2.3 Model distribution
An illustration of the pregnancy PBPK model is shown on Figure 1. A
fetal component within the female reproductive organ was not included
within this pregnancy PBPK model as the main focus on this study was the
PK in the pregnant woman and not fetal exposure. Major assumptions in
the PBPK model include perfusion-limited drug distribution, well-stirred
distribution model, and no drug reabsorption from the colon. The volume
of drug distribution (Vd) was calculated from the volume
and tissue-to-plasma ratio of each compartment as previously described
[38]. Pregnancy effect on the fraction of the unbound drug was also
modelled using equations previously described in literature [23,
39]. Lastly, activity of drug transporters were not included in the
model due to inadequate data for such characterisation.