What causes the low oral bioavailability of cannabinoids?

What causes the low oral bioavailability of cannabinoids?

Cannabinoids are lipophilic (fat soluble) and have low aqueous solubility [8, 9]. Lipophilic drugs with low solubility, such as cannabinoids often have low oral bioavailability [10]. A deeper look at the body’s digestive system reveals that there is an unstirred water layer (UWL) that lines the gastrointestinal tract (GIT). The UWL acts as a barrier to the absorption of lipophilic materials such as cannabinoids. Thus prior to reaching the absorptive surfaces of the GIT a cannabinoid must become water dispersible allowing it to permeate the UWL. Naturally this process of cannabinoid solubilization is inefficient leading to low oral bioavailability.