Postmortem analysis of three methoxyacetylfentanyl-related deaths in Denmark and in vitro metabolite profiling in pooled human hepatocytes

Development of a high-resolution paper-spray mass spectrometry method using street drugs for the early detection of emerging drugs in the unregulated supply

Adulteration of the unregulated opioid supply has contributed to increasing numbers of overdose deaths in North America. Harm-reduction drug checking has emerged as a strategy to address increasing adulteration rates by providing information about sample composition to people who use drugs. While paper-spray mass spectrometry is capable of trace detection for drug checking, the presence of newly emerging substances often goes undetected if not included in the targeted analysis method. High-resolution mass spectrometry has not been widely used in drug-checking efforts to date, but it has advanced capabilities to facilitate the detection of newly emerging substances. We present a high-resolution paper-spray mass spectrometry method developed for the detection of newly emerging compounds in the street-drug supply. The method was used to analyze a selection of opioid samples received at a drug-checking service in Victoria, British Columbia, Canada. Using this approach, newly emerging adulterants, precursors and byproducts were identified in the local street-drug supply.

Advances in analytical methodologies for detecting novel psychoactive substances: a review

Novel psychoactive substances (NPSs) have historically been difficult compounds to analyze in forensic toxicology. The identification, detection, and quantitation of these analytes and their metabolites have been difficult due to their rapid emergence, short lifespan, and various potencies. Advancements in analytical instrumentation are fundamental to mitigating these NPS challenges by providing reliable identification and sensitivity. This review discusses the pros and cons of various analytical instruments that have played a pivotal role in NPS analysis. As analytical technology advanced, the ability to analyze for NPS became easier with high-resolution mass spectrometry (MS); however, traditional immunoassays are still beneficial for some NPS classes such as benzodiazepines. Over 200 articles from 2010-23 were reviewed, and 180 were utilized for this review. Journal articles were categorized according to the technology used during analysis: immunoassay, gas chromatography-MS, liquid chromatography-MS-low resolution, and liquid chromatography-MS-high resolution to allow for quick references based on a laboratory's technologies. Journal articles were organized in table format to outline the authors, NPS drug classes, and instrumentation used, among other important information.

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

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

Fentanyl and its derivatives: Pain-killers or man-killers?

Fentanyl is a synthetic μ-opioid receptor agonist approved to treat severe to moderate pain with faster onset of action and about 100 times more potent than morphine. Over last two decades, abuse of fentanyl and its derivatives has an increased trend, globally. Currently, the United States (US) faces the most serious situation related to fentanyl overdose, commonly referred to as the opioid epidemic. Nowadays, fentanyl is considered as the number one cause of death for adults aged 18-45 in the US. Synthesis and derivatization of fentanyl is inexpensive to manufacture and easily achievable. Indeed, more than 1400 fentanyl derivatives have been described in the scientific literature and patents. In addition, accessibility and efficacy of fentanyl and its derivatives can play a potential role in misuse of these compounds as a chemical weapon. In this review, the properties, general pharmacology, and overdose death cases associated with fentanyl and selected derivatives are presented. Moreover, current opioid epidemic in the US, Moscow theatre hostage crisis, and potential misuse of fentanyl and its derivatives as a chemical weapon are disclosed.

Detection of scopolamine in urine and hair in a drug-facilitated sexual assault

The use of the drug scopolamine in drug-facilitated crimes is known. Nevertheless, given the high potency of the drug and its rapid metabolism, analysis in blood and urine may not be sufficient for drug detection in late crime declaration, especially following a single-dose administration in drug-facilitated sexual assault (DFSA) cases. Hair may constitute an essential supplemental matrix extending the drug detection window in such cases. This case report presents quantitative data on scopolamine findings in urine and hair in a DFSA case. A young female had consumed several alcoholic drinks at a party venue when her behaviour became noticeably peculiar. Later, she woke up next to an unknown man and had no recollection of the night's events. Blood and urine samples were collected 18 h after the incident. The initial toxicological target screening using UHPLC-TOF-MS detected scopolamine in the hydrolysed urine sample, and quantification yielded 41 µg/L scopolamine in urine, while blood was negative. Segmental hair analysis using multitarget UHPLC-MS/MS was performed on three washed 2-cm segments of hair collected five weeks after the incident, yielding 0.37 pg/mg scopolamine only in the relevant hair segment. This case report provides novel insight into the concentration in hair following a single exposure of scopolamine and the feasibility of detecting scopolamine in hair by comparison to published toxicological findings.

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.

