Conjugation of Synthetic Cannabinoids JWH-018 and JWH-073, Metabolites by Human UDP-Glucuronosyltransferases

Abstract

ABSTRACT:K2, a synthetic cannabinoid (SC), is an emerging drug of abuse touted as "legal marijuana" and marketed to young teens and first-time drug users. Symptoms associated with K2 use include extreme agitation, syncope, tachycardia, and visual and auditory hallucinations. One major challenge to clinicians is the lack of clinical, pharmacological, and metabolic information for the detection and characterization of K2 and its metabolites in human samples. Information on the metabolic pathway of SCs is very limited. However, previous reports have shown the metabolites of these compounds are excreted primarily as glucuronic acid conjugates. Based on this information, this study evaluates nine human recombinant uridine diphosphate-glucuronosyltransferase (UGT) isoforms and human liver and intestinal microsomes for their ability to glucuronidate hydroxylated metabolites of 1-naphthalenyl-1(1-pentyl-1H-indol-3-yl)-methanone (JWH-018) and (1-butyl-1H-indol-3-yl)-1-naphthalenyl-methanone (JWH-073), the two most common SCs found in K2 products. Conjugates were identified and characterized using liquid chromatography/tandem mass spectrometry, whereas kinetic parameters were quantified using high-performance liquid chromatography-UV-visible methods. UGT1A1, UGT1A3, UGT1A9, UGT1A10, and UGT2B7 were shown to be the major enzymes involved, showing relatively high affinity with K m ranging from 12 to 18 M for some hydroxylated K2s. These UGTs also exhibited a high metabolic capacity for these compounds, which indicates that K2 metabolites may be rapidly glucuronidated and eliminated from the body. Studies of K2 metabolites will help future development and validation of a specific assay for K2 and its metabolites and will allow researchers to fully explore their pharmacological actions.

First Characterization of AKB-48 Metabolism, a Novel Synthetic Cannabinoid, Using Human Hepatocytes and High-Resolution Mass Spectrometry

“…Oxidation of the N-pentyl side chain forming a ketone appears to be a minor metabolic pathway. Based on the published studies for other synthetic cannabinoids, AKB-48 shares some common metabolic pathways, e.g., mono-or dihydroxylation of the N-pentyl side chain or the indole moiety similar to JWH-018, JWH-073, JWH-081, JWH-122, JWH-210, JWH-250, or RCS-4 (17,21) or hydroxylation of the aliphatic adamantane ring similar to AB-001 (20), followed by glucuronidation (22,23). These data improve detection of AKB-48 consumption in forensic and clinical toxicological testing and document the need for synthesis of AKB-48 metabolites as reference standards for developing quantitative methods.…”

CYP3A4 Mediates Oxidative Metabolism of the Synthetic Cannabinoid AKB-48

“…Here, in addition, knowledge of the metabolic profile is essential as the synthetic cannabinoid parent compounds are usually not found in this matrix (9,10). The biotransformations consist mainly of oxidation reactions to form hydroxylated and/or carboxylated metabolites, which are subsequently conjugated by UDP-glucuronosyltransferases (11).…”

Cytochrome P450-Mediated Oxidative Metabolism of Abused Synthetic Cannabinoids Found in K2/Spice: Identification of Novel Cannabinoid Receptor Ligands

“…In addition to mass spectra comparisons, all metabolic products were confirmed by matching retention times of analytical standards. LC-MS/MS conditions have previously been shown to resolve each of the metabolites assayed from their corresponding conjugates (Chimalakonda et al, 2011a).…”