Bis(4-chlorophenyl) sulphone

Carcinogenicity

Description of key information

DCDPS showed no carcinogenic potential in rats and mice exposed for 2 years via the feed (NIH, 2001).

Justification for classification or non-classification

Based on the key study results, DCDPS is not subject to classification for carcinogenicity according to Directive 67/548/EEC and Regulation 1272/2008/EC.

Additional information

In a carcinogenicity study in rats (NIH, 2001), DCDPS was administered via the diet for a period of 2 years to 50 animals/sex/dose at 0, 0.5, 1.5 or 5.0 mg/kg bw/day for male animals and 0, 1.6, 5.4 or 17 mg/kg bw/day for female animals. Additional 3 animals/sex/dose and timepoint were used for plasma level determinations at 2 weeks, 3, 12 and 18 months. Plasma concentrations were slightly higher in females than in males after 12 and 18 months. Treatment with the test substance did not affect mortality rates, induced no clinical signs of toxicity and resulted in no changes in food consumption or gross lesions attributable to DCDPS. Mean body weights of 1.5 and 5.0 mg/kg bw/day males were generally reduced during the latter part of the study, and mean body weights of 5.4 and 17 mg/kg bw/day females were less from weeks 30 and 18, respectively. There were no increases in the incidences of neoplasms related to DCDPS exposure. Incidences of centrilobular hepatocyte hypertrophy in 5.0 mg/kg bw/day male and 5.4 and 17 mg/kg bw/day female rats were significantly greater than those in the controls. The incidences of bile duct hyperplasia and centrilobular degeneration were also significantly increased in 5.4 and 17 mg/kg bw/day females.

In the corresponding carcinogenicity study in mice, 50 animals/sex/dose were exposed via the diet at 0, 4, 13 or 40 mg/kg bw/day for males and 0, 3, 10 or 33 mg/kg bw/day for females. Additional 3 animals/sex/dose and timepoint were used for DCDPS plasma level determinations at 2 weeks, 3 months and 12 months. Plasma concentrations were higher in females than in males. DCDPS exposure resulted in no treatment-related changes of mortality rates, clinical signs, food consumption and macroscopical findings. There were no increases in the incidences of neoplasms in the liver or any other organ. Mean body weights of high dose mice were less than those of the controls throughout most of the study. The incidences of centrilobular hepatocyte hypertrophy in all exposed groups of male mice and in 10 and 33 mg/kg bw/day females were significantly greater than those in the controls. The incidence of eosinophilic foci in 33 mg/kg bw/day females was significantly increased.

Under the conditions of these 2 -year feed studies, there was no evidence of carcinogenic potential of DCDPS in rats and mice. Therefore, no classification for carcinogenic potential is required for DCDPS according to EU standards.