Fatal cases involving new psychoactive substances and trends in analytical techniques

New psychoactive substances (NPS) are an emerging public health issue and deaths are commonly associated with polydrug abuse. Moreover, the number of new substances available is constantly increasing, causing intoxications in low doses, characteristics that impose to toxicology and forensic laboratories to keep routine methods up to date, with high detectability and constantly acquiring new analytical standards. Likewise, NPS metabolites and respective elimination pathways are usually unknown, making it difficult the detection and confirmation of the drug involved in the fatal case in an analytical routine. A literature search was performed on PubMed, Scopus and Web of Science databases for papers related to chromatographic analyses from fatal cases related to NPS use published from 2016 to 2021. A total of 96 papers were retrieved and reviewed in this study. Opioids, synthetic cathinones, phenethylamines/amphetamines and cannabinoids were the NPS classes most found in the fatal cases. In many cases, multiple compounds were detected in the biological samples, including prescription and other illegal drugs. Liquid chromatography-tandem mass spectrometry, an alternative to overcome the gas chromatography-mass spectrometry limitations for some compounds, was the analytical technique most used in the studies, and high resolution mass spectrometry was often applied to NPS metabolite investigation and structural characterization and identification of unknown compounds. Toxicological screening and quantitation methods need to be continuously updated to include new substances that are emerging on the drug market that can be fatal at very low doses.

Characteristics of fatal 'novel' synthetic opioid toxicity in Australia

BACKGROUND

Aims: To determine 1. The characteristics of all recorded cases of fatal drug poisoning involving novel synthetic opioids (NSOs) in Australia; 2. The toxicology of cases; and 3. The major autopsy findings.

METHODS

Review of all fatal poisonings related to NSOs in Australia 2000-2021 identified in the National Coronial Information System.

RESULTS

Thirty-one cases were identified, 96.8% due to unintentional drug toxicity. The mean age was 31.9 years and 87.1% were male. Only six were aged over forty. A history of substance use problems was documented in 80.6% and 58.1% had a history of injecting drug use. In 32.3% the final route of administration of a NSO was by non-injecting routes of administration. Ten NSOs were identified. Fentanyl analogues were present in 67.2%, most commonly furanylfenatyl (19.4%). Other NSO types were present in 39.7%, most commonly U-47700 (35.5%). Substances other than NSOs were present in 90.3%, most commonly benzodiazepines (67.7%) and other opioids (51.6%). A CNS depressant in addition to NSOs was present in 90.3%, and a new psychoactive substance other than a NSO in 25.8%. Pulmonary oedema was diagnosed in 82.6%, aspiration of vomitus in 30.4%, and acute bronchopneumonia in 17.4%.

CONCLUSIONS

Ten NSOs were identified. Case characteristics suggest a younger cohort whose profile is more typical of use of other NPS than of the established opioids. A large proportion used NSOs by non-injecting routes of administration.

In Vitro and In Vivo Analysis of Fentanyl and Fentalog Metabolites using Hyphenated Chromatographic Techniques: A Review

Fentanyl and fentanyl analogues (also called fentalogs) are used as medical prescriptions to treat pain for a long time. Apart from their pharmaceutical applications, they are misused immensely, causing the opioid crisis. Fentanyl and its analogues are produced in clandestine laboratories and sold over dark Web markets to different parts of the world, leading to a rise in the death rate due to drug overdose. This is because the users are unaware of the lethal effects of the newer forms of fentalogs. Unlike other drugs, these fentalogs cannot be detected easily, as very little data are available, and this is one of the major reasons for the risk of life-threatening poisoning or deaths. Hence, rigorous studies of these drugs and their possible metabolites are required. It is also necessary to develop techniques for the detection of minute traces of metabolites in biological fluids. This Review provides an overview of the application of hyphenated chromatographic techniques used to analyze multiple novel fentalogs, using in vivo and in vitro methods. The article focuses on the metabolites formed in phase I and phase II processes in biological specimens obtained in recent cases of drug abuse and overdose deaths that could be useful for the detection and differentiation of multiple fentalogs.

Blood concentrations of new synthetic opioids

PURPOSE

Over the last decade, there has been a significant growth in the market and number of new psychoactive substances (NPS). One of the NPS groups that has grown rapidly in recent years, bringing a new set of problems, consists of new synthetic opioids. The extreme potency of these compounds poses a high risk of acute poisoning, as an overdose can cause respiratory depression. Most of the information regarding human pharmacokinetics of new opioids is based on toxicological case reports and the data on concentrations of new opioids in human blood are scarce. The interpretation of results usually requires a comparison to previously published cases; therefore, a referenced compilation of previously published concentration data would be useful.

METHODS

The data were collected by searching the PubMed and Scopus databases and by using the Google search engine. All the available data from articles and reports that measured new opioid concentrations in plasma, serum, or whole blood were included in the data analysis.

