[Concentrations of 5-fluorouracil (5-FU) in serum and tissues at venous injection of tegafur or 5-FU--clinical study on colorectal cancer].

Tissue and serum concentrations of 5-fluorouracil (5-FU) after daily slow venous injection of tegafur or 5-FU for 5 days were measured. The serum concentration of 5-FU elevated to the highest level 6 hours after the venous injection (mean: 30 ng/ml). Compared with the tegafur injection, the serum concentration of 5-FU elevated to a higher peak level 6 hours after the 5-FU injection (mean: 827 ng/ml). The serum concentration of 5-FU after the tegafur injection tended to be maintained longer than after the 5-FU injection. When tegafur was injected, the concentration of 5-FU in cancer tissue or lymphnodes was significantly higher than in normal tissue. On the other hand, no significant difference was detected among the concentrations of 5-FU in the above three tissues when 5-FU was injected. Moreover, a significantly higher concentration of 5-FU in lymphnodes was caused by the tegafur injection compared to the 5-FU injection.