ABSTRACT
This chapter focuses on the oral administration of therapeutics.
Patients prefer oral administration because it is painless and
simple to implement. However, oral administration remains a
challenge since it is limited by various physiological barriers.
The first part of this chapter describes the physiological features
of gastrointestinal (GI) tract related to drug absorption. Drug
solubility and permeability across the GI epithelium are the two
main features involved in drug bioavailability. To overcome the
barriers to these features, many different technological solutions
are proposed to increase the bioavailability of poorly water-soluble
and/or poorly permeable drugs. The second part of this chapter
presents various techniques developed to enhance drug solubility,
such as physical (size reduction) and chemical modifications or lipid
formulations, and illustrates them bymarketed products. Finally, the
chapter describes approaches to improve drug permeability, more
specifically novel drug delivery systems such as nanoparticles.
