Fentanyls: Are we missing the signs? Highly potent and on the rise in Europe

Strategies for developing μ opioid receptor agonists with reduced adverse effects

Opioids are currently the most effective and widely used painkillers in the world. Unfortunately, the clinical use of opioid analgesics is limited by serious adverse effects. Many researchers have been working on designing and optimizing structures in search of novel μ opioid receptor(MOR) agonists with improved analgesic activity and reduced incidence of adverse effects. There are many strategies to develop MOR drugs, mainly focusing on new low efficacy agonists (potentially G protein biased agonists), MOR agonists acting on different Gα subtype, targeting opioid receptors in the periphery, acting on multiple opioid receptor, and targeting allosteric sites of opioid receptors, and others. This review summarizes the design methods, clinical applications, and structure-activity relationships of small-molecule agonists for MOR based on these different design strategies, providing ideas for the development of safer novel opioid ligands with therapeutic potential.

Opioid-Based Haptens: Development of Immunotherapy

Over the past decades, extensive preclinical research has been conducted to develop vaccinations to protect against substance use disorder caused by opioids, nicotine, cocaine, and designer drugs. Morphine or fentanyl derivatives are small molecules, and these compounds are not immunogenic, but when conjugated as haptens to a carrier protein will elicit the production of antibodies capable of reacting specifically with the unconjugated hapten or its parent compound. The position of the attachment in opioid haptens to the carrier protein will influence the specificity of the antiserum produced in immunized animals with the hapten-carrier conjugate. Immunoassays for the determination of opioid drugs are based on the ability of drugs to inhibit the reaction between drug-specific antibodies and the corresponding drug-carrier conjugate or the corresponding labelled hapten. Pharmacological studies of the hapten-carrier conjugates resulted in the development of vaccines for treating opioid use disorders (OUDs). Immunotherapy for opioid addiction includes the induction of anti-drug vaccines which are composed of a hapten, a carrier protein, and adjuvants. In this review we survey the design of opioid haptens, the development of the opioid radioimmunoassay, and the results of immunotherapy for OUDs.

Rapid Analysis of Fentanyl and Fentanyl Analogues from Whole Blood Using SPME Coupled to the Microfluidic Open Interface

Fentanyl and its analogues are potent opioids that pose a significant threat to society. Over the last several years, considerable focus has been on the concerning trend of increasing fentanyl usage among drug users. Fentanyl analogues are mainly synthesized to evade analytical detection or increase their potency; thus, very low concentrations are sufficient to achieve a therapeutic effect. In an effort to help combat the synthetic opioid epidemic, developing targeted mass spectrometric methods for quantifying fentanyl and its analogues at ultralow concentrations is incredibly important. Most methods used to analyze fentanyl and its analogues from whole blood require manual sample preparation protocols (solid-phase extraction or liquid-liquid extraction), followed by chromatographic separation and mass spectrometric detection. The main disadvantages of these methods are the tedious sample preparation workflows, resulting in lengthy analysis times. To mitigate these issues, we present a targeted method capable of analyzing 96 samples containing fentanyl, several fentanyl analogues, and a common fentanyl (analogue) precursor simultaneously in 2.4 min per sample. This is possible by using a high-throughput solid phase microextraction workflow on the Concept96 autosampler followed by manual coupling of solid-phase microextraction fibers to the microfluidic open interface for tandem mass spectrometry analysis. Our quantitative method is capable of extremely sensitive analysis, with limits of quantification ranging from 0.002 to 0.031 ng mL-1 and linearity ranging from 0.010 to 25.0 ng mL-1. The method shows very good reproducibility (1-18%), accuracy (81-100%) of calibration and validation points, and good interday reproducibility (6-15%).

Immediate release fentanyl in general practices: Mostly off-label prescribing

BACKGROUND

The immediacy of the onset of opioids may be associated with the risk of dependency and accidental overdose. Nasal and oromucosal fentanyl dosage forms are so called immediate release fentanyl (IRF). These IRFs have been approved to treat breakthrough pain in patients with cancer who are on chronic opioid treatment only. There are signals of increased off-label prescribing of IRFs in general practices.

OBJECTIVES

This study aims to provide insight into the frequency of IRF prescription in Dutch general practices and the extent to which IRF is prescribed off-label.

METHODS

Routinely collected electronic health records of general practices (GPs) participating in Nivel Primary Care Database were used. Adult patients with IRF prescriptions in 2019 were selected from whom dispensing data on 2018 and 2019 was available. Diagnoses were recorded by GPs using International Classification of Primary Care. Descriptive analyses were performed.

RESULTS

This study included 342 GPs with a patient population of 1,297,942 patients, 1,368 patients received at least one IRF prescription in 2019, which is equal to 1.1 patients per 1,000 registered patients. Most patients (74.9%) with an IRF prescription received an off-label prescription. A slight majority had a cancer diagnosis but nearly 65.2% did not have a maintenance therapy and 14% were opioid-naive before receiving their first IRF prescription.

CONCLUSION

IRFs are not prescribed frequently in Dutch general practices. However, when prescribed, a relatively large portion of patients received an off-label prescription.

Spotting as a risk mitigation method: A qualitative study comparing organization-based and informal methods

OBJECTIVES

To explore the similarities and differences of organization-based and informal spotting (remote supervision of substance use) from the perspectives of spotters and spottees across Canada.

METHODS

Spotters and spottees who spot informally and for organizations were recruited across Ontario and Nova Scotia. We interviewed 20 informal and 10 organization-based participants by phone using semi-structured interviews between 08/2020 and 11/2020. Participants were asked about each methods benefits and limitations. Interviews were audio-recorded, transcribed, and analyzed thematically.

RESULTS

Benefits of informal spotting included its ability to strengthen social connections and foster autonomy in overdose response planning. The lack of support for informal spotters created stress and burnout. Organization-based spotters enjoyed the spotting training and support provided. However, regulations surrounding having to call ambulance in overdose events deterred many people from wanting to work for or call these services.

CONCLUSIONS

Both organization-based and informal spotting have a role in mitigating harms associated with the overdose crisis. Moving forward, further research is needed on how to optimize these services for all people who use drugs in varying jurisdictions internationally.

A qualitative exploration of daily path and daily routine among people in Ukraine who inject drugs to understand associated harms

Background

Patterns of movement, heterogeneity of context, and individual space-time patterns affect health, and individuals’ movement throughout the landscape is shaped by addiction, meeting basic needs, and maintaining relationships. Place and social context enable or constrain behavior and individuals use social networks and daily routines to accomplish individual goals and access resources.

Methods

This article explores drug use as part of daily routines and daily paths among people who inject drugs in Dnipro City, Ukraine. Between March and August 2018, we interviewed 30 people who inject drugs living in Dnipro City, Ukraine. Study participants completed a single interview that lasted between 1 and 2 hours. During the interview, participants described their daily routine and daily path using a printed map of Dnipro as a prompt. Participants were asked to draw important sites; give time estimates of arrival and departure; and annotate on the map the points, paths, and areas most prominent or important to them. Participants also described to what extent their daily routines were planned or spontaneous, how much their daily path varied over time, and how drug use shaped their daily routine.