RESULTS

The presented tables list the observed concentrations in fatal and nonfatal cases involving 37 novel synthetic opioids.

CONCLUSIONS

Blood levels of new opioids are extremely difficult to interpret. Low blood concentrations of these substances do not rule out acute poisoning as their high potency creates a risk of respiratory depression even at low doses. Opioid tolerance, frequent presence of other drugs, and additional diseases make it impossible to define concentration ranges, especially the minimum fatal concentrations. This report provides quick access to the source articles quantifying novel synthetic opioids.

Circumstances, Postmortem Findings, Blood Concentrations and Metabolism in a Series of Methoxyacetylfentanyl Related Deaths

Methoxyacetylfentanyl is one of many fentanyl analogs available as new psychoactive substances. It have been encountered in both the European Union and the United States, and existing literature suggest that methoxyacetylfentanyl is around 3 to 5-fold less potent than fentanyl. The aim of the present work was to combine case information with blood concentrations and abundance of urinary metabolites to investigate the importance of these parameters for toxicological interpretation. Quantification of methoxyacetylfentanyl in femoral blood was performed by LC-MS/MS and urinary metabolites were analyzed by LC-QTOF-MS with and without hydrolysis with β-glucuronidase/arylsulfatase. For confirmation of identified metabolites, methoxyacetylfentanyl was incubated with hepatocytes for up to 5 hours and analyzed with the same method as the urine samples. In eleven postmortem cases (27 to 41 years old and including one female) methoxyacetylfentanyl was reported in femoral blood. The cause of death was intoxication by methoxyacetylfentanyl alone or in combination with other drugs in all but one case, where death was attributed to acute complications of an underlying heart disease but with possible contribution from methoxyacetylfentanyl. In total, 27 urinary metabolites were found, including eight glucuronides. Major biotransformations were O-demethylation, dealkylation to form the nor-metabolite, mono- and dihydroxylations of the phenethyl moiety, as well as combinations thereof. The most abundant metabolites in hydrolyzed urine included O-desmethyl-, O-desmethyl-phenethyl-hydroxy-, O-desmethyl-phenethyl-hydroxymethoxy- and nor-methoxyacetylfentanyl.Differences in the abundance of methoxyacetylfentanyl and its major metabolites could be interpreted to indicate fatal intoxications in abstinent or chronic users. We postulate that urinary concentrations of methoxyacetylfentanyl and two metabolites, in combination with the methoxyacetylfentanyl concentration in femoral blood, might be good indicators of the time between administration and death as well as prior use.

Postmortem Brain-Blood Ratios of Codeine, Fentanyl, Oxycodone and Tramadol

The analgesics, codeine, fentanyl, oxycodone and tramadol, frequently occur in postmortem cases and determining their role in the cause of death can be challenging. However, postmortem blood is susceptible to redistribution and may not be available in cases of severe blood loss, putrefaction or burns. Brain tissue may serve as a viable supplement to blood or on its own, as it is resistant to postmortem redistribution and often available as a sample matrix when blood is not available. We present brain and blood concentrations and brain-blood ratios of the four analgesics from 210 autopsy cases. The cases were classified according to the presumed cause of death: A: The compound was believed to have solely caused a fatal intoxication. B: The compound was assumed to have contributed to a fatal outcome in combination with other drugs, alcohol or disease. C: The compound was not regarded as being related to the cause of death. Blood and brain samples were prepared by automatic solid phase extraction and quantified by liquid chromatography-mass spectrometry. The squared correlation coefficients between concentrations in brain tissue and blood ranged 0.45-0.91. The median brain-blood ratios were codeine 1.8 (range 0.47-4.6), fentanyl 2.1 (range 0.29-16), oxycodone 1.8 (range 0.11-6.0) and tramadol 1.8 (range 0.047-6.8). A significantly higher brain-blood ratio of codeine was observed in cases where heroin had been administered, although there was a wide overlap. Intravenous and transdermal fentanyl administration could not be distinguished based on the blood or brain concentration or the brain-blood ratio. The results of this study may benefit the toxicological investigation in postmortem cases where one of the four analgesics are suspected of having contributed to or caused a fatal intoxication.

