A comparative study on the radiosensitizing effects and cytotoxic properties of misonidazole and 2,4-dinitroimidazole-1-ethanol in HeLa S3 cells.

Hypoxic HeLa S3 cells were used to compare the radiosensitizing and cytotoxic properties of misonidazole and 2,4-dinitroimidazole-1-ethanol. To achieve an enhancement ratio of 1.6 (C1.6), the required concentrations of 2,4-dinitroimidazole-1-ethanol and misonidazole were 0.15 and 2.4mM, respectively; at this ratio, the cytotoxicity values (1/To) of the two compounds were 0.054 hr-1 and 0.29 hr-1. These findings indicate that 2,4-dinitroimidazole-1-ethanol had a greater sensitizing effect at lower cytotoxicity, and that it is therefore the clinically more desirable radiosensitizing compound.