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Toxicological information

Carcinogenicity

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Description of key information

For the test substance under investigation currently no data are available to evaluate potential carcinogenic effects to mammalian species in vivo. Nevertheless, data on similar substances within the category of stilbene optical brighteners are available.

A combined 2-year feeding chronic toxicity/ carcinogenicity study, pre-dating GLP- and OECD-test guidelines, was conducted with OB 2 -A using Wistar-II rats (Bomhard and Löser, 1978).

Wistar rats were fed with 0, 100, 1000 and 10,000 ppm of a 89 % 16090-02-1 preparation for two years (daily intake of approx.: 5.33; 54.08; 524.80 mg/kg bw/day (males) and 7.8; 79.97; 791.37 mg/kg bw/day (females)). No pathological or histopathological findings were observed indicating any carcinogenic potential.

The substance is the less soluble member of the category, therefore the most bioavailable and the NOAEL of 524.80 mg/kg bw/day can be taken as conservative also for the whole morpholino family (OB 2 -MSA, for which actually no repeated dose testing is requested because of registration tonnage, and OB 2 -DSA for which no chronic or subchronic repeated dose testing is requested according to Annex IX and X).

Further studies were done in order to investigate wheter the test substance has a carcinogenic effect onto skin under light exposure.

There were in total eight studies available investigating the increase or the appearance of skin tumors after several ultraviolet light exposures after dermal exposure to OB 2 -A, OB 3a-A(free acid), OB 3a-MSA, and OB 3b-A [Data for OB 2 -A are included to section 7.7 of this dossier, remaining data on OB 3a-MSA and OB 3b-A are provided and discussed in the category justification document attached to this dossier]. Photocarcinogenesis testing involved pretreating hairless mouse skin with the test compounds, 8 -methoxypsoralen (8 -MOP; known phototoxic agent), or solvent only before each daily exposure to simulated solar ultraviolet light. In terms of tumor yield and tumor development time, photocarcinogenesis was enhanced by 8 -MOP, but not by test substances.

 

All these tests consistently yielded negative results indicating that Stilbene fluorescent whitening agents have no carcinogenic potential. It is concluded that these negative findings can also be transferred to the stilbenes which were not tested.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
524.8 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

Justification for classification or non-classification

Based on the available information with this category of substances, the substance was considered to be devoid of any carcinogenic potential. Hence, no classification is required according to the CLP (Regulation EC No. 1272/2008) criteria.

Additional information