Caesium carbonate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2010-07-02 to 2010-07-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Caesium carbonate

EC Number:

208-591-9

EC Name:

Caesium carbonate

Cas Number:

534-17-8

Molecular formula:

CCs2O3

IUPAC Name:

caesium carbonate

Test material form:

solid: crystalline

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

The EPISKIN model has been validated for corrosivity testing in an international trial; it is considered to be suitable for this study (STATEMENT ON THE SCIENTIFIC VALIDITY OF THE EPISKINTM TEST (AN IN VITRO TEST FOR SKIN CORROSIVITY); ECVAM JRC Environment Institute, European Commission; Ispra; 03 April 1998).

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm ™
- Tissue batch number(s): 13657
- Delivery date: 01. Jul. 2010
- Date of initiation of testing: 02. Jul. 2010

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 °C

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- Incubation time: 3 hours
- Spectrophotometer: plate spectral photometer Dynatech MRX
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 2

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION:

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than 50% and the viability after 1 hour exposure is greater than 15%.

Control samples:

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

59 mg

Duration of treatment / exposure:

3 min, 1 h

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Negative control (3 min and 1 h)

Value:

100

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Remarks:

(OD570 = 1.598)

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Positive control (1 h)

Value:

20.3

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Remarks:

(OD570 = 0.325)

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Test item (1 h)

Value:

47.4

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Remarks:

(OD570 = 0.757)

Results 4

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Test item (3 min)

Value:

102.6

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Remarks:

(OD570 = 1.656)

Results 5

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Positive control (3 min)

Value:

25.5

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Remarks:

(OD570 = 0.411)

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

According to OECD Guideline 431 study the test item is considered to be not corrosive.

Executive summary:

The test item is considered to be not corrosive. After three minutes treatment, the relative absorbance values were decreased to 102.6 %. This value is well above the threshold for corrosivity (50 %). After one hour treatment relative absorbance values were reduced to 47.4 %. This value is well above the threshold for corrosivity (15 %). The values of the negative control were well above the required acceptability criterion of mean OD > 0.8 for both treatment interval thus showing the quality of the tissues. The value of the positive control induced a decrease in the relative absorbance as compared to the negative control to 25.5 % for the three minutes treatment interval and 20.3 % for the one hour treatment interval thus ensuring the validity of the test system. Although the value of the one-hour-experiment was 20.3 % and therefore higher than the threshold for corrosivity, this is considered as not relevant, as a clear corrosive effect was determined and values above 15 % have been measured for the positive control before: Values for the positive control were within the range of historical data of the test facility.