metabolism and elimination of 25I-NBOMe, or any of the other NBOMe derivatives. Therefore, there are no definitive metabolite biomarkers. We present the identification of fifteen 25I-NBOMe metabolites in phase I and II mouse hepatic microsomal preparations, and analysis of two human urine samples from 25I-NBOMe-intoxicated patients to test the utility of these metabolites as biomarkers of 25I-NBOMe use. The synthesis of two major urinary metabolites, 2-iodo-4-methoxy-5-[2-[(2-methoxyphenyl) methylamino]ethyl]phenol (2-O-desmethyl-5-I-NBOMe, M5) and 5-iodo-4-methoxy-2-[2-[(2-methoxyphenyl)methylamino]ethyl]phenol (5-O-desmethyl-2-I-NBOMe), is also presented. Seven phase II glucuronidated metabolites of the O-desmethyl or the hydroxylated phase I metabolites were identified. One human urine sample contained 25I-NBOMe as well as all 15 metabolites identified in mouse hepatic microsomal preparations. Another human urine sample contained no parent 25I-NBOMe, but was found to contain three O-desmethyl metabolites. We recommend β-glucuronidase enzymatic hydrolysis of urine prior to 25I-NBOMe screening and the use of M5 as the primary biomarker in drug testing.

Metabolic fate of desomorphine elucidated using rat urine, pooled human liver preparations, and human hepatocyte cultures as well as its detectability using standard urine screening approaches

Desomorphine is an opioid misused as "crocodile", a cheaper alternative to heroin. It is a crude synthesis product homemade from codeine with toxic byproducts. The aim of the present work was to investigate the metabolic fate of desomorphine in vivo using rat urine and in vitro using pooled human liver microsomes and cytosol as well as human liver cell lines (HepG2 and HepaRG) by Orbitrap-based liquid chromatography-high resolution-tandem mass spectrometry or hydrophilic interaction liquid chromatography. According to the identified metabolites, the following metabolic steps could be proposed: N-demethylation, hydroxylation at various positions, N-oxidation, glucuronidation, and sulfation. The cytochrome P450 (CYP) initial activity screening revealed CYP3A4 to be the only CYP involved in all phase I steps. UDP-glucuronyltransferase (UGT) initial activity screening showed that UGT1A1, UGT1A8, UGT1A9, UGT1A10, UGT2B4, UGT2B7, UGT2B15, and UGT2B17 formed desomorphine glucuronide. Among the tested in vitro models, HepaRG cells were identified to be the most suitable tool for prediction of human hepatic phase I and II metabolism of drugs of abuse. Finally, desomorphine (crocodile) consumption should be detectable by all standard urine screening approaches mainly via the parent compound and/or its glucuronide assuming similar kinetics in rats and humans.

Pharmacokinetics, pharmacodynamics and toxicology of new psychoactive substances (NPS): 2C-B, 4-fluoroamphetamine and benzofurans

BACKGROUND

Recently, the number of new psychoactive substances (NPS) appearing on the illicit drug market has shown a marked increase. Although many users perceive the risk of using NPS as medium or low, these substances can pose a serious health risk and several NPS have been implicated in drug-related deaths. In Europe, frequently detected NPS are 4-bromo-2,5-dimethoxyphenethylamine (2C-B), 4-fluoroamphetamine (4-FA) and benzofurans (5-(2-aminopropyl)benzofuran (5-APB) or 6-(2-aminopropyl)benzofuran (6-APB)). However, little is known about the health risks of these specific NPS.

METHODS

In this paper, existing literature on the pharmacokinetics and pharmacodynamics of 2C-B, 4-FA and benzofurans (5-APB/6-APB) was reviewed.

RESULTS

Our review showed that the clinical effects of 2C-B, 4-FA and benzofurans (5-APB/6-APB) are comparable with common illicit drugs like amphetamine and 3,4-methylenedioxymethamphetamine (MDMA). Therefore, NPS toxicity can be handled by existing treatment guidelines that are based on clinical effects instead of the specific drug involved. Even so, information on the health risks of these substances is limited to a number of case reports that are complicated by confounders such as analytical difficulties, mislabelling of drugs, concomitant exposures and interindividual differences.

