Chemogenetic Tools and their Use in Studies of Neuropsychiatric Disorders.

Chemogenetics is a newly developed set of tools that allow for selective manipulation of cell activity. They consist of a receptor mutated irresponsive to endogenous ligands and a synthetic ligand that does not interact with the wild-type receptors. Many different types of these receptors and their respective ligands for inhibiting or excitating neuronal subpopulations were designed in the past few decades. It has been mainly the G-protein coupled receptors (GPCRs) selectively responding to clozapine-N-oxide (CNO), namely Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), that have been employed in research. Chemogenetics offers great possibilities since the activity of the receptors is reversible, inducible on demand by the ligand, and non-invasive. Also, specific groups or types of neurons can be selectively manipulated thanks to the delivery by viral vectors. The effect of the chemogenetic receptors on neurons lasts longer, and even chronic activation can be achieved. That can be useful for behavioral testing. The great advantage of chemogenetic tools is especially apparent in research on brain diseases since they can manipulate whole neuronal circuits and connections between different brain areas. Many psychiatric or other brain diseases revolve around the dysfunction of specific brain networks. Therefore, chemogenetics presents a powerful tool for investigating the underlying mechanisms causing the disease and revealing the link between the circuit dysfunction and the behavioral or cognitive symptoms observed in patients. It could also contribute to the development of more effective treatments.

Retrospective screening of new psychoactive substances (NPS) in post mortem samples from 2014 to 2021.

Systematic retrospective processing of previously analysed biological samples has been proven to be a valuable tool in the search for new drugs (e.g. new psychoactive substances (NPS)) and for quality assessment in clinical and forensic toxicology. In a previous study, we developed a strategy for retrospective data-analysis using a personalized library of synthetic cannabinoids, designer benzodiazepines and synthetic opioids obtained from the crowdsourced database HighResNPS (https://highresnps.com). In this study, the same strategy was employed for the compounds within the groups of NPS that were not previously included such as synthetic cathinones, phenethylamines, aminoindanes, arylalkylamines, piperazine derivates, piperidines, pyrrolidines, indolalkylamines and arylcyclohexylamines. Synthetic opioids and designer benzodiazepines, which were not part of the previous study, were also included. To enhance the effectiveness of the retrospective analysis, a predicted retention time was included for all entries. Data files from the analysis of 2186 forensic post mortem samples with an Agilent Technologies 6540 ultra-high pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) performed in the laboratory from January 2014 to December 2021 were retrospectively processed with the up-to-date library. Tentative findings were classified in two groups: The findings where MS/MS data was acquired for library match (category 1) and the less certain findings where such data lacked (category 2). Five compounds of category 1 (three synthetic cathinones and two indolalkylamines) were identified in 12 samples. Only one of the findings, 4-MEAPP (4-methyl-α-ethylaminopentiophenone), was deemed plausible after reviewing case information. As many as 501 presumably positive category 2 findings were detected. Using the predicted retention time as an additional criterion the number was significantly reduced but still too high for a manual review. This work has demonstrated that the strategy developed in the previous study can be applied to other NPS groups. However, it is important to note the limitations such a method may have in detecting compounds at very low concentrations.

Detection of the synthetic cathinone N,N-dimethylpentylone in seized samples from prisons.

Drug use is prevalent in prisons with drugs associated with depressant effects found to be more prevalent than stimulants. Synthetic cathinones (SCats; often sold as "bath salts", "ecstasy", "molly", and "monkey dust") are the second largest category of new psychoactive substances (NPS) currently monitored by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and are commonly used as substitutes for regulated stimulants, such as amphetamine, cocaine, and MDMA. N,N-dimethylpentylone (also known as dimethylpentylone, dipentylone, and bk-DMBDP) was detected for the first time in the Scottish prisons in seven powder samples seized between January and July 2023. Samples were analyzed using gas chromatography-mass spectrometry (GC-MS), ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QToF-MS), and nuclear magnetic resonance imaging (NMR). Dimethylpentylone was detected alongside other drugs in four samples, including the novel benzodiazepine desalkylgidazepam (bromonordiazepam) and the synthetic cannabinoid receptor agonists (SCRAs) MDMB-INACA and MDMB-4en-PINACA.

Effects of the Synthetic Cathinone α-Pyrrolidinobutiothiophenone (α-PBT) on Discriminative Stimulus Effects and Intracranial Self-Stimulation Thresholds in Male Rats.

