11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol glucuronide exhibits acyl-migration isomers

Development of a quick preparation method for the analysis of 11-nor-9-carboxy-∆9-tetrahydrocannabinol in human urine by phenylboronic-acid solid-phase extraction

A rapid preparation method for the analysis of the urine from a cannabis user was established. Generally, 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH), which is one of the main metabolites of ∆9-tetrahydorocannabinol (THC), must be detected from a user's urine to verify cannabis use. However, existing preparation methods are usually multistep and time-consuming processes. Before the analysis by liquid-chromatography tandem mass spectrometry (LC-MS/MS), deconjugation by treatment with β-glucuronidase or alkaline solution, liquid-liquid extraction or solid-phase extraction (SPE), and evaporation are generally performed. In addition, subsequent derivatization (silylation or methylation) are certainly necessary for gas-chromatography mass spectrometry (GC/MS) analysis. Here, we focused on the phenylboronic-acid (PBA) SPE, which selectively binds compounds with a cis-diol moiety. THC-COOH is metabolized as a glucuronide conjugate (THC-COOGlu) which has cis-diol moieties, therefore, we investigated the conditions of its retention and elution to reduce the operating time. We developed four elution conditions, which afford the following derivatives: acidic elution for THC-COOGlu, alkaline elution for THC-COOH, methanolysis elution for the THC-COOH methyl ester (THC-COOMe), and methanolysis elution and following methyl etherification for O-methyl-THC-COOMe (O-Me-THC-COOMe). All repeatability and recovery rates were evaluated by LC-MS/MS in this study. As a result, these four pathways required short times (within 10-25 min) and exhibited good repeatability and recovery rates. Detection limits of pathway I-IV were 10.8, 1.7, 18.9, and 13.8 ng mL-1, respectively. Lower limits of quantification were 62.5, 31.25, 57.3, and 62.5 ng mL-1, respectively. When proof of cannabis use is required, any elution condition can be selected to match the possessing reference standards and analytical instruments. To our knowledge, this is the first report of using PBA SPE for the preparation of the urine samples containing cannabis and achieving partial derivatization when eluting from a PBA carrier. Our method can provide a new and practical solution for the preparation of the urine samples from cannabis users. Although the PBA SPE method cannot recover THC-COOH in urine because of its lack of a 1,2-diol moiety, this method has technological advantages for simplifying the process and reducing the operating time, thereby avoiding human errors.

A rapid Dilute-and-Shoot LC-MS/MS method for quantifying THC-COOH and THC-COO(Gluc) in urine

Cannabis remains one of the most commonly used psychotropes. Cannabis use is frequently evaluated via the testing of suspected patient samples. Thus, there is a high demand for simple, accurate and fast assays to support the increasing needs for testing. This report highlights a reliable, simple and fast liquid chromatography - tandem mass spectrometry assay that quantifies the cannabis metabolites THC-COOH and THC-COO(Gluc) in human urine. The assay employs a direct dilute-and-shoot approach, whereby urine samples are diluted 10X before being directly injected on the liquid chromatography and mass spectrometer. The assay quantification is based on an internal calibration approach that used deuterated analogues for THC-COOH and THC-COO(Gluc) as internal standards. The assay's analysis time was 5 min. The quantification was valid over a wide linear range (25 - 8,000 ng/mL) for both analytes and was free of matrix interferences. The within-day and between-day precision was determined to be ≤ 15 % CV for both analytes. The assay was validated based on the College of American Pathologists (CAP) and Clinical Laboratory Standards Institute (CLSI) guidelines.

Oleamide as analyte protectant in GC analysis of THC and its metabolites in blood

Methods for the analysis of cannabinoids in bio-matrices are continually being developed, to achieve a proper sensitivity required for their detection and accuracy in their quantification. The presented paper shows that the analytical sensitivity of GC-MS to THC and its metabolites in blood samples can be significantly increase by oleamide (OLA) addition to the examined sample, which evokes the matrix effect of transient character. The magnitude of signal increment resulting from oleamide presence in the examined sample is the greatest for THC metabolites and depends on oleamide concentration in the examined sample. The use of transient matrix effect to increase the sensitivity of the analysis can be applied not only in QuEChERS procedure, which is applied in the described experiments, but also in other blood sample preparation methods. Evoking the transient matrix effect by means of OLA in the experimental analytical quantitation of THC and its metabolites in blood allowed to lower limit of detection (LOD) approximately by 20.5%, 87.6% and 90.1% in the case of THC, THC-OH and THC-COOH, respectively.

