Mullite

Skin irritation / corrosion

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

Test material information

Constituent 1

Reference substance name:

Mullite

EC Number:

215-113-2

EC Name:

Mullite

Cas Number:

1302-93-8

Molecular formula:

Al6O13Si2

IUPAC Name:

Mullite; Al6O13Si2

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.