Three different compartment models to understand drug pharmacokinetics & elimination
Single Compartment Model
You would need to consider bolus, infusion and extra-vascular doses
Two Compartment Model
Tissues, into which the drug distributes more slowly, are lumped together as one peripheral compartment. The drug enters and leaves the peripheral from the central at a rate depending on transfer rate constants.
(C0), = back-extrapolated plasma drug concentration at time zero following bolus intravenous injection as if distribution was immediate.
Three Compartment Model
- This now includes vessel rich and poor groups.
K01 = constant of moving from compartment 0 (outside) to C1
K10 = constant of elimination. C1 = central compartment
A semi-log plot of drug concentration versus time will no longer be linear as the drug has two possible paths to move along, each with their own associated rate constants.
These peripheral compartments may act as reservoirs keeping the central compartment full even as elimination is occurring from it.
Elimination always occurs from the central compartment
Dr. David Lyness@Gas_Craic
The 'K' numbers describe movement from compartments (as a constant)
such as K01 really means K, compartment 0 moving to compartment 1 etc.