Human red blood cell acetylcholinesterase activity: a revisit after fifteen years.

Human red blood cell acetylcholinesterase (RBC-AChE) activity is valuable for detecting potential exposure to cholinesterase inhibiting substances (CIS). A reliable population-based RBC-AChE activity reference range is critical for early and massive clinical and occupational toxicology screening. Previous published studies were often limited to small numbers of subjects, various testing methods, and crude statistical data analyses. We tested 4818 adult subjects with a well-established 17-minute modified Michel method over a 2-year period. We conducted a retrospective data analysis and systematically investigated on the influences to testing values from gender, age, age group, and their combinations and interactions. No significant difference was observed in the testing values between males (mean, medium, interquartile range = 0.76, 0.76, 0.71-0.80 ΔpH/h, respectively) and females (mean, medium, interquartile range = 0.76, 0.76, 0.71-0.81 ΔpH/hour, respectively), when gender was the only factor considered (p = 0.7238). However, with age progression, male testing values exhibited a consistent upward trend, while females did not show any clear patterns. Linear regression analysis of the data revealed that gender, age, and age group more or less affected testing values either as independent variables or with their combinations and interactions. However, more potential factors need to be included to achieve better testing value predictions. We recommend the toxicological testing community to adopt a new set of age group specific RBC-AChE activity reference ranges for males (0.68-0.80, 0.69-0.81, 0.70-0.83, 0.71-0.84, and 0.73-0.87 ΔpH/h for 18-29, 30-39, 40-49, 50-59, and ≥60 years old, respectively) while keeping the current reference range (0.63-0.89 ΔpH/hour) for females.

Evaluation of a Highly Efficient Multidrug Biochip Array Technology for a Simultaneous and High-Throughput Urine Drug Screening in Clinical and Toxicological Settings.

BACKGROUND: A high-throughput and highly efficient analytical platform for urine drug screening is critical in both clinical and forensic settings. Mass spectrometry (MS) has better sensitivity and specificity than conventional immunoassays (IA); however, not all laboratories have the necessary resources and workforce to operate MS. The goal of this study was to evaluate a multidrug biochip with 20 discrete testing regions (DTRs) for high-throughput urine drug screening (UDS). METHODS: The Randox DOA Ultra Urine (DOAULT URN) biochip employs chemiluminescent IA to detect various analytes, including stimulants, hallucinogens, sedatives, narcotics, and dextromethorphan. The verification included the evaluation of the limits of detection (LOD), stability of calibrators and controls, cross-reactivity, carryover, interference, and overall performance. RESULTS: LODs < quality control low for each DTR. The reconstituted calibrators were stable for up to 2 weeks at -20°C. Controls were stable for 4-6 hours at 22-25°C, with <20% within-day and ≤23% between-day imprecision. The accuracy of the controls (%bias) was within ±20% of the target concentration, except for dextromethorphan at -23.8%. No interference was observed with common over-the-counter medications. No carryover was detected in the high-concentration samples. Satisfactory cross-reactivity (≥50%) with known analytes produced presumptive positive results, with readings higher than the proposed decision points. The overall biochip performance of 165 confirmed samples showed 98.0% sensitivity, 96.9% specificity, and 97.5% efficiency. CONCLUSIONS: The DOAULT URN biochip is a multidrug analyte IA capable of detecting dozens of parent drugs and their metabolites in urine. It offers clinical and forensic laboratories an alternative UDS tool with LODs comparable to those of MS.

Metabolic profiling of synthetic cannabinoid 5F-ADB and identification of metabolites in authentic human blood samples via human liver microsome incubation and ultra-high-performance liquid chromatography/high-resolution mass spectrometry.

