Gallium

Skin irritation / corrosion

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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 (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Gallium

EC Number:

231-163-8

EC Name:

Gallium

Cas Number:

7440-55-3

Molecular formula:

Ga

IUPAC Name:

gallium

Test material form:

solid: bulk

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Vehicle:

unchanged (no vehicle)

Amount/concentration applied:

Gallium (CAS No. 7440-55-3; EC No. 231-163-8) was warmed to 37°C and was applied as liquid test item topically undiluted to the model skin surface. 30 μL of test item were applied to the skin model and uniformly covered the skin surface with an area of 0.63 cm2.

Duration of treatment / exposure:

The whole exposure period for the used EpiDermTM skin model was 60 minutes. The incubation conditions were 37°C, 5% CO2 and 95% relative humidity for the first 35 minutes followed by 25 minutes at room temperature under a sterile hood.

Duration of post-treatment incubation (if applicable):

At the end of the exposure period, the test item was carefully washed from the skin surface with Dulbecco's phosphate buffered saline (D-PBS). Viability measurements were not performed immediately after the exposure to the test item, but after a post- treatment incubation period of the rinsed tissues in fresh assay medium of 42 hours. This period allows both for recovery from weakly irritant effects and for appearance of clear cytotoxic effects.

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

mean value for 3 replicates

Value:

111.3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

The mean optical density (OD) of 3 negative control tissues was 1.314 and was well within the acceptable range of ≥ 1.0 to ≤ 2.5.

Positive controls validity:

valid

Remarks:

The viability of cells treated with the positive reference item, 5% SDS, was 6.9% of the negative control and fulfilled the acceptance criterion of ≤ 20%.

Remarks on result:

no indication of irritation

Remarks:

The standard deviation determined for all triplicates was below the limit of acceptance of 18%.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the present test conditions, Gallium (CAS No. 7440-55-3; EC No. 231-163- 8) tested at an exposure time of 60 minutes and a 42-hour post-treatment incubation period, was non-cytotoxic and, hence, predicted to be non-irritant to skin in an experiment employing an artificial three-dimensional model of human skin. Hence, the test item did not show irritant properties and is therefore not classified as irritant (UN GHS no category).