LC-MS/MS-Based Method for the Multiplex Detection of 24 Fentanyl Analogues and Metabolites in Whole Blood at Sub ng mL-1 Concentrations

Innovative disposable pipette extraction for concurrent analysis of fourteen psychoactive substances in drug users' sweat

Widespread consumption of drugs of abuse worldwide has caused concern: it adversely affects public health, individual safety, and social structures. Experts are particularly alarmed because new psychoactive substances have been increasingly detected in biological samples. In recent years, several studies have focused on developing methods to identify psychoactive substances in alternative biological matrices, such as sweat. This approach holds promise for monitoring substance use, especially in individuals undergoing rehabilitation. Among the commonly employed analytical procedures, extraction using disposable DPX tips stands out as a novel, miniaturized, and promising technique. This study aimed to validate and to apply a method to analyze various substances, including amphetamine, methamphetamine, MDMA, MDA, MDEA, cocaine, cocaethylene, anhydroecgonine methyl ester, dibutylone, N-ethylpentylone, 25E-NBOMe, 25CNBOMe, 2CC, 2C-E, fentanyl, and carfentanil, in sweat samples simultaneously. In this method, sweat is collected by using laboratory-developed patches, and extraction is conducted with DPX-SCX tips. Gas chromatography coupled to mass spectrometry is employed to separate, to identify, and to quantify the analytes. Validation results indicated that the quantification limit ranged from 2 to 30 ng of analyte/patch, and that the method was linear for analyte concentrations ranging from 2 to 1100 ng/patch. The validated method was applied to analyze 30 sweat samples collected from volunteers drug users and processed by using both the selected ion mode (SIM) and full scan. The method was able to detect and to quantify substances such as cocaine, cocaethylene, anhydroecgonine methyl ester, MDMA, MDA, nicotine, cotinine, caffeine, procaine, lidocaine, and ethylamphetamine simultaneously. The recovery rates ranged from 72.4 % to 97.1 %. The analytes were stable in the biological matrix. In conclusion, the validated method proved effective and allowed the target analytes to be quantified in sweat samples, highlighting that sweat is a viable matrix for analyzing drugs of abuse.

Elucidating the Gas-Phase Behavior of Nitazene Analog Protomers Using Structures for Lossless Ion Manipulations Ion Mobility-Orbitrap Mass Spectrometry

2-Benzylbenzimidazoles, or "nitazenes", are a class of novel synthetic opioids (NSOs) that are increasingly being detected alongside fentanyl analogs and other opioids in drug overdose cases. Nitazenes can be 20× more potent than fentanyl but are not routinely tested for during postmortem or clinical toxicology drug screens; thus, their prevalence in drug overdose cases may be under-reported. Traditional analytical workflows utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) often require additional confirmation with authentic reference standards to identify a novel nitazene. However, additional analytical measurements with ion mobility spectrometry (IMS) may provide a path toward reference-free identification, which would greatly accelerate NSO identification rates in toxicology laboratories. Presented here are the first IMS and collision cross section (CCS) measurements on a set of fourteen nitazene analogs using a structures for lossless ion manipulations (SLIM)-orbitrap MS. All nitazenes exhibited two high intensity baseline-separated IMS distributions, which fentanyls and other drug and druglike compounds also exhibit. Incorporating water into the electrospray ionization (ESI) solution caused the intensities of the higher mobility IMS distributions to increase and the intensities of the lower mobility IMS distributions to decrease. Nitazenes lacking a nitro group at the R1 position exhibited the greatest shifts in signal intensities due to water. Furthermore, IMS-MS/MS experiments showed that the higher mobility IMS distributions of all nitazenes possessing a triethylamine group produced fragment ions with m/z 72, 100, and other low intensity fragments while the lower mobility IMS distributions only produced fragment ions with m/z 72 and 100. The IMS, solvent, and fragmentation studies provide experimental evidence that nitazenes potentially exhibit three gas-phase protomers. The cyclic IMS capability of SLIM was also employed to partially resolve four sets of structurally similar nitazene isomers (e.g., protonitazene/isotonitazene, butonitazene/isobutonitazene/secbutonitazene), showcasing the potential of using high-resolution IMS separations in MS-based workflows for reference-free identification of emerging nitazenes and other NSOs.

Microwave-Enabled Fast Preparation of a Metal-Organic Framework Hybrid Membrane for Filtration-Enhanced Simultaneous Separation and Detection of Aflatoxin B1

Mycotoxin contamination in food and the environment seriously harms human health. Sensitive and timely detection of mycotoxins is crucial. Here, we report a dual-functional hybrid membrane with absorptivity and responsiveness for fluorescent-quantitative detection of mycotoxin aflatoxin B1 (AFB1). A biomineralization-inspired and microwave-accelerated fabrication method was established to prepare a hybrid membrane with a metal-organic framework (MOF) loaded in high density. The MOF presented high efficiency in capturing AFB1 and showed fluorescence intensity alteration simultaneously, enabling a dual adsorption-response mode. Deriving from the inherent porous structure of the hybrid membrane and the absorptive/responsive ability of the loaded MOF, a filtration-enhanced detection mode was elaborated to provide a 1.67-fold signal increase compared with the conventional soaking method. Therefore, the hybrid membrane exhibited a rapid response time of 10 min and a low detection limit of 0.757 ng mL-1, superior to most analogues in rapidity and sensitivity. The hybrid membrane also presented superior specificity, reproducibility, and anti-interference ability and even performed well in extreme environments such as strong acid or alkaline, satisfying the practical requirements for facile and in-field detection. Therefore, the membrane had strong applicability in chicken feed samples, with a detection recovery between 70.6% and 101%. The hybrid membrane should have significant prospects in the rapid and in-field inspection of mycotoxins for agriculture and food.

Electrochemical Determination of Fentanyl Using Carbon Nanofiber-Modified Electrodes

In this work, we report the direct electrochemical oxidation of fentanyl using commercial screen-printed carbon electrodes (SPCEs) modified with carboxyl-functionalized carbon nanofibers (fCNFs). CNFs have surface chemistry and reactivity similar to carbon nanotubes (CNTs), yet they are easier to produce and are of a lower cost than CNTs. By monitoring the current produced during the electrochemical oxidation of fentanyl, variables such as fCNF loading, fentanyl accumulation time, electrolyte pH, and differential pulse voltammetry parameters were optimized. Under an optimized set of conditions, the fCNF/SPCEs responded linearly to fentanyl in the concentration range of 0.125-10 μM, with a limit of detection of 75 nM. The fCNF/SPCEs also demonstrated excellent selectivity against common cutting agents found in illicit drugs (e.g., glucose, sucrose, caffeine, acetaminophen, and theophylline) and interferents found in biological samples (e.g., ascorbic acid, NaCl, urea, creatinine, and uric acid). The performance of the sensor was also successfully tested using fentanyl spiked into an artificial urine sample. The straightforward electrode assembly process, low cost, ease of use, and rapid response make the fCNF/SPCEs prime candidates for the detection of fentanyl in both physiological samples and street drugs.