Results

We identified 3 major types of daily routine: unpredictable, predictable, and somewhat predictable. Participants with unpredictable daily routines had unreliable sources of income, inconsistent drug suppliers and drug use site, and dynamic groups of people with whom they socialized and used drugs. Participants with predictable daily routines had reliable sources of income, a regular drug dealer or stash source, and a stable group of friends or acquaintances with whom they bought and/or used drugs. Participants with somewhat predictable daily routines had some stable aspects of their daily lives, such as a steady source of income or a small group of friends with whom they used drugs, but also experienced circumstances that undermined their ability to have a routinized daily life, such as changing drug use sites or inconsistent income sources.

Conclusions

Greater attention needs to be paid to the daily routines of people who use drugs to develop and tailor interventions that address the place-based and social contexts that contribute to drug-use related risks.

Determination of Nine Fentanyl Drugs in Hair Samples by GC-MS/MS and LC-MS/MS

We established GC-MS/MS and LC-MS/MS analysis methods for nine fentanyl drugs in hair samples. Human hairs were prepared by soaking in a solution of water-dimethyl sulfoxide with target analytes. The drugs were norfentanyl, acetyl fentanyl, para-fluorofentanyl, isobutyryl fentanyl, fentanyl, thiofentanyl, 4-fluoroisobutyr fentanyl, ocfentanil, and tetrahydrofuran fentanyl. For a single-factor experiment, a Box-Behnken design-response surface was used to optimize the pretreatment conditions of samples. The prepared samples were quantitatively analyzed by GC-MS/MS and LC-MS/MS. The working curve method was used for quantitative analysis with fentanyl-D5 as the internal standard. The concentrations of the nine fentanyl drugs in the samples were 1.488-6.494 ng mg^-1, RSDs < 5.0%. For GC-MS/MS, the linear range of the nine fentanyl drugs was 0.5-5.0 ng mg^-1, r ² > 0.999. The detection limits were 0.02-0.05 ng mg^-1, and the recovery rates were >86%. For LC-MS/MS, the nine fentanyl drugs had an excellent linear relationship within the concentration range of 3.0-220.0 pg mg^-1, r ² > 0.999. The detection limits were 0.05 pg mg^-1 and the recovery rates were >84%. The established methods were used for the detection of fentanyl drugs in human hairs, with high sensitivity, accuracy, and specificity. These two methods can be used for the certification of fentanyl certified reference substances (CRMs). In the experiment, the developed hair CRMs, which will continue to be studied in the future, are expected to be used in forensic drug abuse detection.

Real-world study of multiple naloxone administration for opioid overdose reversal among bystanders

Background

The increasing prevalence of highly potent, illicitly manufactured fentanyl and its analogues (IMF) in the USA is exacerbating the opioid epidemic which has worsened during the COVID-19 pandemic. Narcan® (naloxone HCl) Nasal Spray has been approved by the US Food and Drug Administration as a treatment for opioid-related overdoses. Due to the high potency of IMF, multiple naloxone administrations (MNA) may be needed per overdose event. It is essential to determine the patterns of naloxone use, including MNA, and preferences among bystanders who have used naloxone for opioid overdose reversal.

Methods

A cross-sectional web-based survey was administered to 125 adult US residents who administered 4 mg Narcan® Nasal Spray during an opioid overdose in the past year. The survey asked about the most recent overdose event, the use of Narcan® during the event and the associated withdrawal symptoms, and participant preferences regarding dosages of naloxone nasal spray. An open-ended voice survey was completed by 35 participants.

Results

Participants were mostly female (70%) and white (78%), while reported overdose events most frequently occurred in people who were males (54%) and white (86%). Most events (95%) were successfully reversed, with 78% using ≥ 2 doses and 30% using ≥ 3 doses of Narcan® Nasal Spray. Over 90% were worried that 1 Narcan® box may not be enough for a successful future reversal. Reported withdrawal symptoms were similar in overdose events where 1 versus ≥ 2 sprays were given. Eighty-six percent of participants reported more confidence in an 8 mg versus a 4 mg naloxone nasal spray and 77% reported a stronger preference for 8 mg over 4 mg.

Conclusions

MNA occurred in most overdose events, often involving more sprays than are provided in one Narcan® nasal spray box, and participants predominantly expressed having a stronger preference for and confidence in an 8 mg compared to a 4 mg nasal spray. This suggests the need and desire for a higher dose naloxone nasal spray formulation option. Given that bystanders may be the first to administer naloxone to someone experiencing an opioid overdose, ensuring access to an adequate naloxone supply is critical in addressing the opioid overdose epidemic.

Towards an International Consensus on the Prevention, Treatment, and Management of High-Risk Substance Use and Overdose among Youth

Background and Objectives: Now more than ever, there is an obvious need to reduce the overall burden of disease and risk of premature mortality that are associated with mental health and substance use disorders among young people. However, the current state of research and evidence-based clinical care for high-risk substance use among youth is fragmented and scarce. The objective of the study is to establish consensus for the prevention, treatment, and management of high-risk substance use and overdose among youth (10 to 24 years old). Materials and Methods: A modified Delphi technique was used based on the combination of scientific evidence and clinical experience of a group of 31 experts representing 10 countries. A semi-structured questionnaire with five domains (clinical risks, target populations, intervention goals, intervention strategies, and settings/expertise) was shared with the panelists. Based on their responses, statements were developed, which were subsequently revised and finalized through three iterations of feedback. Results: Among the five major domains, 60 statements reached consensus. Importantly, experts agreed that screening in primary care and other clinical settings is recommended for all youth, and that the objectives of treating youth with high-risk substance use are to reduce harm and mortality while promoting resilience and healthy development. For all substance use disorders, evidence-based interventions should be available and should be used according to the needs and preferences of the patient. Involuntary admission was the only topic that did not reach consensus, mainly due to its ethical implications and resulting lack of comparable evidence. Conclusions: High-risk substance use and overdoses among youth have become a major challenge. The system’s response has been insufficient and needs substantial change. Internationally devised consensus statements provide a first step in system improvement and reform.

Design, synthesis, and biological evaluation of C6-difluoromethylenated epoxymorphinan Mu opioid receptor antagonists

The recent widespread abuse of high potency synthetic opioids, such as fentanyl, presents a serious threat to individuals affected by substance use disorder. Synthetic opioids generally exhibit prolonged in vivo circulatory half-lives that can outlast the reversal effects of conventional naloxone-based overdose antidotes leading to a life-threatening relapse of opioid toxicity known as renarcotization. In this manuscript, we present our efforts to combat the threat of renarcotization by attempting to extend the half-life of traditional MOR antagonists through the design of novel, fluorinated 4,5-epoxymorphinans possessing increased lipophilicity. Analogues were prepared via a concise synthetic strategy highlighted by decarboxylative Wittig olefination of the C6 ketone to install a bioisosteric 1,1-difluoromethylene unit. C6-difluoromethylenated compounds successfully maintained in vitro potency against an EC90 challenge of fentanyl and were predicted to have enhanced circulatory half-life compared to the current standard of care, naloxone. Subsequent in vivo studies demonstrated the effective blockade of fentanyl-induced anti-nociception in mice.

