Cobalt molybdate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation / corrosion

Remarks:

other: in-vitro assay

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 - 15 Apr 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions (limited documentation).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline for the Testing of Chemicals, Version 439, 22. July 2010, "In Vitro Skin Irritation: Reconstructed Human Epidermis (RhE) Test Method"

Deviations:

yes

Remarks:

- limited documentation

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Commission Regulation (EC) No. 761/2009, Method B.46, adopted 23. July 2009: " In Vitro Skin Irritation: Reconstructed human epidermis model test"

Principles of method if other than guideline:

The skin irritancy potenial of cobalt molybdendum oxide was tested by using the human skin model EpiDerm(TM) and measurement of cell viability by dehydrogenase conversion of MTT into a blue formazan salt.

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Cobalt molybdate

EC Number:

237-358-4

EC Name:

Cobalt molybdate

Cas Number:

13762-14-6

Molecular formula:

CoMoO4

IUPAC Name:

λ²-cobalt(2+) dioxomolybdenumbis(olate)

Details on test material:

- Name of test material (as cited in study report): cobalt molybdenum oxide
- Physical state: light green powder
- Analytical purity: 99%
- batch No.: EH 110005/1
- Expiration date of the batch: June 2013
- Storage condition of test material: room temperature (20 ± 5 °C)

Test animals

Species:

other: in-vitro assay

Strain:

other: in-vitro assay

Details on test animals or test system and environmental conditions:

not applicable

Test system

Type of coverage:

other: in-vitro assay

Preparation of test site:

other: in-vitro assay

Vehicle:

other: DPBS buffer

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Tissue 1: 24.2 mg; Tissue 2: 24.8 mg; Tissue 3: 25.0 mg

VEHICLE
- Amount(s) applied (volume or weight with unit): 25 µL DPBS (Dulbecco's Phophate Buffered Saline) buffer

Duration of treatment / exposure:

not applicable: see "Any other information on materials and methods incl. tables"

Observation period:

not applicable: see "Any other information on materials and methods incl. tables"

Number of animals:

not applicable: see "Any other information on materials and methods incl. tables"

Results and discussion

Any other information on results incl. tables

Table 1: Absorption values negative control, test item and positive control (Optical Density at 570 nm)

Designation	Measurement	Negative Control	Cobalt molybdenum oxide	Positive Control
Tissue 1	1	1.662	1.837	0.154
	2	1.643	1.807	0.153
Tissue 2	1	1.658	1.833	0.153
	2	1.642	1.809	0.152
Tissue 3	1	1.663	1.824	0.151
	2	1.657	1.824	0.151

Table 2: Mean absorption values (subtracting the blank of 0.070)

Designation	Negative Control	Cobalt molybdenum oxide	Positive Control
Mean – blank (Tissue 1)	1.583	1.752	0.084
Mean- blank (Tissue 2)	1.580	1.751	0.083
Mean - blank (Tissue 3)	1.590	1.754	0.081
Mean of the three Tissues	1.584	1.752	0.083
Relative Standard Deviation of the three tissues	0.3%	0.1%	1.8%

Table 3: % Formazan Production

Designation	Cobalt molybdenum oxide	Positive Control
% Formazan production (Tissue 1)	110.6%	5.3%
% Formazan production (Tissue 2)	110.5%	5.2%
% Formazan production (Tissue 3)	110.7%	5.1%
% Formazan production Mean	110.6%	5.2%

Table 4: Validity

Criterion	Demanded	Found
OD of negative control	between 1.0 and 2.5	1.584
% Formazan production of positive control	<20% of negative control	5.2%
Variation within replicates (RSD)	<18%	0.3% (negative control) 1.8% (positive control) 0.1% (test item)

For the test item, 110.6% Formazan production (mean of three tissues) was calculated in comparison to the negative control. This value is well above the threshold for irritancy of 50%.

For the positive control 5.2% Formazan production (mean of three tissues) was calculated in comparison to the negative control.

Values for negative control and for positive control were within the range of historical data of the test facility. The test item cobalt molybdenum oxide is considered not irritant using this in vitro test with a skin model.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU