Fentanyl as a marker of illicit drug use in morphine-positive urine specimens from workplace drug testing.

Total morphine is an important urinary marker of heroin use but can also be present from prescriptions or poppy seed ingestion. In specimens with morphine concentrations consistent with poppy seed ingestion (<4,000 ng/mL), 6-acetylmorphine has served as an important marker of illicit drug use. However, as illicit fentanyl has become increasingly prevalent as a contaminant in the drug supply, fentanyl might be an alternative marker of illicit opioid use instead of or in combination with 6-acetylmorphine. The aim of this study was to quantify opiates, 6-acetylmorphine, fentanyl and fentanyl analogs in 504 morphine-positive (immunoassay 2,000 ng/mL cutoff) urine specimens from workplace drug testing. Almost half (43%) of morphine-positive specimens had morphine concentrations below 4,000 ng/mL, illustrating the need for markers to differentiate illicit drug use. In these specimens, fentanyl (22% co-positivity) was more prevalent than 6-acetylmorphine (12%). Co-positivity of 6-acetylmorphine and semi-synthetic opioids increased with morphine concentration, while fentanyl prevalence did not. In 110 fentanyl-positive specimens, the median norfentanyl concentration (1,520 ng/mL) was 9.6× higher than the median fentanyl concentration (159 ng/mL), illustrating the possibility of using norfentanyl as a urinary marker of fentanyl use. The only fentanyl analog identified was para-fluorofentanyl (n = 50), with results from most specimens consistent with para-fluorofentanyl contamination in illicit fentanyl. The results confirm the use of fentanyl by employees subject to workplace drug testing and highlight the potential of fentanyl and/or norfentanyl as important markers of illicit drug use.

Pharmacokinetics and pharmacodynamics of five distinct commercially available hemp-derived topical cannabidiol products.

Products containing cannabidiol (CBD) have proliferated after the 2018 Farm Bill legalized hemp (cannabis with ≤0.3% delta-9-tetrahydrocannabinol (Δ9-THC)). CBD-containing topical products have surged in popularity, but controlled clinical studies on them are limited. This study characterized the effects of five commercially available hemp-derived high CBD/low Δ9-THC topical products. Healthy adults (N = 46) received one of six study drugs: a CBD-containing cream (N = 8), lotion (N = 8), patch (N = 7), balm (N = 8), gel (N = 6) or placebo (N = 9; matched to an active formulation). The protocol included three phases conducted over 17 days: (i) an acute drug application laboratory session, (ii) a 9-day outpatient phase with twice daily product application (visits occurred on Days 2, 3, 7 and 10) (iii) a 1-week washout phase. In each phase, whole blood, oral fluid and urine specimens were collected and analyzed via liquid chromatography with tandem mass spectrometry (LC-MS-MS) for CBD, Δ9-THC and primary metabolites of each and pharmacodynamic outcomes (subjective, cognitive/psychomotor and physiological effects) were assessed. Transdermal absorption of CBD was observed for three active products. On average, CBD/metabolite concentrations peaked after 7-10 days of product use and were highest for the lotion, which contained the most CBD and a permeation enhancer (vitamin E). Δ9-THC/metabolites were below the limit of detection in blood for all products, and no urine samples tested "positive" for cannabis using current US federal workplace drug testing criteria (immunoassay cut-off of 50 ng/mL and confirmatory LC-MS-MS cut-off of 15 ng/mL). Unexpectedly, nine participants (seven lotions, one patch and one gel) exhibited Δ9-THC oral fluid concentrations ≥2 ng/mL (current US federal workplace threshold for a "positive" test). Products did not produce discernable pharmacodynamic effects and were well-tolerated. This study provides important initial data on the acute/chronic effects of hemp-derived topical CBD products, but more research is needed given the diversity of products in this market.

Prevalence of ∆8-tetrahydrocannabinol carboxylic acid in workplace drug testing.