Opioids for Treatment of Pre-hospital Acute Pain: A Systematic Review

INTRODUCTION

Acute pain is a frequent symptom among patients in the pre-hospital setting, and opioids are the most widely used class of drugs for the relief of pain in these patients. However, the evidence base for opioid use in this setting appears to be weak. The aim of this systematic review was to explore the efficacy and safety of opioid analgesics in the pre-hospital setting and to assess potential alternative therapies.

METHODS

The PubMed, EMBASE, Cochrane Library, Centre for Reviews and Dissemination, Scopus, and Epistemonikos databases were searched for studies investigating adult patients with acute pain prior to their arrival at hospital. Outcomes on efficacy and safety were assessed. Risk of bias for each included study was assessed according to the Cochrane approach, and confidence in the evidence was assessed using the GRADE method.

RESULTS

A total of 3453 papers were screened, of which the full text of 125 was assessed. Twelve studies were ultimately included in this systematic review. Meta-analysis was not undertaken due to substantial clinical heterogeneity among the included studies. Several studies had high risk of bias resulting in low or very low quality of evidence for most of the outcomes. No pre-hospital studies compared opioids with placebo, and no studies assessed the risk of opioid administration for subgroups of frail patients. The competency level of the attending healthcare provider did not seem to affect the efficacy or safety of opioids in two observational studies of very low quality. Intranasal opioids had a similar effect and safety profile as intravenous opioids. Moderate quality evidence supported a similar efficacy and safety of synthetic opioid compared to morphine.

CONCLUSIONS

Available evidence for pre-hospital opioid administration to relieve acute pain is scarce and the overall quality of evidence is low. Intravenous administration of synthetic, fast-acting opioids may be as effective and safe as intravenous administration of morphine. More controlled studies are needed on alternative routes for opioid administration and pre-hospital pain management for potentially more frail patient subgroups.

Synthetic opioids: a review and clinical update

The term 'opioids' refers to both the natural compounds ('opiates') which are extracted from the opium poppy plant (Papaver somniferum) and their semi-synthetic and synthetic derivatives. They all possess relatively similar biochemical profiles and interact with the opioid receptors within the human body to produce a wide range of physiological effects. They have historically been used for medicinal purposes, their analgesic and sedative effects, and in the management of chronic and severe pain. They have also been used for non-medicinal and recreational purposes to produce feelings of relaxation, euphoria and well-being. Over the last decade, the emergence of an illegal market in new synthetic opioids has become a major global public health issue, associated with a substantial increase in unintentional overdoses and drug-related deaths. Synthetic opioids include fentanyl, its analogues and emerging non-fentanyl opioids. Their popularity relates to changes in criminal markets, pricing, potency, availability compared to classic opioids, ease of transport and use, rapid effect and lack of detection by conventional testing technologies. This article expands on our previous review on new psychoactive substances. We now provide a more in-depth review on synthetic opioids and explore the current challenges faced by people who use drugs, healthcare professionals, and global public health systems.

Trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia (2003-2015)

INTRODUCTION

Fentanyl-related overdose is an ongoing concern among countries with high prescription opioid utilisation. This study examines trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia between 2003 and 2015, overall, and by age/sex.

METHODS

This was a retrospective nationwide study of prescription dispensings and coronial records. Transdermal fentanyl utilisation was examined using Pharmaceutical Benefits Scheme dispensing records. Details of fatal fentanyl overdoses were extracted from the National Coronial Information System.

RESULTS

Transdermal fentanyl utilisation increased 5.1-fold between 2003 and 2015, from 0.28 to 1.39 mg/1000 population/day and was consistently higher among females and adults aged ≥85 years. The utilisation of higher strength patches (75 and 100 mcg/h) was more common among males aged 25-44 years. A total of 291 fatal fentanyl overdoses were recorded, increasing from no recorded deaths in 2003 to 2.23 deaths/1 000 000 population in 2015. Rates were higher among males (increasing from 0 to 3.72 deaths/1 000 000 population) and for adults aged 25-44 years (increasing from 0 to 5.34 deaths/1 000 000 population). The number of deaths/kg fentanyl dispensed was highest among males aged <25 years (45.45, 95% confidence interval 21.80-83.59). Most deaths (70.1%) involved the intravenous administration of fentanyl from transdermal patches.

DISCUSSION AND CONCLUSIONS

Rates of transdermal fentanyl utilisation and fatal fentanyl overdose across Australia increased between 2003 and 2015. Although transdermal fentanyl utilisation was consistently greater among females and older adults, rates of fatal fentanyl overdose were highest among younger males. Interventions to reduce extramedical use among this high-risk population group are necessary to minimise fentanyl-related harms.

Covalently Loaded Naloxone Nanoparticles as a Long-Acting Medical Countermeasure to Opioid Poisoning

The mu opioid receptor antagonist naloxone has been a vital, long-standing countermeasure in the ongoing battle against opioid use disorders (OUD) and toxicity. However, due to its distinctive short elimination half-life, naloxone has shown diminished efficacy in cases of synthetic opioid poisoning as larger or repeated doses of the antidote have been required to achieve adequate reversal of severe respiratory depression and prevent episodes of renarcotization. This report describes the synthesis, characterization, and in vivo evaluation of a novel, nanoparticle-based naloxone formulation that provides extended protection against the toxic effects of the powerful synthetic opioid fentanyl. The strategy was predicated on a modified two-step protocol involving the synthesis and subsequent nanoprecipitation of a poly(lactic-co-glycolic acid) polymer scaffold bearing a covalently linked naloxone chain end (drug loading ∼7% w/w). Pharmacokinetic evaluation of the resulting covalently loaded naloxone nanoparticles (cNLX-NP) revealed an elimination half-life that was 34 times longer than high dose free naloxone (10 mg/kg) in male Sprague-Dawley rats. This enhancement was further demonstrated by cNLX-NP in subsequent in vivo studies affording protection against fentanyl-induced respiratory depression and antinociception for up to 48 h following a single intramuscular injection. These discoveries support further investigation of cNLX-NP as a potential therapeutic to reverse overdose and prevent renarcotization from fentanyl and its potent analogs.