Identification and quantification of cannabinoids in postmortem fluids and tissues by liquid chromatography-tandem mass spectrometry

Cannabis sativa is commonly used worldwide and is frequently detected by forensic laboratories working with biological specimens from potentially impaired drivers or pilots. To address the problem of limited published methods for cannabinoids quantification in postmortem specimens, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify Δ⁹-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), 8β,11-dihydroxy-THC (8β-diOH-THC), 8β-hydroxy-THC (8β-OH-THC), THC-glucuronide (THC-g), THCCOOH-glucuronide (THCCOOH-g), cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), Δ⁹-tetrahydrocannabivarin (THCV), and 11-nor-9-carboxy-THCV (THCVCOOH). Solid phase extraction concentrated analytes prior to analysis on a biphenyl column coupled to a mass spectrometer in electrospray positive ionization mode using multiple reaction monitoring. Linearity ranged from 0.25-50 ng/mL (THC-g), 0.5-100 ng/mL (CBN), 0.5-250 ng/mL (THC, 11-OH-THC, THCCOOH, CBD, and CBG), 1-100 ng/mL (8β-diOH-THC, THCVCOOH, 8β-OH-THC, and THCV) and 1-250 ng/mL (THCCOOH-g). Within-run imprecision was <11.2% CV, between-run imprecision <18.1% CV, and bias was less than ±15.1% of target concentration in blood for all cannabinoids at three concentrations. No carryover or interferences were observed. All cannabinoids were stable in blood at room temperature for 24 h, refrigerated (4°C) for 96 h, and following three freeze/thaw cycles. Matrix effects greater than 25% were observed for most analytes in tissues. The proof of concept for method applicability involved measurement of cannabinoids in a pilot fatally injured in an aviation crash. This new analytical method is robust and sensitive, enabling collection of additional cannabinoid postmortem distribution data to improve interpretation of postmortem cannabinoid results.

Determination of the Cross-Reactivity of the Biological Metabolite (-)-trans-Δ9-Tetrahydrocannabinol-Carboxylic Acid-Glucuronide (THC-COOH-Gluc) for Cannabinoid Immunoassays

The highest concentrated metabolite of (-)-trans-Δ9-tetrahydrocannabinol (THC) in urine, the main psychoactive constituent of Cannabis sativa, is 11-nor-9-carboxy-(-)-trans-Δ9-tetrahydrocannabinol-β-D-glucuronide [(-)-trans-THC-COOH-Gluc]. Even though reference standards for THC, 11-hydroxy-THC (11-OH-THC) and THC-COOH are commercially available as the biological (-)-trans-stereoisomers, the reference standard of THC-COOH-Gluc is only available as the racemic 11-nor-9-carboxy-(±)-cis-Δ9-tetrahydrocannabinol-β-D-glucuronide. This poses the problem for immunoassays, because different stereoisomers may have different cross-reactivity (CR). The aim of the current study was to extract the biological stereoisomer (-)-trans-THC-COOH-Gluc from a urine sample of two marihuana consumers by solid-phase extraction with a Chromabond® C18 cartridge. The cannabinoids in the obtained extract were quantified by Liquid-chromatography coupled to tandem mass spectrometry (LC-MS-MS) and used after dilution for further testing of the CR of (-)-trans-THC-COOH-Gluc with a homogenous enzyme immunoassay assay (hEIA) (Urine HEIA® Cannabinoids (THC), Immunalysis™, Pomona, CA, USA). The CR was determined as the measured HEIA® signal (ng/mL) per THC-COOH-Gluc concentration (ng/mL) in percentage. Results showed that the CR (determined in concentration ratios) is concentration dependent and is 72-87% in the calibration range (20-50 ng/mL). At the cut-off of the hEIA (40 ng/mL), the CR was determined to be 75%. With a molecular weight quotient of 1.51 (MWTHC-COOH-Gluc/MWTHC-COOH = 520.568 g/mol/344.451 g/mol), this means that CR (in molar ratios) is 106-131%. This finding is important, since the major metabolite of THC in urine is (-)-trans-THC-COOH-Gluc and not (-)-trans-THC-COOH, which is used for calibration and no hydrolysis is performed during the determination by hEIA.

