Allan J. Barnes

Simultaneous quantification of cannabinoids and metabolites in oral fluid by two-dimensional gas chromatography mass spectrometry.

Development and validation of a method for simultaneous identification and quantification of Delta9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN), and metabolites 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THCCOOH) in oral fluid. Simultaneous analysis was problematic due to different physicochemical characteristics and concentration ranges. Neutral analytes, such as THC and CBD, are present in ng/mL, rather than pg/mL concentrations, as observed for the acidic THCCOOH biomarker in oral fluid. THCCOOH is not present in cannabis smoke, definitively differentiating cannabis use from passive smoke exposure. THC, 11-OH-THC, THCCOOH, CBD, and CBN quantification was achieved in a single oral fluid specimen collected with the Quantisal device. One mL oral fluid/buffer solution (0.25 mL oral fluid and 0.75 mL buffer) was applied to conditioned CEREX Polycrom THC solid-phase extraction (SPE) columns. After washing, THC, 11-OH-THC, CBD, and CBN were eluted with hexane/acetone/ethyl acetate (60:30:20, v/v/v), derivatized with N,O-bis-(trimethylsilyl)trifluoroacetamide and quantified by two-dimensional gas chromatography electron ionization mass spectrometry (2D-GCMS) with cold trapping. Acidic THCCOOH was separately eluted with hexane/ethyl acetate/acetic acid (75:25:2.5, v/v/v), derivatized with trifluoroacetic anhydride and hexafluoroisopropanol, and quantified by the more sensitive 2D-GCMS-electron capture negative chemical ionization (NCI-MS). Linearity was 0.5-50 ng/mL for THC, 11-OH-THC, CBD and 1-50 ng/mL for CBN. The linear dynamic range for THCCOOH was 7.5-500 pg/mL. Intra- and inter-assay imprecision as percent RSD at three concentrations across the linear dynamic range were 0.3-6.6%. Analytical recovery was within 13.8% of target. This new SPE 2D-GCMS assay achieved efficient quantification of five cannabinoids in oral fluid, including pg/mL concentrations of THCCOOH by combining differential elution, 2D-GCMS with electron ionization and negative chemical ionization. This method will be applied to quantification of cannabinoids in oral fluid specimens from individuals participating in controlled cannabis and Sativex (50% THC and 50% CBD) administration studies, and during cannabis withdrawal.

Oral Fluid Cannabinoids in Chronic, Daily Cannabis Smokers during Sustained, Monitored Abstinence

BACKGROUND Oral fluid (OF) is an accepted alternative biological matrix for drug treatment, workplace, and DUID (driving under the influence of drugs) investigations, but establishing the cannabinoid OF detection window and concentration cutoff criteria are important. METHODS Cannabinoid concentrations were quantified in OF from chronic, daily cannabis smokers during monitored abstinence. Δ(9)-tetrahydrocannabinol (THC)(3), cannabidiol (CBD), cannabinol (CBN), and 11-nor-9-carboxy-THC (THCCOOH) were determined in daily OF samples collected with the Quantisal™ device. GC-MS limits of quantification (LOQ) were 0.5 μg/L for THC and CBD, 1 μg/L for CBN, and 7.5 ng/L for THCCOOH. RESULTS After providing written informed consent for this institutional review board-approved study, 28 participants resided from 4 to 33 days on the secure research unit and provided 577 OF specimens. At the LOQ, THC was generally quantifiable for 48 h, whereas CBD and CBN were detected only at admission. Median THCCOOH detection time was 13 days (CI 6.4-19.6 days). Mean THC detection rates decreased from 89.3% at admission to 17.9% after 48 h, whereas THCCOOH gradually decreased from 89.3% to 64.3% within 4 days. Criteria of THC ≥2 μg/L and THCCOOH ≥20 ng/L reduced detection to <48 h in chronic cannabis smokers. An OF THCCOOH/THC ratio ≤4 ng/μg or presence of CBD or CBN may indicate more recent smoking. CONCLUSIONS THC, THCCOOH, CBD, and CBN quantification in confirmatory OF cannabinoid testing is recommended. Inclusion of multiple cannabinoid cutoffs accounted for residual cannabinoid excretion in OF from chronic, daily cannabis smokers and could reduce the potential for positive test results from passive cannabis smoke exposure and lead to greatly improved test interpretation.

