The volume for pool 1 (blood) is 4 L , pool 2 (tissue fluid) is
16 L, and the dose delivered to the blood in the bolus at t=0
is 400 units (thus the initial concentration is 100). Since the
rates (the Ks) are defined in terms of the total amount in a pool
(not concentration), K12 / K21 must be 4 in order for the equilibrium concentrations to be equal
in the two pools.
Enter a value and hit the "return" key for each of the three parameters. If the value is accepted, an "OK" will appear, while large and small values for the Ks will be rejected. Reasonable values to start with for K12, K21, and Ke might be 2, 0.5, and 1. When you want to enter a new value, first delete the existing text in the box.