IN VIVO CYTOGENETIC EVALUATION OF CHLOROINDAZOLE THIOXANTHENE IA-4 (A HYCANTHONE ANALOG) AND NIRIDAZOLE IN RAT BONE MARROW

¹ Genetic Toxicology Branch, Division of Toxicology, Food and Drug Administration, Department of Health, Education and Welfare, Washington, D.C.

Niridazole and the hycanthone analog chloroindazole, IA-4, which are members of two different classes of antischistosomal drugs, were evaluated cytogenetically in rat bone marrow cells for mutagenic potential. The hycanthone analog was given to rats i.p. at 50, 100 or 200 mg/kg and the animals were killed 24 hours later. Niridazole was injected i.p. at one dose level (450 mg/kg) and rats were killed 6 or 24 hours postinjection. Treated and control animals were given the mitotic inhibitor demecolcine 4 hours prior to sacrifice. Slides of bone marrow cells were examined for the presence of chromosome and chromatid damage. Both compounds failed to elicit a statistically significant mutagenic response with regard to the production of grossly visible chromosomal damage.