Carcinogenesis Bioassay of Di(2-ethylhexyl)adipate (CAS No. 103-23-1) in F344 Rats and B6C3F1 Mice (Feed Study).

Di(2-ethylhexyl)adipate is a plasticizer used to give flexibility to vinyl plastics. A carcinogenesis bioassay was conducted by feeding diets containing 12,000 or 25,000 ppm of di(2-ethylhexyl)adipate to groups of 50 male and 50 female F344 rats and 50 male and 50 female B6C3F1 mice for 103 weeks. Groups of 50 undosed rats and mice of each sex served as controls. All surviving animals were killed at 104 to 107 weeks. Mean body weights of high-dose rats and mice of either sex were lower than those of the controls throughout the study. Compound administration was not associated with tumor formation in F344 rats of either sex. Hepatocellular carcinomas or adenomas occurred in mice of both sexes in a dose-related fashion at incidences that were significantly higher for high-dose males and for low- and high-dose females than those in the controls. When compared with the incidence in historical laboratory control mice, however, the liver tumors in male mice could not be clearly related to compound administration. Under the conditions of this bioassay, di(2-ethylhexyl)adipate was not carcinogenic for F344 rats. Di(2-ethylhexyl)adipate was carcinogenic for female B6C3F1 mice, causing increased incidences of hepatocellular carcinomas, and was probably carcinogenic for male B6C3F1 mice, causing hepatocellular adenomas. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Positive Female Mice: Positive Synonyms: bis(2-ethylhexyl)adipate; DEHA; octyl adipate; dioctyl adipate; DOA