RATIONALE: Indazole carboxamide synthetic cannabinoids, a prevalent class of recreational drugs, are a major clinical, forensic and public health challenge. One such compound, 5F-ADB, has been implicated in fatalities worldwide. Understanding its metabolism and distribution facilitates the development of laboratory assays to substantiate its consumption. Synthetic cannabinoid metabolites have been extensively studied in urine; studies identifying metabolites in blood are limited and no data on the metabolic stability (half-life, clearance and extraction ratio) of 5F-ADB have been published prior to this report. METHODS: The in vitro metabolism of 5F-ADB was elucidated via incubation with human liver microsomes for 2 h at 37°C. Samples were collected at multiple time points to determine its metabolic stability. Upon identification of metabolites, authentic forensic human blood samples underwent liquid-liquid extraction and were screened for metabolites. Extracts were analyzed via ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/QTOFMS) operated in positive electrospray ionization mode. RESULTS: Seven metabolites were identified including oxidative defluorination (M1); carboxypentyl (M2); monohydroxylation of the fluoropentyl chain (M3.1/M3.2) and indazole ring system (M4); ester hydrolysis (M5); and ester hydrolysis with oxidative defluorination (M6). The half-life (3.1 min), intrinsic clearance (256.2 mL min-1 kg-1 ), hepatic clearance (18.6 mL min-1 kg-1 ) and extraction ratio (0.93) were determined for the first time. In blood, M1 was present in each sample as the most abundant substance; two samples contained M5; one contained 5F-ADB, M1 and M5. CONCLUSIONS: 5F-ADB is rapidly metabolized in HLM. 5F-ADB, M1 and M5 are pharmacologically active at the cannabinoid receptors (CB1 /CB2 ) and M1 and M5 may contribute to a user's impairment profile. The results demonstrate that it is imperative that synthetic cannabinoid assays screen for pharmacologically active metabolites, especially for drugs with short half-lives. The authors propose that M1 and M5 are appropriate markers to include in laboratory blood tests screening for 5F-ADB.

Assessment of synthetic cannabinoid FUB-AMB and its ester hydrolysis metabolite in human liver microsomes and human blood samples using UHPLC-MS/MS.

FUB-AMB, an indazole carboxamide synthetic cannabinoid recreational drug, was one of the compounds most frequently reported to governmental agencies worldwide between 2016 and 2019. It has been implicated in intoxications and fatalities, posing a risk to public health. In the current study, FUB-AMB was incubated with human liver microsomes (HLM) to assess its metabolic fate and stability and to determine if its major ester hydrolysis metabolite (M1) was present in 12 authentic forensic human blood samples from driving under the influence of drug cases and postmortem investigations using UHPLC-MS/MS. FUB-AMB was rapidly metabolized in HLM, generating M1 that was stable through a 120-min incubation period, a finding that indicates a potential long detection window in human biological samples. M1 was identified in all blood samples, and no parent drug was detected. The authors propose that M1 is a reliable marker for inclusion in laboratory blood screens for FUB-AMB; this metabolite may be pharmacologically active like its precursor FUB-AMB. M1 frequently appears in samples in which the parent drug is undetectable and can point to the causative agent. The results suggest that it is imperative that synthetic cannabinoid laboratory assay panels include metabolites, especially known or potential pharmacologically active metabolites, particularly for compounds with short half-lives.

Synthetic cannabinoids pharmacokinetics and detection methods in biological matrices.

Synthetic cannabinoids (SC), originally developed as research tools, are now highly abused novel psychoactive substances. We present a comprehensive systematic review covering in vivo and in vitro animal and human pharmacokinetics and analytical methods for identifying SC and their metabolites in biological matrices. Of two main phases of SC research, the first investigated therapeutic applications, and the second abuse-related issues. Administration studies showed high lipophilicity and distribution into brain and fat tissue. Metabolite profiling studies, mostly with human liver microsomes and human hepatocytes, structurally elucidated metabolites and identified suitable SC markers. In general, SC underwent hydroxylation at various molecular sites, defluorination of fluorinated analogs and phase II metabolites were almost exclusively glucuronides. Analytical methods are critical for documenting intake, with different strategies applied to adequately address the continuous emergence of new compounds. Immunoassays have different cross-reactivities for different SC classes, but cannot keep pace with changing analyte targets. Gas chromatography and liquid chromatography mass spectrometry assays - first for a few, then numerous analytes - are available but constrained by reference standard availability, and must be continuously updated and revalidated. In blood and oral fluid, parent compounds are frequently present, albeit in low concentrations; for urinary detection, metabolites must be identified and interpretation is complex due to shared metabolic pathways. A new approach is non-targeted HRMS screening that is more flexible and permits retrospective data analysis. We suggest that streamlined assessment of new SC's pharmacokinetics and advanced HRMS screening provide a promising strategy to maintain relevant assays.