Clinical Pharmacology, Toxicity, and Abuse Potential of Opioids

Opioids were the most common drug class resulting in overdose deaths in the United States in 2019. Widespread clinical use of prescription opioids for moderate to severe pain contributed to the ongoing opioid epidemic with the subsequent emergence of fentanyl-laced heroin. More potent analogues of fentanyl and structurally diverse opioid receptor agonists such as AH-7921 and MT-45 are fueling an increasingly diverse illicit opioid supply. Overdose from synthetic opioids with high binding affinities may not respond to a typical naloxone dose, thereby rendering autoinjectors less effective, requiring higher antagonist doses or resulting in a confusing clinical picture for health care providers. Nonscheduled opioid drugs such as loperamide and dextromethorphan are associated with dependence and risk of overdose as easier access makes them attractive to opioid users. Despite a common opioid-mediated pathway, several opioids present with unique pharmacodynamic properties leading to acute toxicity and dependence development. Pharmacokinetic considerations involve half-life of the parent opioid and its metabolites as well as resulting toxicity, as is established for tramadol, codeine, and oxycodone. Pharmacokinetic considerations, toxicities, and treatment approaches for notable opioids are reviewed.

Predicting the Membrane Permeability of Fentanyl and Its Analogues by Molecular Dynamics Simulations

The lipid membrane is considered a crucial component of opioid general anesthesia. The main drug used for the induction and maintenance of opioid anesthesia is fentanyl and its various analogues. However, these drugs have different clinical effects, and detailed atomic-level insight into the drug–membrane interactions could lead to a better understanding how these drugs exert their anesthetic properties. In this study, we have used extensive umbrella sampling molecular dynamics simulations to study the permeation process of fentanyl and three of its analogues into a variety of simple phospholipid membrane models. Our simulations show that we can accurately predict the permeability coefficients of these drug molecules, which is an important process in understanding how pharmaceuticals reach their molecular targets. We were also able to show that one phospholipid provides more accurate predictions than other lipids commonly used in these types of permeation studies, which will aid future studies of these types of processes.

The opioid overdose crisis as a global health challenge

PURPOSE OF REVIEW

To assess the current state of the opioid overdose crisis along three major axes: drug markets and patterns of use, the effectiveness of systems of care, and international developments.

RECENT FINDINGS

Overdose is a major contributor to mortality and disability among people who use drugs. The increasing number of opioid overdoses in North America especially is an indication of changing drug markets and failing regional systems of care. Globally, we see three clusters of overdose prevalence: (1) a group of countries led by the United States with historically high rates of opioid overdose, (2) a group of countries with increasing rates within a concerning range, (3) a group with very low rates. The contamination of street drugs, the quality and accessibility of treatment, and the overall system of care all contribute to the prevalence of overdose.

SUMMARY

Drug markets and pattern of consumption in parts of the world are shifting towards contamination and opioids like fentanyl as the drug of choice, which dismantles insufficient and largely ineffective systems of care. Furthermore, outside of North America, more countries like Estonia, Lithuania, Sweden, Finland, and Norway show very concerning numbers. Without a consistent system response, effects will be devastating.

Is Europe facing an opioid crisis like the United States? An analysis of opioid use and related adverse effects in 19 European countries between 2010 and 2018

Background

Given the ongoing opioid crisis in the United States (US), we investigated the opioid situation in Europe. The aims of the study are to provide an overview of trends in prescription opioid (PO) use and opioid-related adversities between 2010 and 2018 for different opioids in 19 European countries and to present a comparison with similar data from the US.

Methods

A multisource database study with national data from 19 European countries evaluating trends between 2010 and 2018 in (a) PO consumption, (b) high-risk (HR) opioid users, (c) opioid-related hospital admissions, (d) opioid-related overdose deaths, (e) opioid use disorder treatment entries, and (f) patients in opioid substitution therapy (OST). Within and between-country comparisons and comparisons with data from the US were made.

Results

There was considerable variation between European countries. Most countries showed increased PO consumption with the largest increase and the highest consumption in the United Kingdom (UK) compared to the rest of Europe and the US in 2018 (UK: 58,088 defined daily doses for statistical purposes/1000 population/day). In 2018, Scotland had the highest rates (per 100,000 population) of HR opioid users (16·2), opioid-related hospital admissions (118), opioid-related deaths (22·7), opioid use disorder treatment admissions (190), and OST patients (555) of all included European countries. These rates were similar or even higher than those in the US in 2018. Other countries with high rates of opioid-related adversities were Northern Ireland (synthetic and “other” opioids), Ireland (heroin and methadone), and England (all opioids). All other countries had no or little increase in opioid-related adversities.

Conclusions

Apart from the British Isles and especially Scotland, there is no indication of an opioid crisis comparable to that in the US in the 19 European countries that were part of this study. More research is needed to identify drivers and develop interventions to stop the emerging opioid crisis in the UK and Ireland.

Hyperpolarisation of Mirfentanil by SABRE in the Presence of Heroin

Mirfentanil, a fentanyl derivative that is a μ-opioid partial agonist, is hyperpolarised via Signal Amplification By Reversible Exchange (SABRE), a para-hydrogen-based technique. [Ir(IMes)(COD)Cl] (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazole-2-ylidene, COD=cyclooctadiene) was employed as the polarisation transfer catalyst. Following polarisation transfer at 6.5 mT, the pyrazine-protons were enhanced by 78-fold (polarisation, P=0.04 %). The complex [Ir(IMes)(H)₂ (mirfentanil)₂ (MeOH)]⁺ is proposed to form based on the observation of two hydrides at δ -22.9 (trans to mirfentanil) and -24.7 (trans to methanol). In a mixture of mirfentanil and heroin, the former could be detected using SABRE at concentrations less than 1 % w/w. At the lowest concentration analyzed, the amount of mirfentanil present was 0.18 mg (812 μM) and produced a signal enhancement of -867-fold (P=0.42 %). following polarisation transfer at 6.5 mT.

Quantitative analysis of 20 fentanyl analogues by modified QuEChERS-LC-MS/MS in health products and transdermal patches

The spreading of narcotics especially illicit novel psychoactive substances is a continuing problem in recent years. In response to reduce the morbidity and crime related to fentanyl analogues, the accurate measurement of fentanyl analogues concentrations is significantly important in the analytical laboratories for customs checks and clinical application. In this work, ethyl acetate was selected as extraction solvent, 50 mg of PSA, 100 mg of C18, and 10 mg of GCB were optimized for purification. A modified QuEChERS extraction method followed by high performance liquid chromatography-tandem mass spectrometry with the mode of multiple reaction monitoring has been developed for the simultaneous determination of 20 fentanyl analogues in collagen peptides, slimming capsules and fentanyl transdermal patches. The limits of detection (LODs) varied from 0.004 to 0.02 μg L^-1 with relative standard deviations of 4.89-11.4 % and showed good linearity in the range of 0.02-10 μg L^-1 and 0.01-1.00 mg L^-1, respectively. The recoveries for 20 fentanyl analogues in the low (at μg L^-1 level) and high (at mg L^-1 level) concentration spiked samples were in the range of 77.7-114 % and 83.9-116 %, which demonstrated the application potential of the proposed method for the determination of fentanyl analogues with low and high concentration in real case samples. In addition, the matrix effect and the cross-reactivity were also proved to not interfere with quantitation of targeted fentanyl analogues. Thus, the developed method showed high sensitivity and good accuracy, which makes it suitable for the rapid detection of fentanyl analogues for customs and border service as well as pharmaceuticals.

