Reaction mass of 4-tert-butyl-2,5-xylenol and 6-tert-butyl-2,4-xylenol

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 November 2007 - 11 December 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Meets the requirements of GLP. There are no deviations from the recommended guideline.

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:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

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:

6-tert-butyl-2,4-xylenol

EC Number:

217-533-1

EC Name:

6-tert-butyl-2,4-xylenol

Cas Number:

1879-09-0

Molecular formula:

C12H18O

IUPAC Name:

2-tert-butyl-4,6-dimethylphenol

Test material form:

liquid

Test animals

Species:

rabbit

Strain:

Himalayan

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: LPT Laboratory of Pharmacology and Toxicology GmbH & Co. KG branch Löhndorf 24601 Löhndorf/Post Wankendorf, Germany
- Age at study initiation: approx. 3.5 - 9 months
- Weight at study initiation: Males: 2.1 - 3.0 kg; Females: 2.1 - 2.9 kg
- Housing: singly in cages with dimensions of 380 mm x 425 mm x 600 mm
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: At least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20°C ± 3°C
- Humidity (%): 55% ± 15%
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light (

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Remarks:

(Aqua ad iniectabilia)

Details on dermal exposure:

TEST SITE
- Area of exposure: shaved intact dorsal skin
- % coverage: approx. 15 cm x 15 cm, 1/10 of body surface
- Type of wrap if used: The gauze was covered with a plastic sheet and secured with adhesive plaster on the application site.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): At the end of the exposure period no residual item had to be removed.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.469 mL/kg b.w.

VEHICLE
Aqua ad iniectabilia for the dose levels of 50 and 200 mg/kg b.w.
Used as supplied for the dose level of 450 mg/kg b.w.

Duration of exposure:

24 hours

Doses:

50, 200 and 450 mg/kg b.w.

No. of animals per sex per dose:

3 animals per sex and per dose.

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations were performed before and immediately, 5, 15, 30 and 60 min, as well as 3, 6 and 24 hours after administration. All surviving animals were observed for a period of 14 days (at least once per day). Individual body weights were recorded before administration of the test item and thereafter in weekly intervals up to the end of the study and at death.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:
Clinical signs: changes of skin and fur, eyes and mucous membranes, respiratory and circulatory function, autonomic and central nervous system and somatomotor activity and behaviour pattern, tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma. The skin was observed for the development of erythema and oedema and was rated according to OECD 404.
Body weight: Individual body weight, changes in weight.
Necropsy: All gross pathological changes were recorded.

Statistics:

The LD50 was calculated according to FINNEY (Probit analysis).

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

205 mg/kg bw

Based on:

test mat.

Remarks on result:

other: recalculated for the substance from LD50 = 150 mg/kg b.w.

Mortality:

A single dermal administration of 450 mg/kg b.w. caused death in all 3 of 3 male and 3 of 3 female animals within 24 hours after administration.
A single dermal administration of 200 mg/kg b.w. caused death in all 3 of 3 male and 2 of 3 female animals within 48 hours after administration.
A single dermal administration of 50 mg/kg b.w. did not reveal any signs of toxicity. No mortality did occur.

Clinical signs:

other: No clinical signs were observed.

Gross pathology:

No pathological findings.

Other findings:

No skin reactions were observed.

Applicant's summary and conclusion

Interpretation of results:

other: Category 3 (CLP Regulation EC no. 1272/2008)

Conclusions:

The LD50 was determined to be 205 mg/kg b.w. by dermal route in rabbits.

Executive summary:

An acute dermal toxicity study in rabbits was performed according to EU method B3 and OECD Guideline 402 (GLP study). 3 rabbits per sex and dose were exposed to dose levels of 50, 200 and 450 mg/kg b.w. The test item was applied once for 24 hours on the shaved intact dorsal skin of rabbits (approx. 15 cm x 15 cm, 1/10 of body surface). This treatment was followed by an observation period of 2 weeks. Under the test conditions, a single dermal administration of 450 mg/kg b.w. caused death in all 3 of 3 male and 3 of 3 female animals. All animals died prematurely within 24 hours after administration. A single dermal administration of 200 mg/kg b.w. caused death in all 3 of 3 male and 2 of 3 female animals. These animals died prematurely within 48 hours after administration. A single dermal administration of 50 mg/kg b.w. did not reveal any signs of toxicity. No mortality did occur. All surviving animals gained the expected body weight throughout the whole study period. No clinical signs non skin reactions were observed. No pathological findings were recorded. The LD50 of the test item was determined to be 150 mg/kg b.w. Based on these results the LD50 for the substance reaction mass of 2-tert-butyl-4,6-dimethylphenol and 4-tert-butyl-2,5-dimethylphenol was determined to be 205 mg/kg b.w. by dermal route in rabbits.