Potassium 2-methylbutan-2-olate

Endpoint summary

Description of key information

Skin irritation test (in vitro) shows corrosive potential.

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

Study period:

09.09.2015 to 26.11.2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study conducted in compliance with OECD guidline TG 435, well documented.

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)

Species:

other: Corrositex® kit

Strain:

other: reconstituted collagen matrix

Vehicle:

unchanged (no vehicle)

Controls:

other: control vials with positive and negative control

Amount / concentration applied:

The test substance was applied undiluted. Approximately an amount of 500 mg of the test substance was added onto the membrane disc, which was placed into one vial containing the CDS.

Duration of treatment / exposure:

The time after the application of the test substance is recorded until the first change in the indicator solution occurs (i.e. barrier penetration) .

Observation period:

The vial is observed for three minutes for any change in the CDS

Number of animals:

other: 4 vails

Details on study design:

The Corrositex® assay is a standardized in vitro corrosion test. The Corrositex® assay kit is
commercially available from InVitro International.
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).
The Corrositex® assay is used to determine the corrosive potential of test substances. The
assay is limited to testing those materials which cause detectable pH changes in the CDS.

The experimental design of this study consisted of a qualification screen with the CDS (to
determine if a color change can be detected) and a categorization screen (to categorize weak
acids/bases and strong acids/bases), which were performed as a pretest (experimental
conduct in accordance with GLP but without a GLP status), and a definitive Corrositex® assay.
The Corrositex® assay was evaluated on the basis of the color change of the CDS. The time
that a color change was observed was recorded manually and the breakthrough times of the
four replicates was used to determine the corrosive potential of the test substance.

Irritation / corrosion parameter:

other: overall irritation score

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 24 s. Remarks: mean breakthrough time. (migrated information)

Irritant / corrosive response data:

The mean breakthrough time of the test substance determined in the in vitro membrane barrier test was ca. 24 seconds.

Evaluation scheme:

	Time required for CDS change^1
Category 1	≤ 3 min	> 3 min ≤ 1 h	>1 h ≤ 4 h	> 4 h
Category 2	≤ 3 min	>3 ≤ 30 min	> 30 ≤ 60 min	> 60 min
Corrosive potential	corrosive^2	corrosive^3	corrosive^4	non corrosive^5

¹Occasionally, break through times may overlap the borderline between corrosive potential assignment

columns. If the break through times from 2 or more vials indicate a more severe corrosive potential, this

subcategory was assigned to the test material.

²This break through time indicates that the test substance has an extreme corrosive potential and should be

assigned to UN GHS skin corrosivity subcategories 1A or UN Transport Packing Group I as specified in OECD

TG 435 (adopted 19 July 2006) and the test system manufacturer.

³This break through time indicates that the test substance has an intermediate corrosive potential and should

be assigned to UN GHS skin corrosivity subcategories 1B or UN Transport Packing Group II as specified in

OECD TG 435 (adopted 19 July 2006) and the test system manufacturer.

⁴This break through time indicates that the test substance has a weak corrosive potential and should be

assigned to UN GHS skin corrosivity subcategories 1C or UN Transport Packing Group III as specified in OECD

TG 435 (adopted 19 July 2006) and the test system manufacturer.

⁵This break through time indicates that the test substance does not have a corrosive potential. The result does

not exclude an irritation potential of the test substance as specified in OECD TG 435 (adopted 19 July 2006)

and the test system manufacturer.

Interpretation of results:

Category 1A (corrosive)

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on the observed results and applying the evaluation criteria cited it was concluded, that the test substance shows a corrosive potential in the
Corrositex® - Skin Corrosion Test under the test conditions chosen. The mean breakthrough time determined in the in vitro membrane barrier test was ca. 24 seconds. The breakthrough time indicates that the test substance has an extreme corrosive potential and should be
assigned to UN GHS skin corrosivity subcategories 1A as specified in the cited OECD TG 435.

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

Potassium 2-methylbutan-2-olate was tested for skin corrosion in a GLP-guideline study according to OECD guideline 435. An amount of 500 mg of the test substance was applied onto the membrane disk of a reconstituted collagen matrix. The penetration time and the time required for a change in the Chemical Detection System (CDS) were determined. The mean breakthrough time of the test substance is 24 seconds. Under the chosen test conditions, the test substance shows a corrosive potential.

Potassium 2-methylbutan-2-olate has a corrosive potential. It has to be expected to have a similar effect on the eyes.

Justification for selection of skin irritation / corrosion endpoint:
One valid study available.

Justification for selection of eye irritation endpoint:
Due to the skin corrosive potential a similar effect on the eye has to be expected.

Effects on skin irritation/corrosion: highly corrosive

Effects on eye irritation: corrosive

Justification for classification or non-classification

Potassium 2-methylbutan-2-olate has a corrosive potential. It has to be expected to have similar effect on the eyes. Based on the available data, a classification of potassium 2-methylbutan-2-olate as skin corrosive category 1A according to CLP Regulation (EC) No 1272/2008 is proposed. The corrosive effect has also to be expected for the eyes. Therefore, the test substance should also be classified for eye damage, category 1.

As potassium 2 -methylbutan-2 -olate hydrolyses rapidly, the hydrolysis products are also considered relevant for classification according to CLP regulation (EC) No 1272/2008. 2-methylbutan-2-ol (CAS No. 75-85-4) is classified with STOT SE 3 (H335) according to Annex VI of the CLP regulation. Therefore, also the test substance should be classified with STOT SE 3 (H335).