Studies in radiosensitizing effects of misonidazole and SR-2508 on C3H/He mouse mammary tumors.
The radiosensitizing efficacy of SR-2508, a new 2-nitroimidazole, which is less neurotoxic than misonidazole (MISO) was studied using transplantable mammary carcinoma of C3H/He mice. Tumor responses to treatments were evaluated by growth-delay time assay. In single irradiations, the enhancement ratios of 0.5 mmole/kg of MISO and 1.5 mmole/kg of SR-2508, which were equitoxic to C3H/He mice, were 1.42 and 1.84 respectively. In fractionated irradiations with three fractions over two days or five fractions over four days, the enhancement ratios of 1.5 mmole/kg of SR-2508 were 1.40 and 1.34 respectively. On the other hand the enhancement ratios of MISO at the above mentioned dose in respective fractionated irradiations were 1.15 or 1.11. SR-2508 is considered promising as a hypoxic cell radiosensitizer for clinical use.
D000818:Animals; D017341:Etanidazole; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000532:radiotherapy*; D051379:Mice; D008809:Mice, Inbred C3H; D008920:Misonidazole / Q000627:therapeutic use*; D009368:Neoplasm Transplantation; D009593:Nitroimidazoles / Q000627:therapeutic use*; D011838:Radiation-Sensitizing Agents; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy
D009593:Nitroimidazoles; D011838:Radiation-Sensitizing Agents; D017341:Etanidazole; D008920:Misonidazole