[Studies of the antitumor activity and enzymology of 2'-deoxy-5-fluorouridine (FdUrd) derivatives]

The antitumor activity and enzymology of 2'-deoxy-3', 5'-bis-O-(4-methoxyphenoxycarbonyl)-5-fluoro-3-(4-n-Propoxybenz oyl uridine (FF-707) were examined. It was found that stability in small intestine homogenate of FF-707 was higher than that of FF-705 [2'-deoxy-3', 5'-O-diacetyl-5-fluoro-3-(3 methylbenzoyl) uridine]. Reduction of the tumor weight was greater in mice bearing sarcoma-180 and rats bearing Yoshida sarcoma treated with the oral administration of FF-707 than that FF-705. The relationship between the antitumor activity and the inhibition of thymidylate synthase after the oral administration of FF-707 was examined. The extent of the inhibition of thymidylate synthase seemed to be parallel to that of the inhibition of the tumor growth.