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Description of key information

carcinogenicity study (Huntingdon, 1984): not carcinogenic

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

-No classification required for carcinogenicity.

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008:

-No classification required for carcinogenicity.

Additional information

Three groups of 70 male and 70 female rats received the test compound, by admixture with the diet, at levels of 300, 1000 or 3000 ppm. A further group of 70 male and 70 female rats received untreated diet throughout the same period for control purposes. Treatment continued for 108 weeks after which the main group male and female control rats had reached a 40% survival level and the terminal sacrifice was initiated. The termination of all animals was completed in week 112. There were no clinical signs indicative of a treatment-related effect noted during the study and the survival rate of rats receiving 300 ppm or 1000 ppm and females receiving 3000 ppm was similar to that of the controls. Males receiving 3000 ppm showed a marginally better survival rate than the controls but this finding is of doubtful biological significance. During the first 78 weeks the food intake of males receiving 3000 pm was lower than that of the controls. In addition bodyweight gain of these rats was marginally lower over the first 24 weeks of treatment. The efficiency of food utilization, (as indicated by the food conversion ratios), was similar among control and treated rats, and therefore, the effect upon food intake and hence bodyweight gain among males receiving 3000 ppm may have been due to unpalatability of the test compound in the diet. The water consumption, ophthalmoscopy and hearing function test investigations revealed no treatment-related effects. Laboratory investigations revealed no intergroup differences with respect to hematology and urinalysis that were considered to be indicative of a reaction to treatment. Marginal changes were noted at blood chemistry investigations in glucose, total proteins, albumin and AP levels among treated rats when compared with the controls. However, intergroup differences recorded were not consistent and therefore considered to be of doubtful toxicological significance. The statistical analysis of organ weights taken from main group animals at termination revealed no intergroup differences indicative of a reaction to treatment. The detailed macropathological and histological examination of rats dying or killed during the study or sacrificed at termination revealed no marked intergroup differences considered to be indicative of a reaction to treatment with the test article. All neoplastic changes seen did not suggest any treatment related effect on the incidence or type of tumors seen. Pituitary tumors in males and females, and mammary tumors among females were among the most commonly occurring tumors in this study. 2/50 males and 2/50 females receiving 3000 ppm showed squamous cell carcinomas of Zymbal's gland. These tumors were not seen in any of the control and other main group rats of this study. In view of the low incidence of this sporadically occurring neoplasm, this incidence is not considered to be treatment-related. In conclusion, The continued long-term administration of the test article in the diet resulted in a number of marginal differences from controls among rats receiving 3000 ppm. Therefore the 'no effect level' for this study is concluded to be 1000 ppm (corresponding to a mean calculated intake of 36 mg/kg bodyweight/day for males and 45 mg/kg bodyweight/day for females). No treatment-related effects on the spontaneous tumor incidence were seen. Therefore, it may be concluded that the test substance is not a carcinogen under the conditions of this study.


Justification for selection of carcinogenicity via oral route endpoint:
Comparable to guideline study