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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2009-11-16 - 2010-02-10
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: OECD Guideline for the Testing of Chemicals, Draft Proposal for a New Guideline, In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method, Version 7.6
Deviations:
yes
Remarks:
300µL H2O was used for the pre-test instead of 30µL. The deviation was signed as uncritical, because 30µL was a tipping error in the study plan.
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Mullite
EC Number:
215-113-2
EC Name:
Mullite
Cas Number:
1302-93-8
Molecular formula:
Al6O13Si2
IUPAC Name:
Mullite

Test animals

Species:
other: human skin
Strain:
not specified
Details on test animals or test system and environmental conditions:
The EpiDermTM tissue consists of normal, human-derived epidermal keratinocytes which have been cultured to form a multi-layered, highly differentiated model of the human epidermis. It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo. The EpiDermTM tissues are cultured on specially prepared cell cultures inserts.

Test system

Type of coverage:
open
Preparation of test site:
not specified
Vehicle:
other: solid test item wetted with DPBS-buffer
Controls:
no
Amount / concentration applied:
tissue 1: 24.4 mg
tissue 2: 23.9 mg
tissue 3: 26.2 mg
Duration of treatment / exposure:
60 minutes
Observation period:
42 hours
Number of animals:
3 tissues

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
other: other: % Formazan Production Mean
Value:
113.1
Remarks on result:
other:
Remarks:
Basis: mean. Time point: 60 minutes. Max. score: 50.0. Reversibility: no data. (migrated information)

Any other information on results incl. tables

Skin irritation potential of the test item is assessed as given in the following table:

Assessment of Irritation Potential

% Formazan production

Assessment

< 50% of negative control

Irritant

> 50% of negative control

Non-irritant

For the test item and the positive control, the following percentage values of formazan production were calculated in comparison to the negative control:

 % Formazan Production

Designation

White Fused Mullite

Positive Control

% Formazan production (Tissue 1)

108.2%

9.1%

% Formazan production (Tissue 2)

112.9%

9.6%

% Formazan production (Tissue 3)

118.1%

9.6%

% Formazan production Mean

113.1%

9.4%

The relative absorbance values were increased to 113.1% after the treatment. This value is above the threshold for irritation (50%). Therefore, the test item is considered as not irritant. Validity and Acceptability

Validity criteria and results are stated in the following table:

Validity

Criterion

Demanded

Found

OD of negative control

between 1.0 and 2.5

2.010

% Formazan production of positive control

£20% of negative control

9.4

Variation within replicates (RSD)

< 18%

12.0 % (negative control)
4.4 % (positive control)
2.7 % (test item)

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test item is considered not irritant.
After the treatment, the relative absorbance values were increased to 113.1%. This value is well above the threshold for irritation (50%).

The optical density of the negative control was well within the required acceptability criterion of 1.0 < mean OD < 2.5. The positive control induced a decrease in the relative absorbance as compared to the negative control to 9.4 % (required: <= 20%) for thus ensuring the validity of the test system. Variation within replicates was within the accepted range for negative control, positive control and test item.

For these reasons, the result of the test is considered valid.
Executive summary:

The test item is considered not irritant.

After the treatment, the relative absorbance values were increased to 113.1%. This value is well above the threshold for irritation (50%).

 

The optical density of the negative control was well within the required acceptability criterion of 1.0 < mean OD < 2.5. The positive control induced a decrease in the relative absorbance as compared to the negative control to 9.4 % (required: <=20%) for thus ensuring the validity of the test system. Variation within replicates was within the accepted range for negative control, positive control and test item.

 

For these reasons, the result of the test is considered valid.

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