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Since 2016, illicitly manufactured fentanyls and fentanyl analogs (referred to as IMFs) have contributed to an increase in drug overdoses. Although fentanyl has been characterized and evaluated extensively in animals and humans, many of the clandestinely synthesized analogs of fentanyl have not and users may unknowingly ingest these IMFs leading to overdose and potentially death. The pharmacodynamic (PD) and pharmacokinetic (PK) properties of four IMFs and fentanyl were evaluated in Sprague–Dawley rats. A 300‐μg/kg subcutaneous dose of each compound (fentanyl, acetylfentanyl, cyclopropylfentanyl, butyrylfentanyl, and valerylfentanyl) was given. PD parameters were measured using a tail flick meter and core body temperature. Blood was drawn to evaluate PK parameters utilizing liquid chromatography tandem mass spectrometry (LC–MS/MS). Fentanyl displayed the greatest and longest lasting analgesia with a tail flick response of 10 s (the maximum cutoff). Additionally, fentanyl produced an average −4.9°C in core body temperature resulting in the greatest decrease in core body temperature. Acetylfentanyl, with the shortest carbon side chain, displayed the shortest T½, and lowest AUC and Cmax and resulted in an increase in body temperature. There were no other PK differences among the IMFs assessed. As IMFs are commonly seen on the streets and can pose significant risks to users (although these risks do depend on other factors such as dose and route of administration), there is a benefit to having the pharmacological properties of these compounds characterized to better understand the potential harm to humans. [ABSTRACT FROM AUTHOR]

Fentanyl and fentanyl analogs are the main cause of recent overdose deaths in the United States. The presence of fentanyl analogs in illicit drugs makes it difficult to estimate their potencies. This makes the detection and differentiation of fentanyl analogs critically significant. Surface-enhanced Raman spectroscopy (SERS) can differentiate structurally similar fentanyl analogs by yielding spectroscopic fingerprints for the detected molecules. In previous years, five fentanyl analogs, carfentanil, furanyl fentanyl, acetyl fentanyl, 4-fluoroisobutyryl fentanyl (4-FIBF), and cyclopropyl fentanyl (CPrF), gained popularity and were found in 76.4% of the fentanyl analogs trafficked. In this study, we focused on 4-FIBF, CPrF, and structurally similar fentanyl analogs. We developed methods to differentiate these fentanyl analogs using theoretical and experimental methods. To do this, a set of fentanyl analogs were examined using density functional theory (DFT) calculations. The DFT results obtained in this project permitted the assignment of spectral bands. These results were then compared with normal Raman and SERS techniques. Structurally similar fentanyl analogs show important differences in their spectra, and they have been visually differentiated from each other both theoretically and experimentally. Additional results using principal component analysis and soft independent modeling of class analogy show they can be distinguished using this technique. The limit of detection values for FIBF and CPrF were determined to be 0.35 ng/mL and 4.4 ng/mL, respectively, using SERS. Experimental results obtained in this project can be readily implemented in field applications and smaller laboratories, where inexpensive portable Raman spectrometers are often present and used in drug analysis. [ABSTRACT FROM AUTHOR]

IntroductionThe use of illicitly manufactured synthetic opioids, specifically fentanyl and its analogs, has escalated exponentially in the United States over the last decade. Due to the targeted nature of drug detection methods in clinical laboratories and the ever-evolving list of synthetic opioids of concern, alternative analytical approaches are needed.MethodsUsing the fentanyl analog screening (FAS) kit produced by the Centers for Disease Control and Prevention (CDC), we developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) synthetic opioid spectral library and data acquisition method using information dependent acquisition of product ion spectra. Chromatographic retention times, limits of detection and matrix effects, in urine and serum, for the synthetic opioids in the FAS kit (n = 150) were established. All urine and serum specimens sent to a clinical toxicology laboratory for comprehensive drug testing in 2019 (n = 856) and 2021 (n = 878) were analyzed with the FAS LC-HRMS library to determine the prevalence of fentanyl analogs and other synthetic opioids, retrospectively (2019) and prospectively (2021).ResultsThe limit of detection (LOD) of each opioid ranged from 1 to 10 ng/mL (median, 2.5 ng/mL) in urine and 0.25-2.5 ng/mL (median, 0.5 ng/mL) in serum. Matrix effects ranged from -79 % to 86 % (median, -37 %) for urine, following dilution and direct analysis, and -80 % to 400 % (median, 0 %) for serum, following protein precipitation. The prevalence of fentanyl/fentanyl analogs in serum samples increased slightly from 2019 to 2021 while it remained the same in urine. There were only 2 samples identified that contained a fentanyl analog without the co-occurrence of fentanyl or fentanyl metabolites. Analysis of the established MS/MS spectral library revealed characteristic fragmentation patterns in most fentanyl analogs, which can be used for structure elucidation and drug identification of future analogs.ConclusionsThe LC-HRMS method was capable of detecting fentanyl analogs in routine samples sent for comprehensive drug testing. The method can be adapted to accommodate testing needs for the evolving opioid epidemic.

Abstract Background Fentanyl test strips (FTS) are a commonly deployed tool in drug checking, used to test for the presence of fentanyl in street drug samples prior to consumption. Previous reports indicate that in addition to fentanyl, FTS can also detect fentanyl analogs like acetyl fentanyl and butyryl fentanyl, with conflicting reports on their ability to detect fentanyl analogs like Carfentanil and furanyl fentanyl. Yet with hundreds of known fentanyl analogs, there has been no large-scale study rationalizing FTS reactivity to different fentanyl analogs. Methods In this study, 251 synthetic opioids—including 214 fentanyl analogs—were screened on two brands of fentanyl test strips to (1) assess the differences in the ability of two brands of fentanyl test strips to detect fentanyl-related compounds and (2) determine which moieties in fentanyl analog chemical structures are most crucial for FTS detection. Two FTS brands were assessed in this study: BTNX Rapid Response and WHPM DanceSafe. Results Of 251 screened compounds assessed, 121 compounds were detectable at or below 20,000 ng/mL by both BTNX and DanceSafe FTS, 50 were not detectable by either brand, and 80 were detectable by one brand but not the other (n = 52 BTNX, n = 28 DanceSafe). A structural analysis of fentanyl analogs screened revealed that in general, bulky modifications to the phenethyl moiety inhibit detection by BTNX FTS while bulky modifications to the carbonyl moiety inhibit detection by DanceSafe FTS. Conclusions The different “blind spots” are caused by different haptens used to elicit the antibodies for these different strips. By utilizing both brands of FTS in routine drug checking, users could increase the chances of detecting fentanyl analogs in the “blind spot” of one brand.

Introduction: In 2019, there were over 16,000 deaths from psychostimulant overdose with 53.5% also involving an opioid. Given the substantial mortality stemming from opioid and psychostimulant co-exposure, evaluation of clinical management in this population is critical but remains understudied. This study aims to characterize and compare clinical management and outcomes in emergency department (ED) overdose patients with analytically confirmed exposure to both opioids and psychostimulants with those exposed to opioids alone. Methods: This was a secondary analysis of a prospective consecutive cohort of ED patients age 18+ with opioid overdose at 9 hospital sites from September 21, 2020 to August 17, 2021. Toxicologic analysis was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Patients were divided into opioid-only (OO) and opioid plus psychostimulants (OS) groups. The primary outcome was total naloxone bolus dose administered. Secondary outcomes included endotracheal intubation, cardiac arrest, troponin elevation, and abnormal presenting vital signs. We employed t-tests, chi-squared analyses and multivariable regression models to compare outcomes between OO and OS groups. Results: Of 378 enrollees with confirmed opioid overdose, 207 (54.8%) had psychostimulants present. OO patients were significantly older (mean 45.2 versus 40.6 years, p < 0.01). OS patients had significantly higher total naloxone requirements (mean total dose 2.79 mg versus 2.12 mg, p = 0.009). There were no significant differences in secondary outcomes. Conclusion: Approximately half of ED patients with confirmed opioid exposures were also positive for psychostimulants. Patients in the OS group required significantly higher naloxone doses, suggesting potential greater overdose severity.