Improved separation of fentanyl isomers using metal cation adducts and high-resolution ion mobility-mass spectrometry

Fentanyl is a potent synthetic opioid that has attracted significant attention due to its illegal production and distribution, resulting in misuse, overdose, and fatalities. Because numerous fentanyl analogs, including structural isomers, with different potency have been discovered in the field, there is a critical need to continue developing analytical methodologies capable of accurate identification in forensic and clinical laboratories. This study aimed to develop a rapid method for detecting and separating fentanyl isomers based on ion mobility-mass spectrometry (IM-MS), where IM separates gas-phase ions based on differences in their size, shape, and charge. Several strategies for improved differentiation were implemented, including using unconventional cation adducts (e.g., alkali and transition metals) and data post-processing by high-resolution demultiplexing. A collection of collision cross section (CCS) values for the various metal ion adducts was gathered, which can be used to improve confidence of identification in future samples. Notable examples, such as [M + Cu]+ and [M + Ag]+ adducts, contributed to significant improvement of resolution between isomers. Furthermore, the addition of high-resolution post-processing provided resolving power of >150, which constitutes a significant increase in comparison with the normal 50-60 obtained with low-resolution drift tube instruments. Collectively, these improved separation strategies allowed for confident detection and subsequent quantitative analysis. The optimized IM-MS method resulted in quantification of fentanyl in human urine with limits of detection and quantification of 13 pg/mL and 40 pg/mL, respectively.

Analysis of over 250 novel synthetic opioids and xylazine by LC-MS-MS in blood and urine

Novel Synthetic Opioids (NSO) are frequently found in postmortem (PM) and human performance (HP) forensic toxicology casework, resulting in impairment and fatal overdoses. Developing a broad NSO method benefits public health, as it can be used to identify trends in potent opioid use to develop risk management programs. This project aimed to design a comprehensive, rapid and routine method for the selective analysis of over 250 novel synthetic opioids in blood and urine. This method rapidly extracted 150 µL of blood or urine via protein precipitation followed by size-exclusion filtration, evaporation and reconstitution. Separation and data acquisition were achieved on a 12 min LC-MS-MS method using an F5 column. Data processing was expedited with a custom built-in query created in-house that automated processing and enhanced quality assurance. Validation according to ASB/ANSI Standard 036 was performed and applicability of the method was assessed using proficiency test and authentic casework samples. Assessed in blood and urine qualitatively were 261 unique analytes including fentanyl analogs (fentalogs), nitazenes and other miscellaneous synthetic opioids. As 59 isomeric target analytes were placed into groups due to co-elution, there were 202 distinct acquired targets or target - groups. To demonstrate applicability, 27 proficiency test blood samples received over an approximate 4-year period were analyzed with 126 expected results assessed comprising 25 unique target analytes. Additionally, 617 fatal accidental overdoses within San Francisco in 2022 were retroactively analyzed by this method with almost 10% of cases containing a new NSO substance(s). Such trends and NSO substances were previously unknown in this community.

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%).

Quantification of Fentanyl and Norfentanyl in Whole Blood Using Liquid Chromatography-Tandem Mass Spectrometry

Fentanyl is a synthetic opioid used in pain management with a potency 50-100 times that of morphine. Due to fentanyl's high potency, very low dosages are needed to elicit the desired response. Fentanyl is gaining popularity as a drug of abuse. Overdose of fentanyl causes respiratory depression that can lead to death. Fentanyl undergoes N-dealkylation in the liver to its inactive metabolite norfentanyl. Quantitation of fentanyl and its metabolite norfentanyl in whole blood can be performed using liquid chromatography-mass spectrometry. In this method, whole blood samples are spiked with deuterated internal standards for fentanyl and norfentanyl. The samples are alkalized with potassium hydroxide and the drugs are extracted with an organic solvent. Extracts are dried and reconstituted, then injected on LC-MS/MS. They are quantitated using positive ion multiple reaction monitoring (MRM) mode.

Comparative analysis of the metabolites and biotransformation pathways of fentanyl in the liver and brain of zebrafish

The rise of fentanyl has introduced significant new challenges to public health. To improve the examination and identification of biological samples in cases of fentanyl misuse and fatalities, this study utilized a zebrafish animal model to conduct a comparative investigation of the metabolites and biotransformation pathways of fentanyl in the zebrafish's liver and brain. A total of 17 fentanyl metabolites were identified in the positive ion mode using ultra-high-pressure liquid chromatography Q Exactive HF Hybrid Quadrupole-Orbitrap mass spectrometry (UHPLC-QE HF MS). Specifically, the zebrafish's liver revealed 16 fentanyl metabolites, including 6 phase I metabolites and 10 phase II metabolites. Conversely, the zebrafish's brain presented fewer metabolites, with only 8 detected, comprising 6 phase I metabolites and 2 phase II metabolites. Notably, M'4, a metabolite of dihydroxylation, was found exclusively in the brain, not in the liver. Through our research, we have identified two specific metabolites, M9-a (monohydroxylation followed by glucuronidation) and M3-c (monohydroxylation, precursor of M9-a), as potential markers of fentanyl toxicity within the liver. Furthermore, we propose that the metabolites M1 (normetabolite) and M3-b (monohydroxylation) may serve as indicators of fentanyl metabolism within the brain. These findings suggest potential strategies for extending the detection window and enhancing the efficiency of fentanyl detection, and provide valuable insights that can be referenced in metabolic studies of other new psychoactive substances.

Instrumentation development, improvement, simplification, and miniaturization: The multifunctional plate source for use in mass spectrometry

In remembrance of Prof. Dr Przybylski, we are presenting a vision towards his beloved mass spectrometry (MS) and its far-reaching promises outside of the academic laboratory. Sub-atmospheric pressure (AP) ionization MS is well positioned to make a step-change in direct ionization, a concept that allows sublimation/evaporation ionization and mass analyses of volatile and nonvolatile molecules from clean or dirty samples, directly, accurately, sensitively, and in a straightforward manner that has the potential to expand the field of MS into unchartered application areas. Contrary to ambient ionization MS, ionization commences in the sub-AP region of the mass spectrometer, important for practical and safety reasons, and offers inter alia, simplicity, speed, sensitivity, and robustness directly from real-world samples without cleanup. The plate source concept, presented here, provides an easy to use, rapid, and direct sample introduction from AP into the sub-AP of a mass spectrometer. Utilizing sub-AP ionization MS based on the plate source concept, small to large molecules from various environments that would be deemed too dirty for some direct MS methods are demonstrated. The new source concept can be expanded to include multiple ionization methods using the same plate source "front end" without the need to vent the mass spectrometer between the different methods, thus allowing ionization of more compounds on the same mass spectrometer for which any one ionization method may be insufficient. Examples such as fentanyl, gamma-hydroxybutyric acid, clozapine, 1-propionyllysergic acid, hydrocodone angiotensin I and II, myoglobin, and carbonic anhydrase are included.

The rise and rise of fentanyl in postmortem casework

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.

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

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

An Ultrasensitive Norfentanyl Sensor Based on a Carbon Nanotube-Based Field-Effect Transistor for the Detection of Fentanyl Exposure

The opioid crisis is a worldwide public health crisis that has affected millions of people. In recent years, synthetic opioids, primarily illicit fentanyl, have become the primary driver of overdose deaths. There is a great need for a highly sensitive, portable, and inexpensive analytical tool that can quickly indicate the presence and relative threat of fentanyl. In this work, we develop a semiconductor enriched (sc-) single-walled carbon nanotube (SWCNT)-based field-effect transistor (FET) biosensor functionalized with norfentanyl antibodies for the sensitive detection of norfentanyl, the primary inactive metabolite of fentanyl, in urine samples. Different sensor configurations were explored in order to obtain the most optimized sensing results. Moreover, by employing the "reduced" antibody, we achieved orientated immobilization of the norfentanyl antibody and thus brought the antigen-antibody interaction closer to the sensor surface, further improving the sensitivity. The reported norfentanyl biosensors have a limit of detection in the fg/mL region in both calibration samples and synthetic urine samples, showing ultrasensitivity and high reliability.

