Hypoxic cell sensitizer

Biochemical properties of misonidazole were investigated. It was found that misonidazole has the radiosensitizing effect and the cytotoxicity to hypoxic cells selectively. Further investigation to search more effective radiosensitizer than misonidazole were carried out. Since Adams suggested that the radiosensitizing ability of the compound is related to the electron affinity, many types of sulfur group were introduced to the imidazole ring substituted to the nitro group. However, none of these compounds showed any radiosensitization to hypoxic cells. In contrast, it was found that the radiosensitizing effect of 2,4-dinitroimicasole-1-ethanol, was about ten times greater than misonidazole to hypoxic cells. (author)