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Patton AL, Pacheco IC, Seither JZ, Brown JT, Walterscheid JP, Karschner EL. Cross-Reactivity of 24 Cannabinoids and Metabolites in blood using the immunalysis cannabinoids direct enzyme-linked immunosorbent assay kit. J Anal Toxicol 2024:bkae036. [PMID: 38648393 DOI: 10.1093/jat/bkae036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 04/25/2024] Open
Abstract
With a wider availability of synthetic and semi-synthetic cannabinoids in the consumer space, there is a growing impact on public health and safety. Forensic toxicology laboratories should keep these compounds in mind as they attempt to remain effective in screening for potential sources of human performance impairment. Enzyme-linked immunosorbent assay (ELISA) is a commonly utilized tool in forensic toxicology, as its efficiency and sensitivity make it useful for rapid and easy screening for a large number of drugs. This screening technique has lower specificity, which allows for broad cross-reactivity among structurally-similar compounds. In this study, the Cannabinoids Direct ELISA kit from Immunalysis was utilized to assess the cross-reactivities of 24 cannabinoids and metabolites in whole blood. The assay was calibrated with 5 ng/mL of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol and the analytes of interest were evaluated at concentrations ranging from 5 to 500 ng/mL. Most parent compounds demonstrated cross-reactivity ≥ 20 ng/mL, with increasing alkyl side chain length relative to Δ9-tetrahydrocannabinol resulting in decreased cross-reactivity. Of the 24 analytes, only the carboxylic acid metabolites, 11-nor-9-carboxy-Δ8-tetrahydrocannabinol, 11-nor-9(R)-carboxy-hexahydrocannabinol, and 11-nor-9(S)-carboxy-hexahydrocannabinol, were cross-reactive at levels ≤ 10 ng/mL. Interestingly, 11-nor-9(R)-carboxy-hexahydrocannabinol demonstrated cross-reactivity at 5 ng/mL, where its stereoisomer 11-nor-9(S)-carboxy-hexahydrocannabinol, did not. As more information emerges about the prevalence of these analytes in blood specimens, it is important to understand and characterize their impact on current testing paradigms.
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Affiliation(s)
- Amy L Patton
- Division of Forensic Toxicology, Armed Forces Medical Examiner System, 115 Purple Heart Drive, Dover AFB, DE 19902, USA
- SNA International, LLC, contractor supporting the Armed Forces Medical Examiner System, Alexandria, VA 22314, USA
| | - Igor C Pacheco
- Division of Forensic Toxicology, Armed Forces Medical Examiner System, 115 Purple Heart Drive, Dover AFB, DE 19902, USA
| | - Joshua Z Seither
- Division of Forensic Toxicology, Armed Forces Medical Examiner System, 115 Purple Heart Drive, Dover AFB, DE 19902, USA
| | - Jordan T Brown
- Division of Forensic Toxicology, Armed Forces Medical Examiner System, 115 Purple Heart Drive, Dover AFB, DE 19902, USA
| | - Jeffrey P Walterscheid
- Division of Forensic Toxicology, Armed Forces Medical Examiner System, 115 Purple Heart Drive, Dover AFB, DE 19902, USA
| | - Erin L Karschner
- Division of Forensic Toxicology, Armed Forces Medical Examiner System, 115 Purple Heart Drive, Dover AFB, DE 19902, USA
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Ujváry I. Hexahydrocannabinol and closely related semi-synthetic cannabinoids: A comprehensive review. Drug Test Anal 2024; 16:127-161. [PMID: 37269160 DOI: 10.1002/dta.3519] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 06/04/2023]
