Antitumor activity of new nitrosoureas on Yoshida sarcoma ascites cells implanted into the colon wall of rats.

The chemotherapeutic activity of 12 newly synthesized nitrosoureas was compared in tests using Yoshida sarcoma ascites cells implanted into the wall of the descending colon in Sprague-Dawley rats. Cyclophosphamide and the nitrosoureas BCNU, MeCCNU, and chlorozotocin served as positive controls. Among the nitrosoureas tested, 1-(2-hydroxyethyl)-3-(2-chloroethyl)-3-nitrosourea (hydroxyethyl-CNU), chlorozotocin, 1-(2-chloroethyl)-1-nitroso-3-(4-morpholino) urea, 1-(2-chloroethyl)-1-nitroso-3-(1-piperidino) urea, 4-[1-(2-chloroethyl)-1-nitroso-3-[4-(2,6-dimethylmorpholino)] urea, and 1-(2-chloroethyl)-1-nitroso-3-(3,4-methylenedioxybenzyl) urea were found to be the most active compounds in this tumor model. Based on the present results, morpholino-CNU is considered the most promising compound among these newly synthesized BCNU analogues.