Registration Dossier

Administrative data

Description of key information

Skin irritation (RA from CAS 1185-55-3 and CAS 2031-67-6, OECD TG 404): not irritating 
Eye irritation (RA from 2031-62-1, OCED TG 405): not irritating

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)
Adequacy of study:
key study
Justification for type of information:
Please refer to the attached justification
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Irritation parameter:
erythema score
Basis:
mean
Time point:
24/48/72 h
Score:
0.11
Max. score:
4
Reversibility:
fully reversible
Irritation parameter:
edema score
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: no effects
Irritant / corrosive response data:
Supporting data:
CAS 1185-55-3, Hazelton 1966: intact skin: erythema score 1.0 and edema score 0 at 24 hour reading time point, at 72-reading time point scores were 0 for erythema and edema, respectively
CAS 1185-55-3, Mellon, 1963: no classficiation possible due to methodological deficiencies
CAS 2031-67-6, Hazelton, 1992b: erythema score of 0.11 at 24/48/72 hour reading point (fully reversible within 48 hours), edema score of 0.0 at 24/48/72 hour reading point
CAS 2031-67-6, Bushy Run Research Center, 1981: erythema and edema score of 0.0 at 24/48/72 hour reading point, respectively
Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
No irritation potential was observed with the source substances, thus no irriation potential is estimated for the target substance. As explained in the analogue justification, it is considered that the target and the source substances are unlikely to lead to differences in 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)
Adequacy of study:
key study
Justification for type of information:
see attached analogue justification
Reason / purpose:
read-across source
Irritation parameter:
cornea opacity score
Basis:
mean
Remarks:
over all three animals
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: reversibility: not applicable
Irritation parameter:
iris score
Basis:
mean
Remarks:
over all three animals
Time point:
24/48/72 h
Score:
0
Max. score:
2
Reversibility:
other: reversibility: not applicable
Irritation parameter:
conjunctivae score
Basis:
mean
Remarks:
over all three animals
Time point:
24/48/72 h
Score:
0
Max. score:
3
Reversibility:
other: reversibility: not applicable
Irritation parameter:
conjunctivae score
Basis:
animal #2
Time point:
24/48/72 h
Score:
0.3
Max. score:
3
Reversibility:
fully reversible within: 48 hours
Irritation parameter:
chemosis score
Basis:
mean
Remarks:
out of animals #1 and #3
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: reversibility: not applicable
Irritant / corrosive response data:
Animal No. 1 and 3 showed redness grade 1 of the conjunctivae 1 hour post instillation. 24 hours post instillation until the end of the observation period no signs of irritation were recorded.
Animal No. 2 showed redness grade 1 of the conjunctivae 1 hour, as well as 24 hours post instillation. 48 hours, as well as 72 hours post instillation no signs of irritation were recorded.
Other effects:
Throughout the observation period not weight loss was observed for the test animals.
Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
In conclusion, it was shown that the source substance is not irritating to the eyes. This is also estimated for the target substance. As explained in the analogue justification, it is considered that the target and the source substances are unlikely to lead to differences in eye irritation potential.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

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

 

No measured skin irritation data are available for the registered substance dimethoxymethylsilane (CAS 16881-77-9), however, data are available for the structural analogues triethoxymethylsilane (CAS 2031-67-6) and trimethoxymethylsilane (CAS 1185-55-3). The substances rapidly hydrolyse in contact with water to produce the same common silanol hydrolysis product methylsilanetriol. Therefore, it is considered that read-across between the substances is appropriate.

Additional information is given in a supporting report (PFA, 2013t) attached in Section 13 of the IUCLID 5 dossier.

 

 

Three studies are available for trimethoxymethylsilane (CAS 1185-55-3). In the key study conducted according to OECD 404, and in compliance with GLP (Hazleton, 1992a) trimethoxymethylsilane was found to be not irritating to the skin of 6 New Zealand white rabbits exposed to 0.5 ml of the unchanged substance semiocclusive for 4 hours. A supporting study conducted similar to OECD 404 but prior to commencement of GLP (Hazleton, 1966) did also find the substance not to be irritating after 24 hours occluded exposure of 0.5 ml on rabbit skin.  

Two supporting studies are further available for triethoxymethylsilane (CAS 2031-67-6). An OECD 404 study conducted according to GLP (Hazleton, 1992b) found triethoxymethylsilane not to be irritating to the skin of 6 New Zealand white rabbits exposed to 0.5 ml of the unchanged substance semiocclusive for 4 hours. Another study conducted similar to OECD 404 but not according to GLP (Bushy Run Research Center, 1981) did also find the substance not to be irritating after 4 hours occluded exposure of 0.5 ml on rabbit skin.  

In conclusion, existing data on skin irritation for the structural analogues of dimethoxymethylsilane, trimethoxymethylsilane (CAS 1185-55-3) and triethoxymethylsilane, do not show a skin irritating potential for this group of substances.

  

No measured eye irritation data are available for the registered substance, dimethoxymethylsilane, however, data are available for the structural analogue substance diethoxymethylsilane (CAS 2031-62-1). Both substances hydrolyse in contact with water to produce the common silanol hydrolysis products, methylsilanediol and methylsilanetriol. Therefore, it is considered that read-across between the substances is appropriate.

 

A key eye irritation study, conducted according to OECD TG 405, found diethoxymethylsilane was not irritating to the eyes of rabbits. Solely one animal showed a slight redness of conjunctiva 24 hours post instillation in the unwashed eye which was fully reversible within 48 hours of instillation. No corneal opacity, iritis, chemosis, or discharge was noted in the unwashed treated eyes of any of the animals (BSL BIOSERVICE, 2007b).

Justification for classification or non-classification

The available data on skin and eye irritation of the registered substance 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.