Pharmacokinetics and oral bioavailability of cannabidiol in horses after intravenous and oral administration with oil and micellar formulations.
Authors: Sánchez de Medina Antonia, Serrano-Rodríguez Juan Manuel, Díez de Castro Elisa, García-Valverde María Teresa, Saitua Aritz, Becero Mireia, Muñoz Ana, Ferreiro-Vera Carlos, Sánchez de Medina Verónica
Journal: Equine veterinary journal
Summary
# Editorial Summary: Cannabidiol Pharmacokinetics in Horses Cannabidiol (CBD) is increasingly discussed in equine practice, yet its pharmacological behaviour in horses remained largely unknown until this 2023 investigation. Researchers administered CBD intravenously (1 mg/kg) and orally via two formulations—sesame oil and micellar suspension, both at 10 mg/kg—to eight healthy horses, measuring plasma concentrations by LC-MS/MS and applying three-compartment modelling to characterise the drug's movement through the body. The study revealed CBD exhibits substantial tissue distribution (36 L/kg volume of distribution), rapid systemic clearance (1.46 L/h/kg), and notably prolonged half-lives of 24–34 hours. Oral bioavailability proved consistently low at approximately 14% regardless of formulation, meaning only a small fraction of an orally administered dose reaches systemic circulation. However, the micellar formulation achieved higher and faster peak concentrations, whilst the oil formulation produced lower but more sustained plasma levels, a distinction that may influence dosing strategy depending on clinical intent. Simulation modelling suggested both formulations could maintain therapeutically relevant plasma concentrations with 12- or 24-hourly dosing regimens, though higher oral doses or alternative delivery methods may be necessary to achieve effective systemic exposure. For practitioners considering CBD in cases of pain, anxiety, or inflammation, these findings indicate the drug's feasibility in horses but underscore the need for future clinical trials establishing actual therapeutic efficacy and determining optimal dosing protocols before routine recommendation.
Read the full abstract on PubMed
Practical Takeaways
- •CBD has low oral bioavailability in horses, meaning only ~14% of an oral dose reaches systemic circulation; practitioners considering CBD supplementation should account for this when calculating effective doses
- •The long half-life (24-34 hours) suggests CBD could be administered once or twice daily; both formulations appear suitable for multiple-dose regimens at 10 mg/kg
- •Choice between oil and micellar formulations depends on clinical goals: use micellar for rapid onset/higher peaks, or oil for more sustained blood levels
Key Findings
- •Oral bioavailability of CBD was approximately 14% for both oil and micellar formulations at 10 mg/kg dose
- •CBD demonstrated a high volume of distribution (36 L/kg), high clearance (1.46 L/h/kg), and long half-lives (24-34 hours)
- •Micellar formulation showed faster absorption and higher peak concentration compared to oil formulation, though oil formulation maintained more sustained levels
- •No adverse reactions were detected at any dose or route studied