A preliminary investigation of lung availability of cannabinoids by smoking marijuana or dabbing BHO and decarboxylation rate of THC- and CBD-acids.

Highly potent cannabis concentrates obtained by butane or by supercritical carbon dioxide-extraction are gaining popularity. These extracts called butane hash oil (BHO) with Δ9-tetrahydrocannabinolic acid A (THCA) contents above 60% are consumed by flash vaporization on a glowing titanium nail, followed by inhalation of the resulting vapor through a water pipe in a single puff - a technique referred to as "dabbing". We herein investigated the decarboxylation rate of THCA during artificial smoking of cannabis plant material and simulated dabbing, and the lung availability of Δ9-tetrahydrocannabinol (THC) which we define as the recovery of THC in the smoke and vapor condensates. Preliminary smoking and dabbing experiments were performed using an apparatus built in-house. Due to availability of cannabidiol (CBD)-rich hemp in Switzerland, we included a sample of CBD flowers in our experiments and investigated the decarboxylation and recovery of cannabidiolic acid (CBDA) and CBD, respectively. Decarboxylation of THCA and CBDA during combustion of the plant material and vaporization of the BHO, respectively, was complete. The high recovery of total THC (75.5%) by dabbing cannot be achieved by smoking marijuana. Lung availability ranged from 12% for mixed cannabis material with a rather low THC content, to approximately 19-27% for marijuana flowers, similar for THC in marijuana as for CBD in CBD-rich marijuana. In reality, when smoking a joint, further losses in recovery must be assumed by additional sidestream smoke. The rather high lung availability of THC via dabbing can explain the increased psychoactive and adverse effects associated with this new trend of cannabis consumption.