Characterization of the Formation of the Acyl Glucuronide Metabolite of 7-Carboxy-Cannabidiol in Human Liver, Kidney, and Intestinal Microsomes and In Vivo in Mice

Acyl glucuronides are common metabolites of carboxylic acids. They can be reactive and cause adverse events. The acyl glucuronide metabolite of delta-9-tetrahydrocannabinol (THC) is abundant in humans after THC consumption but acyl glucuronide formation from the cannabidiol (CBD) metabolite 7-carboxy-cannabidiol (7-COOH-CBD) has not been previously described. Here, we identified and characterized both acyl and phenolic glucuronides of 7-COOH-CBD formed in human liver, kidney, and intestinal microsomes. The 7-COOH-CBD-acyl-glucuronide was mostly formed by UGT1A1 and UGT1A3, while the 7-COOH-CBD-phenolic-glucuronide was formed by UGT1A9. 7-COOH-CBD-acyl-glucuronide formation was also detected in vivo in mice. 7-COOH-CBD-acyl-glucuronide showed extensive acyl migration while 11-COOH-THC-glucuronide did not. Human serum albumin enhanced migration, while liver fatty acid binding protein (FABP1) protected against 7-COOH-CBD-acyl-glucuronide migration. When corrected for unbound fraction, FABP1 increased 7-COOH-CBD glucuronidation efficiency. These findings suggest that 7-COOH-CBD-acyl-glucuronide is a metabolite of CBD in humans and may play a role in CBD related liver toxicity.