Characterization of the Formation of the Acyl Glucuronide Metabolite of 7-Carboxy-Cannabidiol in Human Liver, Kidney, and Intestinal Microsomes and <i>In Vivo</i> 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 <i>in vivo</i> 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.