Using measured cannabidiol and tetrahydrocannabinol metabolites in urine to differentiate marijuana use from consumption of commercial cannabidiol products

CONTEXT

Detecting marijuana use is a component of most urine drug screens targeting a single Δ⁹-tetrahydrocannabinol metabolite. Recently, the non-intoxicating cannabinoid, cannabidiol (CBD), has gained popular acceptance for a myriad of reasons. Commercially available CBD products sold without purity regulations have become ubiquitous. Many products contain trace tetrahydrocannabinol. Long-term or high dose use of CBD products can result in tetrahydrocannabinol exposures, potentially producing a positive marijuana drug test. These results are not false positives since marijuana biomarkers are present, but inaccurately identify donors as marijuana users. Addressing this conundrum, we developed an assay discriminating marijuana use from the use of CBD contaminated with tetrahydrocannabinol.

METHODS

Following the synthesis of a primary CBD metabolite, a LC-MS/MS assay was developed measuring the urinary metabolites tetrahydrocannabinol, 11-nor-carboxy-Δ⁹-tetrahydrocannabinol, CBD, and 7-carboxy-cannabidiol. The assay was utilized on 425 patients claiming CBD use, and sixteen samples from trusted users of commercial CBD products.

RESULTS AND DISCUSSION

Clear data clusters enabled metabolic cut-points assignments. Forty-three percent of samples contained CBD metabolites in ten-fold excess to tetrahydrocannabinol metabolites which was then used as a set point to classify donors as CBD users. An excess of tetrahydrocannabinol metabolites classify donors as marijuana users. Additionally, urine samples were procured from donors personally known to use commercial CBD ad libitum, yet abstain from tetrahydrocannabinol. Results from trusted users substantiated the use of the resulting metabolic ratios despite 11-carboxy-tetrahydrocannabinol measured in 75% of these samples.

CONCLUSION

A method has been developed and utilized to distinguish marijuana use from tetrahydrocannabinol exposure from contaminated CBD use.

Validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to detect cannabinoids in whole blood and breath

Background

The widespread availability of cannabis raises concerns regarding its effect on driving performance and operation of complex equipment. Currently, there are no established safe driving limits regarding ∆9-tetrahydrocannabinol (THC) concentrations in blood or breath. Daily cannabis users build up a large body burden of THC with residual excretion for days or weeks after the start of abstinence. Therefore, it is critical to have a sensitive and specific analytical assay that quantifies THC, the main psychoactive component of cannabis, and multiple metabolites to improve interpretation of cannabinoids in blood; some analytes may indicate recent use.

Methods

A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to quantify THC, cannabinol (CBN), cannabidiol (CBD), 11-hydroxy-THC (11-OH-THC), (±)-11-nor-9-carboxy-Δ9-THC (THCCOOH), (+)-11-nor-Δ9-THC-9-carboxylic acid glucuronide (THCCOOH-gluc), cannabigerol (CBG), and tetrahydrocannabivarin (THCV) in whole blood (WB). WB samples were prepared by solid-phase extraction (SPE) and quantified by LC-MS/MS. A rapid and simple method involving methanol elution of THC in breath collected in SensAbues® devices was optimized.

Results

Lower limits of quantification ranged from 0.5 to 2 μg/L in WB. An LLOQ of 80 pg/pad was achieved for THC concentrations in breath. Calibration curves were linear (R2>0.995) with calibrator concentrations within ±15% of their target and quality control (QC) bias and imprecision ≤15%. No major matrix effects or drug interferences were observed.

Conclusions

The methods were robust and adequately quantified cannabinoids in biological blood and breath samples. These methods will be used to identify cannabinoid concentrations in an upcoming study of the effects of cannabis on driving.

Pitfalls in drug testing by hyphenated low- and high-resolution mass spectrometry

This paper reviews various pitfalls observed during developing, validation, application, and interpretation of drug testing approaches using GC-MS and low- and high-resolution LC-MS. They include sampling and storage of body samples, sample adulteration and contamination, analyte stability, sample preparation without or with cleavage of conjugates, extraction, derivatization, internal standardization, false negative and positive results by GC-MS or LC-MS screening and/or confirmation procedures including artifact formation, ion suppression or enhancement by electrospray ionization, and finally pitfalls in data interpretation. Conclusions and prospects close the Tutorial.