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Toxicological information

Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
17 January 2006 to 10 April 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Deviations:
yes
Remarks:
(temporary deviations from the minimum level of relative humidity occurred (27%, a minimum of 30% is recommended))
Qualifier:
according to
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Qualifier:
according to
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
Qualifier:
according to
Guideline:
other: JMAFF guidelines (2000), including the most recent partial revisions at time of reporting
GLP compliance:
yes (incl. certificate)
Test type:
acute toxic class method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: approximately 12 weeks
- Weight at study initiation: not exceeding ± 20% of the mean
- Fasting period before study: food withheld overnight (a maximum of 20 hours) prior to dosing until 3-4 hours after test substance administration
- Housing: in groups of three in labelled Macrolon cages (MIV type)
- Diet (e.g. ad libitum): standard diet ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.5 to 22.6
- Humidity (%): 27 to 63
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 17 January 2006 To: 2 February 2006

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
MAXIMUM DOSE VOLUME APPLIED: 2.667 ml/kg bw

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: no data
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
6 (3 females in first and second set)
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days (dosing on day 1, observation until day 15)
- Frequency of observations and weighing: clinical signs monitored "at periodic intervals on the day of dosing", apparently 0, 2 and 4 hours after treatment, and then once daily until day 15. Body weights were recorded on days 1 (pre-administration), 8 and 15
- Necropsy of survivors performed: yes
Statistics:
No statistical analysis was performed

Results and discussion

Effect levelsopen allclose all
Sex:
female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Remarks:
mortality
Remarks on result:
other: no mortality at 2000 mg/kg bw
Sex:
female
Dose descriptor:
LD50
Effect level:
>= 5 000 mg/kg bw
Based on:
other: OECD Test Guideline 423
Remarks on result:
other: No mortalities in a 2-step test starting with 2000 mg/kg bw suggests an LD50 cut-off value of at least 5000 mg/kg bw, according to the OECD guideline
Mortality:
No mortality occurred over the course of the study.
Clinical signs:
Piloerection or hunched posture was seen in two animals on day 1.
Body weight:
Mean body weight gain considered normal. Slight body weight loss (2 g) between days 8 and 15 in one animal was not considered indicative of toxicity, based on the absence of any corroborative findings.
Gross pathology:
No macroscopic abnormalities found at post mortem.
Other findings:
- Organ weights: not examined
- Histopathology: not examined
- Potential target organs: not examined

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The key acute oral toxicity study, conducted according to OECD Test Guideline 423 and in compliance with GLP, concluded an LD50 value of >2000 mg/kg bw.
Executive summary:

The test substance was tested for acute oral toxicity to rats in study conducted according to OECD Test Guideline 423 and in compliance with GLP.

Three female Wistar rats were given a single oral gavage administration of 2000 mg/kg bw 1,1,3,3-tetramethyldisiloxane. The rats were then observed for fourteen days, after which they were sacrificed and subject to gross necropsy. This process was then repeated with a further three female rats. 

Over the course of the study, there were no deaths or overt signs of systemic toxicity, besides piloerection and hunched posture, each seen in one animal on day 1. No significant, treatment-related effect on body weight was reported, and no macroscopic abnormalities were detected at post mortem examination.

The acute oral LD50 in rats was determined to be greater than 2000 mg/kg bw.