The need to detect fentanyl and its analogs in the field is an important capability to help prevent unintentional exposure or overdose on these substances, which may result in death. Many portable methods historically used in the field by first responders and other field users to detect and identify other chemical substances, such as hazardous materials, have been applied to the detection and identification of these synthetic opioids. This paper describes field portable spectroscopic methods used for the detection and identification of fentanyl and its analogs. The methods described are automated colorimetric tests including lateral flow assays; vibrational spectroscopy (mid‐infrared and Raman); gas chromatography–mass spectrometry; ion mobility spectrometry, and high‐pressure mass spectrometry. In each case the background and key details of these technologies are outlined, followed by a discussion of the application of the technology in the field. Attention is paid to the analysis of complex mixtures and limits of detection, including the required spectral databases and algorithms used to interrogate these types of samples. There is also an emphasis on providing actionable information to the (likely) non‐scientist operators of these instruments in the field. [ABSTRACT FROM AUTHOR]

Forensic toxicology laboratories are navigating a period of time with increasing drug overdose deaths, an opioid epidemic, the impact of the COVID‐19 pandemic, and the illicit drug market flooded with novel psychoactive substances. In New York City, the Department of Forensic Toxicology has experienced a 56% increase in postmortem casework in the past decade with fentanyl detected in 80% of all overdose deaths. Over a period of 2.5 years, 15,638 postmortem cases were tested for the presence of fentanyl and fentanyl analogs using liquid‐chromatography tandem mass spectrometry (LCMSMS). Fentanyl was detected in approximately one third of cases and of these 4447 cases with femoral blood. A twofold increase in cases with high concentrations of fentanyl (>100 ng/mL) was observed between 2021 and 2022. The minor metabolite and precursor chemical, 4‐ANPP (4‐anilino‐N‐phenethylpiperidine) may help differentiate between illicit and licit fentanyl. 4‐ANPP blood concentrations were <10 ng/mL in 98% of the cases and the 4‐ANPP:fentanyl ratio was <0.67 for 99.1% of blood specimens. Only six cases had 4‐ANPP concentrations higher than the corresponding fentanyl blood concentration. This study also highlights, the changing fentanyl analogs found in postmortem cases since 2016 in NYC with the emergence of fluorofentanyl initially identified in 2020 and continuing to dominate in comparison with the prevalence of other analogs, many of which are no longer detected in casework. The detection of one of the latest drugs to be mixed with fentanyl, namely xylazine, has also increased in prevalence by 36.7% in 2022 compared with 2021. [ABSTRACT FROM AUTHOR]

Fentanyl analogs are a class of designer drugs that are particularly challenging to unambiguously identify due to the mass spectral and retention time similarities of unique compounds. In this paper, we use agglomerative hierarchical clustering to explore the measurement diversity of fentanyl analogs and better understand the challenge of unambiguous identifications using analytical techniques traditionally available to drug chemists. We consider four measurements in particular: gas chromatography retention indices, electron ionization mass spectra, electrospray ionization tandem mass spectra, and direct analysis in real time mass spectra. Our analysis demonstrates how simultaneously considering data from multiple measurement techniques increases the observable measurement diversity of fentanyl analogs, which can reduce identification ambiguity. This paper further supports the use of multiple analytical techniques to identify fentanyl analogs (among other substances), as is recommended by the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG). [ABSTRACT FROM AUTHOR]

Definitive identification of fentanyl analogs based on mass spectral comparison is challenging given the high degree of structural and, hence, spectral similarity. To address this, a statistical method was previously developed in which two electron‐ionization (EI) mass spectra are compared using the unequal variance t‐test. Normalized intensities of corresponding ions are compared, testing the null hypothesis (H0) that the difference in intensity is equal to zero. If H0 is accepted at all m/z values, the two spectra are statistically equivalent at the specified confidence level. If H0 is not accepted at any m/z value, then there is a significant difference in intensity at that m/z value between the two spectra. In this work, the statistical comparison method is applied to distinguish EI spectra of valeryl fentanyl, isovaleryl fentanyl, and pivaloyl fentanyl. Spectra of the three analogs were collected over a 9‐month period and at different concentrations. At the 99.9% confidence level, the spectra of corresponding isomers were statistically associated. Spectra of different isomers were statistically distinct, and ions responsible for discrimination were identified in each comparison. To account for inherent instrument variations, discriminating ions for each pairwise comparison were ranked based on the magnitude of the calculated t‐statistic (tcalc) value. For a given comparison, ions with higher tcalc values are those with the greatest difference in intensity between the two spectra and, therefore, are considered more reliable for discrimination. Using these methods, objective discrimination among the spectra was achieved and ions considered most reliable for discrimination of these isomers were identified. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The opioid epidemic in the United States continues to result in an increasing number of deaths and is increasingly dominated by fentanyl and fentanyl analogs. As a result, first responders are likely to come into contact with fentanyl-containing substances daily. Concerns persist regarding occupational exposure resulting in intoxication. We performed a systematic review to describe occupational illnesses from fentanyl and its analogs. We conducted a systematic review of the literature following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to assess the danger of occupational exposure to fentanyl. The PubMed, EMBASE, Google Scholar, SCOPUS, CINAHL, and National Institute for Occupational Safety and Health databases were queried to identify occupational fentanyl exposures. Studies included were single case reports, case series, observational studies, controlled studies, and abstracts from scientific presentations. We reviewed articles meeting the eligibility criteria and abstracted outcome data. Outcomes included study design, number of study subjects and study demographics, description of exposure, personal protective equipment used, duration of symptoms, illness developed, medical evaluation performed, treatment provided, hospitalizations, deaths, drug testing performed, and any situation review performed to prevent illness, analytical confirmation of the identity of culprit agent, and concentrations of drug in serum/blood. Our search yielded 454 citations after deduplication. After abstract and text review, 12 unique reports met the inclusion criteria. All identified studies were observational studies. Ten of the 12 were Health Hazard Evaluation reports from the National Institute for Occupational Safety and Health; two reports describe the same exposure case. There were no reported instances of comprehensive drug testing using liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry in exposed first responders. Among first responders possibly exposed to fentanyl or fentanyl analogs, none were admitted to the hospital, and only three first responders received naloxone. The three officers who received naloxone lacked recommended personal protective equipment and had subjective improvement of symptoms following naloxone. There were no instances of severe respiratory depression requiring assisted ventilation or hospital admission. Among forensic laboratory technicians, only one instance of detectable concentrations of fentanyl in urine was reported, and there were no instances of symptomatic cases. Among published reports of 27 first responders with symptoms after possible ambient fentanyl exposure, symptoms, recorded physical findings, and vital signs were inconsistent with acute opioid toxicity. Breaches in the recommended use of personal protective equipment appeared common. Only three persons received naloxone, although none had plausible effects of fentanyl. No suspected exposure to fentanyl led to hospitalization or death. Based on these low-quality data, there were no plausible opioid effects from ambient exposure to suspected fentanyl. [ABSTRACT FROM AUTHOR]

