Registration Dossier

Administrative data

Description of key information

No reliable acute toxicity data are available for D3, therefore surrogate and supporting data are therefore used to fulfil these endpoints.
An acute oral toxicity study for the hydrolysis product of D3, dimethylsilanediol, was conducted according to OECD test guideline 425 (up & down method) and in compliance with GLP. The acute oral LD50 for female albino rats was >2000 mg/kg. One animal out of five died during the study. Clinical observations limited to the animal that died included partial closure of the right and left eyes, impaired equilibrium, hypoactivity, decreased respiration, soft feces, pale body, pale extremities and body cool to touch. Clinical observations for all animals included wet yellow material on the urogenital, anogenital areas and/or ventral trunk.
No acute inhalation tests are available for D3 or dimethylsilanediol. However, a repeated dose toxicity study via the inhalation route (see Section 7.5.3) tested D3 at exposure levels up to the maximum attainable vapour concentration for this substance, for a duration of 6 hours per day. There was no mortality or evidence of specific target organ toxicity in this study. It can therefore be concluded that D3 would not be acutely toxic by the inhalation route up to the maximum attainable vapour concentration.
No data are available for the dermal route.

Key value for chemical safety assessment

Additional information

Oral

A Reliability 1 acute oral toxicity study for the hydrolysis product of D3, dimethylsilanediol, was conducted according to OECD test guideline 425 (up & down method) and in compliance with GLP. The acute oral LD50 for female albino rats was >2000 mg/kg. In addition, an acute oral toxicity study is available for D3 (DCC, 1980) which broadly followed the now-deleted OECD 401 guideline, but with reduced animal numbers and no GLP. In this study, the approximate LD50 was reported to be 15.4 g/kg. Two studies for repeated dose toxicity via the oral route were conducted (see Section 7.5.1). In a 14-day study, male and female rats were treated with D3 at doses up to 1600 mg/kg/day, while in a 28-day study, male and female rats were treated with D3 at a single dose level of 1500 mg/kg/day. There were no mortalities at any dose level in either of these studies.

The hydrolytic half-life of D3 at pH 7 and 25 °C is ca. 0.4 hours. Following oral dosing, D3 is expected to undergo rapid hydrolysis to dimethylsilanediol and it is therefore appropriate to read-across good quality data for the hydrolysis product, supported by measured data on the parent substance.

Taking all available evidence into account, D3 is not acutely harmful following oral exposure.

Inhalation

No acute inhalation studies are available. However, a repeated dose toxicity study via the inhalation route (see Endpoint Summary for repeated dose toxicity, Section 7.5) tested D3 at exposure levels up to the maximum attainable vapour concentration for this substance, for a duration of 6 hours per day. There was no mortality or evidence of specific target organ toxicity in this study. It can therefore be concluded that D3 would not be acutely toxic by the inhalation route up to the maximum attainable vapour concentration. In accordance with Section 1.1.2 of REACH Annex XI, further testing for acute inhalation toxicity is not required.

Justification for classification or non-classification

Based on the available data for the oral and inhalation routes, D3 is not classified for acute toxicity according to the criteria of EU Directive 67/548/EEC and Regulation 1272/2008.

No data are available for the dermal route.