The drug in the central compartment decreases initially as a result of simultaneous elimination and distribution to the peripheral compartment. Then when the distribution process is completed the drug in the central compartment declines at a rate dependent on its elimination rate.
The drug amount in the peripheral
compartment can be higher or lower than
that in the central compartment depending
on the drug distribution characteristics.
Distribution Phase
Elimination Phase
The drug in the peripheral compartment increases initially because more drug is distributed from the central to the peripheral compartment compared to from the peripheral to the central compartment. Then when pseudo-equilibrium is achieved between the central and the peripheral compartments the drug in the peripheral compartment declines parallel to that in the central compartment.