Impact of motivational interviewing training on emergency department nurses' skills: A one-group pretest-posttest pilot study

BACKGROUND

Overdose from opioid abuse is an increasing cause of mortality worldwide. Emergency department nurses experience barriers when caring for patients with illicit opioid use. Motivational interviewing (MI) may help address these barriers.

METHODS

A one-group pretest-posttest design was used to investigate the impact of an eight-hour MI training workshop for 39 emergency department nurses at a community hospital. Audio-recorded interviews of nurses with standardized patients were assessed before, immediately after, and three to five months after training. Proficiency was assessed using the Motivational Interviewing Treatment Integrity 4.2.1.

RESULTS

Paired t-test analysis found statistically significant technical score increases from 2.20 (SD = 0.64) to 2.51 (SD = 0.52, p = 0.02) but not in relational scores, 2.04 (SD = 0.59) to 2.46 (SD = 0.53, p = 0.06), during the immediate pretest-posttest period. At follow-up, proficiency in MI was unattained and both technical (2.35, SD = 0.61, p = 0.49) and relational scores regressed (2.08, SD 0.74, p = 0.19).

CONCLUSIONS

Although short-term improvements in technical scores were observed, proficiency in MI was not attained and skills regressed over time. This suggests that a one-day training session may be inadequate. On-going coaching and supervision may be beneficial to maintain MI skills.

Structural Assessment of Agonist Efficacy in the μ-Opioid Receptor: Morphine and Fentanyl Elicit Different Activation Patterns

Over the past two decades, the opioid epidemic in the United States and Canada has evidenced the need for a better understanding of the molecular mechanisms of medications used to fight pain. Morphine and fentanyl are widely used in opiate-mediated analgesia for the treatment of chronic pain. These compounds target the μ-opioid receptor (MOR), a class A G protein-coupled receptor (GPCR). In light of described higher efficacy of fentanyl with respect to morphine, we have performed independent μs-length unbiased molecular dynamics (MD) simulations of MOR complexes with each of these ligands, including the MOR antagonist naltrexone as a negative control. Consequently, MD simulations totaling 58 μs have been conducted to elucidate at the atomic level ligand-specific receptor activity and signal transmission in the MOR. In particular, we have identified stable binding poses of morphine and fentanyl, which interact differently with the MOR. Different ligand-receptor interaction landscapes directly induce sidechain conformational changes of orthosteric pocket residues: Asp149^3.32, Tyr150^3.33, Gln126^2.60, and Lys235^5.39. The induced conformations determine Asp149^3.32-Tyr328^7.43 sidechain-sidechain interactions and Trp295^6.48-Ala242^5.46 sidechain-backbone H-bond formations, as well as Met153^3.36 conformational changes. In addition to differences in ligand binding, different intracellular receptor conformational changes are observed as morphine preferentially activates transmembrane (TM) helices: TM3 and TM5, while fentanyl preferentially activates TM6 and TM7. As conformational changes in TM6 and TM7 are widely described as being the most crucial aspect in GPCR activation, this may contribute to the greater efficacy of fentanyl over morphine. These computationally observed functional differences between fentanyl and morphine may provide new avenues for the design of safer but not weaker opioid drugs because it is desirable to increase the safety of medicines without sacrificing their efficacy.

Pharmacokinetics and pharmacodynamics of cyclopropylfentanyl in male rats

BACKGROUND

Illicitly manufactured fentanyl and its analogs are a major driving force behind the ongoing opioid crisis. Cyclopropylfentanyl is a fentanyl analog associated with many overdose deaths, but limited knowledge is available about its pharmacology. In the present study, we developed a bioanalytical method for the determination of cyclopropylfentanyl and its main metabolite cyclopropylnorfentanyl and evaluated pharmacokinetic-pharmacodynamic relationships in rats.

METHOD

An ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for determination of cyclopropylfentanyl and cyclopropylnorfentanyl in rat plasma. Male Sprague-Dawley rats fitted with jugular catheters and temperature transponders received cyclopropylfentanyl (30, 100, and 300 μg/kg) or saline subcutaneously. Blood specimens were withdrawn over an 8-h time period, along with measurements of pharmacodynamic endpoints.

RESULTS

The analytical method was validated, and both analytes exhibited a low limit of quantification (15 pg/mL). Cyclopropylfentanyl caused dose-related increases in hot plate latency (ED₅₀ = 48 µg/kg) and catalepsy (ED₅₀ = 87 µg/kg) and produced long-lasting hypothermia at the highest dose. Plasma cyclopropylfentanyl rose rapidly in a dose-related fashion, reaching maximal concentration (C_max) after 15-28 min, whereas metabolite Cmax occurred later at 45-90 min. Cyclopropylfentanyl C_max values were similar to concentrations measured in non-fatal intoxications in humans; however, differences in parent drug: metabolite ratio indicated possible interspecies variance in metabolism.

CONCLUSION

Our study shows that cyclopropylfentanyl produces typical opioid-like effects in male rats. Cyclopropylfentanyl displays much greater analgesic potency when compared to morphine, suggesting that cyclopropylfentanyl poses increased overdose risk for unsuspecting users.

Alpha-Methylfentanyl and Beta-Hydroxyfentanyl LC-MS-MS Quantification in Rat Plasma after Long-Term Ethanol Exposure

Fentanyl and its analogues are highly abused drugs that dominate the illicit drug trade. alpha-Methylfentanyl (A-F) and beta-hydroxyfentanyl (B-F) are two fentanyl analogues that require the development of rapid detection technologies. The current study established and validated a rapid and high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS-MS) method to measure A-F and B-F concentrations in rat plasma following intravenous drug administration (20 μg/kg). Because fentanyl is primarily metabolized by the liver, we evaluated the concentrations of A-F and B-F in vivo in rats, in a control group and a group with liver damage induced by 55 days of oral ethanol gavage (6.5 g/kg, 22.5% v/v). Liquid-liquid extraction and LC-MS-MS operating in the positive ion multiple reaction monitoring mode were used. A C18 column was used, and the mobile phase consisted of 0.1% formic acid aqueous and acetonitrile. The limit of detection was 3 pg/mL (S/N > 5) for A-F and B-F. The calibration curves were linear within the concentration range of 0.01-5 ng/mL (R2 = 0.9991) and 0.005-20 ng/mL (R2 = 0.9999) for A-F and B-F, respectively. Extraction recoveries were 91.3%-97.6% with RSD ≤ 11.2% and 90.5%-94.3% with RSD ≤ 10.5% for A-F and B-F, respectively. Plasma matrix effects were 80.61%-84.58% for A-F and 80.67%-81.33% for B-F with RSD ≤ 13.9%. The validated assay indicated no significant differences in pharmacokinetic parameters (AUC0-t, Cmax and T1/2) derived from the assessment of A-F and B-F plasma concentrations between control and ethanol-exposed rats. This assay, for which the LOD was 3 pg/mL for A-F and B-F may help the forensic science field to determine fentanyl analogue-related causes of death and identify illicit drug tampering.