Quantitation and Validation of 34 Fentanyl Analogs from Liver Tissue Using a QuEChERS Extraction and LC-MS-MS Analysis

Since 2013, drug overdose deaths involving synthetic opioids (including fentanyl and fentanyl analogs) have increased from 3,105 to 31,335 in 2018. Postmortem toxicological analysis in fentanyl-related overdose deaths is complicated by the high potency of the drug, often resulting in low analyte concentrations and associations with toxicity, multidrug use, novelty of emerging fentanyl analogs and postmortem redistribution. Objectives for this study include the development of a quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and subsequent liquid chromatography-mass spectrometry/mass spectrometry analysis, validation of the method following the American Academy of Forensic Sciences Standards Board (ASB) standard 036 requirements and application to authentic liver specimens for 34 analytes including fentanyl, metabolites and fentanyl analogs. The bias for all 34 fentanyl analogs did not exceed ±10% for any of the low, medium or high concentrations and the %CV did not exceed 20%. No interferences were identified. All 34 analytes were within the criteria for acceptable percent ionization suppression or enhancement with the low concentration ranging from -10.2% to 23.7% and the high concentration ranging from -7.1% to 11.0%. Liver specimens from 22 authentic postmortem cases were extracted and analyzed with all samples being positive for at least one target analyte from the 34 compounds. Of the 22 samples, 17 contained fentanyl and metabolites plus at least one fentanyl analog. The highest concentration for a fentanyl analog was 541.4 μg/kg of para-fluoroisobutyryl fentanyl (FIBF). The concentrations for fentanyl (n = 20) ranged between 3.6 and 164.9 μg/kg with a mean of 54.7 μg/kg. The fentanyl analog that was most encountered was methoxyacetyl fentanyl (n = 11) with a range of 0.2-4.6 μg/kg and a mean of 1.3 μg/kg. The QuEChERS extraction was fully validated using the ASB Standard 036 requirements for fentanyl, metabolites and fentanyl analogs in liver tissue.

Targeted and untargeted detection of fentanyl analogues and their metabolites in hair by means of UHPLC-QTOF-HRMS

Detection of new psychoactive substances and synthetic opioids is generally performed by means of targeted methods in mass spectrometry, as they generally provide adequate sensitivity and specificity. Unfortunately, new and unexpected compounds are continuously introduced in the illegal market of abused drugs, preventing timely updating of the analytical procedures. Moreover, the investigation of biological matrices is influenced by metabolism and excretion, in turn affecting the chance of past intake detectability. In this scenario, new opportunities are offered by both the non-targeted approaches allowed by modern UHPLC-HRMS instrumentation and the investigation of hair as the matrix of choice to detect long-term exposure to toxicologically relevant substances. In this study, we present a comprehensive and validated workflow that combines the use of UHPLC-QTOF-HRMS instrumentation with a simple hair sample extraction procedure for the detection of a variety of fentanyl analogues and metabolites. A simultaneous targeted and untargeted analysis was applied to 100 real samples taken from opiates users. MS and MS/MS data were collected for each sample. Data acquisition included a TOF-MS high-resolution scan combined with TOF-MS/MS acquisition demonstrating considerable capability to detect expected and unexpected substances even at low concentration levels. The predominant diffusion of fentanyl was confirmed by its detection in 68 hair samples. Other prevalent analogues were furanylfentanyl (28 positive samples) and acetylfentanyl (14 positive samples). Carfentanil, methylfentanyl, and ocfentanil were not found in any of the analyzed samples. Furthermore, the retrospective data analysis based on untargeted acquisition allowed the identification of two fentanyl analogues, namely β-hydroxyfentanyl and methoxyacetylfentanyl, which were not originally included in the panel of targeted analytes.

Perspectives and challenges associated with the determination of new psychoactive substances in urine and wastewater - A tutorial

New psychoactive substances (NPS), often designed as (legal) substitutes to conventional illicit drugs, are constantly emerging in the drug market and being commercialized in different ways and forms. Their use continues to cause public health problems and is therefore of major concern in many countries. Monitoring NPS use, however, is arduous and different sources of information are required to get more insight of the prevalence and diffusion of NPS use. The determination of NPS in pooled urine and wastewater has shown great potential, adding a different and complementary light on this issue. However, it also presents analytical challenges and limitations that must be taken into account such as the complexity of the matrices, the high sensitivity and selectivity required in the analytical methods as a consequence of the low analyte concentrations as well as the rapid transience of NPS on the drug market creating a scenario with constantly moving analytical targets. Analytical investigation of NPS in pooled urine and wastewater is based on liquid chromatography hyphenated to mass spectrometry and can follow different strategies: target, suspect and non-target analysis. This work aims to discuss the advantages and disadvantages of the different data acquisition workflows and data exploration approaches in mass spectrometry, but also pays attention to new developments such as ion mobility and the use of in-silico prediction tools to improve the identification capabilities in high-complex samples. This tutorial gives an insight into this emerging topic of current concern, and describes the experience gathered within different collaborations and projects supported by key research articles and illustrative practical examples.

