Identification of glucose conjugates as major urinary metabolites of cannabidiol in the dog.

1. Three dogs were treated i.v. with cannabidiol (CBD) and urine collected at intervals to 30 h. 2. Metabolites were extracted, converted into trimethylsilyl (TMS) derivatives and examined by g.l.c.-mass spectrometry. 3. The major metabolites excreted at early times were identified as the phenol glucosides of 4"-hydroxy-CBD, 5"-hydroxy-CBD and 6-oxo-CBD. 4. These three oxidized metabolites were not found unconjugated, and none of the free oxidized metabolites in urine were found conjugated with glucose. 5. The conjugates were hydrolysed by beta-glucuronidase Type HP-2 from Helix pomatia and acid phosphatase but not by beta-glucuronidase Type VII from E. coli. Differential reactivity towards alpha- and beta-glucosidase indicated that they possessed the beta-configuration.