Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The substance is included in the category of Stilbene Fluorescent Whitening Agents (SFWA) comprising of 14 member substances in total. The category of Stilbene Fluorescent Whitening Agents is defined as a structurally related group of substances that are derivatives of 4,4’-bis(1,3,5-triazinyl-2-yl)amino)stilbene-2,2’-disulphonic acid, each with one aniline and one alkyl derivative amino moiety at the triazine ring. The aniline moiety can also be mono- or di-sulfonic aniline. With the exception of 3a-A(free acid) and OB 3a-A(NaK) all substances are sodium salts. The molecular structures of 3a-A(free acid), OB 3a-A(NaK) and OB 3a-A(Na) are the same except that the first one is the free sulfonic acid and the second one the potassium/sodium salt.

The chemical structures are highly symmetric with an extended chromophor system. Substituents have little influence on the chromophor system; they affect the application properties and substantivity.

To be included in the defined category of SFWA a substance must have the following characteristics:

 •           All substances are derivatives of 4,4’-bis(1,3,5-triazinyl-2-yl)amino)stilbene-2,2’-disulphonic acid, each with one aniline derivative (R1) and one alkyl derivative amino moiety at the triazine ring (R2).

•            The substances have all negative calculated log Pow(< -1), due to the fact that except from the acid form, they are all salts.

•            Molecular weights range from ca. 872 to ca. 1369 g/mol.

•            All category members are very soluble, with an individual solubility ranging from ca. 1 to > 200 g/l. Water solubility tends to increase with the degree of sulfonation. They are all very stable and do not hydrolyze.

•            As a result of the stilbene portion of the molecule, common to all category members, these fluorescent whitening agents have an UV absorption maximum between 340 to 360 nm in water, which makes them subject to direct photo-degradation in the hydrosphere

The structural differences between the substances are determined by the presence of two moieties (R1 and R2) bound to both triazine rings. Each substance is characterized by a combination of two of these moieties to each triazine ring and by the cations of the sulfonic acid group present, which in almost all cases is Na+, in one case it is Na+ and K+; instead of these cations a proton (H+) is present for one substance. R1 is bound to the 3 position of the triazine ring and is described as an aniline function, which may have one or two sulfonate functions

Based on the variability related to R1 or R2 two different sub-categorizations can be considered - Sub-categorization based on R1 or Grouping based on R2. R2 can be constituted by the following:

•            morpholino

•            methyl (2-hydroxyethyl)amino,

•            2-hydroxyethylamino,

•            bis(2-hydroxyethyl)amino,

•            diethylamino

•            (2-carbamoylethyl)(2-hydroxyethyl)amino,

•            bis(2-hydroxypropyl)amino,

For read-across both of these structural differences in moiety R1 and R2 are taking into account. Therefore read-across to OB 2 -A and OB 2 -MSA having also a morpholino residue in position R2 and to OB 3 -DSA and OB 1 -DSA having a disufonato aniline in position R1 is applied.

OECD Toolbox previsions have been found negative for the test substance and for all potential read-across substances. Data generated on the read-across substance OB 2 -A demonstrated no mutagenic effects when tested in bacteria (Ames test) and in mammalian cells. Also no effects have been found when tested for clastogenic effects in vitro and in vivo. Ames tests conducted on read-across substances OB 2 -MSA and OB 1 -DSA confirmed previous results. For OB 3a-DSA a test according to the OECD TG 476 on mutagenicity of mammalian cells has been performed and did not show any mutagenic potential.

Further data available for the whole category demonstrated that based on data currently available no alert for genotoxic activity has been found for any member of the category. Therefore test substance is considered negative for mutagenic and clastogenic behavior and no further data are generated unless new contradictory information becomes evident.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Justification for classification or non-classification

As the substance was considered to be neither mutagenic nor clastogenic, it does not warrant classification for genetic toxicity as per the CLP (Regulation EC No. 1272/2008) criteria.