Trisiloxane, 3-ethyl-1,1,1,3,5,5,5-heptamethyl-

Endpoint summary

Description of key information

The substance was tested according to OECD guidelines 423 (oral), 403 (inhalation) and 402 (dermal). No adverese effects were observed in the three studies.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 March to 25 March 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

17 December 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 (Acute Toxicity (Oral))

Version / remarks:

30 September 1996

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

Specific density: 828 g/L at 20°C
Storage condition: ambient temperature

Species:

rat

Strain:

Wistar

Remarks:

Crl: (WI) WU BR

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 7 - 8 weeks
- Weight at study initiation: 166 -180 g
- Fasting period before study: Prior to dosing, fasted overnight until approx. 4h after dosing
- Housing: maximum of six animals per macrolon cage
- Diet (e.g. ad libitum): standard laboratory diet ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: 13 days

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

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

Administered dose volume: 2.42 mL/kg bw

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

6

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations 1h, 4h after dosing, subsequently daily; weighing on day 0, 3, 7 and 14
- Necropsy of survivors performed: yes

Statistics:

Not conducted

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

not determinable due to absence of adverse toxic effects

Mortality:

no mortality

Clinical signs:

other: no clinical signs (with exception of tremors in 3 animals 1 hour after dosing only)

Gross pathology:

no findings

Table 1: Acute oral toxicity of the test item in rats, individual and mean body weights, doses amounts applied and mortality

Animal no	Dose applied [mL]	Body weights [g] recorded on day:				Mortality [dead/survived]
		0	3	7	14
2000mg/kg bw (first group)
41	0.43	180	195	197	207	--
43	0.42	174	186	194	212	--
45	0.41	169	186	189	201	--
mean		174	189	193	203	0/3
2000mg/kg bw second group)
59	0.4	166	183	187	198	--
61	0.41	170	190	197	213	--
63	0.43	180	196	205	210	--
		172	190	196	207	0/3

Interpretation of results:

GHS criteria not met

Conclusions:

The LD50 for oral toxicity to female rats was determined to be > 2000 mg/kg bw. The substance is not classified according to CLP criteria.

Executive summary:

The acute oral (gavage) toxicitity of heptamethylethyltrisiloxane was investigated in female Wistar derived rats at a dose level of 2000 mg/kg bw followed by a 14 day observation period. The test substance was dosed undiluted. There were no deaths at 2000 mg/kg bw, therefore no further testing was required. There were no treatment related clinical signs, and all animals gained bodyweight during the observation period. Examination at necropsy revealed no effects of the test substance.

The acute oral median lethal dose (LD₅₀) of heptamethylethyltrisiloxane in rats was found to be greater than 2000 mg/kg bw therefore the substance is not classified according to CLP criteria.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003-07-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

GLP compliance:

yes

Limit test:

yes

Specific details on test material used for the study:

Batch/lot number:Taf 002
Purity >95%
Density 828 g/L

Species:

rat

Strain:

Wistar

Remarks:

Crl:(WI) WU BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 5 - 6 weeks
- Mean weight at study initiation: male: 215 g female: 160 g
- Housing: individually during exposure, 5 per cage during 14 days observation (divided by sex)
- Diet (e.g. ad libitum): ad libitum, except during exposure
- Water (e.g. ad libitum): ad libitum, except during exposure
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature: 21,6 +/- 0.2°C
- Humidity: 64 +/- 1%
- Air changes (per hr): 10
- Photoperiod (dark/light): 12 h/12 h

Route of administration:

inhalation: vapour

Type of inhalation exposure:

nose only

Vehicle:

other: humidified air

Remark on MMAD/GSD:

N/A test substance tested as vapour

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose only inhalation chamber
- Exposure chamber volume: ca 50 L
- Method of holding animals in test chamber: Battelle plastic animal holders
- Source and rate of air: compressed dry air and 16.6 L/min
- Method of conditioning air: humidifier
- System of generating particulates/aerosols: N/A test substance tested as vapour
- Method of particle size determination: N/A test substance tested as vapour
- Treatment of exhaust air: filter
- Temperature, humidity, pressure in air chamber: 21.6 +/-0.1°C, 55 +/-1%, not reported except that positive pressure was maintained in chamber

TEST ATMOSPHERE
- Brief description of analytical method used: test atmosphere was sampled by passing metered amounts of test atmosphere through a cascade of a primary and secondary impinger filled with methanol. Samples were analysed after dilution with water. The concentration of test material in the impinger solution was determined by measuring the concentration of elemental Si using ICP-AES
- Samples taken from breathing zone: no

VEHICLE
- Composition of vehicle (if applicable): N/A
- Concentration of test material in vehicle (if applicable): N/A
- Justification of choice of vehicle: N/A
- Lot/batch no. (if required): N/A
- Purity: N/A

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: N/A
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): N/A

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: N/A

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

10.0 +/- 0.4 g/m3 (highest attainable concentration)

No. of animals per sex per dose:

5

Control animals:

no

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 10 mg/L air

Exp. duration:

4 h

Mortality:

Male: 10 mg/L; Number of animals: 5; Number of deaths: 0
Female: 10 mg/L; Number of animals: 5; Number of deaths: 0

Clinical signs:

other: Signs of toxicity related to dose levels: Although observation of the rats was limited during exposure due to the stay in restraining tubes, a slightly decreased breathing rate was observed in all animals at all four (approximately hourly) observation

Body weight:

Although body weight gain in male animals was slightly lower in the first than in the second week, overall, body weight gain was as expected for animals of this strain and age.

