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Diss Factsheets

Administrative data

Description of key information

Skin Sensitization (OECD 406), guinea pig: not sensitizing (RA from CAS 2031-67-6)

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:
Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Induction: 0%; challenge: 10%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema or edema in any animal. Mild desquamation at test substance site at 24 and 48 hour readings (observed in more males than females).
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Induction: 0%; challenge: 10%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema or edema in any animal. Mild desquamation at test substance site at 24 and 48 hour readings (observed in more males than females).
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
Induction: 25%; challenge: 10%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema and edema in any animal. Desquamation in one animal.
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Induction: 25%; challenge: 10%
No. with + reactions:
3
Total no. in group:
20
Clinical observations:
No erythema/edema in males, Grade 1 erythema/edema in three females, where subsequent histopathology revealed no signs of cell mediated delayed hypersensitivity. 7/10 males and 4/10 females showed desquamation (including the three with erythema/edema).
Group:
positive control
Remarks on result:
not measured/tested
Remarks:
but referred to regular positive testing in the laboratory

Signs of irritation were noted during the induction. Although macroscopic examination showed grade 1 erythema/edema in 3 females 48 h after challenge subsequent histopathological examinations did not reveal any lesion of delayed hypersensitivity in the those animals. No noticeable cutaneous abnormality was noted in the 20 guinea pigs examined in the control group.

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008.
Conclusions:
In a guinea pig skin sensitisation study (guinea pig maximisation test) conducted to OECD 406 and to GLP the source substance triethoxy(methyl)silane did not induce any skin sensitization in any of the animals tested at any time point. There were no clinical signs of systemic toxicity. Thus, the source substance is considered to have no skin sensitising potential. As explained in the analogue justification, it is considered that the target and the source substances are unlikely to lead to differences in skin sensitising potential.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

No data on the skin sensitisation of diethoxy(methyl)silane (CAS 2031-62-1) are available. Therefore, the risk assessment was performed based on the available data from the source substance triethoxy(methyl)silane (CAS 2031-67-6). In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and in accordance with the Read across assessment framework (RAAF, ECHA 2017) read across from the analogue substance has been applied to support the human health hazard assessment of diethoxy(methyl)silane (CAS 2031-62-1). Details on read across justifications can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.

Studies were chosen as key when the available study was of relevance and of sufficient quality for classification and labelling and for risk assessment.

In a key guinea pig maximisation study conducted in compliance with GLP and according to OECD TG 406, triethoxy(methyl)silane was found to be a non-sensitiser. A group of ten male and ten female guinea pigs was dosed with multiple intradermal injections on day 0 following a topical application on day 7 in order to investigate sensitisation potential of triethoxy(methyl)silane. The topical induction consisted of a 48 hour occluded dermal exposure to 0.5 ml of the test substance in a 50% (v/v) solution in sterile codex liquid paraffin. Eleven days after topical induction, challenge dosing for detection of sensitisation was performed. For challenge dosing, an essentially non-irritating concentration (10% (v/v)) of the test material was applied under occlusion for 24 hours. Although macroscopic examination showed grade 1 erythema/oedema in 3 females 48 h after challenge subsequent histopathological examinations did not reveal any lesion of delayed hypersensitivity in those animals. Including these 3 females the sensitisation index was calculated to be 15% for the test group following rechallenge. Appropriate positive and negative controls gave expected results (Hazleton, 1992c).

In the absence of any chemical structural features indicative of sensitising potential for the submission substance and the number of negative results in tests with the other members of this group, it is concluded in a weight of evidence approach that substances of this group are not sensitising. Therefore the read-across to triethoxy(methyl)silane is appropriate.


Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The available data on skin sensitisation of the structural analogue substance, triethoxy(methyl)silane (CAS 2031-67-6), do not meet the criteria for classification according to Regulation (EC) 1272/2008 or EU Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification of the registered substance.