CBD Conversion Was Not Detected in Three Minipigs, Within Defined Limits
Synthetic CBD did not produce quantifiable THC or 11-hydroxy-THC in a three-minipig experiment. The finding is relevant to proposed stomach conversion, but it remains a small animal study with specified analytes and sampling times.
An intact gastrointestinal system was tested
Three male minipigs received synthetic CBD in sesame oil, at 15 mg/kg per dose. Dosing occurred twice daily for four days, followed by a final morning dose on day five. Using synthetic CBD helped avoid trace THC in a plant-derived preparation as an alternative explanation for a positive measurement.
Plasma was sampled before and through six hours after the morning doses on days one and five. Stomach and small-intestinal contents were collected six hours after the final dose. CBD was measurable in plasma and at high concentrations in the gastrointestinal contents.
Nondetection had an analytical boundary
THC and 11-hydroxy-THC were below the reported quantification limits: 0.5 ng/mL in plasma and 1 ng/mL in gastrointestinal contents. Those limits define the observation; they do not demonstrate that every molecule of THC was absent at every moment.
One animal partially regurgitated its first dose, and its day-one pharmacokinetic data were excluded from the group calculations. Only two animals therefore contributed to those day-one summaries, while all three contributed on day five. The study should not be described as three complete identical exposure profiles on both days.
What cannot be transferred to people
The investigators acknowledged the small sample and endpoint selection. THC-COOH and delta-8 THC were not included as endpoint analytes, and the sampling schedule did not continuously survey the entire gut or circulation. Industry sponsorship and author employment were disclosed.
This experiment shows that a conversion reaction observed in simulated gastric fluid cannot simply be assumed to occur to the same extent in an intact animal. It does not independently establish a human conversion rate, certify every retail CBD formulation or predict a person’s drug-test outcome. Human evidence and analytical artifacts remain separate questions.
Related: interpreting THC concentrations separately from impairment.
Primary research
Cannabidiol Does Not Convert to Δ9-Tetrahydrocannabinol in an In Vivo Animal Model. DOI: 10.1089/can.2017.0032.