Development and validation of liquid chromatography-tandem mass spectrometry targeted screening of 16 fentanyl analogs and U-47700 in hair: Application to 137 authentic samples

This study was to validate a LC-MS/MS method for the determination of 17 new synthetic opioids (NSOs) in hair including 3-fluorofentanyl, 3-methylfentanyl, acetylfentanyl, acetylnorfentanyl, alfentanyl, butyrylfentanyl, butyrylnorfentanyl, carfentanil, fentanyl, furanylfentanyl, furanylnorfentanyl, methoxyacetylfentanyl, norcarfentanil, norfentanyl, ocfentanil, sufentanil, and U-47700, and to apply it to 137 authentic samples. Twenty milligrams of hair was decontaminated in dichloromethane and underwent liquid extraction. 10 μL of the reconstituted residue were injected onto the system. The separation was performed in 12 minutes in a gradient mode at a flow rate of 300 μL/min using a Hypersyl Gold PFP column (100 × 2.1 mm i.d., 1.9 μm) maintained at 30°C. Compounds were detected in positive ionization and MRM modes using a TSQ Endura mass spectrometer (ThermoFisher). The method was validated according to EMA guidelines. The LLOQ was in the range 1-50 pg/mg, and the calibration ranged from the LLOQ-1000 pg/mg. Intra- and inter-day accuracy (bias) and precision were < 15%. Extraction recoveries of parent drugs and metabolites were 74-120% and 7-62%, respectively. The matrix effect was in the range 59-126% (CVs ≤ 12.9%). Fentanyl was found in six cases at concentrations of < 1-1650 pg/mg (n = 14 segments). Five fentanyl analogs were quantified in two cases: 3-fluorofentanyl (25-150 pg/mg, n = 5), furanylfentanyl (15-500 pg/mg, n = 5), methoxyacetylfentanyl (500-600 pg/mg, n = 2), acetylfentanyl (1 pg/mg, n = 2), carfentanyl (2.5-3 pg/mg, n = 2). This fully validated method allowed us to test for the first time 3-fluorofentanyl and norcarfentanil in hair among 15 other NSOs, and brings new data regarding 3-fluorofentanyl and methoxyacetylfentanyl hair concentrations.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

LC-QTOF-MS Identification of Major Urinary Cyclopropylfentanyl Metabolites Using Synthesized Standards

Cyclopropylfentanyl is a fentanyl analog implicated in 78 deaths in Europe and over 100 deaths in the United States, but toxicological information including metabolism data about this drug is scarce. The aim of this study was to provide the exact structure of abundant and unique metabolites of cyclopropylfentanyl along with synthesis routes. In this study, metabolites were identified in 13 post-mortem urine samples using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Samples were analyzed with and without enzymatic hydrolysis, and seven potential metabolites were synthesized in-house to provide the identity of major metabolites. Cyclopropylfentanyl was detected in all samples, and the most abundant metabolite was norcyclopropylfentanyl (M1) that was detected in 12 out of 13 samples. Reference materials were synthesized (synthesis routes provided) to identify the exact structure of the major metabolites 4-hydroxyphenethyl cyclopropylfentanyl (M8), 3,4-dihydroxyphenethyl cyclopropylfentanyl (M5) and 4-hydroxy-3-methoxyphenethyl cyclopropylfentanyl (M9). These metabolites are suitable urinary markers of cyclopropylfentanyl intake as they are unique and detected in a majority of hydrolyzed urine samples. Minor metabolites included two quinone metabolites (M6 and M7), not previously reported for fentanyl analogs. Interestingly, with the exception of norcyclopropylfentanyl (M1), the metabolites appeared to be between 40% and 90% conjugated in urine. In total, 11 metabolites of cyclopropylfentanyl were identified, including most metabolites previously reported after hepatocyte incubation.

Hair testing for 3-fluorofentanyl, furanylfentanyl, methoxyacetylfentanyl, carfentanil, acetylfentanyl and fentanyl by LC–MS/MS after unintentional overdose

Purpose

To demonstrate the usefulness of hair testing to determine exposure pattern to fentanyls.

Methods

A 43-year-old male was found unconscious with respiratory depression 15 min after snorting 3 mg of a powder labeled as butyrylfentanyl. He was discharged from hospital within 2 days without blood or urine testing. Two locks of hair were sampled 1 month (M1 A: 0–2 cm (overdose time frame); B: 2–4 cm; C: 4–6 cm) and 1 year (Y1: A: 0–2 cm; B: 2–4 cm) later to monitor his exposure to drugs of abuse by liquid chromatography–tandem mass spectrometry after liquid-liquid extraction.