The Synthetic Opioid Fentanyl Increases HIV Replication and Chemokine Co-Receptor Expression in Lymphocyte Cell Lines

BACKGROUND

In the United States, the illicit use of synthetic opioids such as fentanyl has led to a serious public health crisis. Synthetic opioids are known to enhance viral replication and to suppress immunologic responses, but their effects on HIV pathogenesis remain unclear. Thus, we examined the impact of fentanyl on HIV-susceptible and HIV-infected cell types.

METHODS

TZM-bl and HIV-infected lymphocyte cells were incubated with fentanyl at varying concentrations. Expression levels of the CXCR4 and CCR5 chemokine receptors and HIV p24 antigen were quantified with ELISA. HIV proviral DNA was quantified using SYBR RT-PCR. Cell viability was detected with the MTT assay. RNAseq was performed to characterize cellular gene regulation in the presence of fentanyl.

RESULTS

Fentanyl enhanced expression of both chemokine receptor levels in a dose-dependent manner in HIV-susceptible and infected cell lines. Similarly, fentanyl induced viral expression in HIV-exposed TZM-bl cells and in HIV-infected lymphocyte cell lines. Multiple genes associated with apoptosis, antiviral/interferon response, chemokine signaling, and NFκB signaling were differentially regulated.

CONCLUSIONS

Synthetic opioid fentanyl impacts HIV replication and chemokine co-receptor expression. Increased virus levels suggest that opioid use may increase the likelihood of transmission and accelerate disease progression.

Attitudes and experiences with fentanyl contamination of methamphetamine: exploring self-reports and urine toxicology among persons who use methamphetamine and other drugs

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.

Quantitative Label-Free SERS Detection of Trace Fentanyl in Biofluids with a Freestanding Hydrophobic Plasmonic Paper Biosensor

The prevalence of fentanyl abuse raises global public health concerns with an unprecedented surge in overdose deaths. Rapid identification and quantification of fentanyl in biofluids is of paramount importance to combat fentanyl abuse for law enforcement agencies and promptly treat patients for medical professionals. Herein, a freestanding surface-enhanced Raman spectroscopy (SERS) biosensor with excellent condensing enrichment capability, termed FrEnSERS biosensor, is reported for quantitative label-free detection of trace fentanyl in biofluids. This biosensor comprises a reduced graphene oxide membrane decorated with high-density hydrophobic Au nanostars. A combination of the high SERS enhancement and the focusing effect for analyte enrichment of the hydrophobic surface accounts for the remarkable SERS performance of the FrEnSERS biosensor. We demonstrate that the FrEnSERS biosensor achieves the sensitive and quantitative detection of fentanyl in both serum and urine over a wide dynamic range spanning more than 4 orders of magnitude, with a limit of detection of 0.47 ng/mL for serum samples and 0.73 ng/mL for urine samples. Our biosensor is sensitive, cost-effective, and reliable for rapid quantitative analysis of fentanyl in biofluids with great promise for forensic analysis and clinical diagnosis.

Discovery and Structural Explorations of G-Protein Biased μ-Opioid Receptor Agonists

Compounds that activate only the G-protein signalling pathway represent an effective strategy for making safer opioids. In the present study, we report the design, synthesis and evaluation of two classes of novel PZM21 derivatives containing the benzothiophene ring and biphenyl ring group respectively as biased μ-opioid receptor (μOR) agonists. The new compound SWG-LX-33 showed potent μOR agonist activity and produced μOR-dependent analgesia. SWG-LX-33 does not activate the β-arrestin-2 signalling pathway in vitro even at high concentrations. Computational docking demonstrated the amino acid residue ASN150 to be critical for the weak efficacy and potency of μOR agonists in arrestin recruitment.

Analysis, identification and confirmation of synthetic opioids using chloroformate chemistry: Retrospective detection of fentanyl and acetylfentanyl in urine and plasma samples by EI-GC-MS and HR-LC-MS

Electron Impact Gas Chromatography-Mass Spectrometry (EI-GC-MS) and High Resolution Liquid Chromatography-Mass Spectrometry (HR-LC-MS) have been used in the analysis of products arising from the trichloroethoxycarbonylation of fentanyl and acetylfentanyl in urine and plasma matrices. The method involves the initial extraction of both synthetic opioids separately from the matrices followed by detection of the unique products that arise from their reaction with 2,2,2-trichloroethoxycarbonyl chloride (Troc-Cl), namely Troc-norfentanyl and Troc-noracetylfentanyl. The optimized protocol was successfully evaluated for its efficacy at detecting these species formed from fentanyl and acetylfentanyl when present at low and high levels in urine (fentanyl: 5 and 10 ng/mL and acetylfentanyl: 20 and 100 ng/mL) and plasma (fentanyl: 10 and 20 ng/mL and acetylfentanyl: 50 and 200 ng/mL), values that reflect levels reported in overdose victims. The HR-LC-MS method's LOQ (limit of quantitation) for the Troc-norfentanyl and Troc-noracetylfentanyl products was determined to be ~10 ng/mL for both species. Even though the superiority in the detection of these species by HR-LC-MS over EI-GC-MS, the latter method proved to be important in the detection of the second product from the reaction, namely 2-phenylethyl chloride that is crucial in the determination of the original opioid. This observation highlights the importance of using complimentary analytical techniques in the analysis of a sample, whether biological or environmental in nature. The method herein serves as a complementary, qualitative confirmation for the presence of a fentanyl in collected urine, plasma and by extension other biological samples amenable to the common extraction procedures described for opioid analysis. More importantly, the method's main strength comes from its ability to react with unknown fentanyls to yield products that can be not only detected by EI-GC-MS and HR-LC-MS but can then be used to retrospectively identify an unknown fentanyl.

Comparative study of the analysis of seized samples by GC-MS, 1H NMR and FT-IR spectroscopy within a Night-Time Economy (NTE) setting

Rapid analysis of surrendered or seized drug samples provides important intelligence for health (e.g. treatment or harm reduction), and custodial services. Herein, three in-situ techniques, GC-MS, ¹H NMR and FT-IR spectroscopy, with searchable libraries, are used to analyse 318 samples qualitatively, using technique specific library-based searches, obtained over the period 24th - 29th August 2019. 259 samples were identified as consisting of a single component, of which cocaine was the most prevalent (n = 158). Median match scores for all three techniques were ≥ 0.84 and showed agreement except for metformin (n = 1), oxandrolone (identified as vitamin K by IR (n = 4)), diazepam (identified as zolpidem by FT-IR (n = 2)) and 2-Br-4,5-DMPEA (n = 1), a structural isomer of 2C-B identified as a polymer of cellulose (cardboard) by FT-IR. 51 samples were found to consist of two or more components, of which 49 were adulterated cocaine samples (45 binary and 4 tertiary samples). GC-MS identified all components present in the 49 adulterated cocaine samples, whereas IR identified only cocaine in 88 % of cases (adulterant only = 12 %). The breakdown for ¹H NMR spectroscopy was all components identified (51 %), cocaine only (33 %), adulterant only (10 %), cocaine and one adulterant (tertiary mixtures only, 6 %).

