Hafnium

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study conducted without any deviations to the guideline, but quoted with 2 because of the read across

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Hafnium dioxide

EC Number:

235-013-2

EC Name:

Hafnium dioxide

IUPAC Name:

hafnium dioxide

Test material form:

solid: crystalline

Test animals

Species:

other: in vitro test using human skin model

Details on test animals or test system and environmental conditions:

not applicable

Test system

Vehicle:

water

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 10 mg (26.3 mg/cm²) of the crushed powder were applied to the epidermis surface

VEHICLE: 5µL distilled water were used as vehicle

Details on study design:

The study was carried out with the Episkin SM tissues provided as a kit.
The tissues were exposed to the substance during 15 minutes and then post incubated 42h. The viability was determined by optical densimetry at 550nm to check the colouring potential of the substance (= reduction of MTT).

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: other: MTT reduction showed by optical density

Value:

98.4

Remarks on result:

other:

Remarks:

Basis: other: mean tissue viability. Reversibility: other: not applicable. (migrated information)

In vivo

Irritant / corrosive response data:

The mean relative tissues viability is ≥ 50% and then substance showed no irritant effects.

Any other information on results incl. tables

table of results:

	Negative control : PBS			Positive control : SDS 5%			HfO2
Blank corrected mean OD at 550nm	0.847	0.883	0.859	0.049	0.055	0.070	0.892	0.816	0.838
Blank corrected mean OD of the 3 replicates	0.863			0.058			0.849
Standard deviation OD	0.02			0.01			0.04
Relative tissue viabilities %	98.1	102.4	99.5	5.7	6.3	8.1	103.4	94.6	97.1
Mean tissue viabilities %	100			6.7			98.4
Standard deviation tissue viabilities %	2.2			1.3			4.6

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: other: UN GHS and EU CLP

Executive summary:

The potential of the test item to induce skin irritation was tested by using the three dimensional human skin model Episkin-SM. HfO2 was applied with water topically to the tissue for 15 minutes followed by a 42h post incubation period and immediate determination of cytotoxic effects via MTT reduction assay.

Irritant potential was predicted from the relative mean tissue viabilities obtained compared to the negative control treated with PBS.

HfO2 showed no irritant effects as the mean relative tissue viability was ≥ 50% (98.4%).

The controls confirmed the validity of the study:

- the mean optical density of the six blank values was < 0.1

- the mean absolute OD of the three negative control tissues was ≥0.6 and ≤ 1.5

- the mean relative tissue viability of the positive control (SDS 5%) was ≤ 40% (6.7%)

- the maximum standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (1.3 - 4.5%).