Registration Dossier

Administrative data

Description of key information

The key study for sensitisation was conducted according to the appropriate OECD guideline and in compliance with GLP. The study concludes the test material is not sensitising to guinea pig skin (Dow Corning Corporation 2011).

Key value for chemical safety assessment

Skin sensitisation

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

The key study for skin sensitisation was conducted according to current OECD guideline and in compliance with GLP (Dow Corning Corporation 2011). Before initiating main study, an irritation screen was carried out. Skin reactions were observed at all four concentrations tested (100, 75, 50 and 25% in acetone puriss), when applied topically and occlusively. The neat test item showed moderate skin reactions (erythema grade 2) at the 24 hour reading in all three animals; 75% and 50% concentrations showed moderate skin reaction (grade 2) in one animal and mild (grade 1) skin reaction in two animals; 25% showed mild skin reactions (grade 1) in all three animals. At the 48 hour reading, the severity of the skin reactions decreased or remained at grade 1 on all the test sites treated with the neat test item and the three lower concentrations. Due to possible skin irritation produced by the vehicle itself and as the non-irritating concentration could not be determined after the irritation screen, a second irritation screen with three additional animals was performed. In irritation screen 2, three new animals were treated with the test item concentrations of 75, 50, 25, 10, 5% in acetone puriss and with acetone puriss alone. Mild skin reactions (grade 1) were seen in all three animals treated with the test item concentration of 75% in acetone puriss. Therefore, the test item concentration of 75% in acetone puriss was selected for the 3 -week induction. No signs of systemic toxicity were observed in the animals in response to treatment. No skin effect was observed in the control group after treatment with acetone puriss during the three weeks of induction. Discrete/patchy erythema was observed in eight, three and two out of 20 test animals after the first, second and third weeks of induction, respectively when treated with the test item at 75% in acetone puriss. First challenge application was performed on day 29. The test item was applied at 10% (highest non-irritating concentration) in acetone puriss on naive sites, occlusively for 6 hours. The vehicle acetone puriss was applied too. Because equivocal findings were observed after the first challenge, a rechallenge was carried out. The acetone - control animals were not rechallenged since they were considered to be sensitized after the first challenge and no longer "control" value. Instead, new naive control animals were obtained. The second challenge was therefore carried out with additional control animals and the original test animals. The treatment was identical to the first challenge, performed 28 days after the first challenge and using new test sites. The animals were 5-17 weeks of age under the circumstances of the study, an age which was deemed not to influence the sensitivity of the test system. At rechallenge, no signs of sensitisation was evident.

Justification for classification or non-classification

Based on the available information, no classification is required for sensitisation for 3,3 -bis[(dimethylvunylsilyl)oxy]-1,1,5,5 -tetramethyl-1,5 -divinyltrisiloxane, in accordance with Regulation EC (No) 1272/2008.