Abstract
Since the early 2000s, there has been a turmoil on the global illicit cannabinoid market. Parallel to legislative changes in some jurisdictions regarding herbal cannabis, unregulated and cheap synthetic cannabinoids with astonishing structural diversity have emerged. Recently, semi-synthetic cannabinoids manufactured from hemp extracts by simple chemical transformations have also appeared as recreational drugs. The burst of these semi-synthetic cannabinoids into the market was sparked by legislative changes in the United States, where cultivation of industrial hemp restarted. By now, hemp-derived cannabidiol (CBD), initially a blockbuster product on its own, became a "precursor" to semi-synthetic cannabinoids such as hexahydrocannabinol (HHC), which appeared on the drug market in 2021. The synthesis and cannabimimetic activity of HHC were first reported eight decades ago in quest for the psychoactive principles of marijuana and hashish. Current large-scale manufacture of HHC is based on hemp-derived CBD extract, which is converted first by cyclization into a Δ8 /Δ9 -THC mixture, followed by catalytic hydrogenation to afford a mixture of (9R)-HHC and (9S)-HHC epimers. Preclinical studies indicate that (9R)-HHC has THC-like pharmacological properties. The animal metabolism of HHC is partially clarified. The human pharmacology including metabolism of HHC is yet to be investigated, and (immuno)analytical methods for the rapid detection of HHC or its metabolites in urine are lacking. Herein, the legal background for the revitalization of hemp cultivation, and available information on the chemistry, analysis, and pharmacology of HHC and related analogs, including HHC acetate (HHC-O) is reviewed.
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Mullen LD, Hart ED, Vikingsson S, Winecker RE, Hayes E, Flegel R. ∆8-THC-COOH cross-reactivity with cannabinoid immunoassay kits and interference in chromatographic testing methods. J Anal Toxicol 2023; 47:557-562. [PMID: 37405696 DOI: 10.1093/jat/bkad042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 04/07/2023] [Accepted: 06/26/2023] [Indexed: 07/06/2023] Open
Abstract
Because of structural similarities, the presence of 11-Nor-9-carboxy-∆8-tetrahydrocannabinol (∆8-THC-COOH) in a urine specimen might interfere with testing for 11-Nor-9-carboxy-∆9-tetrahydrocannabinol (∆9-THC-COOH). A set of samples containing ∆8-THC-COOH with concentrations ranging from 10 to 120 ng/mL were tested at cut-offs of 20, 50 and 100 ng/mL using cannabinoid immunoassay reagents from three different manufacturers. Cross-reactivities ranged from 87% to 112% for ∆8-THC-COOH at the cut-off of 50 ng/mL for the three different platforms. Additionally, samples containing both ∆8-THC-COOH and ∆9-THC-COOH were fortified by the National Laboratory Certification Program (NLCP). U.S. Department of Health and Human Services (HHS)-Certified Laboratories tested the samples to determine the interference of ∆8-THC-COOH on confirmatory tests commonly used in workplace drug testing laboratories for the confirmation and quantification of ∆9-THC-COOH. When evaluating confirmation and quantification of ∆9-THC-COOH in the presence of ∆8-THC-COOH, unreportable results for ∆9-THC-COOH were observed because of chromatographic interference or mass ratio failures. However, there were no false-positive ∆9-THC-COOH reports from any HHS-certified laboratory.
