1,1,1,3,5,5,5-heptamethyltrisiloxane

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

GLP compliance:

yes

Test type:

up-and-down procedure

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1,3,5,5,5-heptamethyltrisiloxane

EC Number:

217-496-1

EC Name:

1,1,1,3,5,5,5-heptamethyltrisiloxane

Cas Number:

1873-88-7

Molecular formula:

C7H22O2Si3

IUPAC Name:

2,2,4,6,6-pentamethyl-3,5-dioxa-2,4,6-trisilaheptane

Test animals

Species:

rat

Strain:

other: HanRcc:WIST (SPF)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: RCC Ltd., Switzerland
- Age at study initiation: 11-12 weeks
- Weight at study initiation: 176.5-199.5
- Fasting period before study:
- Housing: Individually in Makrolon type-3 cages with wire mesh tops and standard softwood bedding
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: yes, but time period not specified in report

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 0.2 g/ml

- Justification for choice of vehicle: The vehicle was chosen after a non-solubility trial which was performed before the study initiation date. This formulation trial is excluded from the statement of compliance. The test item prepared in corn oil was well-soluble.

- Lot/batch no. (if required): 18787208


MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: The animals were examined daily during the acclimation period and mortality; viability and clinical signs were recorded. All animals were examined for mortality/viability and clinical signs within the first 30 minutes and approximately 1, 2, 3 and 5 hours after treatment on day 1 and once (twice for mortality/viability) daily during test days 2-15. Body weights were recorded on test day 1 (prior to removal of food), on test days 1 (prior to administration) 8 and 15. All animals were necropsied and examined macroscopically.

- Necropsy of survivors performed: yes

Results and discussion

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

dissolved

Mortality:

All animals survived until the end of the study period.

Clinical signs:

Slightly to moderately ruffled fur was noted in all animals from the 1- or 5- hour reading up to test day 2 or 3, with 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.

Body weight:

The body weight of animals was within the range commonly recorded for this strain and age.

Gross pathology:

No macroscopic findings were recorded at necropsy.

Other findings:

None reported.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

An LD50 value of >2000 mg/kg was determined in a reliable study conducted in compliance with GLP.