Urine Mescaline Screening With a Biochip Array Immunoassay and Quantification by Gas Chromatography-Mass Spectrometry.

Mescaline, the primary psychoactive chemical in peyote cactus, has been consumed for thousands of years in ancient religious ceremonies. The US military wanted to determine if mescaline intake was a problem for personnel readiness. Twenty thousand seventeen urine specimens negative for cannabinoids, cocaine, opiates, and amphetamines were tested for mescaline with the Randox Drugs of Abuse V (DOA-V) biochip array immunoassay at the manufacturer's recommended cutoff of 6 mcg/L. A sensitive and specific method for mescaline quantification in urine was developed and fully validated. Extracted analytes were derivatized with pentafluoropropionic anhydride and pentafluoropropanol and quantified by gas chromatography-mass spectrometry (GC/MS) with electron impact ionization. Standard curves, using linear least squares regression with 1/x weighting, were linear from 1 to 250 mcg/L with coefficients of determination >0.994. Intra- and inter-assay imprecision was <4.4 coefficient of variation (%CV), with accuracies >90.4%. Mean extraction efficiencies were >92.0% across the linear range. This fully validated method was applied for the confirmation of urinary mescaline in 526 presumptive-positive specimens and 198 randomly selected presumptive-negative specimens at the manufacturer's 6 mcg/L cutoff. No specimen confirmed positive at the GC/MS limit of quantification of 1 mcg/L. Results indicated that during this time frame, there was insufficient mescaline drug use in the military to warrant routine screening in the drug testing program. However, mescaline stability, although assessed, could have contributed to lower prevalence. We also present a validated GC/MS method for mescaline quantification in urine for reliable confirmation of suspected mescaline intake.

Urinary prevalence, metabolite detection rates, temporal patterns and evaluation of suitable LC-MS/MS targets to document synthetic cannabinoid intake in US military urine specimens.

BACKGROUND: Identifying synthetic cannabinoid designer drug abuse challenges toxicologists and drug testing programs. The best analytical approach for reliably documenting intake of emerging synthetic cannabinoids is unknown. Primarily metabolites are found in urine, but optimal metabolite targets remain unknown, and definitive identification is complicated by converging metabolic pathways. METHODS: We screened 20,017 US military urine specimens collected from service members worldwide for synthetic cannabinoids between July 2011 and June 2012. We confirmed 1432 presumptive positive and 1069 presumptive negative specimens by qualitative liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis including 29 biomarkers for JWH-018, JWH-073, JWH-081, JWH-122, JWH-200, JWH-210, JWH-250, RCS-4, AM2201 and MAM2201. Specimen preparation included enzyme hydrolysis and acetonitrile precipitation prior to LC-MS/MS analysis. We evaluated individual synthetic cannabinoid metabolite detection rates, prevalence, temporal patterns and suitable targets for analytical procedures. RESULTS: Prevalence was 1.4% with 290 confirmed positive specimens, 92% JWH-018, 54% AM2201 and 39% JWH-122 metabolites. JWH-073, JWH-210 and JWH-250 also were identified in 37%, 4% and 8% of specimens, respectively. The United States Army Criminal Investigation Command seizure pattern for synthetic cannabinoid compounds matched our urine specimen results over the time frame of the study. Apart from one exception (AM2201), no parent compounds were observed. CONCLUSIONS: Hydroxyalkyl metabolites accounted for most confirmed positive tests, and in many cases, two metabolites were identified, increasing confidence in the results, and improving detection rates. These data also emphasize the need for new designer drug metabolism studies to provide relevant targets for synthetic cannabinoid identification.

