Di-tert-butyl 1,1,4,4-tetramethylbut-2-yn-1,4-ylene diperoxide

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2003-01-15 to 2003-01-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(June 1996)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

(July 2000)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Di-tert-butyl 1,1,4,4-tetramethylbut-2-yn-1,4-ylene diperoxide

EC Number:

213-944-5

EC Name:

Di-tert-butyl 1,1,4,4-tetramethylbut-2-yn-1,4-ylene diperoxide

Cas Number:

1068-27-5

Molecular formula:

C16H30O4

IUPAC Name:

2,5-bis(tert-butylperoxy)-2,5-dimethylhex-3-yne

Test material form:

liquid

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Wistar strain Crl:(WI) BR (outbred, SPE-Quality)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: Young adult animals (approx. 8 weeks old)
- Weight at study initiation: Body weight variation did not exceed ± 20 % of the sex mean
- Housing: Animals were individually housed in labbelled Macrolon cages (type III, height 15 cm) containing purified sawdust as bedding material (SAWI, Jelu Werk, Rosenberg, Germany).
- Identification: Earmark
- Diet: Free access to standard pelleted laboratory animal diet (from Altromin (code VRF 1), Lage, Germany)
- Water: Free access to tap-water.
- Acclimation period: At least 5 days before start of treatment under laboratory conditions.

ENVIRONMENTAL CONDITIONS
- Temperature: 21 ± 3 °C
- Humidity: 30 - 70 %
- Air changes: 15 per hour
- Photoperiod: 12 hours artificial fluorescent light and 12 hours dark per day.

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Method: dermal application
- Area of exposure: One day before exposure (day -1) an area of approximately 5x7 cm on the back of animal was clipped.
- % coverage: The test substance was applied in an area approx. 10 % of the total body surface, i.e. approx. 25 cm² for males and 18 cm² for females.
- Type of wrap: The test substance was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1D, Laboratoires Stella s.a., Liege, Belgium (surgical gauze) and 3M, St. Paul, minnesota, U.S.A. (Caban & Micropore)), successively covered with aluminium foil and Coban flexible bandage. A piece of Micropore tape was additionaly used for fixation of the bandages in females only.

REMOVAL OF TEST SUBSTANCE
- Washing: the dressing were removed and the skin were cleaned of residual test substance using tap water
- Time after start of exposure: 24 hours

Duration of exposure:

24 hours

Doses:

single dosis of 2000 mg/kg (2.27 mL/kg) body weight

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 15 days
- Frequency of observations:
Mortality/Viability: Twice daily
Body weights: Day 1 (pre-administration), 8 and 15
Clinical signs: At periodic intervals on the day of sosing (day 1) and once daily therafter, until day 15.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Statistics:

No statistical analysis was performed.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred.

Clinical signs:

other: Hunched posture and chromodacryorrhoea were observed in the majority of animals. Lethargy and ptosis were observed in one male. The animals had recovered from the symptoms by day 3. Erythema and scales were seen in the treated skin-area among the females

Gross pathology:

No abnormalities were found at macroscopic post mortem examinations of the animals.

Any other information on results incl. tables

Protocol Deviations: Deviations from the maximum level for relative humidity (with a maximum of 20 %) occurred which might have been caused by cleaning procedures in the room. Since there were no indications that the animals were influenced by this deviation, this deviation was considered not to have affected the study integrity.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the present study, a dermal LD50 of the test substance in Wistar rats was establiehed to exceed 2000 mg/kg bw.

Executive summary:

In an acute dermal toxicity study according to OECD guideline 402, the test substance was administered to five Wistar rats of each sex (females were nulliparous and non-pregnant) by dermal application at 2000 mg/kg body weight for 24 hours. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice (day 15).

No mortality occured. Hunched posture and chromodacryorrhoea were observed in the majority of animals. Lethargy and ptosis were observed in one male. The animals had recovered from the symptoms by day 3. Erythema and scales were seen in the treated skin-area among the females from days 2 to 7. The body weight gain during the observation period was within the range expected for rats used in this type of study. No abnormalities were found at macroscopic post mortem examination of the animals. The dermal LD50 value of the test item in Wistar rats was established to exceed 2000 mg/kg body weight.