Reports of Adverse Events Associated with Use of Novel Psychoactive Substances, 2017-2020: A Review

An important role of modern forensic and clinical toxicologists is to monitor the adverse events of novel psychoactive substances (NPS). Following a prior review from 2013 to 2016, this critical literature review analyzes and evaluates published case reports for NPS from January 2017 through December 2020. The primary objective of this study is to assist in the assessment and interpretation of these cases as well as provide references for confirmation methods. Chemistry, pharmacology, adverse events and user profiles (e.g., polypharmacy) for NPS are provided including case history, clinical symptoms, autopsy findings and analytical results. Literature reviews were performed in PubMed and Google Scholar for publications using search terms such as NPS specific names, general terms (e.g., 'designer drugs' and 'novel psychoactive substances'), drug classes (e.g., 'designer stimulants') and outcome-based terms (e.g., 'overdose' and 'death'). Government and website drug surveillance databases and abstracts published by professional forensic science organizations were also searched. Toxicological data and detailed case information were extracted, tabulated, analyzed and organized by drug category. Case reports included overdose fatalities (378 cases), clinical treatment and hospitalization (771 cases) and driving under the influence of drugs (170 cases) for a total of 1,319 cases providing details of adverse events associated with NPS. Confirmed adverse events with associated toxidromes of more than 60 NPS were reported including synthetic cannabinoid, NPS stimulant, NPS hallucinogen, NPS benzodiazepine and NPS opioid cases. Fifty of these NPS were reported for the first time in January 2017 through December 2020 as compared to the previous 4 years surveyed. This study provides insight and context of case findings described in the literature and in digital government surveillance databases and websites during a recent 4-year period. This review will increase the awareness of adverse events associated with NPS use to better characterize international emerging drug threats.

Analysis of conventional and nonconventional forensic specimens in drug-facilitated sexual assault by liquid chromatography and tandem mass spectrometry

The incidence of drug-facilitated sexual assault (DFSA) has dramatically increased in the last decades. Forensic analytical scientists continuously seek new methods and specimens to prove the incidence of intoxication for the judiciary system. Factors influencing sample selection include the ease of obtaining the samples and the window of detection of the drugs, among others. Both conventional (blood, urine) and non-conventional specimens (hair, nails, fluids) have been proposed as suitable in DFSA cases. Reported sample treatments include a variety of liquid-liquid and solid-phase extraction as well as dilute-and-shoot procedures and microextraction techniques. Regarding analysis, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has emerged as the preferred confirmatory technique, due to its sensitivity, selectivity, and wide-scope applicability. In this review, we critically discuss the most common specimens and sample treatments/analysis procedures (related to LC-MS/MS) that have been reported during the last ten years. As a final goal, we intend to provide a critical overview and suggest analytical recommendations for the establishment of suitable analytical strategies in DFSA cases.

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.

CFM-ID 4.0 - a web server for accurate MS-based metabolite identification

The CFM-ID 4.0 web server (https://cfmid.wishartlab.com) is an online tool for predicting, annotating and interpreting tandem mass (MS/MS) spectra of small molecules. It is specifically designed to assist researchers pursuing studies in metabolomics, exposomics and analytical chemistry. More specifically, CFM-ID 4.0 supports the: 1) prediction of electrospray ionization quadrupole time-of-flight tandem mass spectra (ESI-QTOF-MS/MS) for small molecules over multiple collision energies (10 eV, 20 eV, and 40 eV); 2) annotation of ESI-QTOF-MS/MS spectra given the structure of the compound; and 3) identification of a small molecule that generated a given ESI-QTOF-MS/MS spectrum at one or more collision energies. The CFM-ID 4.0 web server makes use of a substantially improved MS fragmentation algorithm, a much larger database of experimental and in silico predicted MS/MS spectra and improved scoring methods to offer more accurate MS/MS spectral prediction and MS/MS-based compound identification. Compared to earlier versions of CFM-ID, this new version has an MS/MS spectral prediction performance that is ∼22% better and a compound identification accuracy that is ∼35% better on a standard (CASMI 2016) testing dataset. CFM-ID 4.0 also features a neutral loss function that allows users to identify similar or substituent compounds where no match can be found using CFM-ID’s regular MS/MS-to-compound identification utility. Finally, the CFM-ID 4.0 web server now offers a much more refined user interface that is easier to use, supports molecular formula identification (from MS/MS data), provides more interactively viewable data (including proposed fragment ion structures) and displays MS mirror plots for comparing predicted with observed MS/MS spectra. These improvements should make CFM-ID 4.0 much more useful to the community and should make small molecule identification much easier, faster, and more accurate.

Current and Future Perspective of Devices and Diagnostics for Opioid and OIRD

OIRD (opioid-induced respiratory depression) remains a significant public health concern due to clinically indicated and illicit opioid use. Respiratory depression is the sine qua non of opioid toxicity, and early detection is critical for reversal using pharmacologic and non-pharmacologic interventions. In addition to respiratory monitoring devices such as pulse oximetry, capnography, and contactless monitoring systems, novel implantable sensors and detection systems such as optical detection and electrochemical detection techniques are being developed to identify the presence of opioids both in vivo and within the environment. These new technologies will not only monitor for signs and symptoms of OIRD but also serve as a mechanism to alert and assist first responders and lay rescuers. The current opioid epidemic brings to the forefront the need for additional accessible means of detection and diagnosis. Rigorous evaluation of safety, efficacy, and acceptability will be necessary for both new and established technologies to have an impact on morbidity and mortality associated with opioid toxicity. Here, we summarized existing and advanced technologies for opioid detection and OIRD management with a focus on recent advancements in wearable and implantable opioid detection. We expect that this review will serve as a complete informative reference for the researchers and healthcare professionals working on the subject and allied fields.

Determination of synthetic opioids in oral fluid samples using fabric phase sorptive extraction and gas chromatography-mass spectrometry

New psychoactive substances (NPS) continue to emerge in the drug market every year, becoming a global threat to public health and safety. These compounds are mostly synthetic cannabinoids and designer cathinones. However, synthetic opioids have appeared on the recreational drug markets in recent years, particularly fentanyl and its derivatives ("fentanyls"). Fentanyl and its analogs are related to harmful intoxications and an increase in opioid-related mortality in many countries, such as in the United States and Europe in the last years. Taking the drug related global crisis into consideration, this work developed and validated an effective and sensitive method based on fabric phase sorptive extraction (FPSE) followed by gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 11 fentanyl analogs in oral fluid samples. The extraction was carried out using a sol-gel Carbowax 20 M sorbent immobilized on 100% cellulose fabric substrate and using ethyl acetate as the desorption solvent. The limits of detection (LODs) and quantification (LOQs) ranged from 1 to 15 ng mL^-1 and 5 to 50 ng mL^-1, respectively. Intra-day and inter-day precision were found within 8.2% and 8.6%, respectively, while accuracy ranged from -5.5 to 9.1%, in accordance with the established criteria. The absolute recovery values were in the range of 94.5%-109.1%. The validated method demonstrated its great potential to detect and quantify fentanyl analogs in possible forensic work and off-site analysis in road traffic cases.

