Development of a Novel Nanoemulsion Formulation to Improve Intestinal Absorption of Cannabidiol
Cannabidiol (CBD) is highly lipophilic, and its oral bioavailability is known to be very low in humans. In this study, we developed a novel nanoemulsion preparation of CBD (CBD-NE) to improve the poor solubility and absorption of CBD. The pharmacokinetic profiles of CBD in rats were evaluated after oral administrations of CBD oil and CBD-NE, and the effect of bile secretion on CBD absorption was also evaluated. Methods: The CBD-NE formulation developed in this study consisted of vitamin E acetate, ethanol, Tween-20, and distilled water (1.7/3.8/70/24.5, w/w%).
A CBD oil formulation (CBD oil, control) 100 mg/kg or CBD-NE 50 mg/kg was orally administered to rats, and the blood samples were collected over time. Moreover, the CBD oil or CBD-NE was orally administered to bile-fistulated rats, and the pharmacokinetic profiles of CBD were also evaluated. CBD concentrations in plasma were measured using LC-MS/MS. Results: The particle size of CBD-NE was 35.3 ± 11.8 nm. Mean Tmax of CBD-NE was shortened significantly by the factor of 3 (from 8.00 to 2.40 h, p < 0.001) and AUC0–∞/dose increased by 65% (from 0.272 ± 0.045 to 0.448 ± 0.087 h L/kg) compared with CBD oil. AUC0–∞/dose and Cmax/dose after oral administration of CBD oil were significantly reduced by the factor of 27 and 23 (p < 0.05 and p < 0.01), respectively, in bile-fistulated rats compared with the untreated rats.
In contrast, all pharmacokinetic parameters after oral administration of CBD-NE were not significantly different between the untreated and bile-fistulated rats. Therefore, these results demonstrated that conventional CBD oil formulation but not CBD-NE requires bile-mediated micelle formation. Conclusions: The novel NE formulation developed in this study successfully improved the absorption of CBD regardless of bile secretion. The newly developed oral CBD-NE preparation could be useful to achieve a more stable and quicker onset of action by CBD. Download the full Medical Cannabis and Cannabinoids publication here: Development of a Novel Nanoemulsion Formulation to Improve Intestinal Absorption of Cannabidiol