Abstract Background There are growing concerns about illicitly manufactured fentanyl (IMF) contamination of methamphetamine. This study aims to characterize the lay views and experiences with IMF-contaminated methamphetamine (IMF/meth) and identify participants with unknown IMF exposures through urine toxicology analysis. Methods Between December-2019 and November-2021, structured interviews were conducted with 91 individuals who reported past 30-day use of methamphetamine and resided in Dayton, Ohio, USA. Lab-based urine toxicology analyses were conducted to identify fentanyl/analogs, methamphetamine, and other drugs. Bivariate analyses were conducted to identify characteristics associated with attitudes and experiences with IMF/meth, and unknown IMF exposures. Results The majority (95.6%) of the study participants were non-Hispanic white, and 52.7% were female. Past 30-day use of methamphetamine was reported on a mean of 18.7 (SD 9.1) days, and 62.6% also reported past 30-day use of heroin/IMF. Most (76.9%) had a history of an unintentional drug-related overdose, but 38.5% rated their current risk for an opioid overdose as none. Besides fentanyl (71.9%), toxicology analysis identified nine fentanyl analogs/metabolites (e.g., 42.7% acetyl fentanyl, 19.0% fluorofentanyl, 5.6% carfentanil), and 12.4% tested positive for Xylazine. The majority (71.4%) believed that IMF/meth was common, and 59.3% reported prior exposures to IMF/meth. 11.2% tested positive for IMF but reported no past 30-day heroin/IMF use (unknown exposure to IMF). Views that IMF/meth was common showed association with homelessness (p = 0.04), prior overdose (p = 0.028), and greater perceived risk of opioid overdose (p = 0.019). Self-reported exposure to IMF/meth was associated with homelessness (p = 0.007) and obtaining take-home naloxone (p = 0.025). Individuals with unknown IMF exposure (test positive for IMF, no reported past 30-day heroin/IMF use) were older (49.9 vs. 41.1 years, p

The abuse of fentanyl and its analogs has caused a large number of deaths worldwide. Due to the rapid development of new fentanyl analogs, the standard mass spectral library is generally incomplete. The spectra obtained by different mass spectrometers by electrospray ionization (ESI) cannot be used across platforms, resulting in the hysteretic detection of novel fentanyl analogs. This paper reports a machine learning classification model based upon a hybrid similarity search. For the purpose of the identification of fentanyl analogs with different mass spectrometers, a mass spectral library based on the conserved fragmentation behavior (CFB) of fentanyl analogs was established. The results show that the identification accuracy of fentanyl analogs by two mass spectrometers is 100%, and the accuracy of classification model is 97.85%. Furthermore, the model may be applied to linear ion trap mass spectrometry (LIT-MS) and quadrupole time-of-flight mass spectrometry (Q-TOF-MS) with classification accuracies of 100 and 98.17%, respectively. This study provides promising technical support for the real-time and cloud computing detection of unknown fentanyl analogs. [ABSTRACT FROM AUTHOR]

Acetylbenzylfentanyl, benzoylbenzylfentanyl, 3‐fluoro‐methoxyacetylfentanyl, and 3‐phenylpropanoylfentanyl are fentanyl analogs that have been reported to the European Monitoring Centre for Drugs and Drug Addiction in recent years. The aim of this study was to identify metabolic pathways and potential biomarker metabolites of these fentanyl analogs. The compounds were incubated (5 μM) with cryopreserved hepatocytes for up to 5 h in vitro. Metabolites were analyzed with liquid chromatography–quadrupole time of flight–high‐resolution mass spectrometry (LC‐QTOF‐HRMS). The experiments showed that acetylbenzylfentanyl, benzoylbenzylfentanyl, and 3‐phenylpropanoylfentanyl were mainly metabolized through N‐dealkylation (forming nor‐metabolites) and 3‐fluoro‐methoxyacetylfentanyl mainly through demethylation. Other observed metabolites were formed by mono‐/dihydroxylation, dihydrodiol formation, demethylation, dehydrogenation, amide hydrolysis, and/or glucuronidation. The experiments showed that a large number of metabolites of 3‐phenylpropanoylfentanyl were formed. The exact position of hydroxy groups in formed monohydroxy metabolites could not be established solely based upon recorded MSMS spectra of hepatocyte samples. Therefore, potential monohydroxy metabolites of 3‐phenylpropanoylfentanyl, with the hydroxy group in different positions, were synthesized and analyzed together with the hepatocyte samples. This approach could reveal that the β position of the phenylpropanoyl moiety was highly favored; β‐OH‐phenylpropanoylfentanyl was the most abundant metabolite after the nor‐metabolite. Both metabolites have the potential to serve as biomarkers for 3‐phenylpropanoylfentanyl. The nor‐metabolites of acetylbenzylfentanyl, benzoylbenzylfentanyl, and 3‐fluoro‐methoxyacetylfentanyl do also seem to be suitable biomarker metabolites, as do the demethylated metabolite of 3‐fluoro‐methoxyacetylfentanyl. Identified metabolic pathways and formed metabolites were in agreement with findings in previous studies of similar fentanyl analogs. [ABSTRACT FROM AUTHOR]

BACKGROUND: The US has seen a rapid increase in synthetic opioid-related overdose deaths. We investigate Ohio, a state with one of the highest overdose death rates in 2017 and substantial numbers of deaths related to fentanyl, carfentanil, and other fentanyl analogs, to provide detailed evidence about the relationship between changes in the illicit drug market and overdose deaths. METHODS: We investigate the illicit drug market using Ohios Bureau of Criminal Investigations (BCI) crime lab data from 2009 to 2018 that shows the content of drugs seized by law enforcement. We use Poisson regression analysis to estimate the relationship between monthly crime lab data and monthly unintentional drug overdose death data at the county level. RESULTS: During this time period there has been a rapid change in the composition of drugs analyzed by the BCI labs, with a rapid fall in heroin observations, simultaneous rise in synthetic opioids, and an increase in the number of different fentanyl analogs. We find that the increased presence of fentanyl, carfentanil, and other fentanyl analogs have a strong correlation with an increase in overdose deaths. The types of opioids most associated with deaths varies by the population size of the county. CONCLUSIONS: Crime lab data has the potential to be used as an early warning system to alert persons who inject drugs, harm reduction services, first responders, and law enforcement about changes in the illicit opioid risk environment.

Introduction: The use of illicitly manufactured synthetic opioids, specifically fentanyl and its analogs, has escalated exponentially in the United States over the last decade. Due to the targeted nature of drug detection methods in clinical laboratories and the ever-evolving list of synthetic opioids of concern, alternative analytical approaches are needed. Methods: Using the fentanyl analog screening (FAS) kit produced by the Centers for Disease Control and Prevention (CDC), we developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) synthetic opioid spectral library and data acquisition method using information dependent acquisition of product ion spectra. Chromatographic retention times, limits of detection and matrix effects, in urine and serum, for the synthetic opioids in the FAS kit (n = 150) were established. All urine and serum specimens sent to a clinical toxicology laboratory for comprehensive drug testing in 2019 (n = 856) and 2021 (n = 878) were analyzed with the FAS LC-HRMS library to determine the prevalence of fentanyl analogs and other synthetic opioids, retrospectively (2019) and prospectively (2021). Results: The limit of detection (LOD) of each opioid ranged from 1 to 10 ng/mL (median, 2.5 ng/mL) in urine and 0.25–2.5 ng/mL (median, 0.5 ng/mL) in serum. Matrix effects ranged from −79 % to 86 % (median, −37 %) for urine, following dilution and direct analysis, and −80 % to 400 % (median, 0 %) for serum, following protein precipitation. The prevalence of fentanyl/fentanyl analogs in serum samples increased slightly from 2019 to 2021 while it remained the same in urine. There were only 2 samples identified that contained a fentanyl analog without the co-occurrence of fentanyl or fentanyl metabolites. Analysis of the established MS/MS spectral library revealed characteristic fragmentation patterns in most fentanyl analogs, which can be used for structure elucidation and drug identification of future analogs. Conclusions: The LC-HRMS method was capable of detecting fentanyl analogs in routine samples sent for comprehensive drug testing. The method can be adapted to accommodate testing needs for the evolving opioid epidemic.