Feasibility and Preliminary Efficacy of Isradipine During Outpatient Buprenorphine Stabilization and Detoxification: A Pilot Randomized, Placebo-Controlled Trial

Background:

Given the immense burden of the widespread use of opioids around the world, exploring treatments that improve drug use outcomes, and craving and withdrawal measures in individuals with opioid use disorder is crucial. This pilot study examined the feasibility and preliminary efficacy of the L-type calcium-channel blocker isradipine (ISR) to improve drug use outcomes, and craving and withdrawal measures during buprenorphine (BUP)/ISR stabilization and subsequent taper in opioid-dependent individuals.

Methods:

Participants were stabilized on BUP sublingual tablets within the first 2 days of week 1, were then randomized and inducted on either ISR or placebo, gradually increasing the dose over the next 2 weeks, followed by a 10-day BUP taper during weeks 5-6, and ISR/placebo taper during weeks 7 to 8. Assessments included thrice-weekly measures of craving and withdrawal, as well as vital signs and urine drug screens. Medication compliance was assessed by monitoring number of missed clinic visit days.

Results:

Baseline characteristics of participants (n = 25; 60% male, 96% Caucasian, 48% employed, mean age 32.8 years) did not differ significantly between treatment groups (isradipine, n = 11; placebo, n = 14). During the stabilization phase (n = 19), ISR participants had significantly lower rates of illicit opioid-positive urines (treatment × visit: t = -2.16, P = 0.03), as well as reduction in craving intensity (t = –2.50, P = 0.01), frequency (t = –3.43, P < 0.01) and duration (t = –2.51, P = 0.01). ISR was well tolerated with mild adverse effects.

Conclusions:

This study was likely underpowered due to being a pilot trial. Although preliminary results suggest ISR may improve BUP-assisted treatment outcomes, concerns about high number of exclusions (n = 11 during taper phase) based on cardiovascular measures as well as ISR-induced changes in vital signs with the immediate release formulation may limit the feasibility of this approach.

Trial Registration:

Clinicaltrials.gov identifier NCT01895270. Registered 10 July 2013, https://clinicaltrials.gov/ct2/show/NCT01895270?id=NCT01895270&draw=2&rank=1

Estimates of opioid use disorder prevalence from a regression-based multi-sample stratified capture-recapture analysis

BACKGROUND

An epidemic of opioid overdose has spread across North America, with illicit drug-related overdose emerging as a leading cause of death in recent years. Estimates of opioid use disorder (OUD) prevalence at the level of the public health service delivery area are needed to project resource needs and identify priority areas for targeted intervention. Our objective is to estimate the annual prevalence of OUD in British Columbia (BC), Canada, from 2000 to 2017.

METHODS

We performed a multi-sample stratified capture-recapture analysis to estimate OUD prevalence in BC. The analysis included individuals identified from 3 administrative databases for 2000-2011 and 4 databases for 2012-2017, linked at the individual level. Negative binomial regression models on the counts of individuals within these strata were used to estimate prevalence, adjusting for dependency between databases.

RESULTS

OUD prevalence in BC among people aged 12 years or older was 1.00 % (N = 34,663 individuals) in 2000 and increased to 1.54 % (N = 61,080) in 2011. Between 2013 and 2017 prevalence increased from 1.57 % (95 % confidence interval: 1.56-1.58) to 1.92 % (1.89-1.95; N = 83,760; 82,492-84,855). The greatest increases in prevalence were observed among males 12-30 years old and 31-44 years old, with 43.2 % and 40.2 % increases from 2013 to 2017.

CONCLUSIONS

In BC, the OUD prevalence was 1.92 % among people 12 years or older in 2017. We estimated that prevalence has nearly doubled since 2000, with the highest increases in prevalence observed among males under 45.

Fentanyl analogs on the Swedish webforum flashback: Interest and impact of scheduling

BACKGROUND

Sweden regulates new psychoactive substances, including fentanyl analogs, individually. This reactive scheduling procedure enabled the existence of a recreational market for unscheduled fentanyl analogs sold from surface webshops. We measure the interest in 24 named fentanyl analogs and the impact of scheduling.

METHODS

We scraped posts in threads on named fentanyl analogs from the Swedish internet forum Flashback.org, 2012-2019. The sample consists of 24 threads with a total of 8761 posts. We construct five measures of interest based on duration of threads, number of posts, and number of distinct posters, and fit a non-seasonal ARMA model to test if there was a change in mean activity after scheduling.

RESULTS

Across the five measures, there was most interest in acryl fentanyl, butyr fentanyl, and acetyl fentanyl. The number of daily posts was significantly reduced in nine out of 13 threads after scheduling.

CONCLUSION

The scheduling of fentanyl analogs impacted interest on Flashback.org. The biggest effect sizes were from the narcotics scheduling of 2-Me-MAF, acryl, and acetyl fentanyl, while furanyl fentanyl saw the biggest reduction after health scheduling. The reductions were bigger for narcotics scheduling compared to health scheduling.

Analysis of 17 fentanyls in plasma and blood by UPLC-MS/MS with interpretation of findings in surgical and postmortem casework

The opioid crisis is linked to an increased misuse of fentanyl as well as fentanyl analogs that originate from the illicit drug market. Much of our current understanding of fentanyl and fentanyl analog use in our communities comes from postmortem toxicology findings. In the clinical settings of addiction medicine and pain management, where the opioid abuse potential is high, the use of fentanyl, as well as specific fentanyl analogs, may be underestimated due to limited plasma testing and limited availability of assays with suitable analytical sensitivity and selectivity to detect misuse of fentanyls. We report plasma and blood assays for 17 fentanyls (these include fentanyl, fentanyl analogs, fentanyl metabolites and synthetic precursors) in clinical, and medical examiner, casework. A mixed-mode solid phase extraction of diluted plasma or precipitated blood was optimized for maximum recovery of the fentanyls with minimized matrix effects. Analysis was performed using a Waters ACQUITY UPLC I-Class interfaced with a Waters Xevo TQ-S micro tandem quadrupole mass spectrometer. Method parameters were optimized and validated for precision, accuracy, carryover, linearity and matrix effects. Application studies were performed in postmortem blood obtained in 44 fentanyl-related fatalities and in serial plasma samples from 18 surgical patients receiving intravenous fentanyl therapy while undergoing parathyroidectomy. Fentanyls found in postmortem cases included fentanyl, norfentanyl, despropionyl-fentanyl (4-ANPP), beta-hydroxy fentanyl (β-OH fentanyl), acetyl fentanyl, acetyl norfentanyl, methoxyacetyl fentanyl, furanyl fentanyl, cyclopropyl fentanyl, and para-fluorobutyryl fentanyl, with fentanyl, norfentanyl, 4-ANPP and β-OH fentanyl predominating in frequency. Fentanyl concentrations ranged from 0.2 to 56 ng/mL and fentanyl was nearly always found with 4-ANPP, norfentanyl and β-OH fentanyl. Concentrations of other fentalogs ranged from <1 to 84 ng/mL (extrapolated). In the surgical cases, fentanyl was detected and quantified along with norfentanyl and β-OH fentanyl, but without detection of 4-ANPP in any of the samples. The association and relative concentrations of β-OH fentanyl, fentanyl and norfentanyl in the postmortem and clinical studies indicated a metabolic, rather than an illicit, source of β-OH fentanyl.

