Phenylsilsesquioxane fluid: developmental toxicity studies in rats and rabbits following oral administration

Phenylsilsesquioxane fluid (PSF) is used widely in the personal care industry and is a common component of skin and oral care products. The potential developmental toxicity of PSF was evaluated in rats and rabbits. Groups of 25 sperm-positive Sprague-Dawley rats (Taconic Farms) and 15 sperm-positive New Zealand White rabbits (HRP) were administered dose levels of 50, 500, or 1000 mg/kg PSF in corn oil. Vehicle control groups of equal size were administered corn oil alone. Rats were dosed daily (5 ml/kg) on gestation d 6-15 and sacrificed on gestation d 20, while rabbits were dosed daily (1.5 ml/kg) on gestation d 6-18 and sacrificed on gestation d 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 marked effects upon maternal food consumption, body weight, body weight gain, or uterus or liver weight were detected. Fetal viability and body weight, as well as developmental endpoints, were unaffected by treatment. Accordingly, exposure of pregnant rats or rabbits to 50, 500, or 1000 mg/kg of PSF during the period of major organogenesis did not result in any biologically significant adverse or teratogenic effects in the dams or fetuses.