Manganese dioxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-10-13 to 2009-10-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Manganese dioxide

EC Number:

215-202-6

EC Name:

Manganese dioxide

Cas Number:

1313-13-9

Molecular formula:

MnO2

IUPAC Name:

dioxomanganese

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material : MnO2
- Appearance: Black powder
- Physical state: Solid
- Storage condition of test material: Room temperature in the dark

Test animals

Species:

other: Reconstituted Human Epidermal Model

Strain:

other: SkinEthic

Details on test animals or test system and environmental conditions:

- Supplier: SkinEthic Laboratories, Nice, France
- Date received : 13 October 2009
- Pre-incubation: Tissues were aseptically transferred into 6-well plates containing 1 mL maintenance medium at room temperature (Each tissue was inspected for any air bubble between the agarose gel and the tissue culture prior to transfer). The 6-well plated containing the tissues were placed into an incubator overnight at 37 °C, 5 % CO2 in air.
- Medium: Produced in serum-free SkinEthic maintenance medium

Test system

Type of coverage:

other: Topical treatment

Preparation of test site:

other: Tissues on polycarbonate inserts.

Vehicle:

unchanged (no vehicle)

Controls:

other: Positive and negative controls

Amount / concentration applied:

TEST MATERIAL
- Amount applied : 20 mg
- Preparation of test material : Used as received

CONTROL
- Negative control: 40 µL of sterile distilled water
- Positive control : 40 µL of 8.0 N potassium hydroxide (used as supplied)

Duration of treatment / exposure:

3 or 60 minutes

Observation period:

3 hours

Number of animals:

All tests were performed in duplicate

Details on study design:

TEST SITE
- Area of exposure: Tissue surface area
- Wetting : 20 µL of sterile distilled water was used for wetting the test material to ensure adequate contact with the tissue surface.

REMOVAL OF TEST SUBSTANCE
- Washing : At the end of each exposure period, each tissue was removed from the well of the treatment plate using forceps and rinsed using a wash bottle containing DPBS (Dulbecco's Phosphate Buffered Saline). Rinsing was achieved by filling and emptying each tissue insert with a constant soft stream of DPBS for approximately 40 seconds to gently remove any residual test material. Excess DPBS was removed by blotting the bottom of the tissue culture insert with absorbent paper.
- Time after start of exposure: 3 or 60 minutes.


SCORING SYSTEM: Corrosivity was determined by measuring the absorbency at 540 nm (OD 540) after treatment with MTT. The scoring system used is detailed in table 1.

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean of two tissues. Time point: 3 minutes.

Value:

95.7

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean of two tissues. Time point: 60 minutes.

Value:

83

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The OD540 for the 3 and 60 minute exposure of the SkinEthic model to MnO2 were 1.189 and 1.146, respectively.

The relative mean viability of cell cultures compared to negative control tissues were calculated as follows:

Relative mean viability (%) = ((mean OD540 of test material)/(mean OD540 of negative control)) x 100

The test material was found not to directly reduce MTT.

Any other information on results incl. tables

Table 2: Mean OD540 Values and Percentage Viabilities for the Negative Control Material, Positive Control Material and Test Material

 

Material	Exposure Time	Mean OD540^1	Relative Mean Viability (%)
Negative control	3 Minute	1.243	100*
	60 Minute	1.381	100*
Positive control	3 Minute	0.058	4.7
	60 Minute	0.048	3.5
Test Material	3 Minute	1.189	95.7
	60 Minute	1.146	83.0
^1Mean of SkinEthic tissues tested in duplicate *Mean percentage viability of the negative control tissue is set at 100 %.

 

Applicant's summary and conclusion

Interpretation of results:

other: Not classified according to EU criteria.

Conclusions:

The test material was not corrosive in vitro using human skin.

Executive summary:

The skin corrosion potential of the test material was investigated in vitro in a study which was conducted under GLP conditions and in accordance with the standardised guideline OECD 431.

Under the conditions of the study the test material was considered not to have the potential to be corrosive.