In vitro structure-activity relationships and forensic case series of emerging 2-benzylbenzimidazole 'nitazene' opioids.

2-Benzylbenzimidazole 'nitazene' opioids are presenting a growing threat to public health. Although various nitazenes were previously studied, systematic comparisons of the effects of different structural modifications to the 2-benzylbenzimidazole core structure on µ-opioid receptor (MOR) activity are limited. Here, we assessed in vitro structure-activity relationships of 9 previously uncharacterized nitazenes alongside known structural analogues. Specifically, we focused on MOR activation by 'ring' substituted analogues (i.e., N-pyrrolidino and N-piperidinyl modifications), 'desnitazene' analogues (lacking the 5-nitro group), and N-desethyl analogues. The results from two in vitro MOR activation assays (ß-arrestin 2 recruitment and inhibition of cAMP accumulation) showed that 'ring' modifications overall yield highly active drugs. With the exception of 4'-OH analogues (which are metabolites), N-pyrrolidino substitutions were generally more favorable for MOR activation than N-piperidine substitutions. Furthermore, removal of the 5-nitro group on the benzimidazole ring consistently caused a pronounced decrease in potency. The N-desethyl modifications showed important MOR activity, and generally resulted in a slightly lowered potency than comparator nitazenes. Intriguingly, N-desethyl isotonitazene was the exception and was consistently more potent than isotonitazene. Complementing the in vitro findings and demonstrating the high harm potential associated with many of these compounds, we describe 85 forensic cases from North America and the United Kingdom involving etodesnitazene, N-desethyl etonitazene, N-desethyl isotonitazene, N-pyrrolidino metonitazene, and N-pyrrolidino protonitazene. The low-to-sub ng/mL blood concentrations observed in most cases underscore the drugs' high potencies. Taken together, by bridging pharmacology and case data, this study may aid to increase awareness and guide legislative and public health efforts.

MDMB-4en-PINACA-Related Deaths in Cook County Jail: Awareness and Preventive Measures.

ABSTRACT: Since January 2023, a series of fatalities has occurred in the Cook County Jail. Upon reviewing surveillance videos, in some cases, the inmates shared paper strips, and it was followed by the onset of labored breathing and loss of consciousness. Scene investigation revealed burnt paper strips near the body in 3 cases. No trauma was observed during autopsy. The expanded toxicology panels did not detect any illegal drugs in the postmortem blood samples. However, additional analysis specifically targeting synthetic cannabinoids revealed the presence of MDMB-4en-PINACA [methyl 3,3-dimethyl-2-{[1-(pent-4-en-1-yl)-1H-indazole-3-carbonyl]amino}butanoate], a synthetic cannabinoid associated with a wide range of adverse effects, including cardiovascular complications such as tachycardia and hypertension, respiratory depression, and acute kidney injury. There is limited research on the lethality of MDMB-4en-PINACA. This case series suggests that even isolated use can potentially lead to death. This study aims to raise public awareness regarding MDMB-4en-PINACA, highlighting its unpredictable effects and potential for severe adverse reactions, and to facilitate the development of effective prevention and harm reduction strategies. Implementing screening methods in correctional facilities is crucial to prevent the circulation of potentially fatal substances.

Detection, chemical analysis, and pharmacological characterization of dipyanone and other new synthetic opioids related to prescription drugs.

The emergence of structurally diverse new synthetic opioids (NSOs) has caused the opioid crisis to spiral to new depths. Little information is available about the pharmacology of most novel opioids when they first emerge. Here, using a ß-arrestin 2 recruitment assay, we investigated the in vitro µ-opioid receptor (MOR) activation potential of dipyanone, desmethylmoramide, and acetoxymethylketobemidone (O-AMKD) - recent NSOs that are structurally related to the prescription opioids methadone and ketobemidone. Our findings indicate that dipyanone (EC50=39.9 nM; Emax=155% vs. hydromorphone) is about equally active as methadone (EC50=50.3 nM; Emax=152%), whereas desmethylmoramide (EC50=1335 nM; Emax=126%) is considerably less active. A close structural analogue of ketobemidone (EC50=134 nM; Emax=156%) and methylketobemidone (EC50=335 nM; Emax=117%), O-AMKD showed a lower potency (EC50=1262 nM) and efficacy (Emax=109%). Evaluation of the opioid substitution product buprenorphine and its metabolite norbuprenorphine confirmed the increased in vitro efficacy of the latter. In addition to in vitro characterization, this report details the first identification and full chemical analysis of dipyanone in a seized powder, as well as a postmortem toxicology case from the USA involving the drug. Dipyanone was quantified in blood (370 ng/mL), in which it was detected alongside other NSOs (e.g., 2-methyl AP-237) and novel benzodiazepines (e.g., flualprazolam). While dipyanone is currently not commonly encountered in forensic samples worldwide, its emergence is worrisome and representative of the dynamic NSO market. Graphical Abstract.

