Radiosensitization of the RIF-1 murine flank tumor by desmethylmisonidazole (Ro 05 9963) during interstitial brachytherapy
Stem Cell Transplantation
We have investigated the interaction of the nitroimidazole radiosensitizer desmethylmisonidazole (Ro 05 9963) with interstitial radiation using a clonogenic cell assay as the endpoint. Removable I-125 sources were implanted at right angles to the outer surface of globular RIF-1 tumors grown in the flanks of C3H/He mice. Desmethylmisonidazole was administered by continuous intraperitoneal infusion at a rate of 2.7 mg/gm body weight /24 hr. Tumor and serum drug levels were measured by high performance liquid chromatography. Tumor drug levels of 40--100 mugm/gm tumor tissue were achieved consistently. No appreciable cytotoxicity was produced by desmethylmisonidazole alone, but a radiosensitization effect with a dose modifying factor of 1.6 was found.