Increased intestinal permeability correlates with gastrointestinal toxicity among formulations of the fluorouracil analogue tegafur in rats.

Background: S-1 is a new antitumor agent which was developed based on biochemical modulation of fluorouracil. S-1 consists of tegafur (FT), 5-chloro-2,4-dihydroxypyridine (CDHP), an