Results

Hair analysis at M1 showed a repetitive exposure to 3-fluorofentanyl (A/B/C: 150/80/60 pg/mg) with higher concentration in segment A reflecting the overdose period. The non-detection of butyrylfentanyl was consistent with the analysis of the recovered powder identified as 3-fluorofentanyl. Furanylfentanyl (40/20/15 pg/mg) and fentanyl (37/25/3 pg/mg) were also detected in hair. The second hair analysis at Y1 showed the use of three new fentanyls, with probably repetitive exposures to methoxyacetylfentanyl (A/B: 500/600 pg/mg), and single or few exposures to carfentanil (2.5/3 pg/mg) and acetyl fentanyl (1/1 pg/mg). A decreasing exposure to 3-fluorofentanyl (25/80 pg/mg), and increasing consumption of furanylfentanyl (310/500 pg/mg) and fentanyl (620/760 pg/mg) were also observed despite methadone treatment initiation. The patient claimed not consuming three out of the six detected fentanyls.

Conclusions

We report single or repetitive exposure to several fentanyls using hair testing. To our knowledge, this is the first demonstration of 3-fluorofentanyl and methoxyacetylfentanyl in hair samples collected from an authentic abuser.

Distribution of synthetic opioids in postmortem blood, vitreous humor and brain

In the US, the use of synthetic opioids (e.g. fentanyl and derivatives) has become an increasing health issue with thousands of overdose deaths being observed since 2013. With the high mortality rate associated with these substances, postmortem analyses and interpretation of synthetic opioids has become extremely important. However, due to the novelty of these compounds, the available data are limited and provides challenges to toxicologists. The objectives of this study were (1) to develop and validate analytical methods for the determination of synthetic opioids in vitreous humor and brain, and (2) to investigate the postmortem distribution of new synthetic opioids in blood, vitreous humor, and brain tissue. Vitreous humor (0.5mL) and brain tissue (5g) homogenized in water (diluted 1:3, w/w) were extracted by mixed mode cation exchange-reversed phase solid phase extraction. Extracts were analyzed by liquid chromatography tandem mass spectrometry (LC-MSMS). The chromatographic separation was performed by reversed-phase with 0.1% formic acid in water and in acetonitrile as mobile phases in gradient mode, with a total run time of 21min. Data were acquired with ESI+ in dynamic multiple reaction mode (dMRM), monitoring 2 transitions per compound. The methods were succesfully validated following SWGTOX guidelines, with limits of quantification of 0.1ng/mL in vitreous humor and 0.1ng/g in brain. Fifty-eight authentic case samples from the New York City Office of the Chief Medical Examiner (NYC-OCME) were analyzed to assess the distribution and detectability of synthetic opioids in these postmortem samples. Of the fifteen synthetic opioids included in the method, six synthetic opioids and metabolites (4-ANPP, acetylfentanyl, fentanyl, furanylfentanyl, norfentanyl, U-47700) were detected in the authentic cases. Concentrations for most analytes were within the 0.1 to 100ng/mL or ng/g calibration range across all three matrices, with only concentrations from acetylfentanyl and U-47700 exceeding 100ng/mL or ng/g. The highest concentrations were observed in brain (except norfentanyl), followed by blood and vitreous humor. Most analytes were detected in all three matrices in a given case. This was followed by detection of an analyte in combinations of brain and another matrix or brain only. Through the case analyses, vitreous humor and brain demonstrated to be viable alternatives to blood when performing postmortem analyses of synthetic opioids. Brain exhibited a higher detectability for most analytes when compared to blood and vitreous humor.

Studies on the in vitro and in vivo metabolism of the synthetic opioids U-51754, U-47931E, and methoxyacetylfentanyl using hyphenated high-resolution mass spectrometry

New Synthetic Opioids (NSOs) are one class of New Psychoactive Substances (NPS) enjoying increasing popularity in Europe. Data on their toxicological or metabolic properties have not yet been published for most of them. In this context, the metabolic fate of three NSOs, namely, trans-3,4-dichloro-N-[2-(dimethylamino)cyclohexyl]-N-methyl-benzenacetamide (U-51754), trans-4-bromo-N-[2-(dimethylamino)cyclohexyl]-N-methyl-benzamide (U-47931E), and 2-methoxy-N-phenyl-N-[1-(2-phenylethyl)piperidin-4-yl] acetamide (methoxyacetylfentanyl), was elucidated by liquid chromatography high-resolution mass spectrometry after pooled human S9 fraction (phS9) incubations and in rat urine after oral administration. The following major reactions were observed: demethylation of the amine moiety for U-51754 and U-47931E, N-hydroxylation of the hexyl ring, and combinations thereof. N-dealkylation, O-demethylation, and hydroxylation at the alkyl part for methoxyacetylfentanyl. Except for U-47931E, parent compounds could only be found in trace amounts in rat urine. Therefore, urinary markers should preferably be metabolites, namely, the N-demethyl-hydroxy and the hydroxy metabolite for U-51754, the N-demethylated metabolite for U-47931E, and the N-dealkylated metabolite as well as the O-demethylated one for methoxyacetylfentanyl. In general, metabolite formation was comparable in vitro and in vivo, but fewer metabolites, particularly those after multiple reaction steps and phase II conjugates, were found in phS9. These results were consistent with those of comparable compounds obtained from human liver microsomes, human hepatocytes, and/or human case studies.