Biochip array technology immunoassay performance and quantitative confirmation of designer piperazines for urine workplace drug testing.

Designer piperazines are emerging novel psychoactive substances (NPS) with few high-throughput screening methods for their identification. We evaluated a biochip array technology (BAT) immunoassay for phenylpiperazines (PNP) and benzylpiperazines (BZP) and analyzed 20,017 randomly collected urine workplace specimens. Immunoassay performance at recommended cutoffs was evaluated for PNPI (5 µg/L), PNPII (7.5 µg/L), and BZP (5 µg/L) antibodies. Eight hundred forty positive and 206 randomly selected presumptive negative specimens were confirmed by liquid chromatography high-resolution mass spectrometry (LC-HRMS). Assay limits of detection for PNPI, PNPII, and BZP were 2.9, 6.3, and 2.1 µg/L, respectively. Calibration curves were linear (R (2) > 0.99) with upper limits of 42 µg/L for PNPI/PNII and 100 µg/L for BZP. Quality control samples demonstrated imprecision <19.3 %CV and accuracies 86.0-94.5 % of target. There were no interferences from 106 non-piperazine substances. Seventy-eight of 840 presumptive positive specimens (9.3 %) were LC-HRMS positive, with 72 positive for 1-(3-chlorophenyl)piperazine (mCPP), a designer piperazine and antidepressant trazodone metabolite. Of 206 presumptive negative specimens, one confirmed positive for mCPP (3.3 µg/L) and one for BZP (3.6 µg/L). BAT specificity (21.1 to 91.4 %) and efficiency (27.0 to 91.6 %) increased, and sensitivity slightly decreased (97.5 to 93.8 %) with optimized cutoffs of 25 µg/L PNPI, 42 µg/L PNPI, and 100 µg/L BZP. A high-throughput screening method is needed to identify piperazine NPS. We evaluated performance of the Randox BAT immunoassay to identify urinary piperazines and documented improved performance when antibody cutoffs were raised. In addition, in randomized workplace urine specimens, all but two positive specimens contained mCPP and/or trazodone, most likely from legitimate medical prescriptions. Graphical Abstract Biochip array technology (BAT) immunoassay for designer piperazines detection in urine. In chemiluminescent immunoassay, the labeled-drug (antigen) competes with the drug in the urine. In the absence of drug, the labeled-drug binds to the antibody releasing an enzyme (horseradish peroxidase) to react with the substrate and producing chemiluminescence. The higher the drug concentration in urine, the weaker the chemiluminescent signal is produced. All presumptive positive specimens and randomly selected presumptive negative specimens were analyzed and confirmed by a liquid chromatography high-resolution mass spectrometry with limit of quantification of 2.5 or 5 µg/L.

Identifying methamphetamine exposure in children.

OBJECTIVE: Methamphetamine (MAMP) use, distribution, and manufacture remain a serious public health and safety problem in the United States, and children environmentally exposed to MAMP face a myriad of developmental, social, and health risks, including severe abuse and neglect necessitating child protection involvement. It is recommended that drug-endangered children receive medical evaluation and care with documentation of overall physical and mental conditions and have urine drug testing. The primary aim of this study was to determine the best biological matrix to detect MAMP, amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methylenedioxyamphetamine (MDA), and 3,4-methylenedioxyethylamphetamine (MDEA) in environmentally exposed children. METHODS: Ninety-one children, environmentally exposed to household MAMP intake, were medically evaluated at the Child and Adolescent Abuse Resource and Evaluation Diagnostic and Treatment Center at the University of California, Davis Children's Hospital. MAMP, AMP, MDMA, MDA, and MDEA were quantified in urine and oral fluid (OF) by gas chromatography mass spectrometry and in hair by liquid chromatography tandem mass spectrometry. RESULTS: Overall drug detection rates in OF, urine, and hair were 6.9%, 22.1%, and 77.8%, respectively. Seventy children (79%) tested positive for 1 or more drugs in 1 or more matrices. MAMP was the primary analyte detected in all 3 biological matrices. All positive OF (n = 5), and 18 of 19 positive urine specimens also had a positive hair test. CONCLUSIONS: Hair analysis offered a more sensitive tool for identifying MAMP, AMP, and MDMA environmental exposure in children than urine or OF testing. A negative urine or hair test does not exclude the possibility of drug exposure, but hair testing provided the greatest sensitivity for identifying drug-exposed children.

