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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The GLP study was conducted according to an internationally accepted guideline. All study parameters are given in detail.Nevertheless, according to the ECHA's practical guide 6: "How to report read-across and categories" the maximum for read-cross is 2.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
Test material form:
other: liquid
Details on test material:
Description: clear colourless liquid
Storage conditions: ambient temperature (<25 oC), under artificial light
SAS-305 is a mixture of 3 isomeric structures.
Composition:
1-Methylethyl-4-(1-phenylethyl)benzene
1-Methylethyl-3-(1-phenylethyl)benzene
1-Methylethyl-2-(1-phenylethyl)benzene

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
Three New Zealand White rabbits supplied by David Percival Ltd, Moston, Sandbach, Cheshire, UK were used. At the start of the study the animals weighed 2.61 to 2.72 kg and were twelve to sixteen weeks old. After a minimum acclimatisation period of five days each animal was given a number unique within the study which was written with a black indelible marker-pen on the inner surface of the ear and on the cage label.

The animals were individually housed in suspended metal cages. Free access to mains drinking water and food (STANRAB SQC Rabbit Diet, Special Diets Services Ltd, Witham, Essex, UK) was allowed throughout the study.

The animal room was maintained at a temperature of 17 to 20" C and relative humidity of 46 to 65%. The rate of air exchange was approximately fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light and twelve hours darkness.

Test system

Type of coverage:
occlusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
no
Amount / concentration applied:
0.5 ml
Duration of treatment / exposure:
4 hours
Observation period:
14 days
Number of animals:
3
Details on study design:
On the day before the test each rabbit was clipped free of fur from the dorsal flank area using veterinary clippers. Only animals with a healthy intact epidermis by gross observation were selected for the study.

On the day of the test a suitable test site was selected on the back of each rabbit. A quantity of 0.5 ml of the test material was introduced under a 2.5 cm x 2.5 cm cotton gauze patch and placed in position on the shorn skin. The patch was secured in position with a strip of surgical adhesive tape (BLENDERM: approximate size 2.5 cm x 4.0 cm). To prevent the animals interfering with the patches, the trunk of each rabbit was wrapped in an elasticated corset (TUBIGRIP) and the animals were returned to their cages for the duration of the exposure period.
Four hours after application the corset and patches were removed from each animal and any residual test material removed by gentle swabbing with cotton wool soaked in 74% Industrial Methylated Spirits.

Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J H, (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.31.

Erythema and Eschar Formation Value

No erythema ....................................................................................... * 0

Very slight erythema (barely perceptible) ............................................. 1

Well-defined erythema .......................................................................;. 2

Moderate to severe erythema ............................................................... 3

Severe erythema (beet redness) to slight eschar

formation (injuries in depth) ................................................................ 4

Oedema Formation

No oedema ......................................................................................... 0

Very slight oedema (barely perceptible) ............................................... 1

Slight oedema (edges of area well-defined by definite raising) ............. 2

Moderate oedema (raised approximately 1 millimetre) ......................... 3

Severe oedema (raised more than 1 millimetre and

extending beyond the area of exposure) .............................................. 4

Any other skin reactions, if present, were also recorded.

Additional observations were made on Days 7 and 14 to assess the reversibility of skin reactions.

Results and discussion

In vivo

Results
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
mean
Time point:
other: 72
Score:
2.3
Max. score:
8
Reversibility:
not fully reversible within: 14 days

Any other information on results incl. tables

For category rationale and justification see attached category documentation under section 13 "Assessment Reports".

Applicant's summary and conclusion

Interpretation of results:
irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test material, NISSEKI SAS-305, produced a primary irritation index of 2.3 and was classified as a MODERATE IRRITANT to rabbit skin according to the Draize classification scheme. No corrosive effects were noted.The test material produced positive criteria in 2/3 rabbits according to the EU labelling regulations and was classified as IRRITANT to rabbit skin.
Executive summary:

A study was performed to assess the irritancy potential of the test material to the skin of the New Zealand White rabbit. The method used followed the recommendations of the OECD Guidelines for Testing of Chemicals No. 404 "Acute Dermal Irritation/Corrosion" (adopted 17 July 1992) and Method B4 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC). A single 4-hour, semi-occluded application of the test material to the intact skin of three rabbits produced very slight to well-defined erythema and very slight oedema. Other skin reactions noted were crust formation and moderate desquamation. Slight desquamation was noted at all treated skin sites at the 14-day observation. The test material produced a primary irritation index of 2.3 and was classified as a moderate irritant to rabbit skin according to the Draize classification scheme. No corrosive effects were noted. The test material was also classified as irritant according to EU labelling regulations.