Absence of Relevant Thermal Conversion of Cannabidiol to Tetrahydrocannabinol in E-Cigarette Vapor and Low-Tetrahydrocannabinol Cannabis Smoke

Abstract

Introduction: Recent research claimed that CBD in commercial electronic cigarette (e-cigarette) liquids can be converted into psychotropic amounts of Δ 9 -THC. This study aims to validate this claim using a realistic e-cigarette setup. In addition, this study also investigates if such a conversion may occur during smoking of CBD-rich cannabis joints. Materials and Methods: Two different CBD liquids were vaporized using two different e-cigarette models, one of which was operated at extreme energy settings (0.2 Ω and 200 W). The smoke of six CBD joints was collected using a rotary smoking machine according to ISO 4387:2019. Analyses were conducted using nuclear magnetic resonance spectrometry as well as liquid chromatography tandem mass spectrometry. Results: For the condensed e-cigarette liquids, no increase in THC concentration could be observed. For the CBD joints, no THC formation was provable. The recovered THC concentrations were ranging between 1% and 48% (0.034 and 0.73 mg) of the THC amount initially contained in the joints before smoking. Conclusions: Using realistic conditions of consumer exposure, relevant conversion of CBD to THC appears to not be occurring. The health risk of CBD liquids for e-cigarettes, as well as low-THC cannabis intended for smoking, can be assessed by concentrations in the source material without the need to consider significant changes in psychotropic compounds during use by consumers.

Are adverse effects of cannabidiol (CBD) products caused by tetrahydrocannabinol (THC) contamination?

“…Pasteurisation (80°C, 30 s) and sterilisation (105°C, 120 kPa, 15 min) of fruit juices (pH 2.7) containing CBD resulted in its degradation and the formation of THC 59 . Transformation of CBD may also occur in acidified plasma samples, heating at 175°C for 30 min, or during pyrolysis gas chromatography [60][61][62] , but not during vaping or smoking of low-THC cannabis products 63 .…”