Cytotoxic effects were observed following 4 h incubation of human leukaemic cells with the iron chelator 1-hydroxypyridine-2-thione (omadine). Its Cytotoxic activity was comparable to that of the cytotoxic drug doxorubicin. At the same concentration two other effective iron chelators, desferrioxamine and 1,2-dimethyl-3-hydroxypyrid-4-one, were not cytotoxic. Addition of iron augmented the effect of omadine. It is suggested that the lipophilic properties of omadine and of its iron complex cause their intracellular accumulation and potent cytotoxic activity.
