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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well performed GLP and OECD guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
Manganese Oxalate, dihydrate
IUPAC Name:
Manganese Oxalate, dihydrate

Test system

Amount / concentration applied:
Approximately 10 mg of the neat test item were applied to each of triplicate EPISKIN (Skinethic) tissues. In order to improve contact and to guaranty a uniform and complete coverage of the epidermis, the test material was wetted with 15 µL deionised water.
Duration of treatment / exposure:
The skin equivalents were exposed to the test item for 15 minutes. Afterwards the test items was washed off and the equivalents were incubated for further 42 hours.
Details on study design:
Approximately 10 mg of the neat test item were applied to each of triplicate EPISKIN (Skinethic) tissues. In order to improve contact and to guaranty a uniform and complete coverage of the epidermis, the test material was wetted with 15 µL deionised water.

The test item and the positive and negative controls were washed off the skin tissues after 15 minutes treatment. After further incubation for about 42 hours the tissues were treated with the MTT solution for 3 hours following approximately 69 hours extraction of the colorant from the cells. The amount of extracted colorant was determined photometrically at 570 nm.

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean of 3 runs
Value:
92.2
Vehicle controls validity:
valid
Positive controls validity:
valid
Other effects / acceptance of results:
After treatment with the test item Manganese Oxalate Dihydrate the relative absorbance values decreased slightly to 92.2%. This value is well above the threshold for irritancy of ≤ 50%. Therefore, the test item is not considered to possess an irritant potential.

Any other information on results incl. tables

Results after treatment with Manganese Oxalate Dihydrate

 

Dose group

Treat-ment Interval

Absor-bance 570 nm
Tissue 1*

Absor-bance 570 nm
Tissue 2*

Absor-bance 570 nm
Tissue 3*

Mean Absor-bance of 3 Tissues

Relative Absor-bance [%] Tissue 1, 2, 3**

Stan-dard De-viation [%]

Rel. Absor-bance

[% of Negative Control]***

Negative Control

15 min

1.079

0.873

1.021

0.991

108.9
88.1
103.0

10.7

100.0

Positive Control

15 min

0.390

0.324

0.208

0.308

39.4
32.7
21.0

9.3

31.0

Test Item

15 min

0.778

1.015

0.948

0.914

78.5
102.4
95.7

12.3

92.2

*        Mean of two replicate wells after blank correction

**      relative absorbance per tissue [rounded values]: (100 x (absorbance tissue )) / (mean absorbance negetive control)

***    relative absorbance per treatment group [rounded values]: (100 x (mean absorbancetest item)) / (mean absorbancenegetive control)

Optical evaluation of the MTT-reducing capacity of the test item after 1 hour incubation with MTT-reagent did not show blue colour.

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: OECD GHS
Conclusions:
In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item Manganese Oxalate Dihydrate is non irritant to skin.
Executive summary:

This in vitro study was performed to assess the irritation potential of Manganese Oxalate Dihydrate by means of the Human Skin Model Test.

Three tissues of the human skin model EpiSkin™ were treated with the test item, the negative or the positive control for 15 minutes.

Approximately 10 mg of the neat test item were applied to each of triplicate tissues. In order to improve contact and to guaranty a uniform and complete coverage of the epidermis, the test material was wetted with 15 µL deionised water.

The test item and the positive and negative controls were washed off the skin tissues after 15 minutes treatment. After further incubation for about 42 hours the tissues were treated with the MTT solution for 3 hours following approximately 69 hours extraction of the colorant from the cells. The amount of extracted colorant was determined photometrically at 570 nm.

10 µL of either the negative control (deionised water) or the positive control (5% Sodium lauryl sulfate) were applied to each tissue.

After treatment with the negative control the absorbance values were well within the required acceptability criterion of mean OD 0.6 till ≤1.5 for the15 minutes treatment interval thus showing the quality of the tissues.

Treatment with the positive control induced a decrease in the relative absorbance as compared to the negative control to 31.0% thus ensuring the validity of the test system.

The standard deviations between the % variabilities of the test item, the positive and negative controls were below 13% (threshold of the "OECD Guideline for the Testing of Chemicals 439: In vitro Skin Irritation: Reconstructed Human Epidermis Test Method”: 18%), thus ensuring the validity of the study.

After treatment with the test item Manganese Oxalate Dihydrate the relative absorbance values decreased slightly to 92.2%. This value is well above the threshold for irritancy of50%. Therefore, the test item is not considered to possess an irritant potential.