Toxicological and pharmacological characterization of novel cinnamylpiperazine synthetic opioids in humans and in vitro including 2-methyl AP-237 and AP-238.

The recent scheduling actions of fentanyl-related substances in both the United States and China have sparked the emergence and proliferation of other generations of "legal" opioids that are structurally distinct from fentanyl, including the recently emerged class of cinnamylpiperazines. In contrast to fentanyl, which contains a piperidine core and a phenethyl moiety, the primary structural components of cinnamylpiperazines are the piperazine core and a cinnamyl moiety. This manuscript reports on the toxicological profile for antemortem and postmortem cases where a cinnamylpiperazine was detected. Samples were quantitatively confirmed using liquid chromatography tandem mass spectrometry. The cases were received between February 2020 and April 2021. Concentrations of 2-methyl AP-237 from four postmortem cases ranged from 820 to 5800 ng/mL, and concentrations of AP-238 from two postmortem cases were 87 and 120 ng/mL. µ-Opioid receptor (MOR) activation potential for 2-methyl AP-237, AP-237, para-methyl AP-237, and AP-238 were studied using a ßarr2 recruitment assay. Efficacies (Emax, relative to hydromorphone) and potencies (EC50) were derived and of the compounds tested AP-238 was the most potent compound in the panel with an EC50 of 248 nM. 2-Methyl AP-237 was found to be the most efficacious drug (Emax = 125%) of the tested cinnamylpiperazines; however, it had substantially less efficacy than fentanyl. The in vitro MOR activation potential of the studied cinnamylpiperazines was lower than that of fentanyl and other novel synthetic opioids (NSOs), in line with the relatively higher concentrations observed in postmortem toxicology samples-an important observational link between in vitro pharmacology and in vivo toxicology.

Pharmacological evaluation and forensic case series of N-pyrrolidino etonitazene (etonitazepyne), a newly emerging 2-benzylbenzimidazole 'nitazene' synthetic opioid.

Novel synthetic opioids continue to emerge on recreational drug markets worldwide. In response to legislative bans on fentanyl analogues, non-fentanyl structural templates, such as 2-benzylbenzimidazoles ('nitazenes'), are being exploited to create new µ-opioid receptor (MOR) agonists. Here, we pharmacologically characterize an emerging cyclic analogue of etonitazene, called N-pyrrolidino etonitazene (etonitazepyne), using in vitro and in vivo methods. A series of analytically confirmed fatalities is described to complement preclinical findings. Radioligand binding assays in rat brain tissue revealed that N-pyrrolidino etonitazene has high affinity for MOR (Ki = 4.09 nM) over δ-opioid (Ki = 959 nM) and κ-opioid (Ki = 980 nM) receptors. In a MOR-ß-arrestin2 activation assay, N-pyrrolidino etonitazene displayed high potency (EC50 = 0.348 nM), similar to etonitazene (EC50 = 0.360 nM), and largely exceeding the potencies of fentanyl (EC50 = 14.9 nM) and morphine (EC50 = 290 nM). When administered s.c. to male Sprague Dawley rats, N-pyrrolidino etonitazene induced opioid-like antinociceptive, cataleptic, and thermic effects. Its potency in the hot plate test (ED50 = 0.0017 mg/kg) was tenfold and 2,000-fold greater than fentanyl (ED50 = 0.0209 mg/kg) and morphine (ED50 = 3.940 mg/kg), respectively. Twenty-one overdose fatalities associated with N-pyrrolidino etonitazene were found to contain low blood concentrations of the drug (median = 2.2 ng/mL), commonly in the context of polysubstance use. N-Pyrrolidino etonitazene was reported as a cause of death in at least two cases, demonstrating toxicity in humans. We demonstrate that N-pyrrolidino etonitazene is an extremely potent MOR agonist that is likely to present high risk to users. Continued vigilance is required to identify and characterize emergent 2-benzylbenzimidazoles, and other non-fentanyl opioids, as they appear in the marketplace.