Recently, the abuse of synthetic cathinones is increasing among young people. α-Pyrrolidinobutiothiophenone (α-PBT), a synthetic cathinone, is a designer drug that is freely traded online with no legal restrictions. Moreover, there is currently no scientific basis for legal regulation. Here, we examined the addictive properties of α-PBT using a drug discrimination (DD) task. We also investigated the role of α-PBT in brain stimulation reward (BSR) using an intracranial self-stimulation (ICSS) paradigm in rats. Initially, the rats were trained to discriminate between cocaine and saline. After the discrimination training criteria were met, we determined the dose-effect curves of cocaine and conducted generalization tests with α-PBT and α-pyrrolidinopentiothiophenone (α-PVT) using a cumulative dosing protocol. In a separate set of studies, we examined the dopaminergic mechanisms underlying the function of α-PBT as an interoceptive stimulus (17.8 mg/kg) by intraperitoneally injecting either the dopamine (DA) D1 antagonist SCH23390 (0.06 and 0.12 mg/kg) or the D2 antagonist eticlopride (0.05 and 0.1 mg/kg) 15 min before DD testing. Brain reward function was measured using an ICSS procedure to examine the effects of α-PBT on ICSS threshold under the frequency-rate procedure. Our results showed that α-PBT functioned as a discriminative cue similar to cocaine in rats. More importantly, SCH23390 abolished the effects of α-PBT as an interoceptive stimulus in a dose-dependent manner in rats trained to press a lever to receive cocaine. Similarly, eticlopride dose-dependently attenuated the effect of α-PBT used as a discriminative cue. Additionally, cumulative α-PBT administration dose-dependently lowered ICSS thresholds compared with those in saline-treated rats. Furthermore, α-PBT-induced potentiation of BSR was abolished by pretreatment with both SCH23390 and eticlopride. Taken together, our results suggest that α-PBT can function as a cocaine-like discriminative cue via the activation of D1 and D2 receptors. α-PBT also appears to influence BSR by reducing the brain reward threshold via changes in D1 and D2 receptors. The present study suggests that α-PBT could have addictive properties through DA D1 and D2 receptors and thus poses a threat to humans.

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.

[Toxicology of synthetic cannabinoids]. / Toxicologie des cannabinoïdes de synthèse.

Synthetic cannabinoids (CS), or synthetic endocannabinoid receptor agonists, were initially synthesized for basic research into exocannabinoid signaling pathways, as well as in clinical research for their analgesic properties. The use of CS for recreational purposes is a recent phenomenon, but one that has grown very quickly in recent years, since these molecules now represent the main category of new synthetic products (NPS). This literature review aims to bring together current data regarding the use and effects caused by CS in humans. The relationship between the structure and activity of these CSs, the pharmacology and adverse effects of these CSs and finally the different methods of analyzing CSs. A better understanding of this phenomenon is essential to raise awareness among stakeholders in the health field.

The neural basis of resting-state fMRI functional connectivity in fronto-limbic circuits revealed by chemogenetic manipulation.

Measures of fMRI resting-state functional connectivity (rs-FC) are an essential tool for basic and clinical investigations of fronto-limbic circuits. Understanding the relationship between rs-FC and the underlying patterns of neural activity in these circuits is therefore vital. Here we introduced inhibitory designer receptors exclusively activated by designer drugs (DREADDs) into the amygdala of two male macaques. We evaluated the causal effect of activating the DREADD receptors on rs-FC and neural activity within circuits connecting amygdala and frontal cortex. Activating the inhibitory DREADD increased rs-FC between amygdala and ventrolateral prefrontal cortex. Neurophysiological recordings revealed that the DREADD-induced increase in fMRI rs-FC was associated with increased local field potential coherency in the alpha band (6.5-14.5 Hz) between amygdala and ventrolateral prefrontal cortex. Thus, our multi-modal approach reveals the specific signature of neuronal activity that underlies rs-FC in fronto-limbic circuits.

Identification of Gα12-vs-Gα13-coupling determinants and development of a Gα12/13-coupled designer GPCR.