∆8-Tetrahydrocannabinol (∆8-THC) recently became widely available as an alternative to cannabis. ∆8-THC is likely impairing and poses a threat to workplace and traffic safety. In the present study, the prevalence of ∆8-THC in workplace drug testing was investigated by analyzing 1,504 urine specimens with a positive immunoassay cannabinoid initial test using a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method quantifying 15 cannabinoid analytes after hydrolysis. ∆8-tetrahydrocannabinol-9-carboxylic acid (∆8-THC-COOH) was detected in 378 urine specimens (15 ng/mL cutoff), compared to 1,144 specimens containing ∆9-THC-COOH. The data could be divided into three general groups. There were 964 (76%) ∆9-THC-COOH-dominant (<10% ∆8-THC-COOH) and 139 (11%) ∆8-THC-COOH-dominant (>90% ∆8-THC-COOH) specimens, with the remaining 164 (13%) specimens showing a mixture of both analytes (>90% ∆8-THC-COOH). Similar concentrations of ∆9-THC-COOH (median 187 ng/mL) and ∆8-THC-COOH (150 ng/mL) as the dominant species support the use of similar cutoffs and decision rules for both analytes. Apart from the carboxylic acid metabolites, 11-hydroxy-∆9-tetrahydrocannabinol (11-OH-∆9-THC, n = 1,282), ∆9-tetrahydrocannabivarin-9-carboxylic acid (∆9-THCV-COOH, n = 1,058), ∆9-THC (n = 746) and 7-hydroxy-cannabidiol (7-OH-CBD, n = 506) were the most prevalent analytes. Two specimens (0.13%) contained ≥140 ng/mL ∆9-THC without ∆9-THC-COOH, which could be due to genetic variability in the drug-metabolizing enzyme CYP2C9 or an adulterant targeting ∆9-THC-COOH. The cannabinoid immunoassay was repeated, and five specimens (0.33%) generated negative initial tests despite ∆9-THC-COOH concentrations of 54-1,000 ng/mL, potentially indicative of adulteration. The use of ∆8-THC is widespread in the US population, and all forensic laboratories should consider adding ∆8-THC and/or ∆8-THC-COOH to their scope of testing. Similar urinary concentrations were observed for both analytes, indicating that the decision rules used for ∆9-THC-COOH are also appropriate for ∆8-THC-COOH.

Molecular Screening and Toxicity Estimation of 260,000 Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) through Machine Learning.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a class of chemicals widely used in industrial applications due to their exceptional properties and stability. However, they do not readily degrade in the environment and are linked to contamination and adverse health effects in humans and wildlife. To find alternatives for the most commonly used PFAS molecules that maintain their desirable chemical properties but are not adverse to biological lifeforms, a novel approach based upon machine learning is utilized. The machine learning model is trained on an existing set of PFAS molecules to generate over 260,000 novel PFAS molecules, which we dub PFAS-AI-Gen. Using molecular descriptors with known relationships to toxicity and industrial suitability followed by molecular docking and molecular dynamics simulations, this set of molecules is screened. In this manner, increasingly complex calculations are performed only for candidate molecules that are most likely to yield the desired properties of low binding affinity toward two selected protein receptors, the human pregnane x receptor (hPXR) and peroxisome proliferator-activated receptor γ (PPAR-γ), and high industrial suitability, defined by critical micelle concentration (CMC). The selection criteria of low binding affinity and high industrial suitability are relative to the popular PFAS alternative GenX. hPXR and PPAR-γ are selected as they are PFAS targets and facilitate a variety of functions, such as drug metabolism and glucose regulation, respectively. Through this approach, 22 promising new PFAS substitutes that may warrant experimental investigation are identified. This integrated approach of molecular screening and toxicity estimation may be applicable to other chemical classes.

Urinary Excretion Profile of Cannabinoid Analytes Following Acute Administration of Oral and Vaporized Cannabis in Infrequent Cannabis Users.

