Vaping Δ 9 -tetrahydrocannabinol (Δ 9 -THC) in liquid forms: pharmacokinetics, pharmacodynamics, and regulatory implications

Introduction Little is known about the pharmacokinetics (PK) and pharmacodynamics (PD) of Δ9-tetrahydrocannabinol (Δ9-THC) when vaped in liquid formulations. As prevalence of vaping Δ9-THC in liquid forms grows, understanding the factors that influence PK/PD profiles is critical to guide future research and cannabis regulation.Areas covered Currently, no human studies have elucidated the PK/PD profile of Δ9-THC from vaped liquids, as confirmed by searches of PubMed and Embase. Using existing research on smoked cannabis and nicotine-containing e-cigarettes, this review examines the potential influence of product potency, vaporization efficiency, consumer use behaviors, aerosol bioavailability, and other constituents on the PK/PD profile of Δ9-THC vaped in liquid forms. Further, we hypothesize whether the PK/PD of Δ9-THC in liquid forms may differ from smoked cannabis and address potential regulatory implications (United States-focused) of novel vaping products.Expert opinion While more potent than smoked cannabis, vaped liquid formulations with Δ9-THC may have a similar PK/PD profile through modulation of Δ9-THC delivery by consumer use behaviors. Potential health effects of high-potency vaping products with Δ9-THC in liquid form need to be carefully studied. Lastly, researchers should continue to think creatively about how this important work can progress while restrictions on Δ9-THC continue to hinder research.