Proliferation of Novel Synthetic Opioids in Postmortem Investigations After Core-Structure Scheduling for Fentanyl-Related Substances.

ABSTRACT: New generations of novel synthetic opioids (NSOs) have emerged to fill a void in the illicit drug markets left by the decline in popularity of fentanyl analogs subsequent to core-structure scheduling of fentanyl-related substances in the United States and China. These new opioids include members of the 2-benzyl benzimidazole (eg, isotonitazene, metonitazene, N -pyrrolidino etonitazene, protonitazene, etodesnitazene), benzimidazolone (eg, brorphine), and cinnamylpiperazine (eg, AP-238, 2-methyl AP-237) subclasses. Novel synthetic opioids continue to be detected in opioid-related fatal overdoses, demonstrating the harms associated with exposure to these drugs. Between January 2020 and December 2021, 384 casework blood samples were reported by our laboratory to contain 1 or more of the prior listed 8 NSOs. Isotonitazene (n = 144), metonitazene (n = 122), and brorphine (n = 91) were the 3 most prevalent substances, with positivity for isotonitazene and brorphine peaking just before the announcement of emergency scheduling. These NSOs have been documented as significant drivers of drug mortality, and this case series described here highlights the challenges medical examiners and coroners face in staying current with emerging drugs. Challenges include regional differences, rapid turnover, short lifecycles, variable toxicology testing, and difficulty in assessing individual drug toxicity in polydrug cases.

A Case of Unintentional Opioid (U-47700) Overdose in a Young Adult After Counterfeit Xanax Use.

ABSTRACT: We report the case of a young adult who became unresponsive after insufflating what he believed to be "crushed Xanax." Naloxone was administered, reversing his altered mental status and respiratory depression. Clinicians suspected opioid toxicity; however, the patient adamantly denied opioid use. Because of unclear etiology of his symptoms, blood and urine specimens were obtained. A urine specimen was split and then submitted for a clinical comprehensive drug screen using gas chromatography-mass spectrometry. The blood specimen and the remaining urine specimen were sent to a reference laboratory for analysis using liquid chromatography quadrupole time-of-flight mass spectrometry and liquid chromatography tandem mass spectrometry. The standard, clinical gas chromatography-mass spectrometry urine drug testing procedure only detected caffeine; however, analysis by liquid chromatography quadrupole time-of-flight mass spectrometry and liquid chromatography tandem mass spectrometry confirmed the presence of U-47700 (a high-potency clandestine opioid) and its metabolites in the urine and blood. These findings implicate U-47700 as the agent responsible for the patient's signs of opioid toxicity. In this case, a young adult intending to use alprazolam encountered U-47700 with life-threatening effect. Clinicians must remain vigilant for symptoms consistent with opioid overdose, especially with increasing prevalence of counterfeit drugs containing clandestine opioids. Clinicians must also consider obtaining specimens for appropriate analytical testing to improve surveillance and facilitate public health interventions.

Medetomidine Infiltrates the US Illicit Opioid Market.

This Viewpoint discusses the spread of medetomidine in the US illicit opioid market and the need for monitoring and a public health response.

Determination of fentanyl contamination on United States paper currency by LC-QQQ-MS.

Previous research has evaluated the extent to which cocaine and other drugs were detectable on currency in the USA. The literature was in agreement that the majority of bills exhibited some degree of contamination. With the increase of fentanyl in the illicit drug supply, this study was designed to evaluate the extent that fentanyl, cocaine, methamphetamine and other substances were present on circulating currency in 2022. A quantitative assay using liquid chromatography-triple quadrupole mass spectrometry was developed and validated to detect six analytes: fentanyl, 4-anilino-N-phenethylpiperidine, acetylfentanyl, benzylfentanyl, cocaine and methamphetamine. One-dollar bills were collected from 13 cities across the country. Sample preparation consisted of soaking the bills in methanol followed by liquid-liquid extraction. Chromatographic separation was achieved using a C18 analytical column and gradient elution with ammonium formate in water (5 mM, pH 3) and 0.1% formic acid in acetonitrile. The quantitative working range for this assay was 0.1 µg to 1.0 µg per bill (equivalent to 1 ng/mL to 100 ng/mL of extract). Fentanyl was detected on the majority (63%) of samples, with 61% of samples having ≥0.1 µg of fentanyl and 4% of samples having ≥1.0 µg. Cocaine and methamphetamine were detected on 100% and 98% of bills, respectively, typically in amounts >1.0 µg. The remaining fentanyl-related substances were detected in 15% of samples in amounts no >0.69 µg per bill and exclusively in the presence of fentanyl. Unsurprisingly, areas of the country with higher incidence of fentanyl use yielded higher frequency of contaminated bills and higher concentrations. Human exposure to drugs on currency is unlikely to have any significant impacts toxicologically or pharmacologically; however, our research findings suggest that paper currency could serve as a useful substrate for surveillance of drug trends regionally, nationally and/or internationally.

