Influence of pH on the toxicity of nitrogen mustard.

The experiments reported here demonstrate the unexpected finding that, in mice, the pH of nitrogen mustard solution at the time it is injected into the animal appears to determine the toxicity of the material. At certain doses, highly acid solutions of nitrogen mustard show no toxic effects, while alkaline solutions at the same dose are invariably lethal. From further experiments on the antitumor activity of acid solutions of nitrogen mustard, it is cojpcluded that the toxic effect is separable from the antitumor effect.