Oil-based and oil-free formulations for enhancing cannabidiol bioavailability

Area of Science:

• Pharmacology and Drug Delivery
• Nanotechnology and Materials Science

Background:

• Cannabidiol (CBD) possesses therapeutic properties but suffers from low oral bioavailability due to poor solubility and first-pass metabolism.
• Formulation strategies like emulsions and particles aim to improve CBD solubilization and lymphatic uptake.
• This study investigated the impact of oil droplet/particle size and surfactant concentration on CBD oral bioavailability.

Purpose of the Study:

• To evaluate the effect of formulation parameters on the oral bioavailability of Cannabidiol (CBD).
• To compare the efficacy of oil-based emulsions versus oil-free particles in enhancing CBD absorption.
• To determine the optimal formulation characteristics for improved CBD delivery.

Main Methods:

• CBD emulsions and particles were prepared using membrane emulsification, high-pressure homogenization, and solvent emulsification-evaporation.
• Physicochemical properties were characterized using microscopy and light-scattering.
• Pharmacokinetic parameters were assessed in rats following oral administration of various formulations compared to a CBD-sunflower oil solution.

Main Results:

• All tested formulations improved CBD absorption compared to the reference oil solution.
• Medium-sized emulsions (approximately 16 μm) showed the highest bioavailability enhancement (291% AUC_last, 455% C_max).
• Oil-free particles also enhanced absorption, with size having minimal impact; however, excessive surfactants (Tween 20, lecithin) reduced overall exposure.

Conclusions:

• Formulation design is critical for enhancing oral CBD bioavailability.
• Medium-sized emulsions offer the most significant bioavailability improvement, while oil-free particles provide additional benefits.
• Balanced surfactant concentrations are essential to avoid negative impacts on systemic exposure, guiding optimized CBD formulation development.