Reaction mass of disodium hexatitanium tridecaoxide and disodium trititanium heptaoxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-03-29 to 2010-03-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP guideline study reliable without restrictions

Justification for type of information:

Disodium titanate substance (EC 234-802-9) has the molecular formula Na2TiO3 and its composition is expressed as (Na2O)x(TiO2), where x is ranging from 0.1 to 6 according to the SIP. This substance, Reaction mass of Disodium Hexatitanate and Sodium Metatitanate, has a value of x = 0.21, calculated from XRF results, has been identified as a mixture of two specific types of disodium titanate and is therefore within the scope of the disodium titanate SIP.
It is assessed therefore that disodium titanate is an acceptable read-across substance for Reaction mass of Disodium Hexatitanate and Sodium Metatitanate

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: ICCVAM Minimum Performance Standards: In Vitro Membrane Barrier Test Systems for Skin Corrosion, June 23, 2003

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: ICCVAM Recommended Performance Standards for in vitro Test Methods for Skin Corrosion, May 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-03-30

Test material

Test material information

Constituent 1

Reference substance name:

Disodium titanate

EC Number:

234-802-9

EC Name:

Disodium titanate

Cas Number:

12034-34-3

Molecular formula:

Na2TiO3

IUPAC Name:

disodium titanate

Details on test material:

- Name of test material (as cited in study report): Disodium titanate
- Physical state: light yellow powder
- Storage condition of test material: At room temperature, in tightly closed container

No further information on the test material was stated.

Test animals

Details on test animals or test system and environmental conditions:

Not applicable - Since this is a in vitro study there is no information on test animals.

Test system

Amount / concentration applied:

TEST MATERIAL
Qualify Test: approx. 100 mg of the test item were applied into the “Qualify Test Vial”
Categorisation Test: approx. 100 mg of the test item were applied into the “Category A Vial” as well as into the “Category B Vial”
Classification Test: approx. 500 mg of the test item were applied per bio-barrier

Duration of treatment / exposure:

Qualify Test: 1 minute incubation
Categorisation Test: 1 minute incubation
Classification Test: >60 minutes

Observation period:

not applicable

Number of animals:

not applicable

Details on study design:

CHEMICAL DETECTION SYSTEM (CDS)
Corrosive substances are able to disrupt the integrity of the bio-barrier, leading to penetration of the test item through the bio-barrier into the CDS located beneath. The presence of the test item in the CDS results in a colour change that is detected visually. The time it takes a test item to penetrate the bio-barrier into the CDS is inversely proportional to its corrosivity: the more corrosive the test item is, the shorter time required affects a colour change. Non-corrosive test items do not disrupt the bio-barrier, or disrupt the bio-barrier too slowly to be identified as corrosive.

PREPARATION OF THE BIO-BARRIER
Preparation of the synthetic macromolecular bio-barrier matrix (Corrositex TM test kit, Lot no. CT101408, Transia GmbH, 61239 Ober-Mörlen) was completed one day prior to testing and stored at 4 - 8 °C until assay performance. The bio-barrier powder was solved in the bio-barrier diluent and heated for 20  2 minutes at 68 – 70 °C in a water bath under continuous stirring. The temperature did not exceed 70 °C. The mixture was allowed to cool in the turned-off water bath for another 10 minutes. The mixture was then filled into the membrane holders, 200 µL per membrane holder. Air bubbles were avoided. The filled membrane holders were sealed with parafilm and were stored at 4 – 8 °C until further use.

QUALIFY TEST
In order to assess whether the test system is suitable for the test item, approx. 100 mg of test item were applied into the “Qualify Test Vial”. The vial was shaken until the solution appeared homogenous, and incubated for at least 1 minute. Afterwards, the colour change was noted. Since a change in colour was visible in the “Qualify Test Vial”, the test item was considered to be suitable for the next step.

CATEGORISATION TEST
Approx. 100 mg of test item were applied into the “Category A Vial” as well as into the “Category B Vial”. The vials were shaken until the solution appeared homogenous. After at least one minute the colour change was monitored. Based on the colour change obtained, a test item is assigned to a category. If an intense colour change (similar to the category 1 colour chart) is observed in “Category A Vial” or in “Category B Vial” the test item is assigned to category 1. If a less intense colour change is observed (similar to the category 2 colour chart) is observed in “Category A Vial” or in “Category B Vial” the test item will be assigned to category 2. If no colour change is observed in either of the vials, a confirmation test is conducted. For the confirmation test two drops of the confirm reagent are added to the “Category B Vial”. The vial would be shaken for 5 seconds. The colour of the solution would match one of the colours shown in the accompanying colour chart, confirming that the test item is a category 2 substance.

CLASSIFICATION TEST
7 vials containing the CDS were pre-warmed to room temperature. 4 vials were used for quadruplicate measurement of the test item, the vial labelled (+) was used for the positive control (single measurement, Sulfuric acid 95-98%), and the vial labelled (-) was used for the negative control (single measurement, Citric acid (10% solution in deionised water)). The vial labelled C was used as colour reference for the CDS.
Application of the test item formulations and the controls was performed staggered to ensure accurate reaction times to be recorded.
The prepared bio-barriers were placed atop the CDS vials (not longer than 2 min prior to application) and approx. 500 mg of the test item or 500 µL of the controls, respectively, were applied per bio-barrier. Colour change or precipitation in the CDS solution were recorded in the raw data file.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

penetration time (in minutes)

Remarks:

Change in colour in the Chemical Detection System (CDS) solution

Run / experiment:

See details on "Details on Study Design" section

Value:

> 60

Vehicle controls validity:

valid

Remarks:

Qualify test: approx. 100 mg of test item applied into the "Qualify Test Vial". Vial shaken until solution appeared homogenous and incubated for at least 1 minute. Afterwards, the colour change was noted.

Negative controls validity:

valid

Remarks:

Classification test: vial labelled as (-). Single measurement, citric acid (10% solution in deionised water). Colour change in CDS solution was not observed after 60 minutes.

Positive controls validity:

valid

Remarks:

Classification test: vial labelled as (+). Single measurement, sulfuric acid -%. Colour change in CDS solution observed after 1.15 minutes.

Remarks on result:

other: Non corrosive to skin

Remarks:

No change in colour of CDS solution after > 60 minutes.

Other effects / acceptance of results:

The test item was classified as non corrosive.

Any other information on results incl. tables

Qualify Test

The test item induced a change in colour in the qualify test after 1 minute incubation. Since a change in colour was visible in the “Qualify Test Vial”, the test item was considered to be suitable for the categorisation test.

 

Categorisation Test

The test item induced a change in colour in the Category A vial but not in the Category B vial after 1 minute incubation. Therefore, a confirmation experiment did not have to be performed. Therefore, the test item was classified as category II.

Classification Test

 

Test Group	Time to colour change (minutes)	DOT Packing Group	R-Sentence	GHS
Negative Control	Colour change was not observed after 60	-	-	-
Positive Control	1.15	I	R35	1A
Test item	> 60	Non corrosive	-	-

 

Applicant's summary and conclusion

Interpretation of results:

other: non corrosive

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item Disodium titanate is non corrosive to skin.