DARK Classics in Chemical Neuroscience: Carfentanil

Because of its remarkable potency and relative ease of synthesis, carfentanil (1) has recently emerged as a problematic contaminant in other drugs of abuse. Carfentanil and its close analogs, currently approved only for large animal veterinary medicine, have found use both as illicit additives to the clandestine manufacture of scheduled drugs and as chemical weapons. In this Review, the background, synthesis, manufacture, metabolism, pharmacology, approved indications, dosage, and adverse effects of carfentanil will be discussed along with its emergence as a key player in the ongoing opioid crisis.

[Use of synthetic substances in France and in Europe]

This paper aims to present the main information presented at the 9th Meeting about addictovigilance in 2016 by four healthcare professionals and addiction experts on the issue of new psychoactive substance use. A new psychoactive substance (NPS) is defined as a narcotic or psychotropic drug, in pure form or in preparation, that is not controlled by the United Nations drug conventions, but which may pose a public health threat comparable to that posed by substances listed in these conventions. The emergence of NPS consumption is a worldwide concern. Although NPS are less consumed than established drugs, there has been a sharp increase in their use over the last few years, notably of synthetic cathinones, synthetic cannabinoids and, more recently, synthetic opioids. The latter in particular are involved in deaths in Europe. However, "established" drugs (MDMA [methylenedioxymethamphetamine], amphetamines, LSD, methamphetamine) are far from being dethroned by the more recent substances: they are considered "a safe bet" already "tried and tested" by many consumers over the years. MDMA, in particular, also known as ecstasy, which has been used as a recreational drug since the 1990s, saw its consumption decrease until 2010, and then increase again, especially in higher amounts; inexpensive and easily accessible, it is increasingly associated with emergency admissions or deaths in France. The perpetual appearance of new substances on the drug market is obligating to improve knowledge on these products, particularly by focusing on their analytical identification, and also by monitoring their use and harms.

Understanding the increase in opioid overdoses in New Hampshire: A rapid epidemiologic assessment

BACKGROUND

New Hampshire (NH) has had among the highest rates of fentanyl-related overdose deaths per capita in the United States for several years in a row-more than three times the national average in 2016. This mixed-methods study investigated drug-using practices and perspectives of NH residents who use opioids to inform policy in tackling the overdose crisis.

METHODS

Seventy-six participants from six NH counties completed demographic surveys and semi-structured interviews focused on drug-using practices and perspectives, including use precursors, fentanyl-seeking behaviors, and experiences with overdose. Rigorous qualitative methods were used to analyze interview data including transcription, coding and content analysis. Descriptive statistics were calculated on quantitative survey data.

RESULTS

Eighty-four percent of interviewees had knowingly used fentanyl in their lifetime, 70 % reported overdosing at least once, and 42 % had sought a batch of drugs known to have caused an overdose. The majority stated most heroin available in NH was laced with fentanyl and acknowledged that variability across batches increased overdose risk. Participants reported high availability of fentanyl and limited access to prevention, treatment, and harm reduction programs. There was widespread support for expanding education campaigns for youth, increasing treatment availability, and implementing needle exchange programs.

CONCLUSIONS

A confluence of factors contribute to the NH opioid overdose crisis. Despite consensus that fentanyl is the primary cause of overdoses, individuals continue to use it and affirm limited availability of resources to address the problem. Policies targeting innovative prevention, harm reduction, and treatment efforts are needed to more effectively address the crisis.

Distinguishing Between Cyclopropylfentanyl and Crotonylfentanyl by Methods Commonly Available in the Forensic Laboratory

BACKGROUND

The opioid analgesic fentanyl and its analogues pose a major health concern due to its high potency and the increasing number of overdose deaths worldwide. The analogues of fentanyl may differ in potency, toxicity, and legal status, and it is therefore important to develop analytical methods for their correct identification. This can be challenging since many fentanyl analogues are structural isomers. Two fentanyl isomers that have been in the spotlight lately due to difficulties regarding separation and identification are cyclopropylfentanyl and crotonylfentanyl, which have been reported to display nearly identical fragmentation patterns and chromatographic behavior.

METHODS

Chromatographic separation of cyclopropylfentanyl and crotonylfentanyl by ultra-high-performance liquid chromatography was investigated using 3 different stationary phases (high strength silica T3, ethylsiloxane/silica hybrid C18, and Kinetex biphenyl) using gradient elution with a mobile phase consisting of 10 mM ammonium formate pH 3.1 and MeOH. Detection was performed by tandem mass spectrometry. In addition, the major metabolites of the 2 compounds formed on incubation with human liver microsomes were identified by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis.

RESULTS

Baseline separation of cyclopropylfentanyl and crotonylfentanyl was achieved on the ethylsiloxane/silica hybrid C18 column with retention times of 6.79 and 7.35 minutes, respectively. The major metabolites of the 2 analogues formed by human liver microsomes differed, with the main biotransformation being N-dealkylation and carboxylation for cyclopropylfentanyl and crotonylfentanyl, respectively. We demonstrated the usefulness of the 2 approaches by unambiguously identifying cyclopropylfentanyl, as well as its metabolites, in 2 authentic postmortem blood samples.

CONCLUSIONS

In this study, we successfully demonstrated that cyclopropylfentanyl and crotonylfentanyl can be distinguished by methods commonly available in forensic laboratories.

The opioid mortality epidemic in North America: do we understand the supply side dynamics of this unprecedented crisis?

While there has been extensive attention to the 'demand side' - or use and adverse consequences, including mortality - of the 'opioid crisis' presently unfolding across North America, few considerations have focused on the supply side. This paper examines the supply side dynamics of this unprecedented public health phenomenon. We provide evidence for several interrelated supply-side elements that have contributed to the present public health crisis. We observe that initially, persistently high levels of prescription opioid availability and use exposed large proportions of the North American population to opioids, resulting in correspondingly high levels of medical and non-medical use (e.g., involving diversion). While various intervention measures to control prescription opioid availability and use have been implemented in recent years, leading to eventual reductions in opioid dispensing levels, these occurred late in the crisis's evolution. Moreover, these supply reductions have not been met by corresponding reductions in opioid use or demand levels. These growing discrepancies between opioid demand and prescription-based sources have left major gaps in opioid supplies. In response to such supply gaps, highly potent and toxic illicit opioid products have rapidly proliferated across North America, and become a core driver of the dramatic spikes in opioid overdose fatality levels in recent years. These supply-related interrelations are corroborated by a corresponding increase in illicit opioid-related fatalities, which arose just as medical opioid supplies began to decrease in many jurisdictions. Improved analyses and understanding of the supply-side dynamics of the opioid crisis are urgently needed in order to inform future intervention and policy development. Meanwhile, the high mortality toll related to illicit, highly toxic opioid exposure requires sustained solutions, including supply-oriented measures (e.g., safer opioid distribution for at-risk users) towards improved public health protection.