Traditionally, smoking has been the predominant method for administering cannabis, but alternative routes of administration have become more prevalent. Additionally, research examining urinary cannabinoid excretion profiles has primarily focused on 11-nor-9-carboxy-∆9-tetrahydrocannabinol (∆9-THC-COOH), a metabolite of ∆9-tetrahydrocannabinol (∆9-THC), as the primary analyte. The aim of the current study was to characterize the urinary excretion profile of ∆9-THC-COOH, ∆9-THC, ∆8-tetrahydrocannabinol (∆8-THC), 11-hydroxy-∆9-tetrahydrocannabinol (11-OH-∆9-THC), ∆9-tetrahydrocannabivarin (THCV), 11-nor-∆9-tetrahydrocannabivarin-9-carboxlic acid (THCV-COOH), cannabidiol (CBD), cannabinol (CBN) and 8,11-dihydroxytetrahydrocannabinol (8,11-diOH-∆9-THC) following controlled administration of both oral and vaporized cannabis. Participants (n = 21, 11 men/10 women) who were infrequent cannabis users ingested cannabis-containing brownies (0, 10 and 25 mg ∆9-THC) and inhaled vaporized cannabis (0, 5 and 20 mg ∆9-THC) across six double-blind outpatient sessions. Urinary concentrations of ∆9-THC analytes were measured at baseline and for 8 h after cannabis administration. Sensitivity, specificity and agreement between the three immunoassays (IAs) for ∆9-THC-COOH (cutoffs of 20, 50 and 100 ng/mL) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyses (confirmatory cutoff concentrations of 15 ng/mL) were assessed. Urinary concentrations for ∆9-THC-COOH, ∆9-THC, 11-OH-∆9-THC, THCV, CBN and 8,11-diOH-∆9-THC all peaked at 5-6 h and 4 h following oral and vaporized cannabis administration, respectively. At each active dose, median maximum concentrations (Cmax) for detected analytes were quantitatively higher after oral cannabis administration compared to vaporized. Using current recommended federal workplace drug-testing criteria (screening via IA with a cutoff of ≥50 ng/mL and confirmation via LC-MS-MS at a cutoff of ≥15 ng/mL), urine specimens tested positive for ∆9-THC-COOH in 97.6% of oral sessions and 59.5% of vaporized sessions with active ∆9-THC doses. These data indicate that while ∆9-THC-COOH may serve as the most consistent confirmatory analyte under the current drug-testing guidelines, future work examining 11-OH-∆9-THC under similar parameters could yield an alternative analyte that may be helpful in distinguishing between licit and illicit cannabis products.

Prevalence of Cannabidiol, ∆9- and ∆8-Tetrahydrocannabinol and Metabolites in Workplace Drug Testing Urine Specimens.

Given the recent popularity of cannabidiol (CBD) use and the emergence of ∆8-tetrahydrocannabinol (∆8-THC), the prevalence and concentrations of these and other cannabinoids were investigated in 2,000 regulated and 4,000 non-regulated specimens from workplace drug testing. All specimens were screened using liquid chromatography coupled to mass spectrometry (LC-MS-MS) for the presence of 7-hydroxy-CBD (7-OH-CBD) and ∆9-tetrahydrocannabinol-9-carboxylic acid (∆9-THC-COOH), with a cutoff of 2 ng/mL. Specimens screening positive by LC-MS-MS were analyzed by immunoassay at 20, 50 and 100 ng/mL cutoffs and by an LC-MS-MS confirmation method for 11 cannabinoids and metabolites with a 1 ng/mL cutoff. Using a 1 ng/mL cutoff, 98 (4.9%) regulated and 331 (8.3%) non-regulated specimens were positive for ∆9-THC-COOH. Of these, 64% had concentrations below 15 ng/mL. Similarly, 59 (3.0%) regulated and 162 (4.2%) non-regulated specimens were positive for 7-OH-CBD (n = 210), CBD (n = 120) and/or 7-carboxy-cannabidiol (CBD-COOH, n = 120). The median concentrations of 7-OH-CBD, CBD and CBD-COOH in those 221 specimens were 6.3, 1.1 and 1.2 ng/mL, respectively. ∆8-Tetrahydrocannabinol-9-carboxylic acid (∆8-THC-COOH) was identified in 76 (1.3%) specimens. Parent ∆8-THC is a minor cannabinoid in marijuana, which appears to account for the typically low ∆8-THC-COOH concentrations (median 3.4 ng/mL) in most positive specimens. However, elevated concentrations suggested the use of ∆8-THC-containing products in some cases (range 1.0-415 ng/mL). Although 93% agreement was observed between confirmatory LC-MS-MS (15 ng/mL cutoff) and immunoassay (50 ng/mL cutoff), a false-negative specimen (66 ng/mL ∆9-THC-COOH) was identified.

Urinary Pharmacokinetic Profile of Cannabidiol (CBD), Δ9-Tetrahydrocannabinol (THC) and Their Metabolites following Oral and Vaporized CBD and Vaporized CBD-Dominant Cannabis Administration.

