ABSORPTION OF 5-FLUOROURACIL FROM VARIOUS REGIONS OF GASTRO-INTESTINAL TRACT IN RAT - EFFECT OF MIXED MICELLES

The absorption of 5-fluorouracil (5-FU) 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. It was observed that there existed the concentration dependency in absorption of 5-FU from the small intestine, but not in that from the stomach and the large intestine. It was found that the mixed micellar solution enhanced the absorption of 5-FU from these regions of the gastrointestinal tracts except the region where active transport was performed 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. On the other hand, in high concentrations of 5-FU where passive transport is predominant, the pretreatment with mixed micelles enhanced the absorption of 5-FU in some degree. 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. © 1979, The Pharmaceutical Society of Japan. All rights reserved.