Identification and determination of 11-oxo-delta8-tetrahydrocannabinol as an intermediate metabolite of delta8-tetrahydrocannabinol in the mouse brain and liver.

11-Oxo-delta 8-tetrahydrocannabinol (11-oxo-delta THC) was found in the mouse brain and liver extracts as a new in vivo metabolite of delta8-THC. The metabolite was detected by thin-layer chromatography using two aldehyde reagents together with a phenol reagent and identified as a heptafluorobutyrate by ECD-gas chromatography. This identification was further supported by gas chromatography-mass spectrometry. Content of the metabolite in the mouse liver was 0.09 or 0.19 microgram/g at 15 min after the i.v. injection of delta8-THC or 11-hydroxy-delta8-THC (11-OH-delta8-THC) at a dose of 10 mg/kg. On the contrary, 11-oxo-delta 8-THC was not precisely quantified (less than 0.01 microgram/g) in the brain after injection of delta 8-THC, although its content after the injection of 11-OH-delta 8 THC was 0.03 microgram/g.