Toxicology of daily administration to mice of the radiation potentiator SR 4233 (WIN 59075).

We have investigated the feasibility of administration of an effective dose of the hypoxic cytotoxin, SR 4233, Monday-Friday daily for 6 weeks. From a thorough hematological, histopathological and clinical chemistry evaluation throughout the course and during a 3-week recovery period, we conclude that daily administration of a radiopotentiating dose of SR 4233 in mice is well tolerated and that bone marrow suppression is likely to be the dose-limiting toxicity.