Pharmacokinetics of cocaine and metabolites in human oral fluid and correlation with plasma concentrations after controlled administration.

Oral fluid is an attractive alternative matrix for drug testing with a noninvasive and directly observed collection, but there are few controlled cocaine administration studies to guide interpretation. Materials and Methods: While residing on a closed research unit for up to 10 weeks under constant medical supervision, 19 participants were administered 75 mg/70 kg subcutaneous cocaine and 14 received 150 mg/70 kg. The disposition of cocaine, benzoylecgonine (BE), and ecgonine methyl ester (EME) into oral fluid was determined by gas chromatography-mass spectrometry for 0.08 to 48 hours after administration. Results: In oral fluid collected by citric acid candy-stimulated expectoration, cocaine first appeared in oral fluid 0.08 to 0.32 hours after dosing and was rapidly eliminated with half-lives of 1.1 to 3.8 hours. BE and EME were first detected 0.08 to 1.0 hours after dosing with longer half-lives of 3.4 to 13.8 (BE) and 2.4 to 15.5 hours (EME) (P < 0.05). Oral fluid and plasma concentrations were significantly correlated for cocaine, BE, and EME (P < 0.0001). There were no significant differences (P > 0.05) in first and last detection times with the 8-μg/L cutoff proposed by the Substance Abuse and Mental Health Services Administration or the 10-μg/L cutoff from the European initiative, Driving Under the Influence of Drugs, Alcohol and Medicines. Metabolite:cocaine ratios increased after cocaine administration, potentially helpful for interpreting time of last use. Comparison of oral fluid collection through citric acid candy-stimulated expectoration, citric acid-treated Salivette, and neutral cotton Salivette devices did not reveal significant differences between devices for areas under the curve for cocaine, BE, or EME (P > 0.05). Discussion and Conclusion: These results provide additional evidence for interpreting cocaine and metabolite concentrations in oral fluid and oral fluids usefulness as an alternative matrix for drug testing.

Cannabinoid Disposition in Oral Fluid after Controlled Smoked Cannabis

BACKGROUND We measured Δ(9)-tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) disposition in oral fluid (OF) following controlled cannabis smoking to evaluate whether monitoring multiple cannabinoids in OF improved OF test interpretation. METHODS Cannabis smokers provided written informed consent for this institutional review board-approved study. OF was collected with the Quantisal™ device following ad libitum smoking of one 6.8% THC cigarette. Cannabinoids were quantified by 2-dimensional GC-MS. We evaluated 8 alternative cutoffs based on different drug testing program needs. RESULTS 10 participants provided 86 OF samples -0.5 h before and 0.25, 0.5, 1, 2, 3, 4, 6, and 22 h after initiation of smoking. Before smoking, OF samples of 4 and 9 participants were positive for THC and THCCOOH, respectively, but none were positive for CBD and CBN. Maximum THC, CBD, and CBN concentrations occurred within 0.5 h, with medians of 644, 30.4, and 49.0 μg/L, respectively. All samples were THC positive at 6 h (2.1-44.4 μg/L), and 4 of 6 were positive at 22 h. CBD and CBN were positive only up to 6 h in 3 (0.6-2.1 μg/L) and 4 (1.0-4.4 μg/L) participants, respectively. The median maximum THCCOOH OF concentration was 115 ng/L, with all samples positive to 6 h (14.8-263 ng/L) and 5 of 6 positive at 22 h. CONCLUSIONS By quantifying multiple cannabinoids and evaluating different analytical cutoffs after controlled cannabis smoking, we determined windows of drug detection, found suggested markers of recent smoking, and minimized the potential for passive contamination.

