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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018-03-26 to 2018-03-28
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)
Version / remarks:
2015-07-28
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
signed 2015-06-05

Test material

Constituent 1
Chemical structure
Reference substance name:
Strontium bis(2-ethylhexanoate)
EC Number:
219-536-3
EC Name:
Strontium bis(2-ethylhexanoate)
Cas Number:
2457-02-5
Molecular formula:
C16H30O4Sr
IUPAC Name:
strontium(2+) bis(2-ethylhexanoate)
Test material form:
solid: particulate/powder
Details on test material:
- State of aggregation: solid, white powder
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, avoid heat

In vitro test system

Test system:
artificial membrane barrier model
Source species:
other: not specified
Cell type:
other: synthetic macromolecular bio-barrier
Cell source:
other: not specified
Source strain:
not specified
Details on animal used as source of test system:
not applicable
Justification for test system used:
The CORROSITEX™ Assay is a standardized, quantitative in vitro test for skin corrosivity and has been validated by the ECVAM for testing acids, bases and their derivatives (ECVAM, 2000)*. The bio-barrier membrane is constructed to have physico-chemical properties similar to rat skin.

Reference:
- ECVAM (2000) ESAC statement on the application of the Corrositex® assay for skin corrosivity testing
Vehicle:
unchanged (no vehicle)
Details on test system:
SOURCE AND COMPOSITION OF MEMBRANE BARRIER USED
- Was the Corrositex® test kit used: yes (lot no. CT120516; supplier: Invitro International; Irvine, CA 92614)
- Components: a synthetic macromolecular bio-barrier and a chemical detection system (CDS)
- Apparatus and preparation procedures: the preparation was completed at least 2 hours prior to running tests. The entire content of the BIOBARRIER diluent was added to the vial of BIOBARRIER matrix powder. The vial was heated to 68°C (± 1°C) in a water bath under smooth agitation. After complete dissolution (approx. 20 min.) the solution was allowed to sit for 5 min. to allow any air bubbles to rise to the surface. 200 µL of the BIOBARRIER were pipetted into each membrane disc. The BIOBARRIERS were set on the tray and kept in the cold (2 - 8°C) for at least two hours.

WAS THE COMPATIBILITY TEST PERFORMED: yes
In order to test whether the test system is suitable for the test item, 100 mg of the test substance was added to the Qualify test tube. The vial was shaken to allow dissolution of the test substance and let stand for one minute. If the colour or consistency of the CDS changes at the sample/testing fluid interface, the test material is qualified for the assay. If no reaction is observed within five minutes, the sample is not qualified for the CORROSITEX TM assay.

WAS THE TIMESCALE CATEGORY TEST PERFORMED: yes
This step established the category of cut-off times for the sample. 100 mg of the test substance was added to the tubes labelled Tube A and Tube B. The vial was shaken to allow dissolution of the test substance. In case a colour change was observed in either of the tubes and colour was matched to the corresponding colour charts on the CORROSITEX™ Testing Protocol Poster. Test materials having high acid/alkaline reserves are defined as Category 1 materials, while those with low acid/alkaline reserves are defined as Category 2 materials. If no colour change had been observed in either tube, CONFIRM reagent was added to Tube B. After shaking, the resulting colour was matched to the colour chart on the CORROSITEX™ Testing Protocol Poster. If the test item has a strong inherent colour or shows other characteristics impairing a clear categorization according to the colour chart, the pH value can be measured in tubes A and B and is used to confirm/determine the category of the test item, according to the Corrositex® Reference Manual (1995)*.

TEMPERATURE USED DURING TREATMENT: room temperature (17 - 25 °C)

METHOD OF DETECTION
- Chemical or electrochemical detection system: chemical detection system (CDS)

METHOD OF APPLICATION (CLASSIFICATION TEST):
The CDS vials were warmed to room temperature (17 - 25˚C) before using. Four vials were utilized for test item sample replicate testing. One vial was utilized for a positive control sample and another vial for a negative control. Lastly, one vial served as a CDS colour control. One BIOBARRIER disc was added on top of the first vial (discs were not longer in the vial than two minutes before adding the test samples).
500 mg of the test item was applied evenly on the top of the BIOBARRIER disc and starting time was recorded. This step was repeated for the remaining vials, staggering each start time by e.g. 10 seconds (but not longer than 2 minutes). The start time difference for each vial was subtracted from the final time to determine the net response time. As soon as a reaction had been observed, the time was recorded.

NTERPRETATION OF THE RESULTS:
For Category 1 substances, test chemicals were categorized as non-corrosive in case no colour change occurs after 240 minutes. For Category 2 substances, test chemicals were categorized as non-corrosive in case no colour change occurs after 60 minutes. The start time difference for each vial was subtracted from the final time to determine the net response time.
The time (in minutes) elapsed between application and barrier penetration for the test substance was recorded in tabular form as individual replicate data.
The mean time (± standard deviation) of the four sample replicates to activate the CDS was calculated and reported in tabular form. Using the table as shown in the field "Any other information on materials and methods incl. tables" below, the test item was categorised.

TEST ACCEPTANCE CRITERIA:
The test meets acceptance criteria if:
- test item qualifies in qualification test
- positive control activates CDS > 3 - 60 min.
- negative control activates CDS not before 60 min.
The exact breakthrough time of the positive control should be determined to demonstrate, that the response is in the acceptable historical range of breakthrough times for the positive control (mean ± 2 - 3 standard deviations).

*Reference:
- InVitro International (1995), Corrositex® Reference Manual
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 500 mg of the test item

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 500 µL of citric acid (10%) in aqua dest.

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 500 µL of phosphoric acid (85 %)
Duration of treatment / exposure:
60 minutes
Duration of post-treatment incubation (if applicable):
not applicable
Number of replicates:
Test item: quadruplicates
Negative control: single measurement
Positive control: single measurement

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
penetration time (in minutes)
Value:
0
Vehicle controls validity:
not examined
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: Colour change or structural change was not observed up to 60 minutes (treatment period)
Other effects / acceptance of results:
QUALIFICATION TEST:
The test substance was compatible with the CORROSITEX™ Assay, as assessed in the qualification step. The categorization step and the classification step could be performed.

CATEGORIZATION TEST:
A direct colour change was not observed. CONFIRM reagent was added to tube B and the category was read from the CORROSITEX™ colour chart. The chemical has been categorized to category 2.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: negative control did not activate the CDS before 60 minutes (> 60 minutes).
- Acceptance criteria met for positive control: positive control activated the CDS between 3 - 60 minutes (26.04 min).

Please also refer to the field "Any other information on results incl. tables" below.

Any other information on results incl. tables

Table1:  Results of the test item strontium bis(2 -ethylhexanoate)

 

CORROSITEX™ Time [min]

Colour Change

Consistency Change

Replicate 1

> 60

no

no

Replicate 2

> 60

no

no

Replicate 3

> 60

no

no

Replicate 4

> 60

no

no

Mean ± SD

> 60

 

 

 

 

 

 

Positive control

26.04

yes

no

Negative control

> 60

no

no

The mean time, required to activate the CDS was> 60min.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item, strontium bis(2 -ethylhexanoate), is not corrosive to the skin.
According to the Regulation (EC) No 1272/2008 and subsequent regulations, the test item is not corrosive to the skin.