A Hidden Gem: Highlighting the Indispensable Capabilities and History of the DoD Cholinesterase Monitoring Program and DoD Cholinesterase Reference Laboratory.

The DoD Cholinesterase Monitoring Program and Cholinesterase Reference Laboratory have safeguarded U.S. government employees in chemical defense for over five decades. Considering Russia's potential deployment of chemical warfare nerve agents in Ukraine, it is critical to maintain a robust cholinesterase testing program and its efficiency presently and in future.

Impact of cannabis-infused edibles on public safety and regulation.

Popularity of cannabis-infused products has bloomed since legalization for recreational use of marijuana started. Consumption of cannabis edibles has steadily increased, as restrictions on recreational cannabis smoking have become tighter. This phenomenon enhanced the possibility of these products crossing the state line. The most psychoactive component of cannabis, ∆9-tetrahydrocannabinol (THC) is infused in "edibles" and linked to physiological and psychological effects. Consumers unfamiliar with these edibles may mistake them for non-THC containing products, causing unintended use or overconsumption. In addition, these cannabis-infused edibles are posing significant health risks. The FDA has recognized the potential dangers and recommended that cannabis remain as a Schedule I substance and illegal at the federal level. However, states maintain control of determining the legality of cannabis related products, and creating guidelines distinguishing cannabis edibles from the non-cannabis containing products. Recently, the State of Maine offers a blueprint for edible regulation that should be implemented in all states that are considering or have legalized marijuana.

Predicted effector molecules in the salivary secretome of the pea aphid (Acyrthosiphon pisum): a dual transcriptomic/proteomic approach.

The relationship between aphids and their host plants is thought to be functionally analogous to plant-pathogen interactions. Although virulence effector proteins that mediate plant defenses are well-characterized for pathogens such as bacteria, oomycetes, and nematodes, equivalent molecules in aphids and other phloem-feeders are poorly understood. A dual transcriptomic-proteomic approach was adopted to generate a catalog of candidate effector proteins from the salivary glands of the pea aphid, Acyrthosiphon pisum. Of the 1557 transcript supported and 925 mass spectrometry identified proteins, over 300 proteins were identified with secretion signals, including proteins that had previously been identified directly from the secreted saliva. Almost half of the identified proteins have no homologue outside aphids and are of unknown function. Many of the genes encoding the putative effector proteins appear to be evolving at a faster rate than homologues in other insects, and there is strong evidence that genes with multiple copies in the genome are under positive selection. Many of the candidate aphid effector proteins were previously characterized in typical phytopathogenic organisms (e.g., nematodes and fungi) and our results highlight remarkable similarities in the saliva from plant-feeding nematodes and aphids that may indicate the evolution of common solutions to the plant-parasitic lifestyle.

Can synthetic urine replace authentic urine to "beat" workplace drug testing?

Synthetic urine (SU), which was primarily utilized by drug testing laboratories as a matrix for quality control preparations, is now commercially sold and can be used to "fool" a positive drug test. To determine if SU can pass as authentic urine, we challenged Army urine drug testing specimen accessioning and testing procedures using eight different commercial SU products. Adulteration (Sciteck AdultaCheck® 6) and Onsite SU (Synthetic UrineCheck™) test strips were also evaluated. Five of the eight SU were identified by physical observation. All SU products screened negative in the drug immunoassay and additionally passed the specimen validity testing (SVT) as authentic urine. Furthermore, SU was not detected as adulterated with the adulteration test strips (Sciteck AdultaCheck® 6) but was successfully detected as SU with the On-site synthetic urine (Synthetic UrineCheck™). To deter SU use, direct observation, as utilized by the military, may be recommended during the collection process.

