Experimental studies with orally administered MCNU, a water-soluble nitrosourea, yielded the following results. MCNU produced a significant increase in life span, and 60-day survivors were observed by various schedules in L1210 leukemia. The therapeutic ratios of MCNU were almost similar to those of CCNU. With Lewis lung carcinoma and Ehrlich ascites carcinoma implanted into the stomach wall, its antitumor activity by oral administration was slightly more effective than by intravenous route. In Beagle dogs, hematologic toxicity and gastrointestinal toxicity (vomiting, diarrhea) were noted by oral administration, similar to intravenous administration, but its toxicity was mild. The maximum blood level of MCNU was noted at 30 minutes after oral administration in Beagle dogs. The half life (23.7 min) by oral administration was similar to that by intravenous route. From these results, the oral administration of MCNU deserves the consideration as a form of treatment now given other MCNU routes.
Administration, Oral Animals