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Toxicological information

Skin irritation / corrosion

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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:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1977
Report date:
1977

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: Federal Hazardous Substances Act , September 27, 1973
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
4-methylstyrene
EC Number:
210-762-8
EC Name:
4-methylstyrene
Cas Number:
622-97-9
Molecular formula:
C9H10
IUPAC Name:
1-methyl-4-vinylbenzene
Test material form:
liquid
Details on test material:
- Name as cited in study report: MCTR-243-77

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
New Zealand White rabbits weighing 2.05 to 2.15 kg.

Test system

Type of coverage:
open
Preparation of test site:
other: abraded and non-abraded site on each rabbit
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
Single dermal application of 0.5 mL to clipped and abraded rabbit skin. No occlusion. Not stated if wash off performed.
Duration of treatment / exposure:
Single application. 24 h exposure.
Observation period:
Observed at 24 and 72 h. Primary Index calculated.
Number of animals:
3 male and 3 female
Details on study design:
The site of application was clipped and abraded on all rabbits. Observations were made at 24 and 72 h following application for signs of irritation and corrosivity. Irritation scores were recorded and the primary index was calculated. The test substance was applied to the backs and occlusive wrap was not used because the test substance reacted with the dental dam creating unwanted variable. The rabbits were restrained by being put in a Newman harness for the 24 h initial exposure.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
mean
Time point:
other: 24 and 72 h
Score:
1.5
Reversibility:
other: reversibility not investigated
Irritation parameter:
erythema score
Basis:
animal: 1-6
Time point:
24 h
Score:
1.5
Max. score:
2
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: for both intact and abraded skin
Irritation parameter:
edema score
Basis:
animal: 1-6
Time point:
24 h
Score:
0.3
Max. score:
1
Reversibility:
fully reversible within: 72 h
Remarks on result:
other: for both intacts and abraded skin
Irritation parameter:
erythema score
Basis:
animal: 1-6
Time point:
48 h
Remarks on result:
not measured/tested
Irritation parameter:
edema score
Basis:
animal: 1-6
Time point:
48 h
Remarks on result:
not measured/tested
Irritation parameter:
erythema score
Basis:
animal: 1-6
Time point:
72 h
Score:
1
Max. score:
2
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: for noth intact and abraded skin
Irritation parameter:
edema score
Basis:
animal: 1-6
Time point:
72 h
Score:
0
Max. score:
1
Reversibility:
fully reversible
Remarks on result:
other: for both intact and abraded skin
Irritant / corrosive response data:
Well defined erythema (score 2) in 3/6 rabbits with very slight edema (score 1) in other 3/6 rabbits was apparent at 24 h. At 72 h only very slight erythema (score 1) and edema (score 1) remained.
Mean value of > 1.5 - < 2.3 for erythema/eschar or for oedema from gradings in at least 2 of 3 tested animals from grades at 24, 48 and 72 h or, if reactions are delayed, from grades on 3 consecutive days after the onset of dermal reactions (when not included in the irritant category above).
In this study reactions were only measured at 24 and 72 h. However, at 24 hurs 3/6 animals had a score of 2 for erythema and 3/6 a score of 1. At 24 h 6/6 had a score of 1. Therefore the mean score for 3/6 rabbits is 1.5

Applicant's summary and conclusion

Conclusions:
Under the study conditions, the calculated primary index for the test substance was 1.5.
Executive summary:

A study was conducted to determine the skin irritation/corrosion potential of the test substance in rabbits following a single dermal exposure according to Federal Hazardous Substances Act, September 27, 1973. Six New Zealand White rabbits (2.05 to 2.15 kg) were dosed dermally with a single application of 0.5 mL of the test substance. The site of application was clipped and abraded on all rabbits. Observations were made at 24 and 72 h following application for signs of irritation and corrosivity. Irritation scores were recorded and the primary index was calculated. The test substance was applied to the backs and an occlusive wrap was not used. Reactions were only measured at 24 and 72 h. At 24 h, 3/6 animals had a score of 2 for erythema and 3/6 a score of 1. At 24 h, 6/6 had a score of 1. Under the study conditions, the calculated primary index for the test substance was 1.5 (Adamik, 1997).