Metabolic characterization of AH-7921, a synthetic opioid designer drug: in vitro metabolic stability assessment and metabolite identification, evaluation of in silico prediction, and in vivo confirmation.

AH-7921 (3,4-dichloro-N-[(1-dimethylamino)cyclohexylmethyl]benzamide) is a new synthetic opioid and has led to multiple non-fatal and fatal intoxications. To comprehensively study AH-7921 metabolism, we assessed human liver microsome (HLM) metabolic stability, determined AH-7921's metabolic profile after human hepatocytes incubation, confirmed our findings in a urine case specimen, and compared results to in silico predictions. For metabolic stability, 1 µmol/L AH-7921 was incubated with HLM for up to 1 h; for metabolite profiling, 10 µmol/L was incubated with pooled human hepatocytes for up to 3 h. Hepatocyte samples were analyzed by liquid chromatography quadrupole/time-of-flight high-resolution mass spectrometry (MS). High-resolution full scan MS and information-dependent acquisition MS/MS data were analyzed with MetabolitePilot™ (SCIEX) using multiple data processing algorithms. The presence of AH-7921 and metabolites was confirmed in the urine case specimen. In silico prediction of metabolite structures was performed with MetaSite™ (Molecular Discovery). AH-7921 in vitro half-life was 13.5 ± 0.4 min. We identified 12 AH-7921 metabolites after hepatocyte incubation, predominantly generated by demethylation, less dominantly by hydroxylation, and combinations of different biotransformations. Eleven of 12 metabolites identified in hepatocytes were found in the urine case specimen. One metabolite, proposed to be di-demethylated, N-hydroxylated and glucuronidated, eluted after AH-7921 and was the most abundant metabolite in non-hydrolyzed urine. MetaSite™ correctly predicted the two most abundant metabolites and the majority of observed biotransformations. The two most dominant metabolites after hepatocyte incubation (also identified in the urine case specimen) were desmethyl and di-desmethyl AH-7921. Together with the glucuronidated metabolites, these are likely suitable analytical targets for documenting AH-7921 intake. Copyright © 2015 John Wiley & Sons, Ltd.

Simultaneous determination of 40 novel psychoactive stimulants in urine by liquid chromatography-high resolution mass spectrometry and library matching.

The emergence of novel psychoactive substances is an ongoing challenge for analytical toxicologists. Different analogs are continuously introduced in the market to circumvent legislation and to enhance their pharmacological activity. Although detection of drugs in blood indicates recent exposure and link intoxication to the causative agent, urine is still the most preferred testing matrix in clinical and forensic settings. We developed a method for the simultaneous quantification of 8 piperazines, 4 designer amphetamines and 28 synthetic cathinones and 4 metabolites, in urine by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Data were acquired in full scan and data dependent MS(2) mode. Compounds were quantified by precursor ion exact mass, and confirmed by product ion spectra library matching, taking into account product ions' exact mass and intensities. One-hundred µL urine was subjected to solid phase cation exchange extraction (SOLA SCX). The chromatographic reverse-phase separation was achieved with gradient mobile phase of 0.1% formic acid in water and in acetonitrile in 20 min. The assay was linear from 2.5 or 5 to 500 µg/L. Imprecision (n=15) was <15.4%, and accuracy (n=15) 84.2-118.5%. Extraction efficiency was 51.2-111.2%, process efficiency 57.7-104.9% and matrix effect ranged from -41.9% to 238.5% (CV<23.3%, except MDBZP CV<34%). Authentic urine specimens (n=62) were analyzed with the method that provides a comprehensive confirmation for 40 new stimulant drugs with specificity and sensitivity.

Quantitative urine confirmatory testing for synthetic cannabinoids in randomly collected urine specimens.