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Affiliation(s)
- Lawrance D Mullen
- Center for Forensic Science Advancement and Application, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - E Dale Hart
- Center for Forensic Science Advancement and Application, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Svante Vikingsson
- Center for Forensic Science Advancement and Application, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Ruth E Winecker
- Center for Forensic Science Advancement and Application, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA
| | - Eugene Hayes
- Division of Workplace Programs, Substance Abuse and Mental Health Services Administration, 5600 Fishers Lane, Rockville, MD 20857, USA
| | - Ron Flegel
- Division of Workplace Programs, Substance Abuse and Mental Health Services Administration, 5600 Fishers Lane, Rockville, MD 20857, USA
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Moody MT, Ringel MM, Mathews CM, Midthun KM. Determination of Cross-Reactivity of Contemporary Cannabinoids with THC Direct Immunoassay (ELISA) in Whole Blood. J Anal Toxicol 2022; 46:844-851. [PMID: 35867546 DOI: 10.1093/jat/bkac051] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/23/2022] [Accepted: 07/20/2022] [Indexed: 11/12/2022] Open
Abstract
Immunoassay procedures, such as enzyme-linked immunosorbent assay (ELISA), are widely used for screening samples in both driving under the influence of drugs (DUID) and postmortem (PM) investigations. While these are sensitive and widely used techniques, they lack specificity compared to more novel instrumental screening platforms. In this study, the cross-reactivities of several cannabinoid isomers and related compounds were evaluated in whole blood using the Cannabinoids Direct ELISA kit from Immunalysis. The compounds of interest were supplemented individually at three different concentrations, ranging from 10-100 ng/mL or 10-1,000 ng/mL depending on analyte, to determine initial feasibility. Compounds exhibiting cross-reactivity were then tested to create dose-response curves to calculate the percent cross-reactivity. The cross-reactivity was determined to be 200% for delta-8-carboxy-tetrahydrocannabinol (THC) (delta-8-carboxy-THC), 25% for delta-9,11-THC, 13% for delta-10-THC, 7% for delta-6a(10a)-THC, 3% for THC-O-acetate and 0.5% for tetrahydrocannabiphorol (THCP). To determine potential impacts to forensic laboratory casework, a review of DUID and PM casework was also performed. From November 2020 to June 2021, a random sampling of DUID and PM cases was selected monthly and evaluated for the presence of cannabinoid isomer(s) in the absence of a reportable delta-9-carboxy-THC result. While validated techniques for the identification and confirmation of these isomer(s) did not exist at the time of routine testing, delta-8-carboxy-THC was believed to the be the most common isomer finding based on current testing capability. This study demonstrated a noticeable increase in the presence of isomeric cannabinoid compounds in both forensic DUID and PM casework sampled during this period and suggests potential impacts for clinical casework as well.
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Helander A, Johansson M, Andersson A, Villén T. Analytical and medico-legal problems linked to the presence of delta-8-tetrahydrocannabinol (delta-8-THC): Results from urine drug testing in Sweden. Drug Test Anal 2021; 14:371-376. [PMID: 34734479 DOI: 10.1002/dta.3190] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 12/23/2022]
Abstract
During routine urine drug testing for cannabis use targeting delta-9-tetrahydrocannabinol carboxylic acid (delta-9-THC-COOH) at the Karolinska University Laboratory in Sweden, an unknown interfering peak was observed in the liquid-chromatographic-tandem mass-spectrometric (LC-MS/MS) confirmative analysis. The peak showed the same exact mass and most abundant fragments as delta-9-THC-COOH but a slightly shorter retention time, thereby not fulfilling all requirements for a positive identification. The analytical results suggested that it was a similar compound, and with access to reference material, it could be identified as the double bond isomer delta-8-THC-COOH. Delta-8-THC has recently become popular as a recreational drug, although its legality varies and is sometimes unclear. In Sweden, all THC isomers are classified substances. The slight difference in retention times was sufficient to distinguish the THC-COOH isomers in the routine LC-MS/MS method, but another LC method allowed better peak separation and individual quantification. At the Karolinska University Laboratory, delta-8-THC-COOH was first observed in April 2020, and the highest incidence was noted in June 2020 when it was present in 5.3% of all THC-COOH-positive samples. The incidence later decreased to today only occasional findings. Large differences in the relative presence of the isomers in the urine samples indicated different origin, for example, synthetically produced pure delta-8-THC, or mixtures of both THC isomers formed during combustion of cannabidiol (CBD). In conclusion, the appearance of delta-8-THC and other isomers on the recreational drug market risks causing analytical and medico-legal problems, due to confusion with delta-9-THC.