CONCLUSION

To aid in early legislation, data on clinical effects from poisons centres and user fora should be combined with (in vitro) screening methods and collaboration on an (inter)national level is essential. As a result, potentially hazardous NPS could be detected more quickly, thereby protecting public health.

Detection and quantification of 56 new psychoactive substances in whole blood and urine by LC–MS/MS

Background: New psychoactive substances (NPS) have become increasingly prevalent and are sold in internet shops as ‘bath salts’ or ‘research chemicals’ and comprehensive bioanalytical methods are needed for their detection. Methodology: We developed and validated a method using LC and MS/MS to quantify 56 NPS in blood and urine, including amphetamine derivatives, 2C compounds, aminoindanes, cathinones, piperazines, tryptamines, dissociatives and others. Instrumentation included a Synergi Polar-RP column (Phenomenex) and a 3200 QTrap mass spectrometer (AB Sciex). Run time was 20 min. Conclusion: A novel method is presented for the unambiguous identification and quantification of 56 NPS in blood and urine samples in clinical and forensic cases, e.g., intoxications or driving under the influence of drugs.

Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use in investigating mechanisms of hepatotoxicity, cell signaling and ADME

This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4α, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4α), resulting in up- and downregulation of hundreds of genes. An understanding of these changes is crucial for a correct interpretation of in vitro data. The possibilities and limitations of the most useful liver in vitro systems are summarized, including three-dimensional culture techniques, co-cultures with non-parenchymal cells, hepatospheres, precision cut liver slices and the isolated perfused liver. Also discussed is how closely hepatoma, stem cell and iPS cell-derived hepatocyte-like-cells resemble real hepatocytes. Finally, a summary is given of the state of the art of liver in vitro and mathematical modeling systems that are currently used in the pharmaceutical industry with an emphasis on drug metabolism, prediction of clearance, drug interaction, transporter studies and hepatotoxicity. One key message is that despite our enthusiasm for in vitro systems, we must never lose sight of the in vivo situation. Although hepatocytes have been isolated for decades, the hunt for relevant alternative systems has only just begun.

Combination effects of amphetamines under hyperthermia - the role played by oxidative stress

Rise in body temperature is a life-threatening consequence of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) abuse. We evaluated the impact of hyperthermia on the cytotoxicity of combinations of MDMA and three other amphetamines, often co-ingested. For this, Hep G2 cells were exposed to MDMA, d-amphetamine, methamphetamine and 4-methylthioamphetamine, individually or combined, at 40.5 °C. The results were compared with normothermia data (37.0 °C). Mixture additivity expectations were calculated by independent action and concentration addition (CA) models. To delineate the mechanism(s) underlying the elicited effects, a range of stress endpoints was evaluated, including quantification of reactive oxygen/nitrogen species (ROS/RNS), lipid peroxidation, reduced/oxidized glutathione (GSH/GSSG), ATP and mitochondrial membrane potential (Δψm) changes. Our data show that, in hyperthermia, amphetamines acted additively and mixture effects were accurately predicted by CA. At 40.5 °C, even slight increases in the concentrations of each drug/mixture promoted significant rises in cytotoxicity, which quickly shifted from roughly undetectable to maximal mortality. Additionally, the increase of RNS/ROS production, decrease of GSH, ATP depletion and mitochondrial impairment were exacerbated under hyperthermia. Importantly, when equieffective cytotoxic concentrations of the mixture and individual amphetamines were compared for all tested stress endpoints, mixture effects did not deviate from those elicited by individual treatments, suggesting that these amphetamines have a similar mode of action, which is not altered in combination. Concluding, our data indicate that amphetamine mixtures produce deleterious effects, even when individual drugs are combined at negligible concentrations. These effects are strongly exacerbated in hyperthermia, emphasizing the potential increased risks of ecstasy intake, especially when hyperthermia occurs concurrently with polydrug abuse.

