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Description of key information

Skin Irritation: corrosive (OECD 435)

Data waiving for eye irritation was done according to ANNEX VII, column 2 of the REACH regulation: the available information regarding skin corrosion indicate that the criteria for classification as corrosive for the skin are met.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin corrosion: 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
Qualifier:
according to guideline
Guideline:
OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test system:
artificial membrane barrier model
Source species:
other: artificial
Cell type:
other: not applicable
Cell source:
other: not applicable
Source strain:
other: not applicable
Details on animal used as source of test system:
not applicable
Justification for test system used:
The Corrositex® assay is a standardized in vitro corrosion test to determine the corrosive potential of test substances. The Corrositex® assay kit is commercially available from InVitro International (Irvine CA, USA).
Vehicle:
unchanged (no vehicle)
Details on test system:
SOURCE AND COMPOSITION OF MEMBRANE BARRIER USED
- Was the Corrositex® test kit used: yes
- Components: Reagents required for qualification and categorization screen, biobarrier matrix powder and diluent, membrane discs and vials containing the Chemical Detection System.
- Apparatus and preparation procedures: The Corrositex® Biobarrier Membrane is a test system consisting of a reconstituted collagen matrix. The assay is based on the time that is required
for the test substance to penetrate through the Corrositex® Biobarrier Membrane and produce a change in the Chemical Detection System (CDS). Thus, the Corrositex® assay was evaluated on the basis of the color change of the CDS. The assay is therefore limited to testing those materials which cause detectable pH changes in the CDS. The time that a color change was observed was recorded manually (electronic time clocks) and the break through times of four replicates were used to determine the corrosive potential of the test substance. The assay ran in a fume hood.

WAS THE COMPATIBILITY TEST PERFORMED: yes

WAS THE TIMESCALE CATEGORY TEST PERFORMED: yes

METHOD OF DETECTION
- Chemical detection system

NUMBER OF REPLICATES: 4

Control samples:
not specified
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied: 100 mg
Duration of treatment / exposure:
Until a color change of the CDS was observed.
Duration of post-treatment incubation (if applicable):
not applicable
Number of replicates:
4
Irritation / corrosion parameter:
penetration time (in minutes)
Run / experiment:
mean
Value:
7.07
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Positive controls validity:
not specified
Interpretation of results:
Category 1B (corrosive) based on GHS criteria
Conclusions:
Corrosive potential was determined on the basis of the average time recorded for the test substance to produce a change in the CDS.
Executive summary:

Based on the observed results and applying the evaluation criteria it was concluded, that K-Methylat krist. shows a corrosive potential in the Corrositex® - Skin Corrosion Test under the test conditions chosen. The mean break through time determined in the in vitro membrane barrier test was 7 minutes and 4 seconds.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Skin irritation / corrosion

 

The skin corrosion potential of potassium methanolate (CAS No. 865-33-8) was analysed in an in vitro skin corrosion assay according to OECD guideline 435 and under GLP (Evonik, 2001) using the Corrositex® assay. The assay is based on the time that is required for the test substance to penetrate through the Corrositex® biobarrier membrane and produce a change in the chemical detection system (CDS). The time that a color change was observed was recorded manually (by an electronic time clock) and the breakthrough times of four replicates were used to determine the corrosive potential of the test substance. The mean breakthrough time determined in the in vitro membrane barrier test was 7 minutes and 4 seconds. Based on the observed results and applying the evaluation criteria it was concluded, that the test substance potassium methanolate (crist.) shows a corrosive potential in the Corrositex® - Skin Corrosion Test under the test conditions chosen.

 

Eye irritation

There are no studies available for potassium methanolate, but studies on eye irritation do generally not need to be conducted according to Annex VII, Section 8.2, Column 2 of the REACH regulation as methanolates are classified as corrosive to the skin.

 

Conclusion

Potassium methanolate was corrosive in an in vitro skin corrosion assay according to OECD guideline 435. As these effects are based on the alkaline and exothermic reaction with water and the liberation of potassium hydroxide, it can be assumed that potassium methanolates will also cause irritation/corrosion to the mucous membranes of the upper respiratory tract in case of exposure via the inhalation route. Due to the exothermic liberation of potassium hydroxide, the hydroxide data may be important for the evaluation of this endpoint. For potassium hydroxide (CAS No. 1310-58-3), OECD (2002) concluded that KOH is corrosive at concentrations of about 2% and higher. Between 0.5% and 2% it is irritating. Case reports on human accidents or intentional exposure confirm that the risk posed by potassium hydroxide for human health originates from its corrosive properties.

 

References not included in IUCLID:

OECD SIDS Initial Assessment Report for SIAM 13 (2002): Potassium Hydroxide (CAS No: 1310-58-3).

 

Justification for classification or non-classification

According to Annex VI of the CLP regulation (EC 1272/2008), potassium methanolate is classified as corrosive (Skin Corr. 1B - H314). This classification was also confirmed in an in vitro skin corrosion test according to OECD guideline 435 with potassium methanolate. However, based on additional in vivo data for the structural related sodium methanolate (CAS No. 124 -41 -4), which resulted in the classification as corrosive causing severe burns (CLP / UN-GHS: Skin Corr. 1A - H314) for sodium methanolate, this worst-case approach was also undertaken for potassium methanolate. Therefore, potassium methanolate fulfils the criteria for classification as corrosive causing severe burns:

CLP / UN-GHS: Skin Corr. 1A - H314