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Affiliation(s)
- Anders Helander
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Pharmacology, Karolinska University Laboratory, Stockholm, Sweden
| | - Malin Johansson
- Department of Clinical Pharmacology, Karolinska University Laboratory, Stockholm, Sweden
| | - Annika Andersson
- Department of Clinical Pharmacology, Karolinska University Laboratory, Stockholm, Sweden
| | - Tomas Villén
- Department of Clinical Pharmacology, Karolinska University Laboratory, Stockholm, Sweden
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Kroner GM, Johnson-Davis KL, Doyle K, McMillin GA. Cannabinol (CBN) Cross-Reacts with Two Urine Immunoassays Designed to Detect Tetrahydrocannabinol (THC) Metabolite. J Appl Lab Med 2021; 5:569-574. [PMID: 32445358 DOI: 10.1093/jalm/jfaa020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/21/2019] [Indexed: 11/13/2022]
Abstract
BACKGROUND The psychoactive component of cannabis, tetrahydrocannabinol (THC), is one of many cannabinoids present in the plant. Since cannabinoids have extensive structural similarity, it is important to be aware of potential cross-reactivity with immunoassays designed to detect THC metabolite. This is especially important as cannabinoid products are increasingly marketed as legal supplements. The objective of this study was to assess the cross-reactivity of 2 commercial immunoassays designed to detect THC metabolite with 4 cannabinoids: cannabidiol, cannabinol, cannabichromene, and cannabigerol. METHODS Deidentified residual patient urine samples that tested negative for THC metabolite on initial testing were pooled and fortified with the above compounds to detect cross-reactivity. We next tested a range of CBN concentrations to determine what concentration of CBN was required to trigger a positive immunoassay result. Finally, we tested whether CBN has an additive effect with THC in the immunoassay by adding CBN to 21 samples weakly positive for THC by a mass spectrometry method but negative by the EMIT II Plus immunoassay. RESULTS Both the EMIT II Plus assay and the Microgenics MultiGent assay demonstrated cross-reactivity with CBN. For the EMIT II Plus assay, about 5-fold more CBN than THC metabolite was required to produce an assay signal equivalent to the cutoff concentration, and CBN displayed an additive effect with THC metabolite. For the Microgenics assay, 20-fold more CBN than THC metabolite was required to cross the cutoff concentration. CONCLUSIONS These data may help guide the need for confirmatory testing when results of THC metabolite testing by immunoassay are inconsistent with expectations.
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Affiliation(s)
- Grace M Kroner
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT
| | - Kamisha L Johnson-Davis
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT.,ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
| | - Kelly Doyle
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT.,ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
| | - Gwendolyn A McMillin
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT.,ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
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Krasowski MD, Siam MG, Iyer M, Pizon AF, Giannoutsos S, Ekins S. Chemoinformatic methods for predicting interference in drug of abuse/toxicology immunoassays. Clin Chem 2009; 55:1203-13. [PMID: 19342505 DOI: 10.1373/clinchem.2008.118638] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Immunoassays used for routine drug of abuse (DOA) and toxicology screening may be limited by cross-reacting compounds able to bind to the antibodies in a manner similar to the target molecule(s). To date, there has been little systematic investigation using computational tools to predict cross-reactive compounds. METHODS Commonly used molecular similarity methods enabled calculation of structural similarity for a wide range of compounds (prescription and over-the-counter medications, illicit drugs, and clinically significant metabolites) to the target molecules of DOA/toxicology screening assays. We used various molecular descriptors (MDL public keys, functional class fingerprints, and pharmacophore fingerprints) and the Tanimoto similarity coefficient. These data were then compared with cross-reactivity data in the package inserts of immunoassays marketed for in vitro diagnostic use. Previously untested compounds that were predicted to have a high probability of cross-reactivity were tested. RESULTS Molecular similarity calculated using MDL public keys and the Tanimoto similarity coefficient showed a strong and statistically significant separation between cross-reactive and non-cross-reactive compounds. This result was validated experimentally by discovery of additional cross-reactive compounds based on computational predictions. CONCLUSIONS The computational methods employed are amenable toward rapid screening of databases of drugs, metabolites, and endogenous molecules and may be useful for identifying cross-reactive molecules that would be otherwise unsuspected. These methods may also have value in focusing cross-reactivity testing on compounds with high similarity to the target molecule(s) and limiting testing of compounds with low similarity and very low probability of cross-reacting with the assay.
