[The binding of 5-fluorouracil to serum protein fractions, erythrocytes and ghosts under in vitro conditions].

The binding of 5-fluorouracil (1) to erythrocytes and to serum proteins under in vitro conditions was investigated. The binding rate of 1 to erythrocytes is dose-independent and amounts from 16.8 to 31.7% (concentration range 1 to 20 micrograms/ml). The mean coefficient of partition for erythrocytes is 0.25 (+/- 0.03), no binding to ghosts was observed. 1 is bound at about 4% to proteins, whereby 0.7% are bound to alpha-globulin, 0.8% to beta-globulin, 1.6% to gamma-globulin, and 0.8% to albumine. The mean partition coefficient for proteins is 0.04 (+/- 0.006).