Preliminary pharmacokinetic and psychophysical investigations after controlled oral and inhalative consumption of hexahydrocannabinol (HHC)

The semi-synthetic cannabinoid hexahydrocannabinol (HHC) has become a highly discussed topic in forensic toxicology since 2022 due to its legal availability at this time and its psychoactive effects. This study aimed to investigate the pharmacokinetics, effects, and immunological detectability of HHC after oral (25 mg HHC fruit gum) and inhalative (three puffs from HHC vape) consumption with three participants per group. Serum (up to 48 h), urine (up to five days), and saliva (up to 48 h) samples were collected at different relevant time points and analyzed by HPLC-MS/MS for (9R)/(9S)-HHC, 11-hydroxy-HHC, and (9R)/(9S)-HHC carboxylic acid with a fully validated method. Additionally, immunological detectability was investigated with three different commercially available tests. To address the psychoactive effects, the subjective "high" feeling (scale 0-10) was monitored and different psychophysical tests (e.g. modified Romberg test, walk and turn) were conducted. Overall, the pharmacokinetics and effects of HHC were comparable to tetrahydrocannabinol (THC). However, the route of administration as well as inter-individual factors played a crucial role regarding maximum concentrations, pharmacokinetic profiles, and psychoactive effects.