Pharmacokinetics of Two Nanoemulsion Formulations of Δ8-Tetrahydrocannabinol in Rats

The use of Delta(8)-tetrahydrocannabinol (Delta(8)-THC) has increased in recent years. Given that the oral absorption of cannabinoids in oil formulations is typically slow and variable, nanoemulsions may be an improved delivery vehicle. Therefore, we characterized the pharmacokinetics (PK) in Sprague-Dawley rats following the administration of three different oral formulations containing 10 mg/kg Delta(8)-THC: a translucent liquid nanoemulsion, a reconstituted powder nanoemulsion, and a medium chain triglyceride (MCT) oil solution for comparison. Delta(8)-THC was also administered intravenously at 0.6 mg/kg. Plasma samples were quantified for Delta(8)-THC and two metabolites, 11-hydroxy-Delta(8)-THC (11-OH-Delta(8)-THC) and 11-carboxy-Delta(8)-THC (COOH-Delta(8)-THC). Non-compartmental PK parameters were calculated, and a PK model was developed based on pooled data. Despite a smaller median droplet size of the translucent liquid nanoemulsion (26.9 nm) compared to the reconstituted powder nanoemulsion (168 nm), the PK was similar for both. The median T-max values of Delta(8)-THC for the nanoemulsions (0.667 and 1 h) were significantly shorter than the median T-max of Delta(8)-THC in MCT oil (6 h). This resulted in an approximately 4-fold higher Delta(8)-THC exposure over the first 4 h for the nanoemulsions relative to the MCT oil solution. The active 11-OH-Delta(8)-THC metabolite followed a similar pattern to Delta(8)-THC. The non-compartmental bioavailability estimates of Delta(8)-THC for the nanoemulsions (11-16.5%) were lower than for the MCT oil solution (>21.5%). However, a model-based analysis indicated similar bioavailability for all three oral formulations. These results demonstrate favorable absorption properties of both nanoemulsions, despite the difference in droplet sizes, compared to an MCT oil formulation.

Automated summary

The use of Delta(8)-THC has increased recently, and nanoemulsions are found to be a better delivery vehicle. A study on rats showed that nanoemulsions, despite different droplet sizes, had similar pharmacokinetics to MCT oil, but had faster absorption and higher exposure.