A simulated digestion test measures how much cannabidiol a formulation releases into a test fluid. A pharmacokinetic experiment measures what reaches the circulation. Nie and colleagues used both methods to compare two carriers made from zein, a corn protein.
After two hours in simulated gastric fluid, the modified zein particles released about 4% of their CBD, compared with about 90% for the natural zein particles. In the simulated intestinal phase, the reported release percentages were both about 92%. That contrast describes release under the assay conditions.
The modified formulation produced higher peak serum CBD concentrations in rats at the three doses tested. That provides a separate measure of exposure. The release experiment does not establish where CBD was absorbed in a living animal, and the rat results leave human exposure and clinical effects unresolved.