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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:
other: Comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
: longer duration of exposure (24 versus 4 hours); limited details on test material and test conditions
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): aluminium oxide (TBH) coded AK 43/79
-purple coloured solid
- Analytical purity: no data

Test animals

Species:
rabbit
Strain:
New Zealand White

Test system

Type of coverage:
semiocclusive
Preparation of test site:
other: intact or abraded skin
Vehicle:
not specified
Controls:
no
Amount / concentration applied:
0.5 g of the solid test substance was brought into contact with the intact or abraded skin under a surgical patch measuring 1 inch Χ 1 inch.
Duration of treatment / exposure:
24 hours
Observation period:
24 hours and 72 hours after the substance application
Number of animals:
6 rabbits were treated on intact skin and 6 on abraded skin.
Details on study design:
TEST SITE
- Area of exposure: the hair was removed from the backs of the animals with an electric clipper avoiding abrasions. The test material was placed under a surgical patch 1 inch Χ 1 inch (2.5 cm Χ 2.5 cm) on intact or abraded skin.
- Type of wrap if used: surgical patch. The patches were fixed to the application site with adhesive tape. The entire trunk of the animals was wrapped with an impervious material to keep the patches in place.


SCORING SYSTEM: Draize scoring system


The abrasions were “minor incisions through the stratum corneum, but not sufficiently deep to disturb the derma or to produce bleeding.”

The patches were fixed to the application site with adhesive tape. The entire trunk of the animals was wrapped with an impervious material to keep the patches in place

After exposure for 24 hours, the patches and the test material were removed (no information was provided on washing of the skin after patch removal.)

Skin lesions were evaluated at the time of patch and material removal and 48 hours later (24 and 72 hours after the application)

Scoring systems applied:
-24 hours after application -method of Draize (J. Pharmocol. 82 (1944) 377-390).
-72 hours after application – CIVO grading system (because the Draize scoring system does not describe scaliness and necrosis)

Evaluation of skin reactions (Draize, 1944) Value
A. Erythema and eschar formation

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

B. Edema formation

No edema 0
Very slight edema (barely perceptible) 1
Slight edema (edges of area well defined by definite raising) 2
Moderate edema (raised approximately 1 mm) 3
Severe edema (raised more than 1 mm and extending beyond the area of exposure) 4

Evaluation of skin reactions (CIVO) Value
No reaction at all 0
Very slight scaliness 1
Distinct scaliness or very slight incrustation 2
Distinct incrustation 3
Severe incrustation 4

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
mean
Remarks:
6/6
Time point:
other: 24, 48 and 72h
Score:
0.166
Max. score:
4
Reversibility:
other: not reported
Irritation parameter:
edema score
Basis:
mean
Remarks:
6/6
Time point:
other: 24, 48 and 72 hours
Score:
0
Max. score:
4
Irritant / corrosive response data:
Overall, the test material caused slight erythema in 2 of the 12 rabbits (one - 24 hours after application, and the other - 72 hours after application).
Other effects:
Clinical signs of toxicity were not reported

Any other information on results incl. tables

Individual and average skin reaction scores

1)     Intact skin

--------------------------------------------------------------------------------------------

Rabbit number                           24 hour          72 hour

                                                   A-B                                A-B

---------------------------------------------------------------------------------------------

8416                                             0-0                                 0-0

8417                                             0-0                                 0-0

8418                                             0-0                                 1-0

8419                                             0-0                                 0-0

8420                                             1-0                                 0-0

8421                                             0-0                                 0-0

--------------------------------------------------------------------------------------------

Average                                         0.2                                 0.2

--------------------------------------------------------------------------------------------

 

2)     Abraded skin

--------------------------------------------------------------------------------------------

Rabbit number                           24 hour                             72 hour

                                                   A-B                               A-B

---------------------------------------------------------------------------------------------

8410                                             0-0                                0-0

8411                                             0-0                                0-0

8412                                             0-0                                0-0

8413                                             0-0                                0-0

8414                                             0-0                                0-0

8415                                             0-0                                0-0

--------------------------------------------------------------------------------------------

Average                                         0.0                                 0.0

--------------------------------------------------------------------------------------------

A – erythema; B – edema

 

Overall, the test material caused slight erythema in 2 of the 12 rabbits (one - 24 hours after application, and the other - 72 hours after application). Conclusion: Due to the slight character of the observed effects the test substance does not have to be classified according to the criteria of the DSD and the CLP regulation.

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information The applicant’s interpretation of the results are in accordance with the conclusions of the study authors - “AK 43/79 [the code of the test material] caused slight erythema in 2/12 rabbits and is, therefore, not considered to be a primary skin irritant.” Criteria used for interpretation of results: EU
Conclusions:
The observed slight erythema effects do not lead to a classification for the test item. Therefore AK 43/79 is not considered to be a primary skin irritant.
Executive summary:
This study conducted for Degussa corporation investigated dermal irritation effects of aluminium oxide in New Zealand White albino rabbits. 0.5 g of the test substance was placed on the intact or abraded skin of the rabbits under a surgical patch measuring 2.5 Χ 2.5 cm. Six rabbits had intact skin and six rabbits abraded skin. The exposure continued for 24 hours (a 4 hour exposure is recommended by OECD 404), and skin lesions were scored immediately after patch removal and 48 hours later (24 and 72 hours after the application of the test material). Two sets of scoring criteria were used: Draize (1944) - 24 hours after the material application and CIVO - 72 hours after the application. 

Insufficient information was provided on the test material and in what form it was applied to the skin. No information was provided on animal husbandry. Slight erythema was observed on the intact skin of 2 animals (one 24 hours after the substance application and the other 72 hours after application). No signs of skin irritation were observed on the abraded skin at any time. The overall primary irritation score from the study (0.2) would not lead to classification.