Toxicity, antitumor activity, and pharmacokinetics of spin-labeled thioTEPA analogs.

Two spin-labeled analogs of thioTEPA, containing an iminoxyl radical, have been shown to have significant antitumor activity in several experimental tumor systems, combined with a marked decrease in toxicity compared with the parent compound, thioTEPA. Walker 256 carcinosarcoma, Guérin carcinoma, and Schweitz erythromyelosis showed complete regression using one of these analogs. Pharmacokinetic studies have shown that these compounds possess particular affinity towards tumor tissue.