The market for products containing cannabidiol (CBD) is booming globally. However, the pharmacokinetics of CBD in different oral formulations and the impact of CBD use on urine drug testing outcomes for cannabis (e.g., 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (Δ9-THCCOOH)) are understudied. This study characterized the urinary pharmacokinetics of CBD (100 mg) following vaporization or oral administration (including three formulations: gelcap, pharmacy-grade syrup and or Epidiolex) as well as vaporized CBD-dominant cannabis (containing 100 mg CBD and 3.7 mg Δ9-THC) in healthy adults (n = 18). A subset of participants (n = 6) orally administered CBD syrup following overnight fasting (versus low-fat breakfast). Urine specimens were collected before and for 58 h after dosing on a residential research unit. Immunoassay (IA) screening (cutoffs: 20, 50 and 100 ng/mL) for Δ9-THCCOOH was performed, and quantitation of cannabinoids was completed via LC-MS-MS. Urinary CBD concentrations (ng/mL) were higher after oral (mean Cmax: 734; mean Tmax: 4.7 h, n = 18) versus vaporized CBD (mean Cmax: 240; mean Tmax: 1.3 h, n = 18), and oral dose formulation significantly impacted mean Cmax (Epidiolex = 1,274 ng/mL, capsule = 776 ng/mL, syrup = 151 ng/mL, n = 6/group) with little difference in Tmax. Overnight fasting had limited impact on CBD excretion in urine, and there was no evidence of CBD conversion to Δ8- or Δ9-THC in any route or formulation in which pure CBD was administered. Following acute administration of vaporized CBD-dominant cannabis, 3 of 18 participants provided a total of six urine samples in which Δ9-THCCOOH concentrations ≥15 ng/mL. All six specimens screened positive at a 20 ng/mL IA cutoff, and two of six screened positive at a 50 ng/mL cutoff. These data show that absorption/elimination of CBD is impacted by drug formulation, route of administration and gastric contents. Although pure CBD is unlikely to impact drug testing, it is possible that hemp products containing low amounts of Δ9-THC may produce a cannabis-positive urine drug test.

SAMPL6 logP challenge: machine learning and quantum mechanical approaches.

Two different types of approaches: (a) approaches that combine quantitative structure activity relationships, quantum mechanical electronic structure methods, and machine-learning and, (b) electronic structure vertical solvation approaches, were used to predict the logP coefficients of 11 molecules as part of the SAMPL6 logP blind prediction challenge. Using electronic structures optimized with density functional theory (DFT), several molecular descriptors were calculated for each molecule, including van der Waals areas and volumes, HOMO/LUMO energies, dipole moments, polarizabilities, and electrophilic and nucleophilic superdelocalizabilities. A multilinear regression model and a partial least squares model were used to train a set of 97 molecules. As well, descriptors were generated using the molecular operating environment and used to create additional machine learning models. Electronic structure vertical solvation approaches considered include DFT and the domain-based local pair natural orbital methods combined with the solvated variant of the correlation consistent composite approach.

Urinary Pharmacokinetic Profile of Cannabinoids Following Administration of Vaporized and Oral Cannabidiol and Vaporized CBD-Dominant Cannabis.

Cannabis products in which cannabidiol (CBD) is the primary chemical constituent (CBD-dominant) are increasingly popular and widely available. The impact of CBD exposure on urine drug testing has not been well studied. This study characterized the urinary pharmacokinetic profile of 100-mg oral and vaporized CBD, vaporized CBD-dominant cannabis (100-mg CBD; 3.7-mg ∆9-THC) and placebo in healthy adults (n = 6) using a within-subjects crossover design. Urine specimens were collected before and for 5 days after drug administration. Immunoassay (IA) screening (cutoffs of 20, 50 and 100 ng/mL) and LC-MS-MS confirmatory tests (cutoff of 15 ng/mL) for 11-nor-9-carboxy-∆9-tetrahydrocannabinol (∆9-THCCOOH) were performed; urine was also analyzed for CBD and other cannabinoids. Urinary concentrations of CBD were higher after oral (mean Cmax: 776 ng/mL) versus vaporized CBD (mean Cmax: 261 ng/mL). CBD concentrations peaked 5 h after oral CBD ingestion and within 1 h after inhalation of vaporized CBD. After pure CBD administration, only 1 out of 218 urine specimens screened positive for ∆9-THCCOOH (20-ng/mL IA cutoff) and no specimens exceeded the 15-ng/mL confirmatory cutoff. After inhalation of CBD-dominant cannabis vapor, nine samples screened positive at the 20-ng/mL IA cutoff, and two of those samples screened positive at the 50-ng/mL IA cutoff. Four samples that screened positive (two at 20 ng/mL and two at 50 ng/mL) confirmed positive with concentrations of ∆9-THCCOOH exceeding 15 ng/mL. These data indicate that acute dosing of pure CBD will not result in a positive urine drug test using current federal workplace drug testing guidelines (50-ng/mL IA cutoff with 15-ng/mL confirmatory cutoff). However, CBD products that also contain ∆9-THC may produce positive urine results for ∆9-THCCOOH. Accurate labeling and regulation of ∆9-THC content in CBD/hemp products are needed to prevent unexpected positive drug tests and unintended drug effects.

