Antitumor activity of carbamoyl derivatives of 5-fluorouracil by oral administration.

Antitumor activity of 1-carbamoyl derivatives of 5-fluorouracil was tested in L-1210 system by oral administration with two reference compounds, 5-fluorouracil and tetrahydrofuryl-5-fluorouracil (FT-207). The compounds tested were methyl-, ethyl-, isopropyl-, phenyl-, and cyclohexyl-carbamoyl-5-fluorouracil, and the therapeutic ratios (ILSmax/ILS30) of these compounds were 1.9, 2.2, 2.3, 1.0, and greater than 3.3, respectively, those of the two reference compounds being 1.7 and 1.0. Cyclohexylcarbamoyl-5-fluorouracil was the most effective of these compounds.