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Description of key information

No studies were available to assess the skin or eye irritation potential of the registered substance, however, data are available for the structural ananlogue substances trimethoxy(methyl)silane (CAS: 1185-55-3) and triethoxy(methyl)silane (CAS: 2031-67-6), respectively.
WoE approach:
CAS: 1185-55-3 and CAS: 2031-67-6 (according to OECD TG 404): not irritating to the skin
CAS: 1185-55-3 and CAS: 2031-67-6 (according or similar to OECD TG 405): not irritating to the eye

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin irritation: in vivo
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Summary of available data used for the endpoint assessment of the target substance
Adequacy of study:
weight of evidence
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
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Irritation parameter:
erythema score
Basis:
mean
Time point:
24/48/72 h
Score:
0.11
Max. score:
4
Reversibility:
fully reversible
Remarks on result:
no indication of irritation
Remarks:
Hazleton France, 1992a. CAS 1185-55-3
Irritation parameter:
edema score
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: n/a
Remarks on result:
no indication of irritation
Remarks:
Hazleton France, 1992a. CAS 1185-55-3

All together, data from two source substance and two skin irritation studies for each source substance are available and used in a weight of evidence approach. In all studies slight erythema was observed which was latest reversed at the 72 hour reading time point.

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
Several studies are available from structural analogue substances CAS 2031-67-6 and CAS 1185-55-3. Slight erythema was observed in all studies in the first 24 hours which were reversed latest after 72 hours after exposure. As explained in the analogue justification, the differences between the target and the source are unlikely to lead to differences in the skin irritation potential.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vivo
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Summary of available data used for the endpoint assessment of the target substance
Adequacy of study:
weight of evidence
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
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Irritation parameter:
cornea opacity score
Basis:
mean
Remarks:
out of all 3 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: no effects
Remarks on result:
no indication of irritation
Remarks:
Kreiling and Jung, 1991. CAS 1185-55-3.
Irritation parameter:
iris score
Basis:
mean
Remarks:
out of all 3 animals
Time point:
24/48/72 h
Score:
0
Max. score:
2
Reversibility:
other: no effects
Remarks on result:
no indication of irritation
Remarks:
Kreiling and Jung, 1991. CAS 1185-55-3.
Irritation parameter:
conjunctivae score
Basis:
mean
Remarks:
out of all 3 animals
Time point:
24/48/72 h
Score:
0
Max. score:
3
Reversibility:
fully reversible within: 24 h
Remarks on result:
no indication of irritation
Remarks:
Kreiling and Jung, 1991. CAS 1185-55-3.
Irritation parameter:
chemosis score
Basis:
mean
Remarks:
out of all 3 animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
fully reversible within: 24 h
Remarks on result:
no indication of irritation
Remarks:
Kreiling and Jung, 1991. CAS 1185-55-3.
Irritant / corrosive response data:
All together, data from two source substance are available and used in a weight of evidence approach.
Methyltrimethoxysilane was found to be only slightly irritating. The test animals showed irritation in response to the undiluted test substance (lacrimation, congestion and oedema of the mucous membrane) which was reversible within 24 hours. Corneal opacity was present in 3 animals, which was also rapidly reversible. At the 30% concentration, the irritation was very slight, some lacrimation and congestion was present in the first 6 hours. At the 10% and 3% concentrations, no signs of irritation were observed (Juloi, L., 1992: CAS 1185-55-3).
For CAS 2031-67-6 only one out of six animals showed conjuctivae redness with a score of 1 after 24 hours. This was resolved after 48 hours. All other irritation parameter scores were 0 for all reading time points and all animals.
Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No 1272/2008
Conclusions:
Several studies are available from structural analogue substances CAS 2031-67-6 and CAS 1185-55-3. Slight eye irritation was partly observed which were reversed latest after 48 hours after exposure. As explained in the analogue justification, the differences between the target and the source are unlikely to lead to differences in the eye irritation potential.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

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.

The available studies for skin and eye irritation with the structural analogue substance trimethoxy(methyl)silane (CAS 1185-55-3) were conducted in accordance with the appropriate test guidelines and to GLP (Hazelton France, 1992b and Kreiling and Jung, 1991). Trimethoxy(methyl)silane was found to be not irritating to rabbit skin or eyes, although mild effects were observed.

The available skin irritation study on the structural analogue substance triethoxy(methyl)silane (CAS 2031-67-6) which was conducted in compliance with GLP and in accordance with OECD TG 404, found the substance to be a transient, mild irritant in rabbits. However, the results obtained in this study were not sufficient for classification as a skin irritant (Hazelton France, 1992b). Furthermore, an eye irritation study on the structural analogue substance triethoxy(methyl)silane (CAS 2031-67-6) which was not in compliance with GLP, but was equivalent or similar to OECD TG 405, showed that triethoxy(methyl)silane was not irritating to rabbit eyes. Only minor, transient eye irritation was observed following instillation of the test material into the eyes of six rabbits. The Draize score of 0.06 out of 3 indicates that triethoxymethylsilane would not be considered irritating to the eyes of rabbits (Bushy Run Research Center, 1981c). All the studies are in agreement of the lack of skin and eye irritation potential of the structural analogue substances, trimethoxy(methyl)silane and triethoxy(methyl)silane. This therefore strengthens the overall assumption that the registered substance, dimethoxydimethylsilane, will not be a skin or eye irritant.


Justification for classification or non-classification

The available data on Irritation / Corrosion of the structural analogue substances, trimethoxymethylsilane and triethoxymethylsilane, respectively, do not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification of the registered substance.