Fig. 1. PD and PK toxicity of drug-like molecules is shown as a function of in vitro on target IC₅₀ (xt) or C_max (in vivo or extrapolated from in vitro permeability and metabolism assays) respectively. The inset shows that for a drug with an IC₅₀ or C_max value of 100 μM, the toxicity reaches a value of 10 units.