When there is time delay between drug plasma conc and drug effect, the concept of effect compartment can be used to describe the drug conc-effect relationship.
- The effect compartment is a hypothetical compartment that links the pharmacokinetic model and the pharmacodynamic model.
- The drug transfer from the plasma to the effect compartment is negligible and does not affect the pharmacokinetic characters of the drug.
- The drug transfer from the plasma to the effect compartment is
- The drug effect is determined by the drug conc in the effect compartment.
The idea is to use the drug plasma conc-time data to predict the drug conc in the effect compartment. Then the drug conc and effect data are used to estimate the pharmacodynamic model parameters from the model equation.
The described model is an example of the effect compartment linked to one compartment pharmacokinetic model. The and can be linked to the central or the peripheral compartments.