Identification of ADB-5'Br-BINACA in plant material and analytical characterization using GC-MS, LC-QTOF-MS, NMR and ATR-FTIR.

Synthetic cannabinoids are a class of novel psychoactive substances that emerged in the drug market in the early 2010s. Since then, a wide range of different synthetic cannabinoids has been detected in drug materials and in biological specimens collected from intoxication cases. In general, synthetic cannabinoids are reported first in seized materials. In this study, the identification of the novel synthetic cannabinoid, ADB-5'Br-BINACA is reported. A plant material suspected to contain a synthetic cannabinoid was extracted and analyzed. Analyses were performed using gas chromatography-mass spectrometry (GC-MS), liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and one dimensional and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. An aliquot of the sample was extracted using methanol and deuterated chloroform, and analyzed via GC-MS and NMR, respectively. Further dilution of the methanolic extract was analyzed via LC-QTOF-MS. For ATR-FTIR analyses, a few drops of the extract in deuterated chloroform were analyzed. GC-MS, LC-QTOF-MS, and 1H NMRwere successfully used to elucidate and confirm the structure of ADB-5'Br-BINACA in the drug sample. ATR-FTIR and 13C NMR analyses of the extracts did not result in significant information for the confirmation of ADB-5'Br-BINACA in the plant material likely due to low amount of drug material and high background noise. The chemical characterization of ADB-5'Br-BINACA in an authentic sample is reported herein, and chromatographic, mass spectrometric and spectroscopic data are provided for use in future analysis of this drug in suspected samples.

Xylazine awareness, desire, use and exposure: Preliminary findings from the Rhode Island community-based drug checking cohort study.

Background: Xylazine is an ⍺2 adrenergic receptor agonist and a veterinary sedative that can cause severe health complications yet interventions to detect and treat human exposure remain underdeveloped. Community-based drug checking services (DCS) involve the testing of small amounts of drugs to increase community knowledge of unregulated supplies and decrease harms. This study characterized xylazine awareness, desire, use and exposure among people who use drugs (PWUD) in Rhode Island, US. Methods: We analyzed data from an ongoing PWUD cohort study. In 2023, 125 PWUD were enrolled and surveyed. Using point-of-care Fourier Transform infrared spectroscopy (FTIR-S), we tested a drug sample from each participant onsite and confirmed the results offsite at a laboratory. Results were conveyed in real-time, along with harm reduction education, referrals to resources and care. Results: Virtually all participants (99.2 %) wanted to avoid xylazine exposure. Half (51.2 %) knew what xylazine was, and a quarter (26.1 %) suspected previous exposure. Xylazine exposure was primarily surmised through sedating (45.2 %) and ulcerative (29.0 %) effects. Only 8.8 % of participants submitted a sample that they expected to contain xylazine. Xylazine was detected in 14.5 % of samples using FTIR-S and in 21.4 % of samples using a dual laboratory approach of gas chromatography mass spectrometry (GC-MS) and liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). Participants thought that these xylazine-positive samples were fentanyl (78.3 %), heroin (13.0 %), or Percocet® (8.7 %). Conclusion: Implementing point-of-care DCS at harm reduction organizations could be useful in rapidly increasing xylazine awareness and engaging at-risk individuals in prevention, harm reduction, treatment, and rapid care for xylazine-related wounds.

Prevalence and predictors of HIV among patients presenting to US emergency departments with opioid overdose.

