Conversion of water-soluble CBD to Delta9-THC in synthetic gastric fluid - An unlikely cause of positive drug tests (2023)

Cannabidiol (CBD) has been shown to convert to Delta9-tetrahydrocannabinol (Delta9-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 Delta9-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 3h 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 (<0.0006% conversion), and up to 0.063% and 0.0045% conversion to Delta9-THC was observed with the water-soluble CBD and the CBD powder, respectively. No formation of Delta8-THC was observed. In comparison, when the nano-formulated CBD was incubated in SGF with 1% SDS, 33-36% conversion to Delta9-THC was observed. Even though the rate of conversion with the water-soluble CBD was at least 100-fold higher compared to the CBD oil, it was still smaller than Delta9-THC levels reported in CBD products labeled "THC-free" or "<0.3% THC" based on the Agricultural Improvement Act of 2018 (the Farm Bill). Assuming a daily CBD dose of around 30 mg/day, it is unlikely that conversion of CBD to Delta9-THC could produce a positive urinary drug test for 11-Nor-9-carboxy-Delta9-THC (15 ng/mL cut-off).