Disodium 7-[[4,6-bis[(2-hydroxyethyl)amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]naphthalene-2-sulphonate

Endpoint summary

Description of key information

No bioaccumulation potential.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Direct Red 253 (DR253) is a dark brown/purple organic solid, marketed/used in a non-solid or granular form.

DR253 is not toxic/harmful for short-term exposures and it is not skin/eye irritating. It is not able to cause an allergic skin reaction. No CMR activity has been never been reported in literature and has not be observed in specific experiments performed. Therefore, mechanisms of bioactivation leading to adverse effects are not expected to occur.

 

Specific studies or specific literature data on toxicokinetics and metabolism are not available, thus available information about the substance has been taken into account, avoiding further tests.

 

Because of the molecular size and the hydrophilic character of DR253, dermal absorption is expected to be negligible. The skin metabolites simulation proposes possible reduction/oxidation reactions, mainly involving azo bonds and naphthalene ring, break of the azo bond, possibly accompanied by the aniline sulphate removal and removal of phenylenediamine.

Based on the available information, a substance acute dermal toxicity potential is not suspected. Furthermore, the substance gave negative results in skin sensitisation potential investigation, thus it is considered as not able to cause an allergic response in susceptible individuals, after exposure via the skin.

 

Because of the physical state and the trade forms of the substance under registration, inhalation is not an appropriate route of exposure; furthermore, considering the molecular size and the hydrophilic character of DR253, dermal absorption is expected to be negligible.

 

The high water solubility suggests that DR253 is a hydrophilic substance, thus it is expected that only a small rate of substance as such could be absorbed by oral route.

No abnormalities were recorded in the acute toxicity studies available, by oral route.

 

During the subacute oral, the treatment did not produce changes detected in health condition control, except coloured faeces; the extension of substance as such elimination is not know. Findings observed in both sexes were considered to be of no toxicological significance. No significant changes related to test substance administration were recorded up to the highest tested dose of 1000 mg/kg bw/day.

 

DR253 is a di-sulphonated substance; the sulphonation degree contributes to increased solubility and to increased detoxification.   

 

Because the chemical structure, a potential azo bond cleavage has been suspected on the basis of general mechanism described in literature and based on the in silico estimation. From this point of view, a critical aspect is related to the possible formation of aromatic amines, in particular aniline release, which is a known CMR. The genetic toxicity potential of DR253 has been deeply investigated by in vitro and in vivo test systems, assaying mutagenicity and clastogenicity, with and without metabolic activation. No signs of genetic toxicity potential have been reported and it has been concluded that the substance can be considered as non-mutagenic/clastogenic.