Gastrointestinal absorption of drugs.

In this paper, those subjects that are important to drug absorption in the gastrointestinal tract are reviewed. First the anatomy of the gastrointestinal system is discussed in some detail. This is followed by a general review of the some of the animal models that are used to study drug absorption. In later sections, the physiological factors that affect drug absorption (pH and bile fluid), different mechanisms of drug absorption (passive, facilitated, and active transport, peptide and macromolecule absorption, and lymphatic uptake), and adjuvants (promoters of drug absorption) are discussed.