Synthetic cannabinoid intake is an ongoing health issue worldwide, with new compounds continually emerging, making drug testing complex. Parent synthetic cannabinoids are rarely detected in urine, the most common matrix employed in workplace drug testing. Optimal identification of synthetic cannabinoid markers in authentic urine specimens and correlation of metabolite concentrations and toxicities would improve synthetic cannabinoid result interpretation. We screened 20 017 randomly collected US military urine specimens between July 2011 and June 2012 with a synthetic cannabinoid immunoassay yielding 1432 presumptive positive specimens. We analyzed all presumptive positive and 1069 negative specimens with our qualitative synthetic cannabinoid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, which confirmed 290 positive specimens. All 290 positive and 487 randomly selected negative specimens were quantified with the most comprehensive urine quantitative LC-MS/MS method published to date; 290 specimens confirmed positive for 22 metabolites from 11 parent synthetic cannabinoids. The five most predominant metabolites were JWH-018 pentanoic acid (93%), JWH-N-hydroxypentyl (84%), AM2201 N-hydroxypentyl (69%), JWH-073 butanoic acid (69%), and JWH-122 N-hydroxypentyl (45%) with 11.1 (0.1-2,434), 5.1 (0.1-1,239), 2.0 (0.1-321), 1.1 (0.1-48.6), and 1.1 (0.1-250) µg/L median (range) concentrations, respectively. Alkyl hydroxy and carboxy metabolites provided suitable biomarkers for 11 parent synthetic cannabinoids; although hydroxyindoles were also observed. This is by far the largest data set of synthetic cannabinoid metabolites urine concentrations from randomly collected workplace drug testing specimens rather than acute intoxications or driving under the influence of drugs. These data improve the interpretation of synthetic cannabinoid urine test results and suggest suitable urine markers of synthetic cannabinoid intake.

Pentylindole/Pentylindazole Synthetic Cannabinoids and Their 5-Fluoro Analogs Produce Different Primary Metabolites: Metabolite Profiling for AB-PINACA and 5F-AB-PINACA.

Whereas non-fluoropentylindole/indazole synthetic cannabinoids appear to be metabolized preferably at the pentyl chain though without clear preference for one specific position, their 5-fluoro analogs' major metabolites usually are 5-hydroxypentyl and pentanoic acid metabolites. We determined metabolic stability and metabolites of N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (AB-PINACA) and 5-fluoro-AB-PINACA (5F-AB-PINACA), two new synthetic cannabinoids, and investigated if results were similar. In silico prediction was performed with MetaSite (Molecular Discovery). For metabolic stability, 1 µmol/L of each compound was incubated with human liver microsomes for up to 1 h, and for metabolite profiling, 10 µmol/L was incubated with pooled human hepatocytes for up to 3 h. Also, authentic urine specimens from AB-PINACA cases were hydrolyzed and extracted. All samples were analyzed by liquid chromatography high-resolution mass spectrometry on a TripleTOF 5600+ (AB SCIEX) with gradient elution (0.1% formic acid in water and acetonitrile). High-resolution full-scan mass spectrometry (MS) and information-dependent acquisition MS/MS data were analyzed with MetabolitePilot (AB SCIEX) using different data processing algorithms. Both drugs had intermediate clearance. We identified 23 AB-PINACA metabolites, generated by carboxamide hydrolysis, hydroxylation, ketone formation, carboxylation, epoxide formation with subsequent hydrolysis, or reaction combinations. We identified 18 5F-AB-PINACA metabolites, generated by the same biotransformations and oxidative defluorination producing 5-hydroxypentyl and pentanoic acid metabolites shared with AB-PINACA. Authentic urine specimens documented presence of these metabolites. AB-PINACA and 5F-AB-PINACA produced suggested metabolite patterns. AB-PINACA was predominantly hydrolyzed to AB-PINACA carboxylic acid, carbonyl-AB-PINACA, and hydroxypentyl AB-PINACA, likely in 4-position. The most intense 5F-AB-PINACA metabolites were AB-PINACA pentanoic acid and 5-hydroxypentyl-AB-PINACA.

