Figure 1.

Dissociation kinetics of an inhibitor from its target will have an impact on defining the PK/PD relationship. For a hypothetical slow off-rate drug, a transient (<24 h) plasma exposure (blue solid line) would be sufficient to produce a significant and sustained (24 h) PD response (blue dotted line). However, for a drug with readily reversible dissociation kinetics, a sustained plasma exposure (red solid line) above a minimum effective concentration is typically required to maintain target coverage and therefore a sustained PD response (red dotted line).