Development of a Compartment Model to Study the Pharmacokinetics of Medical THC after Oral Administration

The therapeutic potential of delta9-tetrahydrocannabinol (THC), a primary cannabinoid in
the cannabis plant, has led to its development into oral medical products for treating various conditions.
However, THC, being a psychoactive substance, can lead to addiction if taken in inappropriate
amounts. Thus, studying the pharmacokinetics of THC is crucial for understanding how the drug
behaves in the body after administration. This study aims to develop a multi-compartmental model
to investigate the pharmacokinetics of medical THC and its metabolites after oral administration.
Using the law of mass action, the model was converted into ordinary differential equations (ODEs)
to describe the rate of concentration changes of THC and its metabolites in each compartment. The
nonstandard finite difference (NSFD) method was then applied to construct numerical solution
schemes, which were implemented in MATLAB along with estimated pharmacokinetic rate constants.
The results demonstrate that the simulation curves depicting the plasma concentration–time profiles
of THC and 11-hydroxy-THC (THC-OH) closely resemble actual data samples, indicating the model’s
accuracy. Moreover, the model predicts the pharmacokinetics of THC and its metabolites in various
tissues. Consequently, this model serves as a valuable tool for enhancing our understanding of
the pharmacokinetics of THC and its metabolites, guiding dosage adjustments, and determining
administration durations for oral medical THC.