Registration Dossier

Administrative data

Description of key information

The key acute oral toxicity study, conducted according to OECD TG 423, and in compliance with GLP, reports an LD50 value of >= 2000 mg/kg bw for 1,1,1,5,5,5-hexamethyl-3-phenyl-3-[(trimethylsilyl)oxy]trisiloxane.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The key acute oral toxicity study, conducted according to OECD TG 423, and in compliance with GLP, reports an LD50 value of >= 2000 mg/kg bw for 1,1,1,5,5,5-hexamethyl-3-phenyl-3-[(trimethylsilyl)oxy]trisiloxane.

Following a single oral administration of 2000 mg/kg bw of 1,1,1,5,5,5-hexamethyl-3-phenyl-3-[(trimethylsilyl)oxy]trisiloxane to 6 female rats, no mortality occurred during the 14-day observation period. No clinical signs of toxicity or changes to body weight gain were noted in any of the test animals. No abnormalities were observed at necropsy in any of the test animals. Body weights were recorded on days 1, 8 and 15. Clinical examinations were performed several times during the first 4 hours post-dosing, then once daily for the 14-day observation period. All animals were sacrificed at the end of the study period and necropsy was performed.

In the supporting study (Bayer, 1967, Rel 4), the test substance (tris(trimethylsiloxy)phenylsilane) was administered to rats by oral gavage at doses of 1000, 2500 and 5000 mg/kg bw/day. No animals died and there were no unusual clinical observations. Therefore, in this study the oral LD50 in rats was >5000 mg/kg bw/day.

Justification for classification or non-classification

Based on the available data for 1,1,1,5,5,5-hexamethyl-3-phenyl-3-[(trimethylsilyl)oxy]trisiloxane, no classification for acute toxicity is required according to Regulation (EC) No. 1272/2008.