Background: There are growing concerns about illicitly manufactured fentanyl (IMF) contamination of methamphetamine. This study aims to characterize the lay views and experiences with IMF-contaminated methamphetamine (IMF/meth) and identify participants with unknown IMF exposures through urine toxicology analysis. Methods: Between December-2019 and November-2021, structured interviews were conducted with 91 individuals who reported past 30-day use of methamphetamine and resided in Dayton, Ohio, USA. Lab-based urine toxicology analyses were conducted to identify fentanyl/analogs, methamphetamine, and other drugs. Bivariate analyses were conducted to identify characteristics associated with attitudes and experiences with IMF/meth, and unknown IMF exposures. Results: The majority (95.6%) of the study participants were non-Hispanic white, and 52.7% were female. Past 30-day use of methamphetamine was reported on a mean of 18.7 (SD 9.1) days, and 62.6% also reported past 30-day use of heroin/IMF. Most (76.9%) had a history of an unintentional drug-related overdose, but 38.5% rated their current risk for an opioid overdose as none. Besides fentanyl (71.9%), toxicology analysis identified nine fentanyl analogs/metabolites (e.g., 42.7% acetyl fentanyl, 19.0% fluorofentanyl, 5.6% carfentanil), and 12.4% tested positive for Xylazine. The majority (71.4%) believed that IMF/meth was common, and 59.3% reported prior exposures to IMF/meth. 11.2% tested positive for IMF but reported no past 30-day heroin/IMF use (unknown exposure to IMF). Views that IMF/meth was common showed association with homelessness (p = 0.04), prior overdose (p = 0.028), and greater perceived risk of opioid overdose (p = 0.019). Self-reported exposure to IMF/meth was associated with homelessness (p = 0.007) and obtaining take-home naloxone (p = 0.025). Individuals with unknown IMF exposure (test positive for IMF, no reported past 30-day heroin/IMF use) were older (49.9 vs. 41.1 years, p < 0.01), and reported more frequent past 30-day use of methamphetamine (24.4 vs. 18.0 days, p < 0.05). They indicated lower perceived risk of opioid overdose (0.1 vs. 1.9, scale from 0 = "none" to 4 = "high," p < 0.001). Discussion: This study suggests a need for targeted interventions for people who use methamphetamine and expansion of drug checking and other harm reduction services. [ABSTRACT FROM AUTHOR]

There is an ongoing effort in the US illicit drug market to make new psychoactive compounds more potent and addictive. Due to continuous chemical modifications, many fentanyl analogs are developed and mixed with more traditional illicit drugs, such as cocaine and heroin. Detecting fentanyl and fentanyl analogs in these illicit drug mixtures has become more crucial because of the increased potency and associated health risks. Most confirmatory procedures require time-consuming and expensive, highly sophisticated laboratory equipment and experimental procedures, which can delay critical information that might save a victim or find a suspect. In this study, we propose miniaturizing and accelerating this process by combining surface-enhanced Raman spectroscopy (SERS) analysis and paper spray mass spectrometry (PS-MS). For this aim, dual-purposed paper substrates were developed through soaking in Au/Ag nanostars suspensions. These novel, in-house prepared paper SERS substrates showed stability for up to four weeks with and without the presence of drug compounds. Fentanyl analogs with similar SERS spectra were differentiated by coupling with PS-MS. The limit of detection (LOD) for fentanyl on the paper substrates is 34 μg/mL and 0.32 μg/mL for SERS and PS-MS, respectively. Fentanyl and fentanyl analogs show selective SERS enhancement that helped to detect trace amounts of these opioids in heroin and cocaine street samples. In short, we propose the combination of SERS/PS-MS by using modified paper substrates to develop cost-effective, sensitive, rapid, portable, reliable, and reproducible methods to detect illicit drugs, especially trace amounts of fentanyl and fentanyl analogs in illicit drug mixtures. The combination of these two category A techniques allows for the identification of illicit drugs according to the SWGDRUG guidelines. [Display omitted] • The developed method permits both spectral and MS analysis, resulting in a presumptive and confirmatory analysis for illicit drugs. • Dual-purposed paper substrates were developed through soaking in Au/Ag nanostars suspensions. • Fentanyl analogs with similar SERS spectra were differentiated by coupling with PS-MS. [ABSTRACT FROM AUTHOR]

Recent studies report that fentanyl analogs with relatively low pK a values produce antinociception in rodents without other mu opioid-typical side effects due to the restriction of their activity to injured tissue with relatively low pH values. However, it is unclear if and to what degree these compounds may produce mu opioid-typical side effects (respiratory depression, reinforcing effects) at doses higher than those required to produce antinociception. The present study compared the inflammatory antinociceptive, respiratory-depressant, and reinforcing effects of fentanyl and two analogs of intermediate (FF3) and low (NFEPP) pK a values in terms of potency and efficacy in male and female Sprague-Dawley rats. Nociception was produced by administration of Complete Freund's Adjuvant into the hind paw of subjects, and antinociception was measured using an electronic Von Frey test. Respiratory depression was measured using whole-body plethysmography. Reinforcing effects were measured in self-administration using a progressive-ratio schedule of reinforcement. The dose ranges tested for each drug encompassed no effect to maximal effects. All compounds produced full effects in all measures but varied in potency. FF3 and fentanyl were equipotent in antinociception and self-administration, but FF3 was less potent than fentanyl in respiratory depression. NFEPP was less potent than fentanyl in every measure. The magnitude of potency difference between antinociception and other effects was greater for FF3 than for NFEPP or fentanyl, indicating that FF3 had the widest margin of safety when relating antinociception to respiratory-depressant and reinforcing effects. Low pK a fentanyl analogs possess potential as safer analgesics, but determining the optimal degree of difference for pK a relative to fentanyl will require further study due to some differences between the current results and findings from prior work with these analogs. [Display omitted] • FF3 and NFEPP are fentanyl analogs with relatively low pKa values. • Low pKa may restrict activity to the low-pH environment of injured tissue. • FF3 and NFEPP produced analgesic, respiratory, and reinforcing effects in rats. • Efficacy, but not potency, of FF3 and NFEPP in all measures was similar to fentanyl. [ABSTRACT FROM AUTHOR]

Background and Aims: Opioids biosurveillance is a new approach to public health surveillance of non‐fatal overdoses that relies upon laboratory analysis of residual biospecimens from hospitals treating opioids overdoses. In Rhode Island (RI), USA, hospitals report suspected opioid overdoses to the Department of Health. Residual specimens associated with these overdoses are submitted to the State Health Laboratories for further characterization. This surveillance project aimed to characterize non‐fatal overdoses through toxicological testing of urine specimens associated with non‐fatal overdoses during the initial 2‐year period of biosurveillance implementation in RI to assess the feasibility and public health utility of this approach. Methods: This study included individuals who presented for treatment for a suspected opioid overdose in 10 RI hospitals between July 2019 and June 2021. Urine samples were received for 1354 unique overdose encounters corresponding to reported overdoses. Some individuals experienced multiple overdoses during this time. Urine samples were extracted and then analyzed by liquid chromatography tandem mass spectrometry with a panel consisting of 1033 opiates, synthetic opioids, fentanyl analogs and select metabolites. Temporal and spatial trends were evaluated for the studied population. Results: A total of 1354 samples were tested for the presence of opioids in urine collected from individuals who experienced a suspected overdose. Fentanyl (and/or norfentanyl) was present in 79% of all samples in which opioids were found (n = 1033). Fentanyl analogs varied in their contribution to these totals, with observations ranging as high as 35% of all opioid‐containing samples in August 2019 and May 2021. Conclusions: Laboratory identification of opioids involved in suspected overdoses shows that fentanyl and its analogs are the main drivers of the opioids overdose epidemic in Rhode Island, USA. The biosurveillance approach is unique in its ability to quantify contributions of novel fentanyl analogs to the burden of overdoses. [ABSTRACT FROM AUTHOR]

The frequency of opioid overdoses is increasing, and the use of fentanyl and fentanyl analogues in illicit substances has increased toxicity. In British Columbia, the opioid crisis has worsened since it was declared a public health emergency in 2016. Meanwhile, impermanent tent communities of people experiencing homelessness are being dislocated over concerns about illicit substance use. Recognizing the inaccessibility of naloxone for congregate encampment residents, this discussion piece builds upon current public health knowledge and urban forest management strategies to suggest key opportunities for increasing the accessibility of naloxone. These opportunities include recognizing peerbased care and the role of grassroots organizations in promoting naloxone accessibility. [ABSTRACT FROM AUTHOR]