G-protein-coupled receptors (GPCRs) transduce diverse signals into the cell by coupling to one or several Gα subtypes. Of the 16 Gα subtypes in human cells, Gα12 and Gα13 belong to the G12 subfamily and are reported to be functionally different. Notably, certain GPCRs display selective coupling to either Gα12 or Gα13, highlighting their significance in various cellular contexts. However, the structural basis underlying this selectivity remains unclear. Here, using a Gα12-coupled designer receptor exclusively activated by designer drugs (DREADD; G12D) as a model system, we identified residues in the α5 helix and the receptor that collaboratively determine Gα12-vs-Gα13 selectivity. Residue-swapping experiments showed that G12D distinguishes differences between Gα12 and Gα13 in the positions G.H5.09 and G.H5.23 in the α5 helix. Molecular dynamics simulations observed that I378G.H5.23 in Gα12 interacts with N1032.39, S1693.53 and Y17634.53 in G12D, while H364G.H5.09 in Gα12 interact with Q2645.71 in G12D. Screening of mutations at these positions in G12D identified G12D mutants that enhanced coupling with Gα12 and to an even greater extent with Gα13. Combined mutations, most notably the dual Y17634.53H and Q2645.71R mutant, further enhanced Gα12/13 coupling, thereby serving as a potential Gα12/13-DREADD. Such novel Gα12/13-DREADD may be useful in future efforts to develop drugs that target Gα12/13 signaling as well as to identify their therapeutic indications.

Ajuste de dosis según función renal en una paciente polimedicada incluida en el servicio de reacondicionamiento de medicamentos utilizando sistemas personalizados de dosificación (SPD) / Dose adjustment according to renal function in a polymedicated patient included in the medication reconditioning service using personalized dosing systems (SPD)

Paciente de 78 años, polimedicada e incluida en el servicio de Sistema Personalizado de Dosificación de Medicamentos (SPD). Al acudir a retirar su medicación nos informa que desde hace unos meses sufre cansancio, debilidad, mareos y confusión. Se realiza una revisión de la medicación, centrada en la dosificación de los medicamentos de metabolismo o eliminación renal, en función del valor de Filtrado Glomerular estimado de la paciente (FGe). Se realiza derivación al Médico de Atención Primaria (MAP) mediante un informe, en el que se recomienda la reducción de dosis de losartán y manidipino según el valor de FGe de la paciente. El MAP redujo la dosis de los antihipertensivos. Se efectuó seguimiento del caso, que permitió observar que la paciente dejó de presentar los síntomas descritos inicialmente.(AU)

The surge of bromazolam-related fatalities replacing other novel designer benzodiazepines-related fatalities in San Francisco.

BACKGROUND AND AIM: Bromazolam, a novel designer benzodiazepine (NBD), exhibits potent sedative, hypnotic and anxiolytic effects, raising concerns regarding its potential for misuse and fatal outcomes, particularly when combined with opioids such as fentanyl. Despite limited documented fatalities globally, its use poses a significant threat, exacerbated by under-reporting and a lack of routine testing. This study analysed NBD-related deaths in a major US city over a 4-year period. METHODS: Analysis of accidental overdose deaths involving NBDs in San Francisco, CA, USA from 2020 to 2023, was performed utilizing medico-legal death investigations including comprehensive forensic toxicology, pathology and demographic information. San Francisco conducts thorough investigations into all non-natural and sudden unexpected deaths, including routine alcohol and drug testing of decedents under its jurisdiction, including etizolam, flualprazolam, flubromazolam and bromazolam analysis. RESULTS: There was a sudden surge in bromazolam-related deaths, with 44 fatalities documented in 2023, contrasting with relatively fewer deaths related to other NBDs. Bromazolam fatalities frequently involved co-ingestion with opioids, primarily fentanyl, and stimulants such as methamphetamine and cocaine. Demographic characteristics indicated a predominance of males, with a significant proportion lacking fixed addresses. Blood concentrations of bromazolam increased during the study period, suggesting heightened availability and/or purity in the community. CONCLUSION: There was a surge in bromazolam-related deaths during 2023 in San Francisco, CA, USA, contrasting with relatively stable numbers of deaths associated with other NBDs over the preceding years. The findings underscore the urgency for enhanced death investigation, testing and reporting to facilitate targeted harm reduction strategies for individuals at risk of bromazolam-related morbidity and mortality.

Synthetic cathinones in drug-facilitated sexual assault: A case report involving the novel generation substituted cathinone N-ethylpentedrone and a review of the literature.

