p-tert-butylstyrene

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1977

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

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Federal Hazardous Substances Act , September 27, 1973

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Vinyltoluene

EC Number:

246-562-2

EC Name:

Vinyltoluene

Cas Number:

25013-15-4

Molecular formula:

C9H10

IUPAC Name:

Ethenylmethylbenzene

Test material form:

liquid

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. Not stated if wash off performed.

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

Results

Results 1

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24 and 72 h

Score:

1.5

Reversibility:

other: reversibility not investigated

Results 2

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

Results 3

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 intact and abraded skin

Results 4

Irritation parameter:

erythema score

Basis:

animal: 1-6

Time point:

48 h

Remarks on result:

not measured/tested

Results 5

Irritation parameter:

edema score

Basis:

animal: 1-6

Time point:

48 h

Remarks on result:

not measured/tested

Results 6

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

Results 7

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. The calculated primary index for the test substance was 1.5. Under the study conditions, the test substance was determined to be mild irritant (WIL, 1977).