Introduction: Over the last decade, the use of New/Novel Synthetic Opioids (NSO) has emerged as an increasing problem, and especially so in the USA. However, only little is known about the prevalence and history of NSO use in European heroin dependents. Method: A cross-sectional multicenter study, carried out with the means of both standardized interviews and urine toxicology enhanced screening, in a sample of opioid addicted patients referred for an in-patient detoxification treatment. Results: Sample size included here n = 256 patients; prior to admission, 63.7% were prescribed with an opioid maintenance treatment. Lifetime use of heroin and opioid analgesics was reported by 99.2 and 30.4%, respectively. Lifetime NSO/fentanyl use was reported by 8.7% (n = 22); a regular use was reported by 1.6% (n = 4), and ingestion over the 30 days prior to admission by 0.8% (n = 2). Most typically, patients had started with a regular consumption of heroin, followed by maintenance opioids; opioid analgesics; and by NSO. Self-reported data were corroborated by the toxicology screenings carried out; no evidence was here identified for the presence of heroin being contaminated by fentanyl/derivatives. Discussion: NSO and also opioid analgesics did not play a relevant role in the development and the course of opioid/opioid use disorders in German patients referred for an inpatient detoxification treatment. [ABSTRACT FROM AUTHOR]

IntroductionOver the last decade, the use of New/Novel Synthetic Opioids (NSO) has emerged as an increasing problem, and especially so in the USA. However, only little is known about the prevalence and history of NSO use in European heroin dependents.MethodA cross-sectional multicenter study, carried out with the means of both standardized interviews and urine toxicology enhanced screening, in a sample of opioid addicted patients referred for an in-patient detoxification treatment.ResultsSample size included here n = 256 patients; prior to admission, 63.7% were prescribed with an opioid maintenance treatment. Lifetime use of heroin and opioid analgesics was reported by 99.2 and 30.4%, respectively. Lifetime NSO/fentanyl use was reported by 8.7% (n = 22); a regular use was reported by 1.6% (n = 4), and ingestion over the 30 days prior to admission by 0.8% (n = 2). Most typically, patients had started with a regular consumption of heroin, followed by maintenance opioids; opioid analgesics; and by NSO. Self-reported data were corroborated by the toxicology screenings carried out; no evidence was here identified for the presence of heroin being contaminated by fentanyl/derivatives.DiscussionNSO and also opioid analgesics did not play a relevant role in the development and the course of opioid/opioid use disorders in German patients referred for an inpatient detoxification treatment.

Reliable Identification of fentanyl and fentanyl analogs present In seized drug samples Is Imperative to the safety of first responders and laboratory personnel and informs the future analysis process and handling procedures. The electrochemical-surface enhanced Raman spectroscopy (EC-SERS) method developed in this work allows the in-situ preparation of the SERS substrate providing a rapid, efficient, and accurate approach to detect fentanyl, even at low percent by weight concentrations common in seized drugs. Optimization of the electrochemical potentials suitable for the SERS substrate preparation and adsorption of the analyte was achieved using multi-pulse amperometric detection. This method demonstrated large enhancement of the SERS response. This method was applied to six fentanyl analogs with substitutions to the amide group, representing small changes in the fentanyl core structure. Identification of these analogs through differences in the EC-SERS spectra was evident. Interference studies incorporating analytes frequently encountered with fentanyl including heroin, cocaine, methamphetamine, naltrexone, and naloxone were assessed and found to offer limited to no interference. The limits of detection of the fentanyl compounds were in the low to mid nanograms per milliliter range, with the most sensitive compound detected at 10ng/ml. Application of the method to simulated drug mixtures was performed to determine fit-for-purpose. In all mixtures with fentanyl as the minor contributor, fentanyl was correctly identified, including mixture samples comprised of 5 and 1% fentanyl. This approach represents the first in-situ EC-SERS analysis of fentanyl and its analogs and provides accurate and efficient screening for fentanyl in seized drug samples. [ABSTRACT FROM AUTHOR]

What is known and objective: A large percentage of opioid overdose fatalities involve fentanyl or one of its legal or illegal analogs (F/FAs). Is there something about the pharmacology of these drugs that make them unusually dangerous in an overdose? Comment: Some of the reasons for the dangers of overdose of F/FAs is their high potency and low cost (that leads to wide distribution). But it is rarely asked if the basic pharmacology of F/FAs differ in some fundamental way from conventional opioids such as morphine and heroin. In addition to centrally mediated respiratory depression via opioid receptors, F/FAs cause rigidity in the key respiratory muscles of the chest, upper airway and diaphragm ("wooden chest syndrome," WCS) by a non‐opioid mechanism. What is new and conclusion: WCS is an atypical pharmacology of F/FAs. Because of its rapid onset and non‐opioid mechanism, WCS makes F/FA overdose particularly dangerous. [ABSTRACT FROM AUTHOR]

Introduction: Non-pharmaceutical fentanyl and related drugs (NPF) have contributed to increases in drug-related overdose mortality in the U.S. More data are needed to track the shifting composition of fentanyl-containing drug mixtures. The key aims of the study are to characterize the crime lab data from Montgomery County, Ohio on the increased cases of seized drugs containing mixtures of NPF and tramadol. Methods: Crime lab data on seized drugs in Montgomery County, Ohio (2015 - 2020) were analyzed to extract information on cases that tested positive for NPF and tramadol. Descriptive statistics are provided to characterize NPF/tramadol mixtures in terms of the quantity, weight, form of the drug seized (powder, tablet, capsule, residue), and the types of fentanyl analogs and other drugs identified. Results: In December 2017, the first case of NPF/tramadol mixture was identified in the amount of 0.2 g. Subsequently, cases containing NPF/tramadol increased significantly to 149 cases in 2018, 102 in 2019, and 134 in 2020. The total yearly amounts of seized NPF/tramadol mixtures increased to 373.27 g in 2018, 2,601.82 g in 2019, and 13,487.62 g in 2020. The majority (72.6%) of the cases were in powder form. There were 15 other drugs identified along with fentanyl with tramadol mixtures, including heroin (38.8%), 5.7% cocaine (5.7%), and methamphetamine (4.9%). Conclusions: The addition of tramadol to NPF may be viewed as a harm mitigation strategy but contributes to the overall unpredictability of the illicit drug supply. According to Ohio legal statutes, identification of schedule IV drugs such as tramadol with fentanyl (schedule II) may provide a reduction in drug-related charges from a felony to a misdemeanor. More research is needed to characterize potential sources of tramadol in NPF-containing drugs.

