We have recently reported that the fluoroquinolone antibacterial DW-116 induces a significant developmental toxicity in rat. The present study was conducted to better understand the teratogenic effects of DW-116 at several developmental toxic doses in rats. DW-116 was orally administered to pregnant rats from gestational day (GD) 6 through 16 at dose levels of 0, 320, 400, and 500 mg/kg/day. All dams were subjected to caesarean section on GD 20 and their fetuses were examined for external, visceral, and skeletal abnormalities. At above 400 mg/kg, severe decreases in maternal body weight gain, food consumption, litter size, fetal weight and placental weight, and severe increases in resorption rate and fetal morphological alterations were observed. At 320 mg/kg, mild decreases in maternal body weight gain, food consumption, fetal weight and placental weight, and mild increases in fetal variations and retardations were observed. These results suggest that DW-116 is embryotoxic at above 320 mg/kg/day and is embryolethal and teratogenic at above 400 mg/kg in pregnant rats and that DW-116 is a selective developmental toxicant in rat conceptuses.
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