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Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation / corrosion
Remarks:
in vitro
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 21 June 2012 to 22 June 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well-documented GLP study performed according to OECD guideline 435.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)
Version / remarks:
Corrositex
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): zirconium sulfate
- Other names: AZST, Zirconium Sulphate
- Substance type: active ingredient
- Physical state: solid
- Purity: 99 % (on a dry weight basis, test substance is a hydrate of zirconium sulfate, containing 66.75% anhydrous zirconium sulfate)
- Purity test date: 29 May 2012
- Lot/batch No.: 201204015
- Expiration date of the lot/batch: 30 September 2012
- Storage condition of test material: ambient condition

Test animals

Species:
other: Corrositex
Strain:
other: not applicable
Details on test animals and environmental conditions:
The test system is composed of two components, a synthetic macromolecular biobarrier and a Chemical Detection System (CDS).
The test system is part of a commercially available kit (CORROSITEX) supplied by InVitro INTERNATIONAL.
Test system batch number: CT042011

The membrane barrier (biobarrier) consists of two components: a proteinaceous macromolecular aqueous gel and a permeable supporting membrane. The proteinaceous gel is supplied in the form of a powder to be reconstituted, prepared over the supporting membrane and stored. To prepare the gel, and after mixing the components, slow dissolution was allowed at a maximum temperature of 68-70°C by a magneting stirring hot plate for 20 minutes. After 5 minutes of rest, the solution was pipetted over the supporting membrane ensuring the entire membrane was covered and no bubbles were formed. The solidification was by immediate incubation at 2-8°C. The gel was used the day after preparation (stable up to 7 days).

Test system

Type of coverage:
other: not applicable
Preparation of test site:
other: not applicable
Vehicle:
unchanged (no vehicle)
Controls:
other: Details are mentioned in the field 'Any other information on materials and methods incl. tables’
Amount / concentration applied:
Comparability test (Qualification): 100 mg of the test item as supplied.
Timesclae category test (Categorisation): 100 mg of the test item as supplied.
Main Assay (Classification assay): 500 mg of test item as supplied.
Observation period:
Main study:
According to the time category 1 (determined in the preliminary test), test item samples were observed continuously at least during the following intervals: 0-5, 55-65 and 235-245 minutes.

Positive control vial was observed in the interval 0-15 minutes.
Negative control vial was observed at 60 minutes.
Number of animals:
The test item was tested in 4 replicates.
Details on study design:
- Preliminary Study:
A preliminary test was divided in two steps. A qualification of the test item was carried out to verify if the CDS undergoes a physical change (Step 1). A categorising test was then carried out to verify what time scale should have been used in the main experiment (Step 2). Finally the main experiment (classification assay) was performed out including all controls.

- Main Assay (Classification assay):
A main assay was carried out including the test item, positive and negative controls.
The pre-filled CDS vials were kept at room temperature (17-25°C) before use. A cold biobarrier disc, eventually kept on crushed ice on the bench, was added to the top of each vial. A fixed amount of samples was added to the top within 2 minutes from putting the biobarrier at room temperature.

Results and discussion

In vivo

Results
Irritation parameter:
other: Penetration time
Remarks on result:
other: The mean penetration time (CORROSITEX Time) for the test item was estimated to be 32.42 ± 2.23 minutes.
Irritant / corrosive response data:
During an unscheduled control of the test system performed after the 5-minute observation sessions, the test item was found to have penetrated the barrier in all the 4 replicates. The time was recorded. The mean penetration time (CORROSITEX Time) for the test item was estimated to be 32.42 ± 2.23 minutes.

Positive and negative control results indicated a good functioning of the test system.
Negative control was not corrosive at 60 minutes.
Positive control was corrosive at 9.47 minutes (9’28’’), slightly below laboratory's historical control range (the minimum value observed in the range distribution is 11.58 minutes). However, since the number of experiments is limited (n = 10) and the distribution has a very low standard deviation (CV% is equal to 6.6%), the result obtained is considered acceptable.

Applicant's summary and conclusion

Interpretation of results:
other: Corrosive
Remarks:
Criteria used for interpretation of results: other: OECD guideline 435 cut-off values
Conclusions:
According to the OECD guideline for testing of chemicals no. 435 "In vitro membrane barrier test Method for Skin Corrosion" (adopted on 19 July 2006) the test item is defined as corrosive to the skin. The corrosivity sub-category assigned is GHS 1B (Packing Group II).