Availability of fentanyl is at a record high with 3138 kg of fentanyl and related substances being seized in 2019. Fentanyl's high toxicity makes a lethal dose for most mere milligrams. With such a high potency and a consistent rise of abuse, the chances of injury or death of frontline workers increase with every interaction. Development of a non-contact detection method for fentanyl would decrease the chances of a workplace mishap. To aid in the development of a non-contact detection method, target analytes in the vapor profile of fentanyl need to be identified. In order to achieve this goal, semi-quantitative headspace analysis of fentanyl analogs and confiscated fentanyl exhibits was accomplished using solid-phase microextraction and gas chromatography coupled with mass spectrometry (SPME-GC-MS). The vapor signatures of these samples were compared to a previously reported reference-grade fentanyl vapor signature to determine the target analyte(s) for fentanyl detection in the vapor phase. A total of 20 fentalogs and confiscated exhibits, with masses ranging from 2 to 19 mg, were sampled. N-Phenylpropanamide(NPPA) or N-phenethyl-4-piperidone(NPP) was identified as target analytes in 75% of these samples. This is a crucial component for the development of a non-contact detection method for fentanyl. [ABSTRACT FROM AUTHOR]

Oral fluid is a valuable alternative matrix for forensic toxicologists due to ease of observed collection, limited biohazardous exposure, and indications of recent drug use. Limited information is available for fentanyl analog prevalence, interpretation, or analysis in oral fluid. With increasing numbers of fentanyl‐related driving under the influence of drug (DUID) cases appearing in the United States, the development of detection methods is critical. The purpose of the present study was to develop and validate a quantitative method for fentanyl analogs in oral fluid (collected via Quantisal™) using liquid chromatography‐quadrupole‐time‐of‐flight‐mass spectrometry (LC‐QTOF‐MS). Validation resulted in limits of detection and quantification ranging from 0.5 to 1 ng/mL. Established linear range was 1–100 ng/mL for all analytes, except acetyl fentanyl at 0.5–100 ng/mL (R2 > 0.994). Within‐ and between‐run precision and bias were considered acceptable with maximum values of ±15.2%CV and ±14.1%, respectively. Matrix effects exhibited ionization enhancement for all analytes with intensified enhancement at a low concentration (9.3–47.4%). No interferences or carryover was observed. Fentanyl analogs were stable in processed extracts stored in the autosampler (4⁰C) for 48h. The validated method was used to quantify fentanyl analogs in authentic oral fluid samples (n=17) from probationers/parolees. Fentanyl and 4‐ANPP concentrations were 1.0–104.5 ng/mL and 1.2–5.7 ng/mL, respectively. [ABSTRACT FROM AUTHOR]

The prevalence and societal impact of opioid use disorder (OUD) is an acknowledged public health crisis that is further aggravated by the current pandemic. One of the devastating consequences of OUD is opioid overdose deaths. While multiple medications are now available to treat OUD, given the prevalence and societal burden, additional well-tolerated and effective therapies are still needed. To this point, we have developed chimeric monoclonal antibodies (mAb) that will specifically complex with fentanyl and its analogs in the periphery, thereby preventing them from reaching the central nervous system. Additionally, mAb-based passive immunotherapy offers a high degree of specificity to drugs of abuse and does not interfere with an individual’s ability to use any of the medications used to treat OUD. We hypothesized that sequestering fentanyl and its analogs in the periphery will mitigate their negative effects on the brain and peripheral organs. This study is the first report of chimeric mAb against fentanyl and its analogs. We have discovered, engineered the chimeric versions, and identified the selectivity of these antibodies, through in vitro characterization and in vivo animal challenge studies. Two mAb candidates with very high (0.1–1.3 nM) binding affinities to fentanyl and its analogs were found to be effective in engaging fentanyl in the periphery and blocking its effects in challenged animals. Results presented in this work constitute a major contribution in the field of novel therapeutics targeting OUD.

Fentanyl analogs represent an important group of new psychoactive substances and knowing their efficacy and potency might assist in interpreting observed concentrations. The potency of fentanyl analogs can be estimated from in vitro studies and can be used to establish structure–activity relationships. In this study, recombinant CHO‐K1 cells (AequoScreen) expressing the human μ‐opioid receptor were used to establish dose–response curves via luminescent analysis for cyclopropyl‐, cyclobutyl‐, cyclopentyl‐, cyclohexyl‐, and 2,2,3,3‐tetramethylcyclopropylfentanyl (TMCPF), on three separate occasions, using eight different concentrations in an eight‐fold serial dilution in triplicates starting at ~60 μM. Fentanyl was used as a full agonist reference while morphine and buprenorphine were included for comparison. Cyclopropylfentanyl (EC50 = 4.3 nM), cyclobutylfentanyl (EC50 = 6.2 nM), and cyclopentylfentanyl (EC50 = 13 nM) were full agonists slightly less potent than fentanyl (EC50 = 1.7 nM). Cyclohexylfentanyl (EC50 = 3.1 μM, efficacy 48%) and TMCPF (EC50 = 1.5 μM, efficacy 65%) were partial agonists less potent than morphine (EC50 = 430 nM). Based on the results, cyclopropyl‐, cyclobutyl‐, and cyclopentylfentanyl would be expected to induce intoxication or cause fatal poisonings at similar concentrations to fentanyl, while the toxic or fatal concentrations of cyclohexylfentanyl and TMCPF would be expected to be much higher. [ABSTRACT FROM AUTHOR]

BackgroundA wide range of novel psychoactive substances (NPSs) are regularly searched and discussed online by e-psychonauts. Among NPSs, the range of prescription/non-prescription opioids (fentanyl and non-fentanyl analogs) and herbal derivatives currently represents a challenge for governments and clinicians.MethodsUsing a web crawler (i.e., NPS.Finder®), the present study aimed at assessing psychonaut fora/platforms to better understand the online situation regarding opioids.ResultsThe open-web crawling/navigating software identified some 426 opioids, including 234 fentanyl analogs. Of these, 176 substances (162 were very potent fentanyls, including two ohmefentanyl and seven carfentanyl analogs) were not listed in either international or European NPS databases.ConclusionA web crawling approach helped in identifying a large number, indeed higher than that listed by European/international agencies, of unknown opioids likely to possess a significant misuse potential. Most of these novel/emerging substances are still relatively unknown. This is a reason of concern; each of these analogs potentially presents with different toxicodynamic profiles, and there is a lack of docking, preclinical, and clinical observations. Strengthening multidisciplinary collaboration between clinicians and bioinformatics may prove useful in better assessing public health risks associated with opioids.

The review describes fentanyl and its analogs as new synthetic opioids and the possibilities of their identification and determination using electrochemical methods (e.g., voltammetry, potentiometry, electrochemiluminescence) and electrochemical methods combined with various separation methods. The review also covers the analysis of new synthetic opioids, their parent compounds, and corresponding metabolites in body fluids, such as urine, blood, serum, and plasma, necessary for a fast and accurate diagnosis of intoxication. Identifying and quantifying these addictive and illicit substances and their metabolites is necessary for clinical, toxicological, and forensic purposes. As a reaction to the growing number of new synthetic opioid intoxications and increasing fatalities observed over the past ten years, we provide thorough background for developing new biosensors, screen-printed electrodes, or other point-of-care devices.

With the discovery of opium dating back to Ancient Greek and Ancient Egyptian civilizations, there is a rich history stemming from the early use of the poppy plant to the new synthetic opioids that are emerging in drug seizures today. The phrase "opioid crisis" has been used to describe a public health emergency that has developed due to a combination of the over‐prescription of opioid medication, increase in heroin use, and clandestine synthesis of research chemicals previously discovered to have opioid receptor activity. Throughout the rise in opioid use, media outlets have helped inform the public, but they have also helped to rapidly spread misinformation. While receptor binding and metabolism studies have been thoroughly conducted for regulated medications, research chemicals and fentanyl analogs have not received as much attention regarding their pharmacodynamic and pharmacokinetic properties. Sample screening in forensic laboratories routinely uses commercially available enzyme‐linked immunosorbent assay kits and time‐of‐flight analysis. With the ever evolving landscape of emerging drugs, quantitative analytical methods have been developed for both gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry, however, the relevance of these methods truly depends on what drugs are being currently seen in casework, making it imperative to track regional trends. This article is categorized under:Toxicology > Analytical ToxicologyToxicology > New Psychoactive SubstancesToxicology > Opioids [ABSTRACT FROM AUTHOR]