Cannabinoid Stability in Authentic Oral Fluid after Controlled Cannabis Smoking

BACKGROUND Defining cannabinoid stability in authentic oral fluid (OF) is critically important for result interpretation. There are few published OF stability data, and of those available, all employed fortified synthetic OF solutions or elution buffers; none included authentic OF following controlled cannabis smoking. METHODS An expectorated OF pool and a pool of OF collected with Quantisal™ devices were prepared for each of 10 participants. Δ⁹-tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) stability in each of 10 authentic expectorated and Quantisal-collected OF pools were determined after storage at 4 °C for 1 and 4 weeks and at -20 °C for 4 and 24 weeks. Results within ±20% of baseline concentrations analyzed within 24 h of collection were considered stable. RESULTS All Quantisal OF cannabinoid concentrations were stable for 1 week at 4 °C. After 4 weeks at 4 °C, as well as 4 and 24 weeks at -20 °C, THC was stable in 90%, 80%, and 80% and THCCOOH in 89%, 40%, and 50% of Quantisal samples, respectively. Cannabinoids in expectorated OF were less stable than in Quantisal samples when refrigerated or frozen. After 4 weeks at 4 and -20 °C, CBD and CBN were stable in 33%-100% of Quantisal and expectorated samples; by 24 weeks at -20 °C, CBD and CBN were stable in ≤ 44%. CONCLUSIONS Cannabinoid OF stability varied by analyte, collection method, and storage duration and temperature, and across participants. OF collection with a device containing an elution/stabilization buffer, sample storage at 4 °C, and analysis within 4 weeks is preferred to maximize result accuracy.

Disposition of Cannabinoids in Oral Fluid after Controlled Around-the-Clock Oral THC Administration

BACKGROUND Oral fluid, a promising alternative matrix for drug monitoring in clinical and forensic investigations, offers noninvasive sample collection under direct observation. Cannabinoid distribution into oral fluid is complex and incompletely characterized due to the lack of controlled drug administration studies. METHODS To characterize cannabinoid disposition in oral fluid, we administered around-the-clock oral Delta(9)-tetrahydrocannabinol (THC) (Marinol) doses to 10 participants with current daily cannabis use. We obtained oral fluid samples (n=440) by use of Quantisal collection devices before, during, and after 37 20-mg THC doses over 9 days. Samples were extracted with multiple elution solvents from a single SPE column and analyzed by 2-dimensional GC-MS with electron-impact ionization for THC, 11-hydroxy-THC (11-OH-THC), cannabidiol, and cannabinol and negative chemical ionization for 11-nor-9-carboxy-THC (THCCOOH). Linear ranges were 0.5-50 microg/L, with the exception of cannabinol (1-50 microg/L) and THCCOOH (7.5-500 ng/L). RESULTS THCCOOH was the most prevalent analyte in 432 samples (98.2%), with concentrations up to 1117.9 ng/L. In contrast, 11-OH-THC was not identified in any sample; cannabidiol and cannabinol were quantified in 3 and 8 samples, respectively, with maximum concentrations of 2.1 and 13 microg/L. THC was present in only 20.7% of samples, with highest concentrations near admission (median 4.2 microg/L, range 0.6-481.9) from previously self-administered smoked cannabis. CONCLUSIONS Measurement of THCCOOH in OF not only identifies cannabis exposure, but also minimizes the possibility of passive inhalation. THCCOOH may be a better analyte for detection of cannabis use.

Estimating time of last oral ingestion of cannabis from plasma THC and THCCOOH concentrations.