2C or not 2C: phenethylamine designer drug review

New groups of synthetic "designer drugs" have increased in popularity over the past several years. These products mimic the euphoric effects of other well-known illicit drugs but are advertised as "legal" highs and are sold over the internet, at raves and night clubs, and in head shops. The 2C series drugs are ring-substituted phenethylamines that belong to a group of designer agents similar in structure to 3,4-methylenedioxy-N-methylamphetamine (MDMA, Ecstasy). Understanding the pharmacology and toxicology of these agents is essential in order to provide the best medical care for these patients. This review focuses on the pharmacology, pharmacokinetics, clinical effects, and treatment of 2C drug intoxication based on available published literature. Multiple names under which 2C drugs are sold were identified and tabulated. Common features identified in patients intoxicated with 2Cs included hallucinations, agitation, aggression, violence, dysphoria, hypertension, tachycardia, seizures, and hyperthermia. Patients may exhibit sympathomimetic symptoms or symptoms consistent with serotonin toxicity, but an excited delirium presentation seems to be consistent amongst deaths attributed to 2C drugs; at least five deaths have been reported in the literature in patients intoxicated with 2C drugs. 2C drugs are a group of designer intoxicants, many of which are marketed as legal, but may carry risks that consumers are unaware of. These drugs may be characterized by either serotonergic toxicity or a sympathomimetic toxidrome, but a presentation consistent with excited delirium is consistent amongst the reported 2C-related deaths. Treatment of 2C intoxication is primarily supportive, but immediate action is required in the context of excited delirium, hyperthermia, and seizure activity.

Identification of designer drug 2C-E (4-ethyl-2, 5-dimethoxy-phenethylamine) in urine following a drug overdose

In recent years, access to information regarding acquisition and synthesis of newer designer drugs has been at an all-time high due largely to the Internet. As these drugs have become more prevalent, laboratory techniques have been developed and refined to identify and screen for this burgeoning population of drugs. This provides a unique opportunity for learning about many of these methods. Laboratory testing techniques and instrumentation are obscure to many health care professionals, yet their results are crucial. Here, we present a case of an overdose of an uncommon designer drug (2C-E) and discuss the basics of liquid chromatography and mass spectrometry, two important techniques used in isolating and identifying the drug. Although often overlooked and taken for granted, these techniques can play a pivotal role in the diagnosis and subsequent management of select patients.

Behavioral, neurochemical and pharmaco-EEG profiles of the psychedelic drug 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in rats

RATIONALE AND OBJECTIVES

Behavioral, neurochemical and pharmaco-EEG profiles of a new synthetic drug 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in rats were examined.

MATERIALS AND METHODS

Locomotor effects, prepulse inhibition (PPI) of acoustic startle reaction (ASR), dopamine and its metabolite levels in nucleus accumbens (NAc), EEG power spectra and coherence in freely moving rats were analysed. Amphetamine was used as a reference compound.

RESULTS

2C-B had a biphasic effect on locomotion with initial inhibitory followed by excitatory effect; amphetamine induced only hyperlocomotion. Both drugs induced deficits in the PPI; however they had opposite effects on ASR. 2C-B increased dopamine but decreased 3,4-dihydroxyphenylacetic acid (DOPAC) in the NAc. Low doses of 2C-B induced a decrease in EEG power spectra and coherence. On the contrary, high dose of 2C-B 50 mg/kg had a temporally biphasic effect with an initial decrease followed by an increase in EEG power; decrease as well as increase in EEG coherence was observed. Amphetamine mainly induced an increase in EEG power and coherence in theta and alpha bands. Increases in the theta and alpha power and coherence in 2C-B and amphetamine were temporally linked to an increase in locomotor activity and DA levels in NAc.

CONCLUSIONS

2C-B is a centrally active compound similar to other hallucinogens, entactogens and stimulants. Increased dopamine and decreased DOPAC in the NAc may reflect its psychotomimetic and addictive potential and monoaminoxidase inhibition. Alterations in brain functional connectivity reflected the behavioral and neurochemical changes produced by the drug; a correlation between EEG changes and locomotor behavior was observed.

