Differential prenatal toxicity of branched phthalate esters in rats.

Several phthalate esters with alcohol moieties ranging from C5-C10 chains were investigated for prenatal toxicity in 10 rats per group after gavage administration of 0, 40, 200 and 1000 mg/kg/day from gestation day 6 to 15. At 1000 mg/kg di(2-ethylhexyl) phthalate showed clear foetotoxicity, embryolethality and teratogenicity. No significant effects were recorded at 40 and 200 mg/kg. Di-711-phthalate, a phthalic ester with linear components and a predominantly alpha-methyl branching type, and di-isopentylphthalate showed a very similar spectrum of effects. Interestingly, the alcohol moiety of di-711-phthalate, 711-alcohol was developmentally inactive in a previous experiment. Di-iso-decylphthalate and three types of di-iso-nonylphthalate showed foetal effects of borderline significance at 1000 mg/kg/day.