Absorption of 5-fluorouracil from various regions of gastrointestinal tract in rat. Effect of mixed micelles.

Abstract

The absorption of 5-fluorouracil (5-FU one of the most extensively used antineoplastic agents for gastrointestinal tract carcinoma) from the stomach, small intestine and large intestine was investigated using in situ closed loop method of rats, and the effects of monoolein-sodium taurocholate mixed micelles on its absorption were studied. 5-FU absorption from the small intestine was concentration-dependent, but this was not so from the stomach or large intestine. The mixed micellar solution enhanced the absorption of 5-FU from these regions of the gastrointestinal tract, except the region where active transport occurred in the small intestine. The effect of mixed micelles was greater in the large intestine than in the stomach and the small intestine. In the small intestine, coexistence of mixed micelles or sodium taurocholate and the pretreatment with mixed micelles similarly showed a little depression of 5-FU absorption in the active transport process. In high concentrations of 5-FU where passive transport is predominant, the pretreatment with mixed micelles enhanced the absorption of 5-FU. The presence of mixed micelles greatly increased the antimicrobial activity level of 5-FU in blood, thoracic-duct lymph and regional lymph nodes of the large intestine within 30 min after administration into the large intestinal lumen.