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Toxicological information

Carcinogenicity

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Description of key information

Chronic: Oral (similar to OECD 453), rat: NOAEL = 615 mg/kg bw; RA from CAS 16470-24-9
Correction for molecular weight: NOAEL (target substance) = 580 mg/kg bw

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
615 mg/kg bw/day
Study duration:
chronic
Species:
rat

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No data is available on carcinogenicity for the test substance. However, reliable data from carcinogenicity studies performed with CAS 16470-24-9; a close structural analogue, is available.

 

There is one combined chronic/carcinogenicity study performed according to a protocol equivalent to OECD TG 453. The test substance (CAS 16470-24-9; 81% pure) was administered to 50 Wistar rats/sex/dose in diet at dose levels of 0, 100, 1000, and 10000 ppm for 24 months. There were no compound-related effects in mortality, clinical signs, body weight, food consumption, haematology, clinical chemistry, urinanalysis, organ weights, or gross and histologic pathology. From type, localisation and frequency of the observed tumours there is no indication for cancerogenic effect of the test substance, thus, the NOAEL was determined to be 10000 ppm/day. Based on feed intake, the NOAEL for females is 709 mg/kg bw/day and for males 521 mg/kg bw/day, both corresponding to the 10000 ppm, the highest dose in this study. The NOAEL for males and females is set to 615 mg/kg bw/day (Bayer AG, 1978b).

A further study was conducted in order to investigate whether the test substance has a carcinogenic effect onto skin under light exposure.

There is one study available investigating the increase of the appearance of skin tumours after several ultraviolet light exposures after dermal exposure to CAS 16470-24-9 (80% pure). Photocarcinogenesis testing involved pretreating the skin of 50 hairless mice with the test compound, 8-methoxypsoralen (8-MOP, a known phototoxic agent), or solvent (positive and negative control, respectively) only before each daily exposure to simulated solar ultraviolet light. In terms of tumour yield and tumour development time, photocarcinogenesis was enhanced by 8-MOP, but not by the test substance (Bayer AG, 1979b).

Based on the available data the test substance is considered to have no carcinogenic potential.

Justification for classification or non-classification

The available data on carcinogenicity is considered reliable and suitable for classification. Based on this data, classification for carcinogenicity according to 67/584/EEC and EC/1272/2008 is not warranted.