Novel Applications of Microextraction Techniques Focused on Biological and Forensic Analyses

In recent years, major attention has been focused on microextraction procedures that allow high recovery of target analytes, regardless of the complexity of the sample matrices. The most used techniques included liquid-liquid extraction (LLE), solid-phase extraction (SPE), solid-phase microextraction (SPME), dispersive liquid-liquid microextraction (DLLME), microextraction by packed sorbent (MEPS), and fabric-phase sorptive extraction (FPSE). These techniques manifest a rapid development of sample preparation techniques in different fields, such as biological, environmental, food sciences, natural products, forensic medicine, and toxicology. In the biological and forensic fields, where a wide variety of drugs with different chemical properties are analyzed, the sample preparation is required to make the sample suitable for the instrumental analysis, which often includes gas chromatography (GC) and liquid chromatography (LC) coupled with mass detectors or tandem mass detectors (MS/MS). In this review, we have focused our attention on the biological and forensic application of these innovative procedures, highlighting the major advantages and results that have been accomplished in laboratory and clinical practice.

[Analysis of 29 fentanyl analogs and their fragmentation mechanism by liquid chromatography-quadrupole time-of-flight mass spectrometry]

Given the wide variety of fentanyl analogs, the test for this entire group tends to be crucial and particularly difficult since all fentanyl-like substances are listed as controlled substances in China. This study meticulously analyzed the fragmentation pathways and mechanisms of 29 fentanyl analogs and summarized the fragmentation pathways and features for the entire group of fentanyl analogs, thus providing a reference for related screening tests. Fentanyl, thiofentanyl, and sufentanil were selected as the representative compounds in this study, and the fragmentation mechanism of their fragment ions was interpreted. The general fragmentation rules for fentanyl analogs were summarized as well. The fragment ions of the three compounds formed by induced cleavage (i) came with high abundance ratios, such as fragment ions of m/z 188, 105, 194, 111, and 238, while the induced cleavage was due to the amide and piperidinyl groups. Moreover, the induction ability of amide group was significantly stronger than that of the piperidinyl group, and induced cleavage was the main fragmentation pathway for most of the fentanyl analogs. Furthermore, the fragment ions with m/z 281 and 287 for fentanyl and thiofentanyl were formed by loss of the propionyl group after single H rearrangement (rH). The fragment ions with m/z 216, 146, and 132 for fentanyl and thiofentanyl were formed by double H rearrangement (r2H). Although their abundance ratios were not high, they still had specificity and regularity. Elimination reaction (re) was also a very common fragmentation pathway for these compounds, leading to fragment ions with m/z 134 and 140. Phenylethyl substituents were more prone to the elimination reaction with a higher abundance ratio than thiophenethyl substituents. Compounds such as sufentanil with methoxy substituents at the piperidinyl para-position could produce a large number of fragment ions, which were more susceptible to the rH pathway and loss of methanol neutral molecules, leading to the formation of ions with m/z 355. Similarly, compounds such as remifentanil bearing a methyl formate substituent at the piperidine para-position also produced numerous fragment ions, which were more prone to the rH pathway to lose methyl formate or methanol neutral molecules and furnish fragment ions with m/z 317 or 345. Compounds containing hydroxyl substituents, such as β-hydroxyfentanyl and β-hydroxythiofentanyl, produce significant dehydration ions and formed fragment ions with m/z 335 (β-hydroxyfentanyl) and m/z 341 (β-hydroxythiofentanyl). A method based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for the qualitative and quantitative determination of the 29 fentanyl analogs was developed. Drugs and white powder samples were extracted by acetonitrile, as well as protein and milk beverage samples. Sugar-containing solids or powders, drinking water, fruit and vegetable drinks, health drinks, tea drinks, and alcohol samples were extracted by 10% acetonitrile aqueous solution. Following vortexing, centrifugation, and membrane separation, the target compounds were separated on a Kinetex C18 column (100 mm×2.1 mm, 2.6 μm) with gradient elution at a flow rate of 0.4 mL/min. The mobile phases were composed of acetonitrile and 0.08% formic acid aqueous solution. The target compounds were quantified by LC-QTOF-MS using an external standard method in positive ion mode. The 29 fentanyl analogs showed good linear relationships in the range of 1-20 μg/L, and the correlation coefficients were greater than 0.995. The limits of detection (LODs) and limits of quantification (LOQs) were 0.01 mg/kg and 0.05, respectively. The average recoveries were 85.2%-112.9% for hypoglycemic drugs, Lulu drinks, glucose powder, Zhenlu health drink and chocolate, with RSDs of 1.9%-19.8% (n=6). This method is rapid, simple, time-saving, highly sensitivity and stable, and it is applicable to a wide variety of samples. Hence, it is suitable for the identification, confirmation, and quantitative detection of the 29 fentanyl analogs in drugs, solids or powders containing sugar, beverages, drinking water, wine samples, etc.

Use of Diagnostic Ions for the Detection of Fentanyl Analogs in Human Matrices by LC-QTOF

To combat the ongoing opioid epidemic, our laboratory has developed and evaluated an approach to detect fentanyl analogs in urine and plasma by screening LC-QTOF MS/MS spectra for ions that are diagnostic of the core fentanyl structure. MS/MS data from a training set of 142 fentanyl analogs were used to select the four product ions and six neutral losses that together provided the most complete coverage (97.2%) of the training set compounds. Furthermore, using the diagnostic ion screen against a set of 49 fentanyl analogs not in the training set resulted in 95.9% coverage of those compounds. With this approach, lower reportable limits for fentanyl and a subset of fentanyl-related compounds range from 0.25 to 2.5 ng/mL in urine and 0.5 to 5.0 ng/mL in plasma. This innovative processing method was applied to evaluate simulated exposure samples of remifentanil and carfentanil in water and their metabolites remifentanil acid and norcarfentanil in urine. This flexible approach enables a way to detect emerging fentanyl analogs in clinical samples.

Development of a New LC-MS/MS Screening Method for Detection of 120 NPS and 43 Drugs in Blood

In the last few years, liquid chromatography coupled with mass spectrometry (LC/MS) has been increasingly used for screening purposes in forensic toxicology. These techniques have the advantages of low time/resource-consuming and high versatility and have been applied in numerous new multi-analytes methods. The new psychoactive substance (NPS) phenomenon provided a great impulse to this wide-range approach, but it is also important to keep the attention on “classical” psychoactive substances, such as benzodiazepines (BDZ). In this paper, a fully validated screening method in blood for the simultaneous detection of 163 substances (120 NPS and 43 other drugs) by a dynamic multiple reaction monitoring analysis through LC-MS/MS is described. The method consists of a deproteinization of 200 µL of blood with acetonitrile. The LC separation is achieved with a 100 mm long C18 column in 35 min. The method was very sensitive, with limits of quantification from 0.02 to 1.5 ng/mL. Matrix effects did not negatively affect the analytical sensitivity. This method proved to be reliable and was successfully applied to our routinary analytical activity in several forensic caseworks, allowing the identification and quantification of many BDZs and 3,4-methylenedioxypyrovalerone (MDPV).

Novel chimeric monoclonal antibodies that block fentanyl effects and alter fentanyl biodistribution in mice

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.