Analysis of 4-bromo-2,5-dimethoxyphenethylamine abuser's urine: identification and quantitation of urinary metabolites

The metabolites of 4-bromo-2,5-dimethoxyphenethylamine (2C-B), a psychoactive drug with hallucinogenic activity, were investigated in a urine sample from a user of 2C-B. The urine sample was deconjugated enzymatically and the metabolites were recovered by liquid-liquid extraction. The extract was analyzed by gas chromatography/mass spectrometry after derivatization, and the results were used to identify and quantitate the metabolites. 4-Bromo-2,5-dimethoxyphenylacetic acid was the most abundant metabolite of 2C-B in human urine and accounted for 73% of the total amount of detected metabolites, followed by 4-bromo-2-hydroxy-5-methoxyphenylacetic acid (13%) and 4-bromo-2,5-dimethoxyphenylethyl alcohol (4.5%). According to the literature, the main metabolites of 2C-B in rat urine are N-(4-bromo-2-methoxy-5-hydroxyphenylethyl)acetamide and N-(4-bromo-2-hydroxy-5-methoxyphenylethyl)acetamide. However, these metabolites accounted for only a small proportion of the total amount of detected metabolites in human urine, which indicates that there are significant species-specific differences in the metabolism of 2C-B. 4-Bromo-2,5-dimethoxyphenylacetic acid, which was the most abundant metabolite in human urine, is thought to be generated by deamination of 2C-B by monoamine oxidase (MAO) followed by oxidation by aldehyde dehydrogenase. Our results suggest that MAO plays a crucial role in the metabolism of 2C-B in humans.

4-Bromo-2,5-dimethoxyphenethylamine (2C-B): presence in the recreational drug market in Spain, pattern of use and subjective effects

4-Bromo-2,5-dimethoxyphenethylamine (2C-B) is a psychoactive analogue of mescaline that is becoming increasingly popular as a rave and club drug. We investigated its presence in the illicit drug market in Spain, its pattern of use and profile of subjective effects. Drug material was analysed for 2C-B and information on pattern of use and subjective effects was obtained from recreational users. Scores were statistically compared with previously collected data on psychostimulants (d-amphetamine), entactogens (MDMA) and psychedelics (ayahuasca and Salvia divinorum). The percentage of samples containing 2C-B doubled between 2006 and 2009, evolved from powder to tablet form and showed low falsification rates. Respondents reported taking 2C-B orally in doses of about 20 mg. Subjective effects involved perceptual modifications analogous to those observed after ayahuasca and salvia but absent after amphetamine and MDMA. Pleasure and sociability effects did not differ from those after MDMA and incapacitation was lower than for the psychedelics used as comparators. In conclusion, we found 2C-B is consistently present in the illicit drug market in Spain. While it elicits perceptual modifications that are analogous to other psychedelics, the lower impairment and higher pleasurable effects make it comparable with entactogens.

Chemistry, pharmacology, and metabolism of emerging drugs of abuse

In recent years, besides the classic designer drugs of the amphetamine type, a series of new drug classes appeared on the illicit drugs market. The chemistry, pharmacology, toxicology, metabolism, and toxicokinetics is discussed of 2,5-dimethoxy amphetamines, 2,5-dimethoxy phenethylamines, beta-keto-amphetamines, phencyclidine derivatives as well as of herbal drugs, ie, Kratom. They have gained popularity and notoriety as rave drugs. The metabolic pathways, the involvement of cytochrome P450 isoenzymes in the main pathways, and their roles in hepatic clearance are also summarized.

A rapid and easy to handle thermoluminescence based technique for evaluation of carbon tetrachloride-induced oxidative stress on rat hepatocytes

Oxidative stress has become one of the most intensively studied topics in biomedical research and is an often observed mechanism of non-genotoxic carcinogens like carbon tetrachloride. To monitor the oxidative stress status in in vitro hepatocytes, we compared thermoluminescence (TL) measurements with biochemical standard methods for oxidative stress markers. In contrast to biochemical analysis, TL measurements can be performed without any time-consuming extraction procedures by using directly collected cell material. After incubation with CCl(4) (24 h), thermo-induced light emission increased with rising concentration of CCl(4) up to eightfold at 10 mM CCl(4). Simultaneously, we determined the content of different secondary oxidative stress products, like thiobarbituric acid reactive substances and malondialdehyde. The rise of all biochemical markers complied with the increasing concentration of CCl(4). Finally, we could show that the CCl(4)-induced increase of oxidative stress markers determined by time-consuming biochemical methods perfectly correlates with the increase of high temperature bands in rapid TL measurements.