Effects of fluid load on human urine characteristics related to workplace drug testing.

During workplace drug testing, urine is tested for dilution, substitution and adulteration. Donors argue that these findings are due to medical, health or working conditions or diet and genetic differences. There is a paucity of data correlating changes in urine characteristics after a fluid load to various body parameters. Therefore, five urine specimens (one in the morning, one prior to drinking 800 mL of a beverage, and three time intervals thereafter) from 12 males and 12 females were tested for four different beverages on separate occasions. Of the 480 samples, 376 were in sufficient amounts. Of these 376, 36 (10%) had creatinine <20 mg/dL but ≥2 mg/dL; 27 (75%) of 36 had specific gravity <1.0030 but >1.0010. Thus, these 27 samples can be considered to be dilute; 20 (74%) of 27 were from females. For males with at least one dilute sample, body fat was 11% less and resting metabolic rate (RMR) was 29% more than males with no dilute samples (p > 0.05); for females with at least one dilute sample, height was 8% less and weight 20% less than females with no dilute samples (p > 0.05). Individuals with a higher RMR appear to have a greater potential for producing dilute urine specimens than those with a lower RMR. Thus, a dilute sample does not necessarily indicate that it was intentionally diluted. Such samples must be carefully evaluated in consideration with recent consumption of liquid by donors to avoid false accusations.

Detection of THCA in oral fluid by GC-MS-MS.

A major marijuana metabolite, 11-nor-9-carboxy-tetrahydrocannabinol (THCA), has been identified in oral fluids from donors that previously tested positive for Delta(9)-tetrahydrocannabinol (THC). The method consisted of solid-phase extraction of the oral fluid samples followed by gas chromatography-tandem mass spectrometry analysis of the extracts. Testing for THCA was performed on 223 oral fluid samples previously analyzed for THC. The THCA assay was linear from 10 to 240 pg/mL. The mean recovery of spiked THCA in oral fluid was 104%, and precision was 4% at 20 pg/mL using fortified negative samples. This method was rugged and robust, providing detection and quantification of THCA in oral fluids at levels not previously reported. Results of this study showed that THCA was detectable in 21 of 26 oral fluid samples previously reported positive for THC. The range of concentrations from these samples was from 10 pg/mL up to 142 pg/mL THCA.

Disposition of hydrocodone in hair.

The use of prescription drugs, including synthetic opiates, is increasing in the U.S., with emergency room reports showing a dramatic rise in prescription opiate abuse. As part of an ongoing study, the hair of admitted opiate users was analyzed for hydrocodone and hydromorphone, as well as codeine, morphine, and 6-acetylmorphine in order to determine if there was any correlation between self-reported frequency of opiate intake and the concentration of drug detected in hair. The hairs were confirmed using gas chromatography-mass spectrometry following screening by enzyme linked immunosorbent assay (ELISA). Twenty-four hair specimens collected from volunteers showed the presence of hydrocodone (130-15,933 pg/mg); four of those also contained hydromorphone (59-504 pg/mg). The specimens were also analyzed for morphine, codeine, and 6-acetylmorphine. Hair specimens from five self-reported codeine users showed concentrations of hydrocodone between 592 and 15,933 pg/mg. In addition, codeine was present at concentrations of 575-20,543 pg/mg, but neither morphine nor hydromorphone were present in any of those hair specimens. Though the analysis of some opiates in hair has been previously published, this is the first study where the hydrocodone and hydromorphone concentrations have been measured following self-reported opiate intake.