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Toxicological information

Acute Toxicity: dermal

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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other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment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 guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
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 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:
Systemic signs of reaction to treatment restricted to vocalisation in all animals 15 mins after application of the test material
Body weight:
The animals achieved anticipated bodyweight gains
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 DSD or CLP.