Unique Structural/Stereo-Isomer and Isobar Analysis of Novel Fentanyl Analogues in Postmortem and DUID Whole Blood by UHPLC–MS-MS

The presented analytical method enabled the Toxicology Department at the Cuyahoga County Medical Examiner’s Office to identify 26 and quantitatively report 24 compounds in 500 μL of whole blood, including fentanyl analogues (fentalogues) such as methoxyacetyl fentanyl (MeOAF) and cyclopropyl fentanyl (CPF). This second-generation method (FG2) was developed with the objective to improve the existing analysis (FG1) by decreasing sample size, lowering limits of detection (LOD) and lower limit of quantitation, minimizing ion suppression and resolving chromatographic interferences. Interferences may occur in the analysis of fentanyl, MeOAF, CPF, 3-methylfentanyl (3MF), butyryl fentanyl and isobutyryl fentanyl due to isobars and structural or geometric isomerism with another analogue or metabolite. The isomeric and isobaric fentalogues were grouped into three sets. The LOD established for Set 1 [MeOAF, para-methoxyacetyl fentanyl, para-fluoro acryl fentanyl (isobar), fentanyl carbamate], 2-furanyl fentanyl, Set 2 [CPF, (E)-crotonyl fentanyl] and carfentanil was 0.0125 ng/mL. The LOD established for N-methyl norfentanyl, norfentanyl, norcarfentanil, despropionyl fentanyl (4-ANPP), acetyl fentanyl, β-hydroxy fentanyl, benzyl fentanyl, acryl fentanyl, alfentanil, fentanyl, para-fluoro fentanyl, Set 3 [(±)-trans-3MF, (±)-cis-3MF, isobutyryl and butyryl fentanyl], para-fluoroisobutyryl fentanyl, sufentanil, phenyl fentanyl and cyclopentenyl fentanyl was 0.0625 ng/mL. Seven-point linear calibration curves were established between 0.025 and 4.0 ng/mL for the 8 analytes with the lower LOD and 0.125 and 20 ng/mL for the 18 analytes with the higher LOD. 4-ANPP and cyclopentenyl fentanyl met qualitative reporting criteria only. The results for five postmortem and two driving under the influence of drugs authentic case samples are presented. To the authors’ knowledge, FG2 is the first published method that achieved baseline resolution of the nine structural/stereo isomers and one isobar by ultra-high performance liquid chromatography–MS-MS and provided quantitative validation data for nine compounds. FG2 may be used as the new baseline for future isomers that need to be chromatographically separated.

A case report on potential postmortem redistribution of furanyl fentanyl and 4-ANPP

Fatal intoxications due to accidental or voluntary intake of synthetic opioids represent an actual emerging issue. We report a case where we have analyzed furanyl fentanyl and its metabolite 4-anilino-N-phenetyl-piperidine (4-ANPP) in blood, urine, gastric content, bile and cerebrospinal fluid. In this case, a 53-year-old man was found dead at home with a needle still inserted in a vein; a plastic bag containing a white powder (later identified as a furanyl fentanyl-based product) was discovered in the room. Biological samples were collected during autopsy and extracted/purified onto a SPE cartridge before instrumental analysis. Qualitative and quantitative analyses were performed by LC-MS/MS on peripheral and cardiac blood, urine, cerebrospinal fluid (CSF), bile and gastric content. Furanyl fentanyl was identified and quantified in all the biological fluids collected. Interestingly, gastric content revealed an unexpected high amount of furanyl fentanyl; yet, cardiac blood and femoral blood provided significantly different concentrations (11.8 and 2.7 ng/g respectively). The concentration of furanyl fentanyl in CSF was similar to that measured in femoral blood (2.6 ng/mL), thus confirming that CSF could be a good alternative biological fluid whenever a postmortem redistribution is suspected. Concentrations of 93.5, 50.4, 171.7, 41.9, 10.2 ng/mL(g) were measured for 4-ANPP in cardiac blood, femoral blood, urine, bile and cerebrospinal fluid, respectively. The outcomes from the presented case report suggest that the two substances have been not only injected intravenously, but probably also ingested by the man. Fentanyl derivative and its precursor seemed to undergo an extensive postmortem redistribution.