Blood concentrations of new synthetic opioids

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Respiratory depressant effects of fentanyl analogs are opioid receptor-mediated

Opioid-related fatalities involving synthetic opioids have reached unprecedented levels. This study evaluated the respiratory depressant effects of seven fentanyl analogs that have either emerged in the illicit drug supply or been identified in toxicological analyses following fatal or non-fatal intoxications. Adult male Swiss Webster mice were administered fentanyl analogs (isobutyrylfentanyl, crotonylfentanyl, para-methoxyfentanyl, para-methoxybutyrylfentanyl, 3-furanylfentanyl, thiophenefentanyl, and benzodioxolefentanyl) and their effects on minute volume as compared to mu-opioid receptor (MOR) agonist standards (fentanyl, morphine, and buprenorphine) were measured using whole body plethysmography (WBP). All drugs elicited significant (p ≤ 0.05) hypoventilation relative to vehicle for at least one dose tested: morphine (1, 3.2, 10, 32 mg/kg), buprenorphine, (0.032, 0.1, 0.32, 1, 3.2 mg/kg), fentanyl (0.0032, 0.01, 0.032, 0.1, 1, 32 mg/kg), isobutyrylfentanyl (0.1, 0.32, 1, 3.2, 10 mg/kg), crotonylfentanyl (0.1, 0.32, 1, 3.2, 10 mg/kg), para-methoxyfentanyl (0.1, 0.32, 1, 3.2, 10 mg/kg), para-methoxybutyrylfentanyl (0.32, 1, 3.2, 10 mg/kg), 3-furanylfentanyl (0.1, 0.32, 1, 3.2, 10 mg/kg), thiophenefentanyl (1, 3.2, 10, 32, 100 mg/kg), and benzodioxolefentanyl (3.2, 10, 32, 100 mg/kg). The ED₅₀ values for hypoventilation showed a rank order of potency as follows: fentanyl (ED₅₀ = 0.96 mg/kg) > 3-furanylfentanyl (ED₅₀ = 2.60 mg/kg) > crotonylfentanyl (ED₅₀ = 2.72 mg/kg) > para-methoxyfentanyl (ED₅₀ = 3.31 mg/kg) > buprenorphine (ED₅₀ = 10.8 mg/kg) > isobutyrylfentanyl (ED₅₀ = 13.5 mg/kg) > para-methoxybutyrylfentanyl (ED₅₀ = 16.1 mg/kg) > thiophenefentanyl (ED₅₀ = 18.0 mg/kg) > morphine (ED₅₀ = 55.3 mg/kg) > benzodioxolefentanyl (ED₅₀ = 10,168 mg/kg). A naloxone pretreatment (10 mg/kg) attenuated the hypoventilatory effects of all drugs. These results establish that the respiratory depressant effects of these fentanyl analogs are at least in part mediated by the MOR.

Lay knowledge and practices of methamphetamine use to manage opioid-related overdose risks

AIM

Methamphetamine use has increased among individuals with opioid use disorder. The key aims of this study are to detail and contextualise lay knowledge, attitudes, and behaviours related to methamphetamine use in relation to opioid overdose risks in an area dominated by non-pharmaceutical fentanyl-type drugs (NPF).

METHODS

The study recruited 41 individuals in Dayton, Ohio, who reported past 30-day use of methamphetamine and heroin/fentanyl. Interviews included structured and qualitative questions. Urine toxicology analysis was conducted to identify NPFs and other drugs. Open-ended interview sections were audio-recorded, transcribed, and analysed qualitatively using NVivo.

RESULTS

The mean age was 38.3 years, 51% were female, and 100% non-Hispanic white. Participants described an exceedingly unpredictable local opioid market that became saturated with NPFs. The sample tested positive for 10 NPFs, including fentanyl (100%), acetyl fentanyl (61%), tetrahydrofuran fentanyl (29%), and carfentanil (12%). Most participants believed that methamphetamine could help prevent and/or reverse an opioid-related overdose. Nearly half had personally used it to help manage overdose risks related to NPF. These beliefs were embedded in a lay understanding of how methamphetamine works to stimulate the cardiovascular system. They were acted upon in the context of last resort situations that were determined by a lack of immediate access to naloxone, ambiguities surrounding overdose symptomatology, and easy access to plentiful and inexpensive methamphetamine.

CONCLUSION

Lay efforts to rely on methamphetamine to manage NPF-related overdose risks highlight the need for a continuing expansion of take-home-naloxone programs and implementation of other novel harm reduction approaches in communities affected by NPFs.

Lipemia in the Plasma Sample Affects Fentanyl Measurements by Means of HPLC-MS2 after Liquid-Liquid Extraction

Examination of fentanyl levels is frequently performed in certain scientific evaluations and forensic toxicology. It often involves the collection of very variable blood samples, including lipemic plasma or serum. To date, many works have reported the methods for fentanyl detection, but none of them have provided information about the impact on the assay performance caused by an excessive amount of lipids. This aspect may be, however, very important for highly lipophilic drugs like fentanyl. To address this issue, we developed the liquid chromatography method with mass spectrometry detection and utilized it to investigate the impact of lipids presence in rabbit plasma on the analytical method performance and validation. The validation procedure, conducted for normal plasma and lipemic plasma separately, resulted in good selectivity, sensitivity and linearity. The limits of detection and quantification were comparable between the two matrices, being slightly lower in normal plasma (0.005 and 0.015 µg/L) than in lipemic plasma (0.008 and 0.020 µg/L). Liquid–liquid extraction provided a low matrix effect regardless of the lipid levels in the samples (<10%), but pronounced differences were found in the recovery and accuracy. In the normal plasma, this parameter was stable and high (around 100%), but in the lipemic matrix, much more variable and less efficient results were obtained. Nevertheless, this difference had no impact on repeatability and reproducibility. In the present work, we provided reliable, convenient and sensitive method for fentanyl detection in the normal and lipemic rabbit plasma. However, construction of two separate validation curves was necessary to provide adequate results since the liquid-liquid extraction was utilized. Therefore, special attention should be paid during fentanyl quantification that involves lipemic plasma samples purified by this technique.

Fentanyl, Acetylfentanyl, and Carfentanil in Impaired Driving Cases: A Review of 270 Cases

The detection of fentanyl and fentanyl analogs has been widely communicated throughout the scientific community. While most of the reporting has been in relation to overdose deaths, these drugs are commonly detected in impaired driving cases. A retrospective study of impaired driving cases analyzed between 2017 and 2019 produced 270 cases positive for fentanyl, carfentanil, and/or acetylfentanyl. Fentanyl was the predominant drug found in these 270 cases (65.5%) with concentrations ranging from less than 1.0 ng/mL to 64 ng/mL. Carfentanil was found alone in 6.6% cases with three concentrations above 1.0 ng/mL. Acetylfentanyl was always found when fentanyl was positive with concentrations ranging from less than 1.0 ng/mL to 9.2 ng/mL. Detailed case histories are provided with corresponding toxicology results. Toxicology results show impaired drivers using multiple drugs with a wide range of observed behaviors. The inclusion of these drugs in routine impaired driver toxicology testing is extremely important when attempting to determine their overall prevalence.