Purpose: 4-Fluoroisobutyrylfentanyl (FIBF) was first identified at the New York City Office of Chief Medical Examiner (OCME) in May 2017 and was reported qualitatively due to the constant changes in "fentalogs" (analogs of fentanyl) identified. However, by the year's end, FIBF was the fifth most common non-methadone synthetic opioid detected and a quantitative method was developed to better understand the significance of this compound. Methods: A full quantitative validation was performed utilizing liquid chromatography–tandem mass spectrometry (LC–MS/MS). All cases submitted between May 2017 and December 2018 that tested positive for FIBF qualitatively were chosen for quantitation. In addition to compiling FIBF concentrations, user demographics and concurrent drug use were also investigated. Results: There were 247 FIBF-positive cases that were tested with blood concentrations ranging from < 0.1 to 331 ng/mL. The most commonly detected drugs in conjunction with FIBF were other opioids, benzodiazepines, cocaine, cannabinoids and ethanol. The most frequent users were male, White, and between 35 and 54 years of age. The concentrations of FIBF varied widely and showed no clear distinction when considering various case types. Although most often used in tandem with other drugs of abuse, the danger of this compound was demonstrated by the fact that FIBF was also reported as the sole intoxicant responsible for death. Conclusions: The development of a quantitative method for FIBF has been beneficial at the OCME due to the significant number of positive cases reported and the current lack of sufficient published information on this analog. To our knowledge, there are only two papers that include FIBF concentrations in four cases; this article gives the largest number (247 cases) of FIBF levels in blood samples of its users to aid in the interpretation and analysis of significance of this compound. [ABSTRACT FROM AUTHOR]

Fentanyl is a synthetic opioid that has been approved by the FDA as a general anesthetic because of its rapid onset and high potency. However, since 2013 an opioid epidemic involving fentanyl or fentanyl‐related compounds (FRCs) has swept the United States and caused numerous deaths in every state. The identification of novel FRCs is complicated by the rapid turnover of modifications to the core fentanyl structure. In this study, a series of 16 FRCs were analyzed using electrospray ionization tandem mass spectrometry (ESI‐MS/MS) to gain a deeper understanding of the conserved and unique fragmentation behaviors associated with substitution to the core fentanyl structure. This work provides an approach, based on the product ions from ESI‐MS/MS, to identify the modification site(s) on the core fentanyl structure for FRCs. Five common locations of substitution to the core fentanyl structure were used to assess the effect of substitution on the fragmentation behavior of FRCs. The proposed fragmentation pathways are supported through the combination of isotopic labeling, multi‐stage mass spectrometry (MSn), and accurate mass measurements with high‐resolution mass spectrometry (HRMS). The identification of primary product ions specific to regions of substitution provides an additional tool for the identification of the location of substitution to the core fentanyl structure, which ultimately will assist toxicologists and seized drug analysts in the identification of emerging FRCs. [ABSTRACT FROM AUTHOR]

Background: A wide range of novel psychoactive substances (NPSs) are regularly searched and discussed online by e-psychonauts. Among NPSs, the range of prescription/non-prescription opioids (fentanyl and non-fentanyl analogs) and herbal derivatives currently represents a challenge for governments and clinicians. Methods: Using a web crawler (i.e., NPS.Finder®), the present study aimed at assessing psychonaut fora/platforms to better understand the online situation regarding opioids. Results: The open-web crawling/navigating software identified some 426 opioids, including 234 fentanyl analogs. Of these, 176 substances (162 were very potent fentanyls, including two ohmefentanyl and seven carfentanyl analogs) were not listed in either international or European NPS databases. Conclusion: A web crawling approach helped in identifying a large number, indeed higher than that listed by European/international agencies, of unknown opioids likely to possess a significant misuse potential. Most of these novel/emerging substances are still relatively unknown. This is a reason of concern; each of these analogs potentially presents with different toxicodynamic profiles, and there is a lack of docking, preclinical, and clinical observations. Strengthening multidisciplinary collaboration between clinicians and bioinformatics may prove useful in better assessing public health risks associated with opioids. [ABSTRACT FROM AUTHOR]

• A LC-QTOF method for detection of fentanyl analogs was developed for human urine and plasma matrices. • A spectral library of 174 synthetic opioids and related compounds was created with assistance from FAS kits. • Method was validated under SWGTOX guidelines for subset of 10 compounds and applied to analysis of CAP NOB survey samples. Human exposures to fentanyl analogs, which significantly contribute to the ongoing U.S. opioid overdose epidemic, can be confirmed through the analysis of clinical samples. Our laboratory has developed and evaluated a qualitative approach coupling liquid chromatography and quadrupole time-of-flight mass spectrometry (LC-QTOF) to address novel fentanyl analogs and related compounds using untargeted, data-dependent acquisition. Compound identification was accomplished by searching against a locally-established mass spectral library of 174 fentanyl analogs and metabolites. Currently, our library can identify 150 fentanyl-related compounds from the Fentanyl Analog Screening (FAS) Kit), plus an additional 25 fentanyl-related compounds from individual purchases. Plasma and urine samples fortified with fentanyl-related compounds were assessed to confirm the capabilities and intended use of this LC-QTOF method. For fentanyl, 8 fentanyl-related compounds and naloxone, lower reportable limits (LRL 100), defined as the lowest concentration with 100 % true positive rate (n = 12) within clinical samples, were evaluated and range from 0.5 ng/mL to 5.0 ng/mL for urine and 0.25 ng/mL to 2.5 ng/mL in plasma. The application of this high resolution mass spectrometry (HRMS) method enables the real-time detection of known and emerging synthetic opioids present in clinical samples. [ABSTRACT FROM AUTHOR]

Introduction: Deaths due to drug overdose in the US in 2017 amounted to approximately 72,000, an increase of 12% from the previous year. There was a near tenfold increase in deaths involving synthetic opioids from 3,105 in 2013 to approximately 30,000 in 2017. Recent data from the United States (US) Centers for Disease Control and Prevention (CDC) identified fentanyl as most frequently involved in overdose deaths in the US as of 2016. This is consistent with statistics in New York State, where opioid-related overdose deaths increased by nearly 35% between 2015 and 2016, with fentanyl-related deaths increasing by 160%. The objective of this study is to report the incidence of deaths involving fentanyl and fentanyl analogs across five counties in Central New York between January 1, 2013 and December 17, 2017. Methods: All unintentional drug-related deaths across five counties in Central New York between January 1, 2013 and December 17, 2017 reported by the Medical Examiner's (ME) Office were included. Ante-mortem and post-mortem specimens were obtained for analysis. Results: A total of 417 deaths involving fentanyl and/or fentanyl analogs were reported, increasing from 10 cases in 2013 to 184 cases in 2017. Despropionyl fentanyl and furanylfentanyl were the analogs identified most frequently. Discussion: The study's data demonstrates an increase in the number of deaths related to fentanyl and/or fentanyl analogs. The number of deaths associated with fentanyl or an analog rose year to year, with despropionyl fentanyl and furanylfentanyl most commonly identified. The increase in fentanyl- and/or fentanyl analog-related deaths is consistent with national and international data. Conclusions: This study highlights the current crisis occurring in Central New York and serves to emphasize the ongoing global health threat posed by these chemical derivatives. [ABSTRACT FROM AUTHOR]

• CDC developed the Traceable Opioid Material§ Kits (TOM Kits§) product line. • TOM Kits§ provide over 150 opioid standards, including over 100 fentanyl analogs. • This work establishes a model for addressing chemical, public health emergencies. In 2017, the U.S. Department of Health and Human Services and the White House declared a public health emergency to address the opioid crisis (Hargan, 2017). On average, 192 Americans died from drug overdoses each day in 2017; 130 (67%) of those died specifically because of opioids (Scholl et al., 2019). Since 2013, there have been significant increases in overdose deaths involving synthetic opioids – particularly those involving illicitly-manufactured fentanyl. The U.S. Drug Enforcement Administration (DEA) estimates that 75% of all opioid identifications are illicit fentanyls (DEA, 2018b). Laboratories are routinely asked to confirm which fentanyl or other opioids are involved in an overdose or encountered by first responders. It is critical to identify and classify the types of drugs involved in an overdose, how often they are involved, and how that involvement may change over time. Health care providers, public health professionals, and law enforcement officers need to know which opioids are in use to treat, monitor, and investigate fatal and non-fatal overdoses. By knowing which drugs are present, appropriate prevention and response activities can be implemented. Laboratory testing is available for clinically used and widely recognized opioids. However, there has been a rapid expansion in new illicit opioids, particularly fentanyl analogs that may not be addressed by current laboratory capabilities. In order to test for these new opioids, laboratories require reference standards for the large number of possible fentanyls. To address this need, the Centers for Disease Control and Prevention (CDC) developed the Traceable Opioid Material§ Kits product line, which provides over 150 opioid reference standards, including over 100 fentanyl analogs. These kits were designed to dramatically increase laboratory capability to confirm which opioids are on the streets and causing deaths. The kits are free to U.S based laboratories in the public, private, clinical, law enforcement, research, and public health domains. [ABSTRACT FROM AUTHOR]

