Dodecamethylpentasiloxane

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 January 2009 to 10 February 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

(all male rats exceeded 300 g in body weight (mean 312.4) at time of dosing, humidity was noted to possibly exceed 70% during cleaning process)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dodecamethylpentasiloxane

EC Number:

205-492-2

EC Name:

Dodecamethylpentasiloxane

Cas Number:

141-63-9

Molecular formula:

C12H36O4Si5

IUPAC Name:

2,2,4,4,6,6,8,8,10,10-decamethyl-3,5,7,9-tetraoxa-2,4,6,8,10-pentasilaundecane

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories
- Age at study initiation: 9 weeks (males), 11 weeks (females)
- Weight at study initiation: 229.5 to 330.1 g
- Fasting period before study: no data available
- Housing: in groups of 5/sex (acclimation period), then individually (study)
- Diet (e.g. ad libitum): standard pellet diet [presumably ad libitum]
- Water (e.g. ad libitum): tap water [presumably ad libitum]
- Acclimation period: 6 days

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

IN-LIFE DATES: From: 21 January 2009 To: 10 February 2009

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: ~ 5 x 5 cm
- % coverage: ~10
- Type of wrap if used: gauze pad with semi-occlusive dressing and an elastic adhesive restrainer bandage

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 24 h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2.3 ml/kg bw (2000 mg/kg bw)
- Constant volume or concentration used: no

Duration of exposure:

24 h

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 (administered on day 1, observed until day 15)
- Frequency of observations and weighing: weighed on test days 1 (prior to administration), 8 and 15. Observed for clinical signs and mortality 30 mins, 1, 2, 3 and 5 hours, and twice daily during days 2 to 15. Dermal signs checked daily from days 2 to 15.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, gross pathology

Statistics:

No statistical analysis performed

Results and discussion

Preliminary study:

None performed

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: no signs of toxicity/mortality at this dose

Mortality:

No deaths occurred during the study

Clinical signs:

other: No clinical signs were observed during the study

Gross pathology:

No macroscopic findings reported at necropsy

Other findings:

No local signs were observed during the study

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In a GLP study conducted according to OECD Test Guideline 402, no toxic effects were observed when dodecamethylpentasiloxane (L5) was applied to the skin of rats for 24 hours at 2000 mg/kg bw. The LD50 value was determined to be greater than 2000 mg/kg bw.

Executive summary:

In a GLP study conducted according to OECD Test Guideline 402 (acute dermal toxicity), five male and five female Sprague-Dawley rats were treated with 2000 mg/kg bw undiluted dodecamethylpentasiloxane (L5), under semi-occlusive dressing, for 24 hours.

Rats were observed for 14 days after treatment for changes in body weight, clinical signs of toxicity, and signs of local toxicity at the site of application. At the end of this period of observation, rats were sacrificed and necropsy was performed to identify any gross pathological changes.

There were no signs of toxicity or mortality over the period of this study.

The acute dermal LD50 was determined to be greater than 2000 mg/kg bw.