Conversion of water-soluble CBD to ∆9-THC in synthetic gastric fluid—An unlikely cause of positive drug tests

Abstract Cannabidiol (CBD) has been shown to convert to ∆9-tetrahydrocannabinol (∆9-THC) in acidic environments, raising a concern of conversion when exposed to gastric fluid after consumption. Using synthetic gastric fluid (SGF), it has been demonstrated that the conversion requires surfactants, such as sodium dodecyl sulfate (SDS), due to limited solubility of CBD. Recently, water-compatible nanoemulsions of CBD have been prepared as a means of fortifying beverages and water-based foods with CBD. Since these emulsions contain surfactants as part of their formulation, it is possible that these preparations might enhance the production of ∆9-THC even in the absence of added surfactants. Three THC-free CBD products, an oil, an anhydrous powder and a water-soluble formulation, were incubated for 3 h in SGF without SDS. The water-soluble CBD product produced a dispersion, while the powder and the oil did not mix with the SGF. No THC was detected with the CBD oil (