Outcome of the in vitro studies on drug absorption employing the isolated rat small intestine.

The in vitro methods for studying the intestinal absorption of drugs involving the use of the isolated rat small intestine are reviewed in order to provide indications on their actual usefulness and limitations. The most significant works dealing with the structural integrity of the intestinal mucosa, the functional integrity of the isolated intestine, the factors influencing passive transport such as pH, sugars, ions, physiological and synthetic surface-active agents, and complexation, are reviewed.