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Diss Factsheets

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
supporting 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other: Non-GLP, available as unpublished report, near guideline study, minor restrictions in design and/or reporting but otherwise adequate for assessment
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
no
Type of study:
guinea pig maximisation test
Species:
guinea pig
Strain:
other: Shell Toxicology Unit 'P' strain
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Shell Toxicology Laboratory Breeding Unit
- Age when received: 8-12 weeks
- Weight at study initiation: males 439 - 700 g and females 337- 596 g
- Housing:Five animals per cage in hanging-stainless steel cages with all mesh floors and tops and half mesh fronts (43 x 36 x 36 cm)
- Diet: SG1 with vitamin C supplement (Grain Harvesters Ltd) ad libitum
- Water:Flitered public water ad libitum
- Acclimation period: not reported

ENVIRONMENTAL CONDITIONS: not reported
-
IN-LIFE DATES: From: 7 May 1980 To: 18 July 1980
Route:
intradermal and epicutaneous
Vehicle:
corn oil
Concentration / amount:
Intradermal induction: 0.01% w/v; topical induction 50% w/v, topical challenge 25% w/v
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
Intradermal induction: 0.01% w/v; topical induction 50% w/v, topical challenge 25% w/v
No. of animals per dose:
10 males and 10 females test group, 5 males and 5 females control group.
Details on study design:
RANGE FINDING TESTS:
2 male and 2 female guinea pigs/group tested with intradermal injection at 0.05, 0.1, 0.5 and 1.0 % w/v 2-methyl-2-butene in corn oil. 2 male and 2 female guinea pigs/group treated with a topical application of 100%, 50% or 25% 2-methyl-2-butene in corn oil.

MAIN STUDY
A. INDUCTION EXPOSURE
Test animals:
2 x 0.1mL injections of Freund's complete adjuvant (FCA)
2 x 0.1 mL injections of TS in corn oil
2 x 0.1 mL injections of TS in 50:50 FCA/corn oil
Control animals:
2 x 0.1mL injections of Freund's complete adjuvant (FCA)
2 x 0.1 mL injections of corn oil
2 x 0.1 mL injections of 50:50 FCA/corn oil

B. CHALLENGE EXPOSURE
Topical challenge of test and control animals was carried out two weeks after the topical induction with 0.15 mL of a 25% w/v preparation of 2-methyl-2-butene in corn oil. After 24 hours the patch was removed and the site was examined for response, immediately, 24 hours and 48 hours after removal. The responses were scored using a standard four point scale.
Reading:
1st reading
Hours after challenge:
0
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 0.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
other: 3rd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
0
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 0.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
24
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
other:
Hours after challenge:
48
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: other:. . Hours after challenge: 48.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0.
Interpretation of results:
not sensitising
Conclusions:
2-methyl-2-butene is not a sensitiser to guinea pig skin.
Executive summary:

2-methyl-2-butene is not a sensitiser to guinea pig skin.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Non-human information

There are no relevant studies available for isoprene. However, the skin sensitization potential of 2-methyl-2 -butene (2M2B), which is structurally similar to isoprene, was assessed using the guinea-pig maximization method of Magnusson and Kligman (1969).  None of the animals showed any positive reactions 24 or 48 hours after the removal of the challenge patch (SRC, 1980).  Thus, it can be concluded that isoprene is not expected to be a skin sensitiser in guinea pigs.

Results from QSAR Toolbox show that no protein binding alerts for skin sensitisation according to GHS and by OASIS are found. The QSAR results suggest that isoprene should be "not classified" for skin sensitisation.

Human information

No information is available to assess skin sensitisation in humans.


Short description of key information:
There are no relevant animal or human studies available for isoprene.. However, 2M2B, which is structurally similar to isoprene, has been shown not to be a skin sensitiser in guinea pigs. Thus, isoprene is expected not to be a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Non human information

There are no specific animal studies to assess respiratory sensitisation but a wide range of inhalation studies in a number of animal species have shown no evidence of respiratory sensitisation potential.

 

Human information

No information is available to assess respiratory sensitisation in humans.

Short description of key information:
There are no standardized test methods to assess respiratory sensitisation. However, results from existing animal studies do not show any evidence of respiratory sensitisation from the. No information is available to assess respiratory sensitisation in humans.

Justification for classification or non-classification

There are no animal studies on isoprene; however, a structurally-similar substance, 2-methyl-2-butene, was shown to be non-sensitising in a guideline skin sensitisation study in animals. It is concluded that no classification is warranted under CLP.

Since there is no evidence for respiratory sensitisation in a range of inhalation studies in various animal species, isoprene is considered not to warrant classification under CLP.