Developmental effects of plasticizer butyl benzyl phthalate after a single administration in rats

The objective of this study was to determine the susceptible day for the developmental toxicity of butyl benzyl phthalate (BBP) by a single administration on one of the days during organogenesis. Pregnant rats were given a single dose of BBP by gastric intubation at a dose of 1000 mg kg super(-1) on one of days 13-15 of pregnancy and at 1500mg kg super(-1) on one of days 6-16 of pregnancy. Post-implantation embryolethality was found in pregnant rats given on one of days 6-16, except for day 7. Teratogenicity was noted after a single dosing of BBP on one of days 6, 7, 9, 10, 12, 14 and 15. Deformity of the cervical vertebrae frequently was observed after administration of BBP on day 7. Cleft palate and fusion of the sternebrae were found exclusively, after administration of BBP on day 15. It can be concluded that the manifestation of deviant development induced by BBP varies with the developmental stage at the time of administration and that BBP induces two discrete responses from embryos to teratogenicity during early and late organogenesis.