2011 Anniversary Yearbook - EUFEPS today and history

The procedure is safe and of relative ease
for experimental subjects. Furthermore,
it is possible to predict human in
vivo permeability using preclinical
permeability models, such as perfusion
of the rat jejunum, the Caco-2 model and
excised intestinal segments using the
Using chamber. Through a collaborative
academic-regulatory project*, P err in man
for a number of drugs have now been
determined (2). As shown in Figure 1,
there is a good (non-linear) relationship
between extent of intestinal absorption in
man (as determined by pharmacokinetics)
and in vivo membrane permeability.
Permeability-Solubility
Classification
The BCS divide drugs into 4 different
classes based on their solubility and
permeability (Table 1).
Class 1. High Solubility-High
Permeability Drugs.
These drugs are well absorbed (although
systemic availability may be low due
to first-pass metabolism) and the rate
limiting step is drug dissolution or gastric
emptying if dissolution is very rapid. The
dissolution profile must be well defined
and reproducible to insure bioavailability.
A dissolution specification for IR drugs
of 85 % dissolved in