2-methylglutaric acid

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2014-05-16 to 2014-07-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study, OECD 435 compliant

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-methylglutaric acid

EC Number:

210-521-7

EC Name:

2-methylglutaric acid

Cas Number:

617-62-9

Molecular formula:

C6H10O4

IUPAC Name:

2-methylglutaric acid

Test material form:

solid: crystalline

Test system

Details on study design:

Test system
Corrositex® is a test system that is composed of two components, a hydrated collagen matrix (bio-barrier) on a supporting filter membrane and CDS, an underlying aqueous solution of two pH indicator dyes.

The Corrositex® kit contained:
- Bio-barrier matrix.
- Bio-barrier diluent.
- Vials with Chemical Detection System (= CDS).
- Membrane discs.
- Compatibility test tubes.
- Timescale categorize test tubes with buffer A and B.
- Confirm reagent.

The batch number of the kit used for the experiment was CT 040113.

Rationale
Recommended test system in international guideline (OECD 435).

Source
InVitro International Inc., Irvin CA, USA

Preparation of the bio-barrier
The bio-barrier diluent (10 ml) was added to the bio-barrier matrix powder (1 gram) which contained a micro stir bar. This was stirred and heated slowly to 68°C in a water bath container. The membrane discs (at room temperature) were filled with 200 µl solubilised bio-barrier matrix. The entire membrane was covered with matrix and care was taken to avoid air bubbles.
The bio-barrier was prepared 2 days before testing. The biobarrier was stored in the refrigerator until
usage.

Study design
All tests were performed at room temperature. The samples were at room temperature when applied.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: other: Mean penetration time

Value:

65 - 142

Remarks on result:

other:

Remarks:

Time point: not applicable. Reversibility: not reversible. (migrated information)

In vivo

Irritant / corrosive response data:

Test substance compatibility test
Methylglutaric acid was evaluated for the compatibility with the CDS. Because a colour change (red) was observed after 1 minute, Methylglutaric acid was compatible with the Corrositex® test system.

Test substance timescale category test
Methylglutaric acid was classified into one of the two timescale categories. The timescale category test showed that Methylglutaric acid is a timescale 1 substance (after one minute tube A showed a colour change into pink).

Membrane barrier penetration test
The membrane barrier test was performed and the elapsed time between the application of Methylglutaric acid and controls and penetration through the membrane was recorded. The mean penetration times of Methylglutaric acid and controls are presented in Table 1. The individual penetration times are presented in Table 2.

Since Methylglutaric acid is a timescale 1 test substance and showed a mean penetration time between 65 and 142 minutes, Methylglutaric acid is classified in UN packing group III (= GHS 1C).

The negative control citric acid (10%) showed a mean penetration time of >60 minutes and was therefore non-corrosive. The positive control sodium hydroxide (tested as it is) showed a mean penetration time of 22 minutes and was therefore classified as UN packing group II (=GSH 1B). It was therefore concluded that the test system functioned properly.

Any other information on results incl. tables

Table 1: Timescale category, mean penetration time and UN GHS subcategory determined with Corrositex^®

 

Chemical	Timescale category	Mean penetration time (minutes)	UN packing group (GHS subcategory) determined with Corrositex^®
Citric acid (10%)	2^1	>60	Non-corrosive
Methylglutaric acid	1	>65, <142	III (GSH 1C)
Sodium hydroxide (as it is)	1^1	22	II (GSH 1B)

¹Not determined in the present study; category obtained from OECD 435

Table 2: Timescale category, penetration times and UN packing group (GSH subcategory) determined with Corrositex^®

Chemical	Timescale category	Penetration time (minutes)	UN packing group (GHS subcategory)
Citric acid (10%)	2^1	>60	Non-corrosive
	1
Sample A		>65, <144	III (GSH 1C)
Sample B		>65, <142.5	III (GSH 1C)
Sample C		>65, <141	III (GSH 1C)
Sample D		>65, <139.5	III (GSH 1C)
Sodium hydroxide (as it is)	1^1	22	Group II (GSH 1B)

¹Not determined in the present study; category obtained from OECD 435

Applicant's summary and conclusion

Interpretation of results:

corrosive

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Methylglutaric acid is classified as UN packing group III (= GHS 1C) in the Corrositex® assay under the experimental conditions described in this report.

Executive summary:

In vitro membrane barrier test for skin corrosion (Corrositex^®) with Methylglutaric acid was realised according to the OECD 435 guideline and under GLP conditions.

 

This study describes the ability of Methylglutaric acid to pass through a bio-barrier and to elicit a colour change in the underlying liquid chemical detection system.

 

Methylglutaric acid were white crystals with a purity of 89.5 %± 1.8 w/w. The test substance compatibility test showed that Methylglutaric acid was compatible with the chemical detection system. Based on the acid reserve of the chemical, the test substance was classified as a timescale 1 compound. Approximately 500 mg of Methylglutaric acid was applied on top of the bio-barrier matrix. The elapsed time between application and penetration was determined by monitoring changes in the chemical detection system. 

 

The mean penetration time of Methylglutaric acid was between 65 and 142 minutes. Since Methylglutaric acid was a timescale 1 test substance and showed a mean penetration time between 65 and 142 minutes, Methylglutaric acid is classified in UN packing group III (= GHS 1C).

 

The negative control citric acid (10%) showed a mean penetration time of >60 minutes and was therefore non-corrosive. The positive control sodium hydroxide (tested as it is) showed a mean penetration time of 22 minutes and was therefore classified as UN packing group II (=GSH 1B). It was therefore concluded that the test system functioned properly.

 

Finally, it is concluded that this test is valid and that Methylglutaric acid is classified as UN packing group III (= GHS 1C) in the Corrositex^®assay under the experimental conditions described in this report.