Fentanyl-related substances elicit antinociception and hyperlocomotion in mice via opioid receptors

Synthetic opioids have been implicated as the single greatest contributor to rising drug-related fatalities in recent years. This study evaluated mu-opioid receptor (MOR) mediated effects of seven fentanyl-related substances that have emerged in the recreational drug marketplace, and for which there are no existing or only limited in vivo data. Adult male Swiss Webster mice were administered fentanyl-related substances and their effects on nociception and locomotion as compared to MOR agonist standards were observed. In locomotor activity tests, morphine (100, 180 mg/kg), fentanyl (1, 10 mg/kg), beta-methylfentanyl (10 mg/kg), para-methoxyfentanyl (10 mg/kg), fentanyl carbamate (100 mg/kg), and 3-furanylfentanyl (10 mg/kg), elicited significant (p ≤ 0.05) dose-dependent increases in locomotion. However, para-methylfentanyl and beta'-phenylfentanyl did not produce significant effects on locomotion at doses up to 100 mg/kg and phenylfentanyl (100 mg/kg) significantly decreased locomotion. In warm-water tail-withdrawal tests, all substances produced significant dose-dependent increases in antinociception with increasing ED₅₀ values (95% CI) of fentanyl [0.08 mg/kg (0.04-0.16)] > para-methoxyfentanyl [0.43 mg/kg (0.23-0.77)] > 3-furanylfentanyl [0.51 mg/kg (0.36-0.74)] > beta-methylfentanyl [0.74 mg/kg (0.64-0.85)] > para-methylfentanyl [1.92 mg/kg (1.48-2.45)] > fentanyl carbamate [5.59 mg/kg (4.11-7.54)] > morphine [7.82 mg/kg (5.42-11.0)] > beta'-phenylfentanyl [19.4 mg/kg (11.0-34.4)] > phenylfentanyl [55.2 mg/kg (33.5-93.0)]. Naltrexone (1 mg/kg) increased ED₅₀ values several fold with decreasing magnitudes of para-methylfentanyl (63.1×) > para-methoxyfentanyl (22.5×) > beta'-phenylfentanyl (21.0×) > 3-furanylfentanyl (20.6×) > beta-methylfentanyl (19.2×) > phenylfentanyl (5.23×) > fentanyl (3.95×) > fentanyl carbamate (2.21×) > morphine (1.48×). These findings expand upon in vivo results from previous studies and establish that the effects of these fentanyl related-related substances are at least in part mediated by the MOR.

Rapid Determination of Sufentanil in Human Plasma by UHPLC-QqQ-MS-MS

This paper presents a rapid, sensitive and precise method developed and validated for the quantification of sufentanil in biological samples using ultra-performance liquid chromatography coupled with QqQ-MS-MS. Plasma samples were extracted with simple and fast liquid-liquid extraction (ethyl acetate, pH 9). Calibration curve showed linearity in the concentration range of 0.005-30 µg/L. The lower limit of quantification was 0.010 µg/L. The most important method features are low lower limit of quantification value, simple plasma extraction and small sample volume. This method is suitable not only for evaluation of the pharmacokinetics, toxicology, bioavailability and clinical pharmacology of sufentanil but also for the detection and identification of this compound in human plasma samples for forensic purposes.

Suspect Screening of Fentanyl Analogs Using Matrix-Assisted Ionization and a Miniature Mass Spectrometer with a Custom Expandable Mass Spectral Library

The reliable identification of fentanyl and its analogs is of great significance for public security. However, with the growing prevalence of fentanyl compounds, current analytical strategies cannot fully meet the need for fast and high-throughput detection. In this study, a simple, rapid, and on-site analytical protocol was developed based on a miniature mass spectrometer. A dramatically simplified workflow was implemented using matrix-assisted ionization, bypassing complex sample pretreatment and chromatographic separation. The tandem mass spectrometry (MS/MS) capability afforded by the miniature ion trap mass spectrometer facilitated the investigation of fragmentation patterns for 49 fentanyl analogs during collision-induced dissociation, revealing valuable information on marker fragment ions and characteristic neutral loss. Calculations on Laplacian bond order values further verified the mass spectrometric behavior. A computation-assisted expandable mass spectral library was constructed in-house for fentanyl compounds. Smart suspect screening was carried out based on the full-scan MS and MS/MS data. The present study demonstrates an appealing potential for forensic applications, enabling streamlined screening for the presence of illicit fentanyl compounds at the point of seizures of suspect samples.

Cations Derived from Fentanyls Generated by Atmospheric Pressure Photoionization in the Presence of Ammonia: An IMS-MS Study

A set of fentanyl molecules when subjected to vacuum UV atmospheric pressure photoionization (VUV-APPI) in the presence of dopants (ammonia and anisole) shows two major bands in the ion mobility-mass spectrometry (IMS-MS) spectrum corresponding to (a) the protonated fentanyl, [M+H]⁺ and (b) a unique [M-74]⁺ ion. For the parent fentanyl, the [M-74]⁺ ion is at m/z 262 but, in the absence of ammonia, the product ion is shifted to m/z 245, corresponding to a difference of NH₃. Collision-induced dissociations (CID) of the [M-74]⁺ ions for all the different fentanyls examined here show the same pattern of neutral losses, namely NH₃ and HN=CH₂, and the dominant product ion is at m/z 84 (shifted to m/z 98 for 3-methylfentanyl and m/z 142 and 231 for carfentanyl). Dissociation of the [M-74-NH₃]⁺ ion derived from the fentanyls yields the same product ions as found in the electron impact (EI) ionization spectra of the fentanyls. The dissociation products of the [M-74-HN=CH₂]⁺ ion are different, include the ion at m/z 84, and correspond to the fragmentation products of protonated norfentanyls. Theoretical modeling supports the opening of new fragmentation channels as a result of the reaction of the initially formed iminium cation with ammonia at atmospheric pressure.

Quantification and distribution of 4-fluoroisobutyryl fentanyl (4-FiBF) in postmortem biological samples using UHPLC–QqQ-MS/MS

Purpose

Development of ultra-high-performance liquid chromatography-triple quadrupole tandem mass spectrometry method for quantification of 4-fluoroisobutyryl fentanyl (4-FiBF) and its distribution in postmortem biological samples in four fatal intoxication cases, which occurred in September 2018, in Poland.

Methods

Biological fluids (blood, urine, vitreous humor, bile, gastric content) and tissues (brain, kidney, liver, stomach wall) were extracted with ethyl acetate from alkaline medium (pH 9). Fentanyl-d5 was used as internal standard.

Results

The validation parameters were as follows: lower limit of quantification: 0.1 ng/mL (biological fluids) and 0.1 ng/g (solid tissues), intra- and inter-day accuracies and precisions: not greater than 20%; recovery values: 86.9–110%; matrix effect: − 13.1–10.4%. Among all tested biological fluid, the highest concentration of 4-FiBF was found in bile (average concentration of 3390 ng/mL) while among the tissues, in liver (average concentration of 1650 ng/g). Furthermore, in collected specimens, there were also found other drugs and new psychoactive substances (NPS) e.g. N-ethylpentylon, 4-chloromethcathinone (4-CMC) and α-pyrrolidinoisohexanophenone (α-PiHP). Concentrations and distributions of these substances in postmortem samples have been also detailed. Examinations of seized drug (in case 4) revealed that it included the mix of 4-FiBF and α-PiHP.

Conclusions

The developed and fully validated method enabled for determination of 4-FiBF in postmortem biological fluids and tissues. To our knowledge, this is the first report of distribution study of 4-FiBF with other NPS (N-ethylpentylon, 4-CMC and α-PiHP) in authentic fatal intoxication cases.

