Mechanistic Rationale for Ketene Formation during Dabbing and Vaping.

Ketene is one of the most toxic vaping emissions identified to date. However, its high reactivity renders it relatively challenging to identify. In addition, certain theoretical studies have shown that realistic vaping temperature settings may betoo low to produce ketene. Each of these issues is addressed herein. First, an isotopically labeled acetate precursor is used for the identification of ketene with enhanced rigor in vaped aerosols. Second, discrepancies between theoretical and experimental findings are explained by accounting for the effects of aerobic (experimental) versus anaerobic (simulated and theoretical) pyrolysis conditions. This finding is also relevant to explaining the relatively low-temperature production of aerosol toxicants beyond ketene. Moreover, the study presented herein shows that ketene formation during vaping is not limited to molecules possessing a phenyl acetate substructure. This means that ketene emission during vaping, including from popular flavorants such as ethyl acetate, may be more prevalent than is currently known.

Reviewing the Risk of Ketene Formation in Dabbing and Vaping Tetrahydrocannabinol-O-Acetate.

Introduction: In the wake of continued consumer demand despite increasing regulatory scrutiny, there is a need to develop systematic methods for identifying the harm profile of new psychoactive substances derived from hemp. Tetrahydrocannabinol-O (THC-O)-acetate, colloquially known as THCO, is the acetate ester of the principal psychoactive compound in cannabis. The heating of THCO can create ketene gas, which is harmful to the lungs. Materials and Methods: The research team used a multidisciplinary, iterative process to develop a survey to incorporate consumers' perspectives of semisynthetic cannabinoids. The survey was then distributed across the social media platform Reddit to learn about delivery device preferences and associated use styles when consuming THCO. Results: Most participants (74.9%) vaped THCO and one-quarter of participants (24.3%) dabbed THCO and tended to report higher temperatures for dabbing than vaping THCO. A small portion (12.0%) of participants reported concerns regarding ketene risk. Conclusion: As there are multiple variables associated with the formation of ketene, and consumer responses indicate temperatures use that might enable ketene formation, more research is needed to understand the risk profile of hemp-derived substances like THCO. Further studies are needed to understand the how various routes of administration and delivery devices used with THCO may exacerbate the risk of ketene formation and other potential harms.

Vaping Cannabinoid Acetates Leads to Ketene Formation.

Δ8-THC acetate is a relatively new psychoactive cannabis product that is available online and in vape shops across the United States since it is currently largely unregulated. Because it contains a similar substructure to vitamin E acetate, which has been shown to form the poison gas ketene during vaping, we investigated potential ketene formation from Δ8-THC acetate, as well as two other cannabinoids acetates, CBN acetate and CBD acetate, under vaping conditions. Ketene was consistently observed in vaped condensates from all three cannabinoid acetates as well as from a commercial Δ8-THC acetate product purchased online.