Plots of the steady state solutions A
for varying values of λ
(see equation (9)). Other parameter values: λ3 = 0, μ
= 100, δ
= 1. Although the concentration of the complex, c, declines rapidly away from the tissue boundary, the level of a is rapidly increasing. Thus, for the prodrug example, apparently poor prodrug penetration into the tissue can, in fact, correspond to high levels of active drug in the tissue, due to efficient conversion of the prodrug to active form.