
164 Exposure-Response Modeling: Methods and Practical Implementation
0 2 4 6 8 10
0.0 0.2 0.4 0.6 0.8 1.0
hour
y1
0 2 4 6 8 10
0.0 0.2 0.4 0.6 0.8 1.0
hour
y2
FIGURE 6.2
Solution to the system of ODEs consists of a central compartment, an indirect
response model (6.6) and an Emax model for exposure effects, with K
e
=
0.3, EC
50
= 0.3 (solid line), K
e
= 0.6, EC
50
= 0.3 (dash line) and K
e
=
0.6, EC
50
= 0 .9 (dot line) using the deSolve(.) library. Left panel: respons e;
right panel: concentration in the central compar tment.
6.3.1 Empirical models
Empirical models always play an important role in the situation where mech-
anistic disease models are not available or