The use of 3,4-methylenedioxymethamphetamine (MDMA) in drug-facilitated sexual assault (DFSA) is not uncommon. Indeed, the effects associated with the use of this substance may lead to disinhibition. Several synthetic cathinones, such as mephedrone or methylone, also possess marked entactogenic properties. This manuscript aims to (i) report a DFSA case involving a novel cathinone derivative, namely N-ethyl-pentedrone (NEPD) and (ii) review previously reported DFSA cases involving synthetic cathinones. Using liquid chromatography-high-resolution mass spectrometry (LC-HRMS), NEPD was detected in both plasma and urine collected from a 36-year-old male who had been victim of DFSA. Furthermore, an exhaustive, non-period-specific English-language literature search was performed using several different electronic databases to identify DFSA cases involving synthetic cathinones. Overall, five synthetic cathinones have been associated with DFSA:methylenedioxypyrovalerone, 4-methylethcathinone, α -pyrrolidinopentiophenone, mephedrone, α -pyrrolidinohexiophenone, and methylone, which appears to be the most frequently reported. Methylone is the ß-keto analog of MDMA, with which it shares substantial pharmacological similarities. Indeed, the pharmacological effects of methylone are similar to those associated with MDMA. By contrast, little is known regarding NEPD's pharmacological effects in humans. Based on subjective reports, NEPD can produce both positive and negative effects in human. Unlike what is reported in the case of methylone or mephedrone, only a small minority of NEPD users report slightly entactogenics effects. Such properties theoretically make NEPD more suitable for use in a chemsex context than in DFSA context; even though, the boundary between these two specific forms of sexualized drug use can sometimes appear tenuous.

Designer Receptor Exclusively Activated by Designer Drug (DREADD)-Mediated Activation of the Periaqueductal Gray Restores Nociceptive Descending Inhibition After Traumatic Brain Injury in Rats.

Traumatic brain injury (TBI) patients frequently experience chronic pain that can enhance their suffering and significantly impair rehabilitative efforts. Clinical studies suggest that damage to the periaqueductal gray matter (PAG) following TBI, a principal center involved in endogenous pain control, may underlie the development of chronic pain. We hypothesized that TBI would diminish the usual pain control functions of the PAG, but that directly stimulating this center using a chemogenetic approach would restore descending pain modulation. We used a well-characterized lateral fluid percussion model (1.3 ± 0.1 atm) of TBI in male rats (n = 271) and measured hindpaw mechanical nociceptive withdrawal thresholds using von Frey filaments. To investigate the role of the PAG in pain both before and after TBI, we activated the neurons of the PAG using a Designer Receptor Exclusively Activated by Designer Drug (DREADD) viral construct. Immunohistochemical analysis of brain tissue was used to assess the location and confirm the appropriate expression of the viral constructs in the PAG. Activation of the PAG DREADD using clozapine N-oxide (CNO) caused hindpaw analgesia that could be blocked using opioid receptor antagonist, naloxone, in uninjured but not TBI rats. Due to the importance of descending serotonergic signaling in modulating nociception, we ablated spinal serotonin signaling using 5,7-DHT. This treatment strongly reduced CNO-mediated anti-nociceptive effects in TBI but not uninjured rats. To define the serotonergic receptor(s) required for the CNO-stimulated effects in TBI rats, we administered 5-HT7 (SB-269970) and 5-HT1A (WAY-100635) receptor antagonists but observed no effects. The selective 5-HT2A receptor antagonist ketanserin, however, blocked CNO's effects in the DREADD expressing TBI but not DREADD expressing sham TBI animals. Blockade of alpha-1 adrenergic receptors with prazosin also had no effect after TBI. Descending pain control originating in the PAG is mediated through opioid receptors in uninjured rats. TBI, however, fundamentally alters the descending nociceptive control circuitry such that serotonergic influences predominate, and those are mediated by the 5-HT2A receptor. These results provide further evidence that the PAG is a key target for anti-nociception after TBI.

Alpha-methyltryptamine and 5-(2-methylaminopropyl)-benzofuran (5-MAPB) fatal co-intoxication: case report and review of literature.

The scientific literature contains little reliable data regarding new psychoactive substances and designer drugs, making it difficult to assess toxic blood levels and potentially lethal threshold. Here, we report a fatal co-intoxication involving two uncommon drugs ‒ alpha-methyltryptamine (AMT) and 5-(2-methylaminopropyl)-benzofuran (5-MAPB) ‒ combined with exposure to benzodiazepines, ephedrine, and norephedrine. AMT and 5-MAPB were quantified using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC/MS-MS), revealing concentrations of AMT 4690 ng/mL and 5-MAPB 101 ng/mL in postmortem peripheral blood. We additionally reviewed the literature to help interpret the likely roles of these molecules in the occurrence of death.

