Developmental toxicity study of orally administered resorcinol bis-diphenylphosphate (RDP) in rabbits

Fyrolflex resorcinol bis-diphenylphosphate (RDP) is a nonhalogen phosphate eater product that is widely used as a flame retardant for petrochemical plastics and high-temperature lubricant additive applications. The potential developmental toxicity of RDP was evaluated in rabbits. Groups of 27 sperm-positive New Zealand white rabbits (Hazelton Research Products Int., Denver, PA) were administered graded concentrations of 50, 200, or 1000 mg/kg/day of RDP in corn oil. A vehicle control group of equal size was administered core oil alone. Rabbits were dosed daily (1.5 ml/kg) on gestation days 6 to 28 and sacrificed on gestation day 29, The fetuses were removed by cesarean section and examined for gross external, visceral, cephalic, and skeletal anomalies. No treatment-related clinical signs of toxicity were observed, No treatment-related effects in maternal food consumption, body weight, body weight gain, or on uterus, liver, kidney, and spleen weights were detected. Fetal viability and body weight, as well as developmental end points were also unaffected by treatment, Accordingly, exposure of pregnant rabbits to doses ranging from 50 to 1000 mg/kg/day of RDP during the periods of major organogenesis and histogenesis did not result in any biologically significant toxic or teratogenic/developmental effect in the dams or fetuses.