Germanium dioxide

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:

2016

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)

Version / remarks:

version 28 July 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Germanium dioxide

EC Number:

215-180-8

EC Name:

Germanium dioxide

Cas Number:

1310-53-8

Molecular formula:

GeO2

IUPAC Name:

Germanium dioxide

Test material form:

solid: particulate/powder

Details on test material:

Batch number: 968
Description: White Solid (powder)
Purity: 99.9%
Storage conditions: Controlled room temperature (15-25°C, below 70% RH%)
Safety precautions: Routine safety precautions (lab coat, gloves, safety glasses and face mask) for unknown materials were applied to assure personnel health and safety."
Grain size: d50: 14.3 µm
Bulk density: 0.9-1.2 kg/l
Moisture: ≤ 0.5%
Chlorine (Cl): 118 ppm
Aluminium (Al): <0.2 ppm
Calcium (Ca) <0.2 ppm
Iron (Fe) <0.2 ppm
Silicon (Si) <1ppm
solubility >4.5g/l

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

skin obtained from plastic surgery from multiple donors

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKINTM (SM) (Manufacturer: SkinEthic, France
- Tissue batch number(s):16-EKIN-023
- Expiry Date: 13 June 2016

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 25.1-26.8°C
- Temperature of post-treatment incubation (if applicable): 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 1wahsing step: rinsing thoroughly with PBS 1x solution (0.9%)

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 2 mL of 0.3 mg/mL MTT per well
- Incubation time: 3h
- Spectrophotometer: 96-well plate spectrophotometer
- Wavelength: 570nm

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE (see any other info on mat and meth)

Control samples:

yes, concurrent negative control

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied: 10mg

VEHICLE
- Amount(s) applied (volume or weight with unit): na; no formulation was required

NEGATIVE CONTROL: PBS
- Concentration (if solution): 50µl

POSITIVE CONTROL: SDS 5%
- Concentration (if solution): 50µl

Duration of treatment / exposure:

15 minutes (± 0.5 min)

Duration of post-treatment incubation (if applicable):

42h

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

83.3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Any other information on results incl. tables

The results of the optical density (OD) measured at 570 nm of each sample and the

calculated relative viability % values are presented below: 

 

Table: Optical Density mean (OD) and the calculated relative viability % of the samples

Substance		Optical Density (OD)			Viability  (% RV)
			Measured	Blank corrected
Negative Control:		1	0.697	0.649	90.1
Phosphate buffered saline		2	0.792	0.744	103.4
		3	0.815	0.767	106.5
		mean	--	0.720	100.0
Positive Control:		1	0.082	0.034	4.8
5% (w/v) SDS solution		2	0.096	0.048	6.7
		3	0.082	0.034	4.8
		mean	--	0.039	5.4
Test Item:		1	0.691	0.643	89.4
GERMANIUM DIOXIDE		2	0.612	0.564	78.3
		3	0.639	0.591	82.1
		mean	--	0.600	83.3

Notes:

1. Mean blank value was 0.048.

2. Optical density means the mean value of the duplicate wells for each sample (rounded to three

decimal places).

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In this in vitro skin irritation test in the EPISKIN model with germanium dioxide the results indicated that the test item is Non Irritant

Executive summary:

Disks of EPISKIN^TM(SM) (three units) were treated with the test item and incubated for 15 minutes at room temperature. Exposure of the test item was terminated by rinsing with Phosphate Buffered Saline (PBS). The epidermis units were then incubated at 37°C for 42 hours in an incubator with 5% CO₂. The viability of each disk was assessed by incubating the tissues for 3 hours with MTT solution atin an incubator with 5% CO₂protected from light. The precipitated formazan crystals were then extracted using acidified isopropanol and quantified spectrophotometrically.

PBS and 5% (w/v) Sodium Dodecyl Sulphate (SDS) solution treated epidermis were used as negative and positive controls, respectively (three units /control). Two additional disks were used to provide an estimate of colour contribution (NSC_living) from the test item. For each treated tissue, the viability was expressed as a % relative to the negative control. If the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50% of the negative control, the test item is considered to be irritant to skin.

Following exposure with GERMANIUM DIOXIDE, the mean cell viability was 83.3% compared to the negative control. This is above the threshold of 50%, therefore the test item was considered as being non-irritant to skin. The experiment met the validity criteria, therefore the study was considered to be valid.

In conclusion, in this in vitro EPISKIN model test with GERMANIUM DIOXIDE(Batch number: 968), the results indicate that the test item is non-irritant to skin.