
Modeling dynamic exposure–response relationships 169
uses the same solver and similar model spe cification as in R. For example, to
fit the models:
dR(t)
dt
= E
maxi
/(EC
50
/C(t) + 1) − K
out
R(t)
C(t)
dt
= −θC(t) (6.29)
where E
maxi
|u
i
∼ N(E
max
+ u
i
, σ
e
) is the only ra ndom c oefficient in the
models, the following program, similar to that in Chapter 3, can be used.
bdata=bdata[order(bdata$Subject,bdata$Time),]
gdata=groupedData(conc~Time|Subject,bdata)
OneComp <- list(DiffEq=list(
dy1dt = ~ Emax*y2/(EC50+y2) -kout*y1 , #Absoprtion dynamic
dy2dt = ~ - theta*y2, #Central comp. with elimination rate ke
ObsEq=list(
c1 = ~ y1, #No measure for absorption
c2 = ~ y2, #Observe ...