Larger Analytical Batches Produced CBD-to-THC Conversion During Saliva Preparation
A cannabinoid study found that a saliva-preparation procedure could generate THC from CBD in the laboratory. Conversion emerged with larger production batches even though the smaller validation batches had not shown it.
The experiment involved controlled human dosing
Eighteen participants received oral CBD, vaporized CBD, CBD-dominant cannabis containing a small THC dose, and placebo in a blinded laboratory study. Blood and oral fluid were collected to compare cannabinoid pharmacokinetics.
The important analytical observation concerned oral-fluid processing, not a demonstrated chemical conversion in participants’ stomachs. Blood findings and saliva-preparation experiments therefore must remain separate in the interpretation.
Exposure to acid changed with workflow
The oral-fluid extraction procedure used an acidic buffer. Follow-up experiments found conversion of CBD to delta-9 THC and delta-8 THC, with longer acid exposure during larger batches contributing to the problem.
The small batches used during initial validation did not reproduce the same degree of exposure time. Consequently, successful validation at one batch size did not guarantee unchanged analyte composition when the production workflow expanded.
Why the authors restricted saliva interpretation
The investigators supplied individual oral-fluid data but did not conduct the planned additional analyses on those data. That restraint recognized that an analytically generated compound cannot reliably be treated as an unchanged biological measurement.
This does not prove that every CBD-associated THC result is an artifact. Actual THC in a product, residual prior exposure and other explanations require case-specific evaluation. It identifies a testable concern about the particular preparation process.
A laboratory review should examine reagents, holding times, batch size and experiments assessing conversion. This report offers a concrete example of workflow-dependent analytical chemistry; it does not establish that oral CBD universally becomes THC in humans or invalidate blood results produced by a different validated method.
Related: Separating cannabinoid exposure from impairment.
Primary research
Pharmacokinetic Profile of ∆9-Tetrahydrocannabinol, Cannabidiol and Metabolites in Blood following Vaporization and Oral Ingestion of Cannabidiol Products. Journal of Analytical Toxicology (2022).