The synthetic opioid fentanyl enhances viral replication in vitro

The US is in the midst of a major drug epidemic fueled in large part by the widespread recreational use of synthetic opioids such as fentanyl. Persons with opioid use disorder are at significant risk for transmission of injection-associated infections such as hepatitis B virus (HBV) and hepatitis C virus (HCV). Commonly abused substances may antagonize immune responses and promote viral replication. However, the impact of synthetic opioids on virus replication has not been well explored. Thus, we evaluated the impact of fentanyl and carfentanil using in vitro systems that replicate infectious viruses. Fentanyl was used in cell lines replicating HBV or HCV at concentrations of 1 ng, 100 ng, and 10 ug. Viral protein synthesis was quantified by ELISA, while apoptosis and cell death were measured by M30 or MTT assays, respectively. HCV replicative fitness was evaluated in a luciferase-based system. RNAseq was performed to evaluate cellular gene regulation in the presence of fentanyl. Low dose fentanyl had no impact on HCV replication in Huh7.5JFH1 hepatocytes; however, higher doses significantly enhanced HCV replication. Similarly, a dose-dependent increase in HCV replicative fitness was observed in the presence of fentanyl. In the HepG2.2.15 hepatocyte cell line, fentanyl caused a dose-dependent increase in HBV replication, although only a higher doses than for HCV. Addition of fentanyl resulted in significant apoptosis in both hepatocyte cell lines. Cell death was minimal at low drug concentrations. RNAseq identified a number of hepatocyte genes that were differentially regulated by fentanyl, including those related to apoptosis, the antiviral / interferon response, chemokine signaling, and NFκB signaling. Collectively, these data suggest that synthetic opioids promote viral replication but may have distinct effects depending on the drug dose and the viral target. As higher viral loads are associated with pathogenesis and virus transmission, additional research is essential to an enhanced understanding of opioid-virus pathogenesis and for the development of new and optimized treatment strategies.

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

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

Carfentanil - from an animal anesthetic to a deadly illicit drug

The use of novel synthetic opioids as recreational drugs has become a public health concern as they are implicated in numerous fatal intoxications across the world. Synthetic opioids have played a major role in the United States opioid crisis and may contribute to a similar opioid epidemic in Europe. The most prominent group of designer opioids consists of fentanyl and its analogues. At present, carfentanil is the most dangerous fentanyl derivative. It was recently detected as an adulterant to other illicit drugs and counterfeit pharmaceuticals, contributing to life-threatening hospital admissions and fatalities. Toxic exposure to carfentanil typically occurs through injection, insufflation or inhalation. Carfentanil produces similar pharmacotoxicological effects to other opioids. However, due to its extraordinary potency, reversing carfentanil-induced severe and recurring respiratory depression requires administration of multiple or higher than standard doses of naloxone. Toxicological reports indicate that carfentanil use is strongly connected to polydrug use. Detection of carfentanil requires specific and sensitive analytical methods that are not commonly available in hospitals. Since abuse of carfentanil is an emerging problem, particularly in the United States, there is an urgent need to develop new techniques for rapid determination of intoxication evoked by this drug as well as new treatment regimens for effective overdose maintenance. This review presents current knowledge on pharmacological activity of carfentanil, prevalence and patterns of use, and analytical methods of its detection. Special emphasis is given to carfentanil-related non-fatal and lethal overdose cases.

Detecting Fentanyl Analogs in Urine Using Precursor Ion Scan Mode

The opioid crisis has led many providers to inquire about the capabilities of urine drug testing to detect contemporary compounds such as fentanyl and fentanyl analogs. However, current methods for clinical urine drug testing, including immunoassays and targeted liquid chromatography tandem mass spectrometry, are not designed to broadly screen for the variety of fentanyl analogs that may be encountered. In this proof-of-principle study we developed a precursor ion scan method to enable semi-targeted data acquisition for structurally related fentanyl analogs. Based on the knowledge that many analogs fragment to m/z=188 and m/z=105, data was acquired on all precursor ions 250-400 Da that fragmented to these product ions. Using a tandem mass spectrometer we analyzed 102 residual urine specimens, in which we identified fentanyl, acetylfentanyl and acrylfentanyl. In 30 contrived urine samples, the precursor ion scan was also able to identify furanylfentanyl, butryrlfentanyl, 4-fluroisobutrylfentanyl, and despropionylfentanyl with accuracy ranging from 83-100%.

U-47700 and Its Analogs: Non-Fentanyl Synthetic Opioids Impacting the Recreational Drug Market

The recreational use of opioid drugs is a global threat to public health and safety. In particular, an epidemic of opioid overdose fatalities is being driven by illicitly manufactured fentanyl, while novel synthetic opioids (NSOs) are appearing on recreational drug markets as standalone products, adulterants in heroin, or ingredients in counterfeit drug preparations. Trans-3,4-dichloro-N-[2-(dimethylamino)cyclohexyl]-N-methylbenzamide (U-47700) is a prime example of a non-fentanyl NSO that is associated with numerous intoxications and fatalities. Here, we review the medicinal chemistry, preclinical pharmacology, clandestine availability, methods for detection, and forensic toxicology of U-47700 and its analogs. An up-to-date summary of the human cases involving U-47700 intoxication and death are described. The evidence demonstrates that U-47700 is a potent μ-opioid receptor agonist, which poses a serious risk for overdosing and death. However, most analogs of U-47700 appear to be less potent and have been detected infrequently in forensic specimens. U-47700 represents a classic example of how chemical entities from the medicinal chemistry or patent literature can be diverted for use in recreational drug markets. Lessons learned from the experiences with U-47700 can inform scientists, clinicians, and policymakers who are involved with responding to the spread and impact of NSOs.

Determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 and 33 compounds from eight different drug classes in whole blood by LC-MS/MS

INTRODUCTION

Most bioanalytical LC-MS/MS methods are developed for determination of single drugs or classes of drugs, but a multi-compound LC-MS/MS method that can replace several methods could reduce both analysis time and costs. The aim of this study was to develop a high-throughput LC-MS/MS method for determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 (PEth 16:0/18:1) and 33 other compounds from eight different drug classes in whole blood.

METHODS

Whole-blood samples were prepared by 96-well supported liquid extraction (SLE). Chromatographic separations were performed on a biphenyl core shell column with a mobile phase consisting of 10 mM ammonium formate, pH 3.1 and methanol. Each extract was analyzed twice by LC-MS/MS, injecting 0.4 μL and 2 μL, in order to obtain narrow and symmetrical peaks and good sensitivity for all compounds. Stable isotope-labeled internal standards were used for 31 of the 34 compounds.

RESULTS

A 96-well SLE reversed phase LC-MS/MS method for determination of PEth 16:0/18:1 and 33 other compounds from eight different drug classes was developed and validated. By using an organic solvent mixture of isopropanol/ methyl tert-butyl ether (1:5, v:v), all compounds, including the polar and ampholytic compounds pregabalin, gabapentin and benzoylecgonine, was extracted by 96-well SLE.

DISCUSSION/CONCLUSION

For the first time an LC-MS/MS method for the determination of alcohol biomarker PEth 16:0/18:1 and drugs and metabolites from several different drug classes was developed and validated. The developed LC-MS/MS method can be used for high-throughput analyses and sensitive determinations of the 34 compounds in whole blood.