A route described as oral transmucosal is intended to expose the lining of the mouth to a drug. Whether this changes the amount reaching the bloodstream depends on the formulation and how it is given. Della Rocca and colleagues compared two ways of administering the same pure CBD oil in 12 dogs with mild chronic pain.
Six dogs received the oil orally and six received it by the oral transmucosal route. The groups received the same amount per kilogram. The mean peak plasma concentrations were about 207 and 200 ng/mL, respectively, with substantial variability in both groups.
The similar observed means describe this experiment. A small study with wide variation has limited ability to resolve differences between routes. The formulation and administration technique also matter. An exposure review should identify the preparation actually used before applying concentration data from a study of CBD oil.