Primary rat hepatocytes as in vitro system for gene expression studies: comparison of sandwich, Matrigel and 2D cultures

Recent studies have presented evidence that in vivo obtained gene expression data can be used for carcinogen classification, for instance to differentiate between genotoxic and non-genotoxic carcinogens. However, although primary rat hepatocytes represent a well-established in vitro system for drug metabolism and enzyme induction, they have not yet been systematically optimized for toxicogenomic studies. The latter may be confounded by the fact that cultured hepatocytes show strong spontaneous alterations in gene expression patterns. Therefore, we addressed the following questions: (1) which culture system is optimal, comparing sandwich, Matrigel and 2D cultures, (2) how critical is the impact of culture period on substance-induced alterations in gene expression and (3) do these substance-induced alterations in cultured hepatocytes occur already at in vivo relevant concentrations? For this purpose we analyzed the expression of four genes, namely Abat, Gsk3beta, Myd116 and Sult1a1 that recently have been reported to be influenced by the antihistamine and non-genotoxic carcinogen methapyrilene (MPy). The most reproducible effects of MPy were observed in sandwich cultures. Induction factors of Gsk3beta and Myd116 at 100 microM MPy were 2 and 4 (medians), respectively, whereas expression of Abat and Sult1a1 were inhibited by factors of 7 and 5, respectively. Similar results were observed in hepatocytes maintained for 24 h or 3 weeks in sandwich culture with respect to the influence of MPy on the expression of Abat, Gsk3beta, Myd116 and Sult1a1. To determine whether MPy influences gene expression at in vivo relevant concentrations, 3.5 mg/kg MPy were administered to male Wistar rats intraperitoneally, resulting in plasma concentrations ranging between 1.72 and 0.32 microM 5 and 80 min after injection. Inhibition of Abat and Sult1a1 expression in vitro already occurred at in vivo relevant concentrations of 0.39 microM MPy. Induction of Myd116 was observed at 6.25 microM which is higher but in the same order of magnitude as in vivo relevant concentrations. In conclusion, the presented data strongly suggest that sandwich cultures are most adequate for detection of MPy-induced gene expression alterations and the effect of MPy was detected at in vivo relevant concentrations.

Chronic exposure to ethanol exacerbates MDMA-induced hyperthermia and exposes liver to severe MDMA-induced toxicity in CD1 mice

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is an amphetamine derivative drug with entactogenic, empathogenic and hallucinogenic properties, commonly consumed at rave parties in a polydrug abuse pattern, especially with cannabis, tobacco and ethanol. Since both MDMA and ethanol may cause deleterious effects to the liver, the evaluation of their putative hepatotoxic interaction is of great interest, especially considering that most of the MDMA users are regular ethanol consumers. Thus, the aim of the present study was to evaluate, in vivo, the acute hepatotoxic effects of MDMA (10mg/kg i.p.) in CD-1 mice previously exposed to 12% ethanol as drinking fluid (for 8 weeks). Body temperature was continuously measured for 12h after MDMA administration and, after 24h, hepatic damage was evaluated. The administration of MDMA to non pre-treated mice resulted in sustained hyperthermia, which was significantly increased in ethanol pre-exposed mice. A correspondent higher increase of hepatic heat shock transcription factor (HSF-1) activation was also observed in the latter group. Furthermore, MDMA administration resulted in liver damage as confirmed by histological analysis, slight decrease in liver weight and increased plasma transaminases levels. These hepatotoxic effects were also exacerbated when mice were pre-treated with ethanol. The activities of some antioxidant enzymes (such as SOD, GPx and Catalase) were modified by ethanol, MDMA and their joint action. The hepatotoxicity resulting from the simultaneous exposure to MDMA and ethanol was associated with a higher activation of NF-kappaB, indicating a pro-inflammatory effect in this organ. In conclusion, the obtained results strongly suggest that the consumption of ethanol increases the hyperthermic and hepatotoxic effects associated with MDMA abuse.

