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Description of key information

To assess the skin sensitisation potential of the substance, an in vivo study has been conducted on a similar substance (read-across). The observations of the study support that the substance is not a skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance Direct Red 254 TEA salt (CAS No 64683-40-5 / EC 265-016-4) is defined as a mono-constituent substance with cations triethanolammonium.
The available toxicological data on this substance are insufficient to fulfil the data requirements for a REACH Annex VIII dossier.
In order to prevent unnecessary animal testing, the occurring data gaps on toxicity studies might be filled by applying read-across from the similar substance Direct Red 254 sodium salt (CAS No 6300-50-1 / EC 228-589-1). Both salts of Direct Red 254 are synthetized using the same raw materials and following the same manufacturing process.
The only difference between the query structure Direct Red 254 TEA salt (CAS 64683-40-5) and Direct Red 254 sodium salt (CAS 6300-50-1) is the counter ion. CAS 6300-50-1 is the result of a neutralization with NaOH, whilst the alkaline agent used in CAS No. 64683-40-5 is triethanolamine.
Both substances are identical in relation to the anionic components.

The read-across is based on the hypothesis that source and target substances have similar toxicological properties because both molecules have the following similarities: a) Identical raw materials; b) Identical manufacturing process; c) Identical anionic structure composition; d) Identical degradation products by reductive cleavage; e) Both have affinity to the same type of substrates/molecules. The substances are able to be adsorbed on the same type of substance, e.g. polysaccharides (cellulose), polyphenols (lignin) and proteins; f) Both substances have similar physicochemical properties

In summary, it is considered that both substances have the same mode of action with regard to the following endpoints:Acute Oral toxicity, Skin irritation, Eye irritation, Skin sensitisation, Mutagenicity and Repeated dose and reproduction / developmental (screening).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Read across is possible provided that there is no impact of impurities on the toxicological properties of the target and source chemicals. For both, impurities are comparable.
The composition and impurities of the target and source substances are shown in table 1 of the attached document to this record.

3. ANALOGUE APPROACH JUSTIFICATION

The target chemical Direct Red 254 TEA salt (CAS No 64683-40-5) is a mono-constituent substance, with cations triethanolammonium.
Direct Red 254 Sodium salt (CAS No 6300-50-1) is assumed as source chemical since it is identical to the target chemical Direct Red 254 TEA salt (CAS No 64683-40-5) in respect of the different chemical anionic component but varies in the cation. The physicochemical properties of both substances are nearly identical. No experimental data on absorption, distribution and excretion is available for the source and target substances and their hydrolysis products. The toxicokinetics assessment is based on the physicochemical properties and the available toxicological data of the substances.
The source chemical CAS No 6300-50-1 is ionisable and is assumed that will be dissociated in aqueous media or in biological fluids to the anionic component and free Na+ cation. Sodium ion is a naturally occurring cation in the body with a blood plasma concentration of 140 mmol/L. It is excreted with the urine and does not cause any toxic effects when administered in low concentrations.
In analogy to the source chemical also CAS No 64683-40-5 (target chemical) is expected to be dissociated shortly after absorption and the cation TEA+ is also assumed to be readily available in the body. The TEA+ cation can be assimilated to triethanolamine (CAS No 102-71-6).
Base on that the only difference between the target structure (CAS No 64683-40-5) and the source structure (CAS 6300-50-1) is the counter ion, and the influence to the human health toxicity, irritation and / or sensitisation effects due to the presence of TEA+ in the target chemical CAS No 64683-40-5 is not expected. Consequently, read-across to the source chemical CAS No 6300-50-1 is regarded as feasible.
A broad and more detailed explanation is included in the attached document in section 13 of this dossier.

4. DATA MATRIX
Two data matrix are included in the attached document in section 13 of this dossier: Matrix 1 (Toxicity data on the source and target substance) and Matrix 2 (Main potential metabolites data)
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
assessment report
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no erythema, no oedema
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
18
Clinical observations:
Females no. 383 and 387 died on day 25 of test. No toxic symptoms were evident in the guinea pigs of neither the control nor test group.
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
10% HCHO
No. with + reactions:
6
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
vehicle only
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
vehicle only
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
no indication of skin sensitisation
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the results of the available data and studies on the skin sensitisation, the substance has not to be classified for this hazard class following the classification criteria of the EU Regulation 12/2008 (CLP Regulation)

Regarding respiratory sensitisation, there are no data available. Based on the non-sensitising potential for skin sensitisation, it is not expected that the substance could be a respiratory sensitiser.