Registration Dossier

Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, available as unpublished report, near guideline study, minor restrictions in design and/or reporting but otherwise adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980
Report Date:
1980

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 2-methyl-2-butene
- Physical state: Strong smelling, colourless liquid with a specific gravity of 0.66
- Stability under test conditions: Stable for duration of experiment, expiry date 1 January 1981
- Storage condition of test material: In fridge

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Shell Toxicology Laboratory, Breeding Unit, Tunstall, UK
- Age at study initiation: 10-11 weeks
- Weight at study initiation: 260-366 g males, 177-248 g females
- Fasting period before study: 18 hours
- Housing: Individually for the duration of the dermal application, 3 per cage thereafter in hanging polypropylene cages with stainless steel wire mesh floors and tops (33 x 21 x 17 cm)
- Diet: PRD (Labsure Animal Foods Ltd) ad libitum (except for the duration of the dermal application)
- Water: Filtered public supply ad libitum
- Acclimation period: 4 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 19-25 °C
- Humidity: 50-60%
- Air changes (per hr): Not reported
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 7 May 1980 To: 18 July 1980

Administration / exposure

Type of coverage:
occlusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
TEST SITE
- Area of exposure: Approximately 60% of the dorsal area.
- Preparation of skin site: 24 hours prior to application site closely shorn with electric clippers.
- Type of wrap if used: Aluminium foil held in place by a double overwrap of waterproof adhesive tape.

DOSING:
- Dose levels selected following a range-finding test in which 2 rats/sex/group were given a single dermal dose at 0.5, 1.0 or 2.0 mL/kg.
- Due to volatility of 2-methyl-2-butene, it was stored on ice, temperature of substance at dosing was approximately 5°C.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Warm dilute detergent.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 3.03 mL/kg bw.
Duration of exposure:
24 hours
Doses:
3.03 mL/kg
No. of animals per sex per dose:
6
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations daily, bodyweights initial, days 7 and 14
- Necropsy of survivors performed: no

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 3.03 mL/kg bw
Remarks on result:
other: >2000 mg/kg
Mortality:
No mortalities
Clinical signs:
Some animals bled from the nose on day 1 and many of the animals had sores and scabs on their backs
Body weight:
All animals gained weight within one week of dosing

Applicant's summary and conclusion

Interpretation of results:
practically nontoxic
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The acute dermal LD50 of 2-methyl-2-butene to male and female rats was >2000 mg/kg.
Executive summary:

The acute dermal LD50 of 2 -methyl-2 -butene to male and female rats was >3.03 mL/kg (>2000 mg/kg).