Rising exposure to Fentanyl and Fentanyl + is causing both intentional and unintentional effects. Besides the increasing number of overdoses and deaths from these toxic substances, there are risks for many others such as first responders in law enforcement, fire services, the medical sector, as well as those in transportation, and the public-at-large. Fentanyl and its derivatives (labeled here as Fentanyl+) can be over 20 times more profitable than heroin. The powder is cheap and easy to obtain on the Dark Web; and, is shipped via the United States Postal Service, or other delivery firms, almost undetected from China where it is produced. Mexico is also becoming a major producer and distributor of Fentanyl and its derivatives. In November 2017, the National Institute for Occupational Safety and Health – a division of the Centers for Disease Control- developed recommendations to address a wide area release of Fentanyl + as a weapon of terrorism. This paper seeks to articulate the threat posed by rising Fentanyl and Fentanyl + usage; and, identifies the potential at-risk populations from intentional and unintentional exposure to these dangerous chemicals. [ABSTRACT FROM AUTHOR]

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.

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).

Introduction: In 2019, there were over 16,000 deaths from psychostimulant overdose with 53.5% also involving an opioid. Given the substantial mortality stemming from opioid and psychostimulant co-exposure, evaluation of clinical management in this population is critical but remains understudied. This study aims to characterize and compare clinical management and outcomes in emergency department (ED) overdose patients with analytically confirmed exposure to both opioids and psychostimulants with those exposed to opioids alone., Methods: This was a secondary analysis of a prospective consecutive cohort of ED patients age 18+ with opioid overdose at 9 hospital sites from September 21, 2020 to August 17, 2021. Toxicologic analysis was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Patients were divided into opioid-only (OO) and opioid plus psychostimulants (OS) groups. The primary outcome was total naloxone bolus dose administered. Secondary outcomes included endotracheal intubation, cardiac arrest, troponin elevation, and abnormal presenting vital signs. We employed t-tests, chi-squared analyses and multivariable regression models to compare outcomes between OO and OS groups., Results: Of 378 enrollees with confirmed opioid overdose, 207 (54.8%) had psychostimulants present. OO patients were significantly older (mean 45.2 versus 40.6 years, p < 0.01). OS patients had significantly higher total naloxone requirements (mean total dose 2.79 mg versus 2.12 mg, p = 0.009). There were no significant differences in secondary outcomes., Conclusion: Approximately half of ED patients with confirmed opioid exposures were also positive for psychostimulants. Patients in the OS group required significantly higher naloxone doses, suggesting potential greater overdose severity., Competing Interests: The authors report no commercial conflicts of interest., (© 2024 The Authors. Published by Elsevier B.V.)

The National Institute on Drug Abuse has observed an increase in fentanyl deaths in the United States. One epidemic related to the abuse of fentanyl happened in Cook County in 2005–2007 (350 deaths). Another outbreak of fentanyl deaths occurred in 2015–2017 in the same area. The database of the Cook County Medical Examiner's Office was searched for cases of fentanyl deaths between 2015 and 2017: 1244 deaths were found. A comparison was performed with the previous data: an increase in the number of females was observed in 2015–2017. Also, in 2005–2007, the majority of deaths occurred among African American, while in 2015–2017, Caucasians were more involved. Within our population, some drug combinations were more common in specific demographic subgroups (male/females; Caucasian/African American; and certain age groups). The epidemiology and the most significant drug associations found at the toxicology are discussed, highlighting the usefulness of the knowledge about this outbreak for public health. [ABSTRACT FROM AUTHOR]

We examined fentanyl and its six analogs using wB97XD/cc‐pVTZ density functional theoretical (DFT) calculations as well as Raman and Surface‐enhanced Raman spectroscopy (SERS). The in silico DFT calculations provided the vibrational frequencies, Raman activities, and normal mode assignment for each analog. Raman spectroscopy can detect crystalline fentanyl analogs but cannot obtain bands for samples in solution. Therefore, we utilized gold/silver nanospheres and gold/silver nanostars to examine them. The gold/silver nanostars provided stronger signals for the fentanyl analogs, and their SERS spectra can easily distinguish these fentanyl analogs from nonfentanyl opioids and other common drugs of abuse using principle component analysis and other statistical tests. Overall, our results demonstrate that SERS shows great potential to distinguish fentanyl analogs and detect trace quantities of these compounds in mixtures of seized drugs. [ABSTRACT FROM AUTHOR]

Purpose: Since the early 2010s, deaths due to the use of new synthetic opioids (NSO) including fentanyl and its analogs have been increasing dramatically. As fentanyl analogs bear strong structural similarities, they can share common metabolites. In some clinical or forensic cases, it can be important to demonstrate the presence of both the metabolite and the parent product to confirm that the compound is responsible for the intoxication. Norcarfentanil is a common metabolite of carfentanil (NSO) and remifentanil (widely used in medical care). This article reported the investigation of norcarfentanil origin in three cases. Methods: Comprehensive screenings were performed using gas chromatography coupled to mass spectrometry and liquid chromatography coupled to a diode array detection, whereas targeted screening of NSO were performed using liquid chromatography coupled to tandem mass spectrometry. Results: Norcarfentanil was detected at concentrations ranging from 0.05 to 15.8 ng/mL in plasma and from 8.8 to 1820 ng/mL in urine, but carfentanil was detected in two out of the three cases. The presence of norcarfentanil has been supposed to be due to the treatment with remifentanil during the medical care of the patient. Conclusions: In the first two cases, norcarfentanil was present as the metabolite of carfentanil, whereas in the last case, norcarfentanil was the metabolite of remifentanil. Without the identification of remifentanil, confusion could occur, and norcarfentanil could be attributed to carfentanil misuse. [ABSTRACT FROM AUTHOR]

Introduction: There is a lack of information on illicitly manufactured fentanyl and fentanyl analogue-related (IMF) unintentional overdose death trends over time. The study analyzes IMF-related unintentional overdose fatalities that occurred between July 2015 and June 2017 in Montgomery County, Ohio, an area with the highest rates of unintentional overdose mortality in Ohio.Methods: LC-MS/MS-based method was used to identify fentanyl analogs and metabolites in 724 unintentional overdose death cases. The Chi-square statistic was used to assess differences over time in demographic and drug-related characteristics.Results: The number of unintentional overdose death cases testing positive for IMFs increased by 377% between second half of 2015 and first half of 2017. The majority of decedents were white (82.5%) and male (67.8%). The proportion of fentanyl-only (no other analogs) cases declined from 89.2%-24.6% (p < 0.001), while proportion of fentanyl analogue-containing cases increased from 9.8%-70.3% (p < 0.001) between the second half of 2015 and first half of 2017. The most commonly identified fentanyl analogs were carfentanil (29.7%), furanyl fentanyl (14.1%) and acryl fentanyl (10.2%). Proportion of IMF cases also testing positive for heroin declined from 21.6% to 5.4% (p < 0.001), while methamphetamine positive cases increased from 1.4%-17.8% (p < 0.001) over the same time period.Discussion: Emergence of fentanyl analogs contributed to substantial increases in unintentional overdose deaths. The data indicate a growing overlap between the IMF and methamphetamine outbreaks. Continuous monitoring of local IMF trends and rapid information dissemination to active users are needed to reduce the risks associated with IMF use. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]