A deadly trend in fentanyl fatalities (England, 1998-2017)

AIM

To identify trends in drug-related deaths associated with fentanyl and its derivatives, including novel variants, in England, 1998-2017.

METHODS

Case reports from the National Programme on Substance Abuse Deaths (NPSAD) where a pharmaceutical fentanyl or non-pharmaceutical fentanyl derivative (NPFD) was found at post-mortem and/or implicated in the death were extracted for analysis.

RESULTS

NPSAD has received case reports detailing 298 deaths in England from 1998-2017 where a fentanyl was found at post-mortem and/or implicated in the death. Hospital administered fentanyl is "very safe", whereas pharmaceutical fentanyls in the community, procured either legitimately via prescription or illegitimately, carry high risk of unintentional death. Deaths involving NPFDs, which possess extreme potencies in comparison to morphine, have drastically risen over the past three years, and correlate with an increasing number of available compounds. Males, and those with existing opioid abuse disorders, are particularly susceptible to death related to NPFD intake.

CONCLUSIONS

The increasing availability of both pharmaceutical fentanyls and NPFDs represents a serious risk to public health. Unintentional misuse of these compounds in England is contributing to the exponential increase in fentanyl-associated deaths that is being observed at the global scale.

Application of the fentanyl analog screening kit toward the identification of emerging synthetic opioids in human plasma and urine by LC-QTOF

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 (LRL₁₀₀), 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.

Hyperpolarization of Pyridyl Fentalogues by Signal Amplification By Reversible Exchange (SABRE)

Fentanyl, also known as 'jackpot', is a synthetic opiate that is 50-100 times more potent than morphine. Clandestine laboratories produce analogues of fentanyl, known as fentalogues to circumvent legislation regarding its production. Three pyridyl fentalogues were synthesized and then hyperpolarized by signal amplification by reversible exchange (SABRE) to appraise the forensic potential of the technique. A maximum enhancement of -168-fold at 1.4 T was recorded for the ortho pyridyl 1H nuclei. Studies of the activation parameters for the three fentalogues revealed that the ratio of ligand loss trans to hydride and hydride loss in the complex [Ir(IMes)(L)3(H)2]+ (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazole-2-ylidene) ranged from 0.52 to 1.83. The fentalogue possessing the ratio closest to unity produced the largest enhancement subsequent to performing SABRE at earth's magnetic field. It was possible to hyperpolarize a pyridyl fentalogue selectively from a matrix that consisted largely of heroin (97 : 3 heroin:fentalogue) to validate the use of SABRE as a forensic tool.

Structure-Based Approach for the Prediction of Mu-opioid Binding Affinity of Unclassified Designer Fentanyl-Like Molecules

Three quantitative structure-activity relationship (QSAR) models for predicting the affinity of mu-opioid receptor (μOR) ligands have been developed. The resulted models, exploiting the accessibility of the QSAR modeling, generate a useful tool for the investigation and identification of unclassified fentanyl-like structures. The models have been built using a set of 115 molecules using Forge as a software, and the quality was confirmed by statistical analysis, resulting in being effective for their predictive and descriptive capabilities. The three different approaches were then combined to produce a consensus model and were exploited to explore the chemical landscape of 3000 fentanyl-like structures, generated by a theoretical scaffold-hopping approach. The findings of this study should facilitate the identification and classification of new μOR ligands with fentanyl-like structures.

Illicit fentanyls in the opioid street market: desired or imposed?

BACKGROUND

Illicitly manufactured fentanyl and its analogues are appearing in countries throughout the world, often disguised as heroin or counterfeit prescription pills, with resulting high overdose mortality. Possible explanations for this phenomenon include reduced costs and risks to heroin suppliers, heroin shortages, user preferences for a strong, fast-acting opioid and the emergence of Dark Web cryptomarkets. This paper addresses these potential causes and asks three questions: (1) can users identify fentanyl; (2) do users desire fentanyl; and (3) if users want fentanyl, can they express this demand in a way that influences the supply?

ARGUMENT/ANALYSIS

Existing evidence, while limited, suggests that some users can identify fentanyl, although not reliably, and some desire it, but because fentanyl is frequently marketed deceptively as other drugs, users lack information and choice to express demand effectively. Even when aware of fentanyl's presence, drug users may lack fentanyl-free alternatives. Cryptomarkets, while difficult to quantify, appear to offer buyers greater information and competition than offline markets. However, access barriers and patterns of fentanyl-related health consequences make cryptomarkets unlikely sources of user influence on the fentanyl supply. Market condition data indicate heroin supply shocks and shortages prior to the introduction of fentanyl in the United States and parts of Europe, but the much lower production cost of fentanyl compared with heroin may be a more significant factor CONCLUSION: Current evidence points to a supply-led addition of fentanyl to the drug market in response to heroin supply shocks and shortages, changing prescription opioid availability and/or reduced costs and risks to suppliers. Current drug users in affected regions of the United States, Canada and Europe appear largely to lack both concrete knowledge of fentanyl's presence in the drugs they buy and access to fentanyl-free alternatives.

Determination of Fentanyl Analog Exposure Using Dried Blood Spots with LC-MS-MS

Fentanyl, and the numerous drugs derived from it, are contributing to the opioid overdose epidemic currently underway in the USA. To identify human exposure to these growing public health threats, an LC-MS-MS method for 5 μL dried blood spots (DBS) was developed. This method was developed to detect exposure to 3-methylfentanyl, alfentanil, α-methylfentanyl, carfentanil, fentanyl, lofentanil, sufentanil, norcarfentanil, norfentanyl, norlofentanil, norsufentanil, and using a separate LC-MS-MS injection, cyclopropylfentanyl, acrylfentanyl, 2-furanylfentanyl, isobutyrylfentanyl, ocfentanil and methoxyacetylfentanyl. Preparation of materials into groups of compounds was used to accommodate an ever increasing need to incorporate newly identified fentanyls. This protocol was validated within a linear range of 1.00-100 ng/mL, with precision ≤12% CV and accuracy ≥93%, as reported for the pooled blood QC samples, and limits of detection as low as 0.10 ng/mL. The use of DBS to assess fentanyl analog exposures can facilitate rapid sample collection, transport, and preparation for analysis that could enhance surveillance and response efforts in the ongoing opioid overdose epidemic.