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EC number: 217-496-1
CAS number: 1873-88-7
The key study for acute oral
toxicity reports an LD50 value greater than 2000 mg/kg bw which was
determined in a reliable study with 1,1,1,3,5,5,5-heptamethyltrisiloxane
(H-L3), carried out in accordance with OECD Test Guideline 425
and in compliance with GLP (RCC 2008).
The acute inhalation study is read
across from octamethyltrisiloxane (L3, CAS 107-51-7). The animals were
exposed to vapour and an LC50 value greater than 22.6 mg/l (analytical)
was determined in a reliable study conducted according to OECD Test Guideline
403 and in compliance with GLP (Dow Corning 2004).
In addition, a study was
conducted according to OECD Test Guideline 403 and in compliance with
GLP for the read-across substance 1,1,3,3-tetramethyldisiloxane (H2 -L2,
CAS 3277-26-7). The animals were exposure to vapour and an LC50 value greater
than 5.8 mg/l (measured) was determined (Dow Corning Corporation, 1994).
In accordance with Column 2 of
REACH Annex VIII, the acute toxicity study via the dermal route
(required in Section 8.5.2) does not need to be conducted as reliable
data via the oral and inhalation routes are available.
The key study for acute oral toxicity reported an LD50 value
greater than 2000 mg/kg bw in rat, in a reliable study conducted
according to OECD Test Guideline 425 and in compliance with GLP (RCC
2008). There were no mortalities during the study period. Slightly to
moderately ruffled fur was noted in all animals from the 1- or 5- hour
reading up to test day 2 or 3, persisting in one animal through test day
7. Slight to marked sedation was recorded in all animals from the 2-, 3-
or 5-hour observation up to 5 hours post-dose or test days 2 or 3. Two
animals showed slightly poor coordination on test day 2 only, while two
other animals showed slight to markedly or slightly to moderately poor
coordination from 5 hours post-dose until test day 2. Hunched posture
was observed in four animals at the 1-hour reading and persisted through
the 5-hour evaluation in one animal and through test day 2 in three
animals. Ventral recumbency was noted in one animal on test day 2. The
body weight of animals was within normal range. No macroscopic findings
were recorded at necropsy.
The key study for acute inhalation was read across from the related
substance octamethyltrisiloxane (L3, CAS 107-51-7). The study was
conducted according to the OECD Test Guideline 403, and in compliance
with GLP. The reported LC50 value is greater than 22.6 mg/l
(Dow Corning 2004). There were no mortalities, no clinical signs or
macroscopic abnormalities reported at necropsy. Furthermore, all body
weight gains were considered normal for both sexes.
Read across was also included for acute inhalation from another related
substance 1,1,3,3-tetramethyldisiloxane (H2 -L2, CAS 3277-26-7).
The study was conducted according to the OECD Test Guideline 403, and in
compliance with GLP. No toxicity was found when male and female rats
were exposed for 4 hours to a measured atmosphere containing 5.8 mg/l
(vapour) of the test material. The LC50 would exceed this
value. There were no treatment-related abnormalities reported. Clinical
signs of rapid respiration and salivation were recorded. There were no
mortalities (Dow Corning Corporation, 1994).
Based on the available
does not require classification for acute toxicity in accordance
with Regulation (EC) No 1272/2008.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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