INTRODUCTION: Opioid overdose deaths in the U.S. have risen dramatically in the past decade, largely due to the surge in illicitly manufactured fentanyl. Injection drug use is a known risk factor for HIV, further complicating the long-term consequences of opioid use. The baseline prevalence of HIV among adults in the US is 0.46 %. The primary purpose of this study was to determine the prevalence and risk factors of HIV among patients presenting to the emergency departments (ED) with an acute opioid overdose. METHODS: This study is a prospective observational cohort study from the ToxIC Fentalog Study group. Patients age 18 years of age or older are included if they present to one of 10 participating U.S. hospitals in 9 states between September 2020 and May 2023 with a suspected opioid overdose and had waste serum available after routine laboratory testing. Clinical data is collected from the medical record and patient serum is sent for comprehensive toxicologic analysis via liquid chromatography quadrupole time-of-flight mass spectroscopy to detect the presence of over 1200 substances including illicit opioids, novel synthetic opioids, medications, and adulterants. Logistic multivariable regression was performed to examine the association between demographic, behavioral, and serum toxicology data with risk factors and HIV status. RESULTS: Among the total cohort (n=1690), 1062 cases had known HIV status (62.8 % of total sample). Among patients with a known HIV status, 60 (5.6 % [95 % CI: 4.2 %, 7.0 %]) were HIV positive. Patients with HIV reported stimulant use more frequently (13.3 %) than those without HIV (6.8 %; p=0.003). After controlling for confounding, bipolar psychiatric history was a significant independent predictor of HIV positivity (aOR: 1.08; 95 % CI: 1.02, 1.13) in this population. CONCLUSIONS: In this large multicenter cohort, the prevalence of HIV for ED patients with illicit opioid overdose was 9 times higher than that expected by the general population. Bipolar disorder appears to be a novel risk factor for HIV positivity in this patient population.

Metabolic profile determination of 2F-viminol - A novel synthetic opioid identified in forensic investigations.

Novel synthetic opioid (NSO) continue to emerge in the United States in the midst of an opioid crisis. The NSO 2F-viminol was identified in casework at the Center for Forensic Science Research and Education through its NPS Discovery program in 2019. Little information and published literature were available for this new opioid at the time. To address this, human liver microsomes (HLMs) were used to perform in vitro metabolism studies with a drug standard. The goal was to predict in vivo metabolism. Experimental samples were prepared using HLMs, NADPH, phosphate buffer (pH 7.4), and a 2F-viminol standard. Standard samples were prepared containing only drug, control samples were prepared with drug and HLMs but no NADPH cofactor, and metabolism reaction mixtures contained drug, HLMs and NADPH. The subsequent mixtures were incubated with light shaking to allow metabolism to occur. After cleanup, metabolite mixtures were analyzed via a SCIEX TripleTOF 5600+ liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS). The generated metabolic structures were elucidated using SCIEX MetabolitePilot software (version 2.0). In addition to remaining parent drug, seven metabolites of 2F-viminol were discovered, including N-dealkylated and hydroxylated species. The proposed primary metabolites of 2F-viminol were N-dealkylation (sec-butyl) + hydroxylation and N-dealkylation (sec-butyl); however, they should be confirmed in authentic samples, and forensic laboratories should consider adding 2F-viminol and its metabolites to screening protocols to help in extending the window of detection for the parent drug in toxicological samples. As NSOs continue to appear, forensic laboratories must continue metabolism experiments to generate information about pharmacokinetics.

Review of analytical methods for screening and quantification of fentanyl analogs and novel synthetic opioids in biological specimens.

Fentanyl, fentanyl analogs, and other novel synthetic opioids (NSO), including nitazene analogs, prevail in forensic toxicology casework. Analytical methods for identifying these drugs in biological specimens need to be robust, sensitive, and specific. Isomers, new analogs, and slight differences in structural modifications necessitate the use of high-resolution mass spectrometry (HRMS), especially as a non-targeted screening method designed to detect newly emerging drugs. Traditional forensic toxicology workflows, such as immunoassay and gas chromatography mass spectrometry (GC-MS), are generally not sensitive enough for detection of NSOs due to observed low (sub-µg/L) concentrations. For this review, the authors tabulated, reviewed, and summarized analytical methods from 2010-2022 for screening and quantification of fentanyl analogs and other NSOs in biological specimens using a variety of different instruments and sample preparation approaches. Limits of detection or quantification for 105 methods were included and compared to published standards and guidelines for suggested scope and sensitivity in forensic toxicology casework. Methods were summarized by instrument for screening and quantitative methods for fentanyl analogs and for nitazenes and other NSO. Toxicological testing for fentanyl analogs and NSOs is increasingly and most commonly being conducted using a variety of liquid chromatography mass spectrometry (LC-MS)-based techniques. Most of the recent analytical methods reviewed exhibited limits of detection well below 1 µg/L to detect low concentrations of increasingly potent drugs. In addition, it was observed that most newly developed methods are now using smaller sample volumes which is achievable due to the sensitivity increase gained by new technology and new instrumentation.

