| abstract |
A composition for increasing the anti-cancer activity of an anti-cancer compound selected from among 5-fluorouracil and a compound capable of producing 5-fluorouracil in vivo, the composition comprising an effective amount of a pyridine derivative represented by the formula <IMAGE> (1) wherein R1 is hydroxy or acyloxy, R2 and R4 are each hydrogen, halogen, amino, carboxyl, carbamoyl, cyano, nitro, lower alkyl, lower alkenyl or lower alkoxycarbonyl, R3 and R5 are each hydrogen, hydroxy or acyloxy; when at least one or R1, R3 and R5 is hydroxy, the structure of 1-position on the pyridine ring can be <IMAGE> due to the keto-enol tautomerism, said hydrogen attached to nitrogen being optionally substituted with a substituent selected from the group consisting of lower alkyl, tetrahydrofuranyl, tetrahydropyranyl, lower alkoxy-lower alkyl, phthalidyl, carbamoyl, lower alkoxycarbonyl-lower alkylcarbamoyl, phenyl-lower alkoxy-lower alkyl, phenylcarbamoyl which may have a substituent on the phenyl ring, lower alkylcarbamoyl, carboxy-lower alkylcarbamoyl, lower alkylthio-lower alkyl and lower alkenyl, provided that the compound having the following formula is excluded, <IMAGE> wherein alpha is hydrogen, lower alkyl, tetrahydrofuranyl, tetrahydropyranyl, lower alkoxy-lower alkyl, lower alkylcarbamoyl, lower alkylthio-lower alkyl or lower alkenyl. |