ABSTRACT
The oral route is considered the best way of dosing drugs [1]. Most drugs
orally administrated are absorbed by passive diffusion of the dissolved solid
through the gastrointestinal (GI) cellular membranes. The oral bioavailability
of a specific solid drug is thus determined by its solubility and permeability
within the GI tract, which is an aqueous environment. For a given drug that
dissolves into the GI tract, its molecular structure and the environment are the
fixed parameters, and the solid phase dissolution becomes a key parameter for
assessing the bioavailability and the onset of action of oral dosage forms
[2,3]. Since an increasing number of newly developed chemical entities
present poor water solubility, advances in enhancing oral bioavailability of
poorly water-soluble drugs represent an actual challenge for pharmaceutical
research, with the aims of improving therapeutic effectiveness and creating
new market opportunities.