Disposition of 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and its metabolite 4-bromo-2-hydroxy-5-methoxyphenethylamine in rats after subcutaneous administration

The psychedelic compound 4-bromo-2,5-dimethoxyphenethylamine (2C-B) has appeared as an agent in drug abuse or overdose cases in humans. The human pharmacokinetics of this drug is unknown and only partial information is available on its metabolites. Our experimental study was focused on the disposition and kinetic profile of 2C-B in rats after subcutaneous administration using a GC-MS validated method. One of the major metabolites 4-bromo-2-hydroxy-5-methoxyphenethylamine (2H5M-BPEA) was confirmed in rat tissues of lung, brain, liver and was quantitatively evaluated as well. The disposition of 2C-B was characterized by its estimated half-life 1.1h and estimated volume of distribution 16L/kg. The lung susceptibility for drug retention and gradual temporal release parallel to the brain were ascertained. The drug penetrating the blood/brain barrier was without significant delay. 2C-B brain to serum ratio attained a maximum value of 13.9 and remained over the value of 6.5 to the end of our observation (6h after the dose). The distribution of the hydroxylated metabolite 2H5M-BPEA into the lipophilic brain tissue was less efficient in relation to the parent compound. The kinetics of the drug partitioning between blood to brain may be important for the subsequent assessment of its psychotropic or toxic effects.

"Research chemicals": tryptamine and phenethylamine use among high-risk youth

Tryptamines and phenethylamines are two broad categories of psychoactive substances with a long history of licit and illicit use. Profiles of users of recently emerging tryptamines and phenethylamines are nonexistent, however, since surveillance studies do not query the use of these substances. This manuscript describes the types, modes of administration, onset of use, and context of use of a variety of lesser known tryptamines and phenethylamines among a sample of high-risk youth. Findings are based upon in-depth interviews with 42 youth recruited in public settings in Los Angles during 2005 and 2006 as part of larger study examining health risks associated with injecting ketamine. Youth reported that their use of tryptamines and phenethylamines was infrequent, spontaneous, and predominately occurred at music venues, such as festivals, concerts, or raves. Several purchased a variety of these "research chemicals" from the Internet and used them in private locations. While many described positive experiences, reports of short-term negative health outcomes included nausea, vomiting, diarrhea, disorientations, and frightening hallucinations. These findings, based upon pilot study data, move toward an epidemiology of tryptamine and phenethylamine use among high-risk youth.

Amine oxidases and monooxygenases in the in vivo metabolism of xenobiotic amines in humans: has the involvement of amine oxidases been neglected?

In this review, the major enzyme systems involved in vivo in the oxidative metabolism of xenobiotic amines in humans are discussed, i.e. the monooxygenases [cytochrome P450 system (CYPs) and flavin-containing monooxygenases (FMOs)] and the amine oxidases (AOs). Concerning the metabolism of xenobiotic amines (drugs in particular) by monoamine oxidases (MAOs), this aspect has been largely neglected in the past. An exception is the extensive investigation carried out on the inhibition of the metabolism of tyramine, when tyramine-containing food is ingested by subjects taking inhibitors of MAO A or of both MAO A and B. Moreover, investigations in humans on the metabolism of drug amines on the market by AOs, such as semicarbazide-sensitive amine oxidases (SSAOs) and polyamine oxidases (PAOs), are practically nonexistent, with the exception of amlodipine. In contrast to MAOs, monooxygenases (CYP isoenzymes more than FMOs) have been extensively investigated concerning their involvement in the metabolism of xenobiotics. It is possible that the contribution of AOs to the overall metabolism of xenobiotic amines in humans is underestimated or erroneously estimated, as most investigations of drug metabolism are performed using in vitro test systems optimized for CYP activity, such as liver microsomes, and most investigations of drug metabolism in vivo in humans carry out only the identification of the final, stable metabolites. However, for some drugs on the market, the involvement of MAOs in their in vivo metabolism in humans has been demonstrated recently, among these drugs citalopram, sertraline and the triptans are examples that can be mentioned.

Primary hepatocytes: current understanding of the regulation of metabolic enzymes and transporter proteins, and pharmaceutical practice for the use of hepatocytes in metabolism, enzyme induction, transporter, clearance, and hepatotoxicity studies

This review brings you up-to-date with the hepatocyte research on: 1) in vitro-in vivo correlations of metabolism and clearance; 2) CYP enzyme induction, regulation, and cross-talk using human hepatocytes and hepatocyte-like cell lines; 3) the function and regulation of hepatic transporters and models used to elucidate their role in drug clearance; 4) mechanisms and examples of idiosyncratic and intrinsic hepatotoxicity; and 5) alternative cell systems to primary human hepatocytes. We also report pharmaceutical perspectives of these topics and compare methods and interpretations for the drug development process.