REPRODUCTIVE TOXICITY STUDIES OF BENZALAZINE IN RATS AND RABBITS

Embryotoxicity studies of benzalazine (2-hydroxy-5-[(4-carboxyphenyl) azo]benzoic acid CAS 64896-26-0), a new agent for the treatment of ulc erative colitis and Crohn's disease of the large intestine, were perfo rmed in rats and rabbits. Benzalazine elicited no evidence of teratoge nicity when administered orally during the fetal organogenesis period to pregnant rats at doses up to 2000 mg/kg b.w./d, or to pregnant rabb its at doses up to 1000 mg/kg b.w./d. Rat fetuses in the 400 and 2000 mg/kg groups exhibited decreased body weights; the placentae weights w ere decreased in these dose groups too. Rabbit fetuses in the high-dos e group (1000 mg/kg b.w./d p.o.) also showed decreased body weights. D ecreased body weight gain and reduced food intake were seen in rat dam s in the high-dose group (2000 mg/kg b.w./d p.o.). In rabbit dams a de crease in body weight gain in the high-dose group (1000 mg/kg b.w./d p .o.) and a dose-dependent reduction in food intake from 200 mg/kg b.w. /d p.o. onwards were noted. No further disturbances were observed in t he behaviour of the rat and rabbit dams. External appearance, faeces, consumption of drinking water and macroscopical inspection during auto psy did not indicate any influence of the test compound. No retardatio ns or malformations were seen even at the highest tested dose levels ( rat: 2000 mg/kg b.w./d p.o; rabbit: 1000 mg/kg b.w./d p.o.).