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Affiliation(s)
- Matthew D Krasowski
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Flemming T, Muntendam R, Steup C, Kayser O. Chemistry and Biological Activity of Tetrahydrocannabinol and its Derivatives. TOPICS IN HETEROCYCLIC CHEMISTRY 2007. [DOI: 10.1007/7081_2007_084] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Simpson D, Braithwaite RA, Jarvie DR, Stewart MJ, Walker S, Watson IW, Widdop B. Screening for drugs of abuse (II): Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs. Ann Clin Biochem 1997; 34 ( Pt 5):460-510. [PMID: 9293303 DOI: 10.1177/000456329703400502] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Requirements for the provision of an efficient and reliable service for drugs of abuse screening in urine have been summarized in Part I of this review. The requirements included rapid turn-around times, good communications between requesting clinicians and the laboratory, and participation in quality assessment schemes. In addition, the need for checking/confirmation of positive results obtained for preliminary screening methods was stressed. This aspect of the service has assumed even greater importance with widespread use of dip-stick technology and the increasing number of reasons for which drug screening is performed. Many of these additional uses of drug screening have possible serious legal implications, for example, screening school pupils, professional footballers, parents involved in child custody cases, persons applying for renewal of a driving licence after disqualification for a drug-related offence, doctors seeking re-registration after removal for drug abuse, and checking for compliance with terms of probation orders; as well as pre-employment screening and work-place testing. In many cases these requests will be received from a general practitioner or drug clinic with no indication of the reason for which testing has been requested. This also raises the serious problems of a chain of custody, provision of two samples, stability of samples, and secure and lengthy storage of samples in the laboratory-samples may be requested by legal authorities several months after the initial testing. The need for confirmation of positive results is now widely accepted but it may be equally important to confirm unexpected negative results. Failure to detect the presence of maintenance drugs may lead to the patient being discharged from a drug treatment clinic and, if attendance at the clinic is one of the terms of continued employment, to dismissal. It seems likely that increasing abuse of drugs and the efforts of regulatory authorities to control this, will lead to the manufacture of more designer drugs. Production of substituted phenethylamines was facilitated by the drug makers' cook book, 'PIHKAL' (Phenethylamines I Have Known And Loved) by Dr Alexander Shulgin and Ann Shulgin, and production of substituted tryptamines is promised in their next book, TIHKAL. Looking to the future, laboratories will need to ensure that they can detect and quantitate an ever-increasing number of drugs and related substances. The question of confidence in results of drugs of abuse testing raised in 1993 by Watson has assumed even greater importance as a result of attention focused on the OJ Simpson trial in Los Angeles. Toxicological investigations are likely to be challenged more frequently in the future. Even if analyses have been performed by GC-MS, there is a need to establish the level of match between the spectrum of the unknown substance and a library spectrum which is considered acceptable for legal purposes. It will also be essential to ensure that computer libraries contain spectra for all substances likely to be encountered in drugs of abuse screening.
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Affiliation(s)
- D Simpson
- Department of Clinical Biochemistry, Royal Infirmary, Edinburgh, UK
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Bronner WE, Xu AS. Gas chromatographic-mass spectrometric methods of analysis for detection of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in biological matrices. JOURNAL OF CHROMATOGRAPHY 1992; 580:63-75. [PMID: 1328271 DOI: 10.1016/0378-4347(92)80528-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Gas chromatographic-mass spectrometric methods of analysis for the detection of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid, a major metabolite of delta 9-tetrahydrocannabinol, are reviewed. Emphasis is on analytical methodology including numerous derivatization techniques developed specifically for this analyte. The majority of procedures cited in the literature were developed to detect this metabolite in the blood and urine of man.
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Affiliation(s)
- W E Bronner
- Armed Forces Institute of Pathology, Division of Forensic Toxicology, Washington, DC 20306-6000
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