High-resolution mass spectrometric metabolite profiling of a novel synthetic designer drug, N-(adamantan-1-yl)-1-(5-fluoropentyl)-1H-indole-3-carboxamide (STS-135), using cryopreserved human hepatocytes and assessment of metabolic stability with human liver microsomes.

N-(Adamantan-1-yl)-1-(5-fluoropentyl)-1H-indole-3-carboxamide (STS-135) is a new synthetic cannabinoid in herbal incense products discussed on Internet drug user forums and identified in police seizures. To date, there are no STS-135 clinical or in vitro studies identifying STS-135 metabolites. However, characterizing STS-135 metabolism is critical because synthetic cannabinoid metabolites can possess pharmacological activity and parent compounds are rarely detectable in urine. To characterize the metabolite profile, human hepatocytes were incubated with 10 µmol/L STS-135 for up to 3 h. High-resolution mass spectrometry with software-assisted data mining identified 29 STS-135 metabolites. Less than 25% of STS-135 parent compound remained after 3 h incubation. Primary metabolites were generated by mono-, di- or trihydroxylation with and without ketone formation, dealkylation, and oxidative defluorination of N-fluoropentyl side chain or possible oxidation to carboxylic acid, some of them further glucuronidated. Hydroxylations occurred mainly on the aliphatic adamantane ring and less commonly on the N-pentyl side chain. At 1 h, phase I metabolites predominated, while at 3 h, phase II metabolites were present in higher amounts. The major metabolites were monohydroxy STS-135 (M25) and dihydroxy STS-135 (M21), both hydroxylated on the adamantane system. Moreover, metabolic stability of STS-135 (1 µmol/L) was assessed in human liver microsomes experiments. The in vitro half-life of STS-135 was 3.1 ± 0.2 min and intrinsic clearance (CLint ) was 208.8 mL · min(-1) · kg(-1) . This is the first report characterizing STS-135 hepatic metabolic pathways. These data provide potential urinary targets to document STS-135 intake in clinical and forensic settings and potential candidates for pharmacological testing.

Performance characteristics of an ELISA screening assay for urinary synthetic cannabinoids.

Synthetic cannabinoids are marketed as legal alternatives to cannabis, as routine urine cannabinoid immunoassays do not detect synthetic cannabinoids. Laboratories are challenged to identify these new designer drugs that are widely available and represent a major public health and safety problem. Immunoassay testing offers rapid separation of presumptive positive and negative specimens, prior to more costly and time-consuming chromatographic confirmation. The Neogen SPICE ELISA kit targets JWH-018 N-pentanoic acid as a marker for urinary synthetic cannabinoids. Assay performance was evaluated by analyzing 2469 authentic urine samples with the Neogen immunoassay and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Two immunoassay cut-off concentrations, 5 and 10 µg/L, classified samples as presumptive positive or negative, followed by qualitative LC-MS/MS confirmation for 29 synthetic cannabinoids markers with limits of detection of 0.5-10 µg/L to determine the assay's sensitivity, specificity and efficacy. Challenges at ±25% of each cut-off also were investigated to determine performance around the cut-off and intra- and inter-plate imprecision. The immunoassay was linear from 1 to 250 µg/L (r(2) = 0.992) with intra- and inter-plate imprecision of ≤5.3% and <9%, respectively. Sensitivity, specificity, and efficiency results with the 5 µg/L cut-off were 79.9%, 99.7%, and 97.4% and with the 10 µg/L cut-off 69.3%, 99.8%, and 96.3%, respectively. Cross-reactivity was shown for 18 of 73 synthetic cannabinoids markers evaluated. Good sensitivity, specificity, and efficiency, lack of sample preparation requirements, and rapid semi-automation documented that the Neogen SPICE ELISA kit is a viable method for screening synthetic cannabinoids in urine targeting JWH-018 N-pentanoic acid.