Metabolic Pathways and Potencies of New Fentanyl Analogs

Up to now, little is known about the metabolic pathways of new fentanyl analogs that have recently emerged on the drug markets worldwide with high potential for producing addiction and severe adverse effects including coma and death. For some of the compounds, limited information on the metabolism has been published, however, for others so far no information is available. Considering the well characterized metabolism of the pharmaceutically used opioid fentanyl and the so far available data, the metabolism of the new fentanyl analogs can be anticipated to generally involve reactions like hydrolysis, hydroxylation (and further oxidation steps), N- and O-dealkylation and O-methylation. Furthermore, phase II metabolic reactions can be expected comprising glucuronide or sulfate conjugate formation. When analyzing blood and urine samples of acute intoxication cases or fatalities, the presence of metabolites can be crucial for confirmation of the uptake of such compounds and further interpretation. Here we present a review on the metabolic profiles of new fentanyl analogs responsible for a growing number of severe and fatal intoxications in the United States, Europe, Canada, Australia, and Japan in the last years, as assessed by a systematic search of the scientific literature and official reports.

Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Assay for Quantifying Fentanyl and 22 Analogs and Metabolites in Whole Blood, Urine, and Hair

Recently, synthetic opioid-related overdose fatalities, led by illicitly manufactured fentanyl and analogs, increased at an alarming rate, posing a global public health threat. New synthetic fentanyl analogs have been constantly emerging onto the drug marked for the last few years, to circumvent the laws and avoid analytical detection. Analytical methods need to be regularly updated to keep up with the new trends. In this study, we aimed to develop a new method for detecting the newest fentanyl analogs with a high sensitivity, in whole blood, urine, and hair. The method is intended to provide to clinical and forensic toxicologists a tool for documenting consumption. We developed a comprehensive ultra-high-performance liquid chromatography-tandem mass spectrometry method for quantifying fentanyl and 22 analogs and metabolites. Urine samples were simply diluted before injection; a liquid-liquid extraction was performed for blood testing; and a solid phase extraction was performed in hair. The chromatographic separation was short (8 min). The method was validated with a high sensitivity; limits of quantifications ranged from 2 to 6 ng/L in blood and urine, and from 11 to 21 pg/g in hair. The suitability of the method was tested with 42 postmortem blood, urine, or hair specimens from 27 fatalities in which fentanyl analogs were involved. Average blood concentrations (±SD) were 7.84 ± 7.21 and 30.0 ± 18.0 μg/L for cyclopropylfentanyl and cyclopropyl norfentanyl, respectively (n = 8), 4.08 ± 2.30 μg/L for methoxyacetylfentanyl, (n = 4), 40.2 ± 38.6 and 44.5 ± 21.1 μg/L for acetylfentanyl and acetyl norfentanyl, respectively (n = 3), 33.7 and 7.17 μg/L for fentanyl and norfentanyl, respectively (n = 1), 3.60 and 0.90 μg/L for furanylfentanyl and furanyl norfentanyl, respectively (n = 1), 0.67 μg/L for sufentanil (n = 1), and 3.13 ± 2.37 μg/L for 4-ANPP (n = 9). Average urine concentrations were 47.7 ± 39.3 and 417 ± 296 μg/L for cyclopropylfentanyl and cyclopropyl norfentanyl, respectively (n = 11), 995 ± 908 μg/L for methoxyacetylfentanyl, (n = 3), 1,874 ± 1,710 and 6,582 ± 3,252 μg/L for acetylfentanyl and acetyl norfentanyl, respectively (n = 5), 146 ± 318 and 300 ± 710 μg/L for fentanyl (n = 5) and norfentanyl (n = 6), respectively, 84.0 and 23.0 μg/L for furanylfentanyl and furanyl norfentanyl, respectively (n = 1), and 50.5 ± 50.9 μg/L for 4-ANPP (n = 10). Average hair concentrations were 2,670 ± 184 and 82.1 ± 94.7 ng/g for fentanyl and norfentanyl, respectively (n = 2), and 10.8 ± 0.57 ng/g for 4-ANPP (n = 2).

Death cases involving certain new psychoactive substances: A review of the literature

In the last decades, more and more new psychoactive substances (NPS) were introduced on the drug market which were sold as "legal" alternatives for classic drugs and misused medications. Due to an increased number of available substances and a growing utilization by users of common drugs but also by inexperienced users because of the supposed "legal" status, also undesired adverse effects of these NPS, at worst leading to death, became apparent. This review summarizes fatalities previously described in scientific literature which were attributed to the use of NPS or such cases, in which intake of NPS was proven or even assumed to contribute to death. This summary includes an overview of substances involved (particularly synthetic cannabinoids ("spice"), novel opioids and synthetic cathinones ("bath salts")) as well as of postmortem concentrations determined in various biological matrices. The compiled data assist forensic toxicologists with the interpretation of death cases involving NPS.