ORAL-ADMINISTRATION OF BOF-A2 TO RATS WITH LUNG TRANSPLANTED TUMORS RESULTS IN INCREASED 5-FLUOROURACIL LEVELS

A new tumor model was developed in which solid Yoshida sarcoma tissue injected intravenously developed into tumors in the lungs of about 30% (13/42) of the inoculated rats. Histological examination revealed tha t alveoli were occupied with tumor cells and the tumors were similar t o those obtained by subcutaneous inoculation. Using this model, the co ncentrations of 5-fluorouracil (5-FU) in tumor tissue 12 h after oral administration of oxycarbonyl)benzoyl]-1-ethoxymethyl-5-fluorouracil ( BOF-A2, 36 mu mol/kg) or a combination of tegafur and uracil in a mola r ratio 1 to 4 (UFT, 50 mu mol/kg) were found to be 129.8 ng/g and 19. 2 ng/g, respectively. Thus, compared to treatment with UFT, BOF-A2 res ulted in higher levels of 5-FU in lung tumor tissues. Increased concen trations of 5-FU should have a superior anti tumor effect and so BOF-A 2 merits clinical trial in the treatment of patients with lung cancer.