Gross pathology:

At necropsy, macroscopic abnormalities consisted of petechiae on the lobes of the lungs in three male animals. In one male animal petechiae were seen on one lobe and in two male animals these petechiae were seen on all lobes.

Interpretation of results:

GHS criteria not met

Conclusions:

There were no mortalities in male and female rats following a 4-hour nose-only exposure to heptamethylethyltrisiloxane at the maximum attainable concentration of 10 g/m3. Therefore the LC50 of vapour of heptamethylethyltrisiloxane >10 g/m3 for both sexes

Executive summary:

In an acute inhalation study, groups of Wistar derived rats (5/sex) were exposed by the inhalation route (nose-only) for a single 4-hour period to the maximium attainable concentration of 10 g/m3 heptamethylethyltrisiloxane vapour. Following exposure, animals were observed for 14 days. No mortalities occurred. Shortly after exposure cinical signs consisted of red/brown discolouration of the head in all female animals. No other treatment related clinical signs of toxicity were observed. Body weight gain was within limits of that expectd for animals of this age and strain. At necropsy, macroscopic changes were limited to petechiae seen on one or more lobes of the lungs in three male animals. Under the conditions of this study the rat acute inhalation 4 hour nose-only body LC₅₀was >10 g/m3 in males and females.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

> 10 mg/L air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 Oct 2016 - 17 Oct 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

24 February 1987

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Remarks:

RccHAN (TM); WIST

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 8 to 12 weeks
- Weight at study initiation: at least 200g, weight variation did not exceed +/- 20% of the mean weight for each sex
- Housing: individually during 24h exposure period, in groups of 5, by sex, for the remainder of the study
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19 - 25°C
- Humidity: 30 - 70%
- Air changes (per hr): 15
- Photoperiod (dark / hrs light): 12h/12h

IN-LIFE DATES: From: 03 Oct 2016 To: 17 Oct 2016

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: back and flanks
- % coverage: approx. 10%

REMOVAL OF TEST SUBSTANCE
- Washing (if done): treated skin and surrounding hair wiped with cotton wool moistened with distilled water
- Time after start of exposure: 24h

TEST MATERIAL
- Amount applied: 2.44mL/kg bw

Duration of exposure:

24h

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 observation after dosing: 30min, 1, 2, 3 and 4 h and subsequently daily for 14 days, body weights recorded on days 0, 7 and 14
Evaluation of skin reactions: after removal of dressing and subsequently once daily for 14 days
- Necropsy of survivors performed: yes

Statistics:

Not performed

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

no indication of skin irritation up to the relevant limit dose level

Mortality:

no mortality observed

Clinical signs:

other: no signs of systemic toxicity observed

Gross pathology:

no abnormalities were noted at necropsy

table1: results male

male animal nr		observation time
		1-7d	8-14d
1-0	erythema	0	0
	edema	0	0
1-1	erythema	0	0
	edema	0	0
1-2	erythema	0	0
	edema	0	0
1-3	erythema	0	0
	edema	0	0
1-4	erythema	0	0
	edema	0	0

table 2: results female

female animal nr		observation time
		1-7d	8-14d
2-0	erythema	0	0
	edema	0	0
2-1	erythema	0	0
	edema	0	0
2-2	erythema	0	0
	edema	0	0
2-3	erythema	0	0
	edema	0	0
2-4	erythema	0	0
	edema	0	0

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2000 mg/kg bw.
The test item does not meet the criteria for classification according to the Globally Harminized System of Classification and labelling of Chemicals.

Executive summary:

The acute dermal toxicity of heptamethylethyltrisiloxane was investigated in male and female RccHan:WIST rats at a dose level of 2000 mg/kg bw (24 hour exposure) followed by a 14 day observation period. There were no deaths at 2000 mg/kg bw. There were no treatment related clinical signs, nor effects on bodyweight gain with the exception of 2 females during the first week of observation. Histopathological examination revealed no effects of the test substance.

The acute dermal median lethal dose (LD₅₀) of heptamethylethyltrisiloxane in rats was found to be greater than 2000 mg/kg bw

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Justification for classification or non-classification

According to CLP (1272/2008/EC) classification criteria for acute toxicity, no classification is warranted.