Abstract: Tegafur ［1-(tetrahydro-2-furanyl)-5-fluorouracil］(TF), a masked form of 5-fluorouracil (5-FU), is an effective antitumor agent. Oral administration of TF plus uracil (U) (1∶4 mole/mole) (UFT) is more effective than that of TF alone. The relative bioavailability of UFT was studied in beagle dogs. A single oral administration of UFT test capsules or reference capsules containing 100 mg TF and 224 mg U was given to each dog according to a random crossover design. The drug concentrations in plasma were determined by high performance liquid chromatography (HPLC). The relative bioavailabilities of TF and 5-FU were (106.89±21.74)% and (102.32±24.02)%, respectively. The pharmacokinetic parameters, including C_max, AUC_0~t and AUC_0~∞, show no significant difference (P>0.05). Statistical results show that the two preparations are bioequivalent (P>0.05).

Key words: relative bioavailability, tegafur, 5-fluorouracil