Can an Oral Cannabis Carrier Change Measured Exposure? A Rat Formulation Comparison
The liquid carrying an oral cannabis extract changed cannabinoid concentration profiles in rats. A labeled THC/CBD ratio therefore does not fully describe the exposure a formulation may produce.
The formulation comparison
The investigators administered a CBD-dominant, THC-containing extract to Wistar rats using either Rapae oleum or a Cremophor-based preparation. They measured cannabinoids in whole blood and brain over time.
This was an animal pharmacokinetic experiment. The extract dose, constituent doses, and carrier volume are different quantities; they should not be substituted for one another when comparing products.
More CBD did not mean zero THC
CBD concentrations exceeded THC concentrations with both preparations. Exposure profiles nevertheless differed by carrier, and CBD/THC ratios changed over time. The authors reported greater overall availability with Rapae oleum, while some THC differences were less pronounced than CBD differences.
A concentration ratio is influenced by the absorption, distribution, and elimination of both compounds. Its change does not independently identify a unique chemical conversion pathway. Establishing conversion requires evidence beyond observing a shifting ratio in an extract that already contains both substances.
What follows for product interpretation?
The comparison supports formulation-specific investigation. It does not establish that one carrier is clinically superior in humans or provide a universal conversion between a bottle’s labeled content and a patient’s blood concentration.
No driving or therapeutic-efficacy endpoint in this experiment establishes the functional meaning of the concentration differences. Expert interpretation should identify the exact preparation, dose basis, matrix, and sampling interval, preserving the difference between demonstrated exposure and proposed biological mechanisms.
The experiment involved 48 Wistar rats and an oral dose expressed as 30 mg/kg cannabidiol equivalent. That dose basis is critical: it should not be described as 30 mg/kg THC. Because the preparation already contained both cannabinoids, identifying the starting composition is also necessary before interpreting a later blood or brain ratio.
Related reading: route-specific timing after oral and inhaled cannabis.
Primary research
Joanna Bartkowiak-Wieczorek; Edyta Mądry; Michał Książkiewicz; Jakub Winkler-Galicki; Milena Szalata; Marlena Szalata; Ulises Elizalde Jiménez; Karolina Wielgus; Edmund Grześkowiak; Ryszard Słomski; Agnieszka Bienert. THC-Reduced Cannabis sativa L.—How Does the Solvent Determine the Bioavailability of Cannabinoids Given Orally?. Nutrients (2023). DOI: 10.3390/nu15122646.