Estimating the time of last cannabis use is important in assessing possible impairment of drivers involved in accidents, in verifying accuracy of court testimony and in the future, helpful in therapeutic monitoring of cannabis agonists. In 1992, Huestis et al developed model 1, based on plasma Δ9-tetrahydrocannabinol (THC) concentrations, and model 2, on plasma 11-nor-9-carboxy-Δ9-tetrahydrocannbinol/THC ratios, that predicted 95% confidence intervals for time of last cannabis use. These models seemed to be valuable when applied to the small amount of data from published studies of oral ingestion, a route of administration more popular with the advent of cannabis therapies. A study was designed to further validate the models after oral ingestion of THC, and to determine whether they could predict last usage after multiple oral doses. Eighteen subjects in IRB-approved studies participated after providing informed consent. Each of 12 subjects in one group received a single 10 mg oral dose of dronabinol (synthetic THC). In another protocol, 6 subjects received 4 different oral daily doses, divided into thirds and administered with meals for 5 consecutive days. There was a 10-day washout period between each dosing regimen. Daily doses were 0.39, 0.47, and 14.8 mg THC in hemp oil and 7.5 mg dronabinol. Blood specimens were collected throughout the study and analyzed for plasma THC and 11-nor-9-carboxy-Δ9-tetrahydrocannbinol by gas chromatography/mass spectrometry with limits of quantification (LOQs) of 0.5 and 1.0 ng/mL, respectively. Actual times between ingestion of THC and blood collection spanned 0.5 to 16 hours. All plasma specimens with analyte concentrations >LOQ (n=90) were evaluated. Models 1 and 2 correctly predicted time of last THC ingestion for 74.4% and 90.0% of plasma specimens, respectively. 96.7% of predicted times were correct with one overestimate and 2 underestimates using the time interval defined by the lowest and highest 95% confidence limit of both models. These results provide further evidence of the usefulness of the predictive models in estimating the time of last oral THC ingestion after single or multiple doses.

Delta(9)-tetrahydrocannabinol, 11-hydroxy-delta(9)-tetrahydrocannabinol and 11-nor-9-carboxy-delta(9)-tetrahydrocannabinol in human plasma after controlled oral administration of cannabinoids.

A clinical study to investigate the pharmacokinetics and pharmacodynamics of oral tetrahydrocannabinol was performed. This randomized, double-blind, placebo-controlled, within-subject, inpatient study compared the effects of THC-containing hemp oils in liquid and capsule form to dronabinol (synthetic THC) in doses used for appetite stimulation. The National Institute on Drug Abuse Institutional Review Board approved the protocol and each participant provided informed consent. Detection times and concentrations of THC, 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) in plasma were determined by gas chromatography-mass spectrometry [limits of quantification (LOQ)=0.5, 0.5, and 1.0 ng/mL, respectively] after oral THC administration. Six volunteers ingested liquid hemp oil (0.39 and 14.8 mg THC/d), hemp oil in capsules (0.47 mg THC/d), dronabinol capsules (7.5 mg THC/d), and placebo. Plasma specimens were collected during and after each dosing condition. THC and 11-OH-THC concentrations were low and never exceeded 6.1 ng/mL. Analytes were detectable 1.5 hour after initiating dosing with the 7.5 mg THC/d regimen and 4.5 hour after starting the 14.8 mg THC/d sessions. THCCOOH was detected 1.5 hour after the first dose, except for the 0.47 mg THC/d session, which required 4.5 hour for concentrations to reach the LOQ. THCCOOH concentrations peaked at 3.1 ng/mL during dosing with the low-dose hemp oils. Plasma THC and 11-OH-THC concentrations were negative for all participants at all doses within 15.5 hours after the last THC dose. Plasma THCCOOH persisted for at least 39.5 hours after the end of dosing and at much higher concentrations (up to 43.0 ng/mL). This study demonstrated that subjects who used high THC content hemp oil (347 μg/mL) as a dietary supplement had THC and metabolites in plasma in quantities comparable to those of patients using dronabinol for appetite stimulation. There was a significant correlation between body mass index and Cmax and body mass index and number of specimens positive for THC and 11-OH-THC.