Cannabinoid-based vaping products and supplement formulations reported by consumers to precipitate adverse effects.

Cannabinoid-based products submitted by consumers experiencing adverse effects were analyzed to identify and quantitate ingredients. Product testing identified several synthetic cannabinoids and products with inaccurate or incomplete labeling.

Plasma pharmacokinetics and pharmacodynamic effects of the 2-benzylbenzimidazole synthetic opioid, isotonitazene, in male rats.

RATIONALE: Isotonitazene is an illicit synthetic opioid associated with many intoxications and fatalities. Recent studies show that isotonitazene is a potent µ-opioid receptor (MOR) agonist in vitro, but little information is available about its in vivo effects. OBJECTIVES: The aims of the present study were to investigate the pharmacokinetics of isotonitazene in rats, and relate pharmacokinetic parameters to pharmacodynamic effects. METHODS: Isotonitazene and its metabolites were identified and quantified by liquid chromatography tandem quadrupole mass spectrometry (LC-QQQ-MS). Male Sprague-Dawley rats with jugular catheters and subcutaneous (s.c.) temperature transponders received isotonitazene (3, 10, 30 µg/kg, s.c.) or its vehicle. Blood samples were drawn at 15, 30, 60, 120, and 240 min post-injection, and plasma was assayed using LC-QQQ-MS. At each blood draw, body temperature, catalepsy scores, and hot plate latencies were recorded. RESULTS: Maximum plasma concentrations of isotonitazene rose in parallel with increasing dose (range 0.2-9.8 ng/mL) and half-life ranged from 23.4 to 63.3 min. The metabolites 4'-hydroxy nitazene and N-desethyl isotonitazene were detected, and plasma concentrations were below the limit of quantitation (0.5 ng/mL) but above the limit of detection (0.1 ng/mL). Isotonitazene produced antinociception (ED50 = 4.22 µg/kg), catalepsy-like symptoms (ED50 = 8.68 µg/kg), and hypothermia (only at 30 µg/kg) that were significantly correlated with concentrations of isotonitazene. Radioligand binding in rat brain tissue revealed that isotonitazene displays nM affinity for MOR (Ki = 15.8 nM), while the N-desethyl metabolite shows even greater affinity (Ki = 2.2 nM). CONCLUSIONS: In summary, isotonitazene is a potent MOR agonist whose pharmacodynamic effects are related to circulating concentrations of the parent drug. The high potency of isotonitazene portends substantial risk to users who are exposed to the drug.

N,N-Dimethylpentylone (dipentylone)-A new synthetic cathinone identified in a postmortem forensic toxicology case series.

Synthetic cathinones emerged on the novel psychoactive substance (NPS) drug market as alternatives to controlled stimulants and entactogens such as methamphetamine and 3,4-methylenedioxymethamphetamine. The majority of synthetic cathinones can be subclassified into two groups: beta-keto amphetamines (i.e., NPS with the suffix "drone") and beta-keto methylenedioxyamphetamines (i.e., NPS with the suffix "lone"). Although a significant number of beta-keto amphetamines have been identified, beta-keto methylenedioxyamphetamines have dominated the NPS market, including notable drugs like methylone, butylone, N-ethyl pentylone (ephylone), eutylone and now N,N-dimethylpentylone. N,N-Dimethylpentylone, also known as dipentylone or beta-keto-dimethylbenzodioxolylpentanamine, emerged into the illicit drug supply <2 months of the international control of eutylone (September 2021). A novel standard addition method was developed and validated for N,N-dimethylpentylone, pentylone and eutylone, and 18 postmortem cases were quantitated using the method described in this manuscript. The resulting blood concentration range for N,N-dimethylpentylone in this case series was 3.3 to 970 ng/mL (median: 145 ng/mL, mean: 277 ± 283 ng/mL). Pentylone, a metabolite of N,N-dimethylpentylone, was detected in all cases (range: 1.3-420 ng/mL, median: 31 ng/mL and mean: 88 ± 127 ng/mL). Due to the rise in identifications of N,N-dimethylpentylone in postmortem investigations as well as the potential misidentification of N,N-dimethylpentylone as N-ethyl pentylone, samples testing positive for pentylone should be additionally confirmed for the presence of N,N-dimethylpentylone. Based on prior trends of new synthetic cathinones, it can be theorized that N,N-dimethylpentylone may predominate the US synthetic stimulant market for the next 1-2 years; however, given the emergence of additional closely related isomeric compounds, it is important to utilize methodology capable of differentiating N,N-dimethylpentylone from its isomers (N-isopropylbutylone, N-ethyl pentylone, N-ethyl N-methyl butylone, hexylone, N-propylbutylone, diethylone and tertylone).

