Registration Dossier

Administrative data

Description of key information

In the key mouse local lymph node assay, conducted according to the appropriate OECD 429 Test Guideline and in compliance with GLP, 3-(trimethoxysilyl)propyl methacrylate (CAS 2530-85-0) was reported not to elicits a SI = 3 when tested up to 10% and it was established that the EC3 value exceeds 10%. The test material was concluded to be not sensitising to skin (Charles River, 2018). The mouse local lymph node assay was performed due to final decision of substance evaluation.

Two related read-across substances were both non-sensitising in a guinea pig maximisation tests. A second study on the registered substance was selected as relevant but not selected as key due to the confounding response in the negative controls. The read-across studies were conducted acccording to appropriate guidelines and in compliance with GLP.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

The sensitising potential of 3-(trimethoxysilyl)propyl methacrylate (CAS 2530-85-0) was assessed in a mouse local lymph node assay, conducted according to the appropriate OECD 429 Test Guideline and in compliance with GLP (Charles River, 2018). Three experimental groups of five female mice were treated with test item concentrations of 2, 5 or 10% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with the vehicle alone (Acetone/Olive oil (4:1 v/v)). The vehicle was chosen from the vehicles specified in the test guideline (in order of preference): Acetone/Olive oil (4:1 v/v), N,N-dimethylformamide, methylethylketone, propylene glycol, dimethylsulfoxide and 1% Pluronic© L92 in Elix water (in case an aqueous vehicle is suitable). The vehicle was selected on the basis of maximizing the solubility based on trial preparations performed at Charles River Den Bosch and on information provided by the Sponsor. Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal.  After precipitating the DNA of the lymph node cells, radioactivity measurements were performed.

No irritation was observed in any of the animals. The mean body weight gain shown by the animals over the study period was considered to be normal. The majority of the auricular lymph nodes were considered normal in size, except for one node of one animal treated at a 2% test item concentration.  No macroscopic abnormalities of the surrounding area were noted for any of the animals.

3-(Trimethoxysilyl)propyl methacrylate (CAS 2530-85-0) was reported not to elicits a SI = 3 when tested up to 10% and it was established that the EC3 value exceeds 10%. The test material was concluded to be not sensitising to skin.

The registered substance was tested in a guinea pig maximisation test (WIL, 1994) (reliability 4 due to reactions in the negative control group) and a strict interpretation of the results would conclude that it was a not sensitising in the guinea pig since there were no reactions in the treated group that exceeded the highest reaction in the Negative Control Group at challenge. However, both the treated group and the Negative Control Group exhibited a high incidence of grade 1 sites, suggesting that the vehicle (cottonseed oil) may itself have irritant properties. However, there was a significantly increased number of moderate (grade 2) reactions to 50% test substance in the Test Group (14/20 and 5/20 at 24 and 48 hours, respectively, as compared to only 1/10 and 0/10 at 24 and 48 hours, respectively, in the Negative Control Group). This increased incidence of moderate reactions suggests a sensitization response to 50% test substance. Although increased severity of the delayed response was not seen for 3-trimethoxysilylpropylmethacrylate, the irritant properties of the cottonseed oil vehicle were a potential confounding factor. Given the overall increased incidence and duration of responsiveness observed in the treated group, the report author concluded that data suggested that 3-trimethoxysilylpropylmethacrylate had the potential for weak dermal sensitisation.

In order to base the classification decision on unequivocal information, supporting information was acquired from two read-across substances 2-Propenoic acid, 2-methyl-, (trimethoxysilyl)methyl ester (CAS 121177-93-3) and 2-Propenoic acid, 2-methyl-, (dimethoxymethylsilyl)methyl ester (CAS 54586-78-6) which are also alkoxysilanes with methacrylate groups in the side chain. Both studies were guinea pig maximisation tests of high reliability (BSL Bioservice 2003a and 2003b, Reliability 2) and found the test materials to be not sensitising.

In the study with 2-propenoic acid, 2-methyl-, (trimethoxysilyl) methyl ester (CAS 121177-93-3)

the test item was applied at a 5% concentration (diluted in corn oil) for intradermal injection. For the topical application the test item was applied as a 100% concentration. For the topical challenge application the test item was applied at a 100% concentration.There were no signs of irritation or sensitisation at any time point, at any dose in any of the animals (BSL Bioservice 20013a).

In the study with 2-propenoic acid, 2-methyl-, (trimethoxysilyl) methyl ester the test item was applied at a 2.5% concentration (diluted in corn oil) for intradermal induction. For the topical challenge application the test item was applied at 100% concentration. Slight signs of erythema were noted at 24 and 48 hours after first induction application in all animals. No signs of irritation were observed after induction second stage. No signs of irritation were observed after the challenge. The percentage of animals sensitised was 0% (BSL Bioservice 2003b).

 

 

 

 

 


Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the available data 3-trimethoxysilylpropyl methacrylate does not require classification for sensitisation according to Regulation (EC) No 1272/2008.