Registration Dossier

Administrative data

Endpoint:
skin irritation: in vivo
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other: Non-GLP, available as unpublished report, near guideline study, minor restrictions in design and/or reporting but otherwise adequate for assessment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 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
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:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Shell Toxicology Laboratory, Breeding Unit, Tunstall, UK
- Age at study initiation: 4-6 months
- Weight at study initiation: 2982-4208 g males, 3930-4915 g males
- Housing: Individually in hanging stainless steel cages with all mesh floors and tops and half mesh fronts (58 x 43 x 43 cm)
- Diet: SG1 with vitamin C supplement (Grain Harvesters Ltd.) ad libitum
- Water: Filtered public water ad libitum.
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature: 16-19 °C

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

Test system

Type of coverage:
occlusive
Preparation of test site:
other: closely shorn. One site abraded and one site intact
Vehicle:
unchanged (no vehicle)
Controls:
no
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL
Duration of treatment / exposure:
24 hours
Observation period:
7 days
Number of animals:
3 males and 3 females
Details on study design:
TEST SITE
- Area of exposure: 2cm x 2 cm
- Type of wrap if used: 2 cm x 2 cm lint patch, occluded by an impervious polythene sheet held in place with elastic adhesive bandage

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Not washed
- Time after start of exposure: Dressings removed after 24 hours

SCORING SYSTEM: Graded scale of 0-4 for both erythema and oedema

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 24, 48 and 72 hours
Score:
0.8
Remarks on result:
other: non-abraded skin sites only
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 24, 48 and 72 hours
Score:
0.6
Remarks on result:
other: non-abraded skin sites only
Irritation parameter:
other: Primary irritation score (according to Draize)
Basis:
mean
Score:
1.79
Reversibility:
not fully reversible within: 7 days
Remarks on result:
other: mildly irritating to skin (grade 4)
Irritant / corrosive response data:
Application sites at day 7 were dry and flaking.

Any other information on results incl. tables

Table1: Individual and mean skin irritation scores of 2-methyl-2-butene (non-abraded skin) according to the Draize scheme

Time

Erythema

Oedema

Animal number

1564F

1565F

1573F

1574M

1576M

1575M

1564F

1565F

1573F

1574M

1576M

1575M

after 24 hours

1

1

0.5

1

0

0

1

0.5

0.5

1

0

0

after 48 hours

1.5

2

0.5

1

0

0

1

1

0.5

1

0

0

after 72 hours

1.5

2

1

1

0

0

1

1

1

1

0

0

mean score 24-72 h

0.8

0.6

after 7 days

2

2

1

2

0

0

1

1

1

2

0

0

 

Table2: Individual and mean skin irritation scores of 2-methyl-2-butene (abraded skin) according to the Draize scheme

Time

Erythema

Oedema

Animal number

4915

3930

4155

4208

4030

3074

4915

3930

4155

4208

4030

3074

after 24 hours

1

1

1

2

1

0.5

1

0.5

0.5

1

0.5

0

after 48 hours

1.5

2

1.5

2

1

0.5

1

1

0.5

1

0.5

0

after 72 hours

2

2

2

2

1

0.5

1

1

0.5

1

0.5

0

mean score 24-72 h

1.4

0.6

after 7 days

2

2

2

2

1

0.5

1

1

1

2

0

0

 

Applicant's summary and conclusion

Interpretation of results:
slightly irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
2-methyl-2-butene was mildly irritating to rabbit skin (grade 4).
Executive summary:
2-methyl-2-butene was mildly irritating to rabbit skin (grade 4).