Detection in seized samples, analytical characterization, and in vitro metabolism of the newly emerged 5-bromo-indazole-3-carboxamide synthetic cannabinoid receptor agonists.

Synthetic cannabinoid receptor agonists (SCRAs) are a diverse class of new psychoactive substances (NPS) and new structural scaffolds have emerged on the recreational drug market since the enactment of Chinese SCRA analog controls in 2021. This study reports the first SCRAs to be detected with a bromide at the 5 position (5'Br) on the phenyl ring of the indazole core and without a tail moiety. ADB-5'Br-INACA (ADMB-5'Br-INACA) and MDMB-5'Br-INACA were detected in seized samples from Scottish prisons, Belgian customs, and US forensic casework. The brominated analog with a tail moiety, ADB-5'Br-BUTINACA (ADMB-5'Br-BUTINACA), was also detected in Scottish prisons and US forensic casework. The metabolites of these compounds and the predicted compound MDMB-5'Br-BUTINACA were identified through incubation with primary human hepatocytes to aid in their toxicological identification. The bromide on the indazole remains intact on metabolites, allowing these compounds to be easily distinguished in toxicological samples from their non-brominated analogs. Glucuronidation was more common for tail-less analogs than their butyl tail-containing counterparts. Forensic toxicologists are advised to update their analytical methods with the characteristic ions for these compounds, as well as their anticipated urinary markers: amide hydrolysis and monoOH at tert-butyl metabolites (after ß-glucuronidase treatment) for ADB-5'Br-INACA; monoOH at tert-butyl and amide hydrolysis metabolites for ADB-5'Br-BUTINACA; and ester hydrolysis metabolites with additional metabolites for MDMB-5'Br-INACA and MDMB-5'Br-BUTINACA. Toxicologists should remain vigilant to the emergence of new SCRAs with halogenation of the indazole core and tail-less analogs, which have already started to emerge.

Opioid overdoses involving xylazine in emergency department patients: a multicenter study.

INTRODUCTION: Illicit opioids, consisting largely of fentanyl, novel synthetic opioids, and adulterants, are the primary cause of drug overdose fatality in the United States. Xylazine, an alpha-2 adrenergic agonist and veterinary tranquilizer, is being increasingly detected among decedents following illicit opioid overdose. Clinical outcomes in non-fatal overdose involving xylazine are unexplored. Therefore, among emergency department patients with illicit opioid overdose, we evaluated clinical outcome differences for patients with and without xylazine exposures. METHODS: This multicenter, prospective cohort study enrolled adult patients with opioid overdose who presented to one of nine United States emergency departments between 21 September 2020, and 17 August 2021. Patients with opioid overdose were screened and included if they tested positive for an illicit opioid (heroin, fentanyl, fentanyl analog, or novel synthetic opioid) or xylazine. Patient serum was analyzed via liquid chromatography quadrupole time-of-flight mass spectroscopy to detect current illicit opioids, novel synthetic opioids, xylazine and adulterants. Overdose severity surrogate outcomes were: (a) cardiac arrest requiring cardiopulmonary resuscitation (primary); and (b) coma within 4 h of arrival (secondary). RESULTS: Three hundred and twenty-one patients met inclusion criteria: 90 tested positive for xylazine and 231 were negative. The primary outcome occurred in 37 patients, and the secondary outcome occurred in 111 patients. Using multivariable regression analysis, patients positive for xylazine had significantly lower adjusted odds of cardiac arrest (adjusted OR 0.30, 95% CI 0.10-0.92) and coma (adjusted OR 0.52, 95% CI 0.29-0.94). CONCLUSIONS: In this large multicenter cohort, cardiac arrest and coma in emergency department patients with illicit opioid overdose were significantly less severe in those testing positive for xylazine.