Hydrocarbons, C4, 1,3-butadiene-free, polymd., triisobutylene fraction

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 002

Cas Number:

25167-70-8

Molecular formula:

C8H16

Constituent 2

Reference substance name:

2,2,4-trimethylpentane

EC Number:

208-759-1

EC Name:

2,2,4-trimethylpentane

Cas Number:

540-84-1

Molecular formula:

C8H18

IUPAC Name:

2,2,4-trimethylpentane

Details on test material:

- Name of test material (as cited in study report): 2,4,4-trimethylpentene (also known as diisobutylene and diisobutene).
- Physical state: clear, colourless liquid
- Analytical purity: 95.19%
- Lot/batch No.: Batch No.2 (a 50:50 mixture of two original batches of 2,4,4-Trimethyl pentene - the details of which are as follows: Batch No. R11
supplied by Shell and Batch No, 155833 supplied by Erdolchemie).
- Expiration date of the lot/batch: 29 April 1997
- Storage condition of test material: under nitrogen, protected from light, in a cool store.

Test animals

Species:

rat

Strain:

other: CD (remote Sprague-Dawley origin)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Limited, Margate, Kent, England.
- Age at study initiation: not specified (young adult)
- Weight at study initiation (Day -1): 206-224 g (males); 205-218 g (females)
- Fasting period before study: No
- Housing: Stainless steel grid cages. Five animals of the same sex / cage.
- Diet: Complete pelleted rodent diet (RMI(E) SQC, from Special Diets Services Limited, Witham, Essex, England) ad libitum
- Water: Tap water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 18-28°C
- Humidity: 54-70%
- Air changes: at least 10/hr
- Photoperiod: 12 hrs dark / 12 hrs light):

IN-LIFE DATES: From: 11 June 1996 To: 25 June 1996

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: 5 cm x 5 cm of the dorsum
- % coverage: 10%
- Type of wrap if used: 5 cm x 5 cm gauze patch, occluded with aluminium foil. The foil was kept in place and protected by a pad of cotton wool and a
bandage of waterproof plaster and tape wrapped twice around the trunk of the body with sufficient tension to ensure the dose remained securely in place.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Site gently wiped with wet disposable tissues to remove residual test material.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg bw

Duration of exposure:

24 hours

Doses:

2000 mg/kg (limit dose)

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 and weighing: Observations made 3 times during 1st hour after application, 2 further observations during day 1, twice daily thereafter. Bodyweight recorded on the day before dosing and on Days 1, 8 and 15.
- Necropsy of survivors performed: yes (on day 15)
- Other examinations performed: none

Statistics:

Not applicable (limit test, no mortalities)

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

No mortalities

Clinical signs:

other: Systemic signs of reaction to treatment restricted to vocalisation in all animals 15 mins after application of the test material

Gross pathology:

No macroscopic abnormalities

Applicant's summary and conclusion

Interpretation of results:

other: low dermal toxicity

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

The acute dermal median lethal dosage (LD50) of 2,4,4-trimethylpentene was greater than 2000 mg/kg. 2,2,4-trimethyl pentene is considered to be of low dermal toxicity.

Executive summary:

The acute dermal toxicity of 2,4,4-trimethylpentene was assessed in a group of 5 male and 5 female CD rats exposed to 2000 mg/kg under an occlusive dressing for 24 hours. Animals were observed daily and weighed weekly during a 14 days observation period. There were no mortalities and no overt signs of toxicity. The only treatment -related finding was vocalisation in all animals 15 mins after application of the test material.

The acute dermal median lethal dosage (LD₅₀) of 2,4,4-trimethylpentene was greater than 2000 mg/kg. 2,2,4-trimethyl pentene is considered to be of low dermal toxicity and does not require classification under Dir 67/548/EEC.