[Detoxification after use of new psychoactive substances purchased online]. / Avrusning etter bruk av nye rusmidler fra internett.

Background: The knowledge base on new psychoactive substances (NPS) is generally limited. This introduces new challenges and increased unpredictability in substance abuse treatment. Case presentation: A man in his thirties was submitted to detoxification after reportedly using flubromazolam, a high potency designer benzodiazepine, which he had purchased on the dark web. Extensive drug testing of serum, urine and hair, and the remains in a dropper bottle delivered by the patient, did not reveal flubromazolam or possible metabolites, but did reveal several common drugs of abuse, and 8-aminoclonazolam, a metabolite of clonazolam, another designer benzodiazepine sold on the dark web. The detoxification was uncomplicated. An excessive treatment protocol based on the patient's information, involving high preparedness and increased resources, both clinically and analytically, turned out to be unnecessary. Interpretation: The drug use and clinical course in this case proved to be more common than the unit prepared for. The case history illustrates both the challenges with users of NPS and the general unpredictability in substance abuse treatment.

Identification of clobromazolam in Australian emergency department intoxications using data-independent high-resolution mass spectrometry and the HighResNPS.com database.

The proliferation of novel psychoactive substances (NPSs) continues to challenge toxicology laboratories. In particular, the United Nations Office on Drugs and Crime considers designer benzodiazepines to be a current primary threat among all NPSs. Herein, we report detection of a new emerging designer benzodiazepine, clobromazolam, using high-resolution mass spectrometry and untargeted data acquisition in combination with a "suspect screening" method built from the crowd-sourced HighResNPS.com database. Our laboratory first detected clobromazolam in emergency department presenting intoxications included within the Emerging Drugs Network of Australia-Victoria project in the state of Victoria, Australia, from April 2022 to March 2023. Clobromazolam was the most frequent designer benzodiazepine detected in this cohort (100/993 cases, 10%). No patients reported intentional administration of clobromazolam, although over half reported exposure to alprazolam, which was detected in only 7% of cases. Polydrug use was prevalent (98%), with phenazepam (45%), methylamphetamine (71%) and other benzodiazepines (60%) most frequently co-detected. This is the first case series published in the literature concerning clobromazolam in clinical patients. The identification of clobromazolam in patients presenting to emergency departments in Victoria demonstrates how high-resolution mass spectrometry coupled with the HighResNPS.com database can be a valuable tool to assist toxicology laboratories in keeping abreast of emerging psychoactive drug use.

Effects of the designer drug 4-methylamphetamine on core temperature and serotonin levels in the striatum and hippocampus of rats.

New psychoactive substances (NPS) are typically synthesized in clandestine laboratories in an attempt to chemically modify already federally regulated drugs in an effort to circumvent the law. Drugs derived from a phenethylamine pharmacophore, such as 4-chloroamphetamine and 3,4-methylenedioxymethamphetamine (MDMA), reliably induce thermogenesis and serotonergic deficits in the striatum and hippocampus of rodents. 4-methylamphetamine (4-MA), a relative newcomer to the NPS scene, was originally investigated in the mid-1900 s as a potential anorexigenic agent. With its phenethylamine pharmacophore, 4-MA was hypothesized to produce similar toxicological alterations as its chemical analogs. In the present study, three doses (1.0, 2.5, and 5.0 mg/kg, ip.) of 4-MA were administered to rats twice daily for two days. Core temperature data were calculated and analyzed as temperature area under the curve (TAUC). On the second day of dosing, a hypothermic response to 4-MA (2.5 and 5.0 mg/kg) was noted between 0.5 and 2.0 h post-treatment. Only the highest dose of 4-MA decreased body weight on the second day of treatment and maintained this reduction in weight for seven days after treatment ceased. None of the doses of 4-MA evaluated significantly altered serotonin levels in the hippocampus or striatum seven days after final treatment. The present findings demonstrate that the 4-methyl substitution to amphetamine generates a pharmacological and toxicological profile that differs from other similar phenethylamine analogs.

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 â„ƒ, 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.