Evaluation of a homogenous enzyme immunoassay for the detection of synthetic cannabinoids in urine

INTRODUCTION The recent emergence and widespread availability of many new synthetic cannabinoids support the need for an accurate and high-throughput urine screen for these new designer drugs. We evaluated performance of the immunalysis homogeneous enzyme immunoassay (HEIA) to sensitively, selectively, and rapidly identify urinary synthetic cannabinoids. METHODS 2443 authentic urine samples were analyzed with the HEIA that targets JWH-018 N-pentanoic acid, and a validated LC-MS/MS method for 29 synthetic cannabinoids and metabolites. Semi-quantitative HEIA results were obtained, permitting performance evaluation at and around three cutoffs (5, 10 and 20 μg/L), and diagnostic sensitivity, specificity and efficiency determination. Performance challenges at ±25 and ±50% of each cutoff level, cross-reactivity and interferences also were evaluated. RESULTS Sensitivity, specificity, and efficiency of the immunalysis HEIA K2 Spice kit with the manufacturers recommended 10 μg/L cutoff were 75.6%, 99.6% and 96.8%, respectively, as compared to the reference LC-MS/MS method with limits of detection of 0.1-10 μg/L. Performance at 5 μg/L was 92.2%, 98.1% and 97.4%, and for the 20 μg/L cutoff were 62.9%, 99.7% and 95.4%. Semi-quantitative results for in-house prepared standards were obtained from 2.5-30 μg/L, and documented acceptable linearity from 5-25 μg/L, with inter-day imprecision <30% (n = 17). Thirteen of 74 synthetic cannabinoids evaluated were classified as highly cross-reactive (≥50% at 10 μg/L); 4 showed moderate cross-reactivity (10-50% at 10 μg/L), 30 low cross-reactivity (<10% at 500 μg/L), and 27 <1% cross-reactivity at 500 μg/L. There was no interference from 102 investigated compounds. Only a mixture containing 1000 μg/L each of buprenorphine/norbuprenorphine produced a positive result above our proposed cutoff (5 μg/L) but below the manufacturers recommended cutoff concentration (10 μg/L). CONCLUSION The Immunalysis HEIA K2 Spice kit required no sample preparation, had a high-throughput, and acceptable sensitivity, specificity and efficiency, offering a viable method for screening synthetic cannabinoids in urine that cross-react with JWH-018 N-pentanoic acid antibodies.

Monitoring pregnant women's illicit opiate and cocaine use with sweat testing.

Dependence on illicit drugs during pregnancy is a major public health concern as there may be associated adverse maternal, fetal, and neonatal consequences. Sweat patches (n = 389) were collected from 39 pregnant volunteers who provided written informed consent for this Institutional Review Board-approved protocol and wore patches, replaced approximately weekly, from study entry until delivery. Patches were analyzed for opiates (heroin, 6-acetylmorphine, 6-acetylcodeine, morphine and codeine) and cocaine (cocaine, benzoylecgonine, ecgonine methyl ester, anhydroecgonine methyl ester) by solid phase extraction and gas chromatography mass spectrometry. Seventy-one percent (276) of collected sweat patches were ≥5 ng per patch (limit of quantification) for one or more analytes. Cocaine was present in 254 (65.3%) patches in concentrations ranging from 5.2 to 11,835 ng per patch with 154 of these high enough to satisfy the proposed Substance Abuse and Mental Health Services Administration guidelines for a confirmatory drug test (25 ng per patch). Interestingly, 6-acetylmorphine was the most prominent opiate analyte documented in 134 patches (34.4%) with 11.3% exceeding the proposed opiate Substance Abuse and Mental Health Services Administration cut-off (25 ng per patch). Heroin was identified in fewer patches (77), but in a similar concentration range (5.3-345.4 ng per patch). Polydrug use was evident by the presence of both cocaine and opiate metabolites in 136 (35.0%) patches. Sweat testing is an effective method for monitoring abstinence or illicit drug use relapse in this high-risk population of pregnant opiate- and/or cocaine-dependent women.