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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018-03-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)
Version / remarks:
2015-07-28
Deviations:
yes
Remarks:
but the deviations are of no relevance regarding the study results or the validity of the study.
GLP compliance:
yes (incl. QA statement)
Remarks:
signed 2015-09-14

Test material

Constituent 1
Chemical structure
Reference substance name:
Cobalt(2+) disulphamate
EC Number:
237-834-1
EC Name:
Cobalt(2+) disulphamate
Cas Number:
14017-41-5
Molecular formula:
Co(H2NO3S)2
IUPAC Name:
lambda2-cobalt(2+) disulfamate
Test material form:
solid
Details on test material:
- State of aggregation: red-brown solid
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at +15 to 25°C, store in the tighly closed original container, in a cool, dry and well-ventilated place.

In vitro test system

Test system:
artificial membrane barrier model
Source species:
other: not specified
Cell type:
other: synthetic macromolecular bio-barrier
Cell source:
other: not specified
Source strain:
not specified
Details on animal used as source of test system:
not applicable
Justification for test system used:
Corrositex TM is a validated and accepted in vitro method to assess if a test item can produce skin corrosion and to distinguish between GHS corrosivity categories 1A, 1B, and 1C.
Vehicle:
unchanged (no vehicle)
Details on test system:
SOURCE AND COMPOSITION OF MEMBRANE BARRIER USED
- Was the Corrositex® test kit used: yes (lot no. CT120516; supplier: ROMER Labs Deutschland GmbH, 35510 Butzbach, Germany)
- Components: a synthetic macromolecular bio-barrier and a chemical detection system (CDS)
- Apparatus and preparation procedures: three days prior to testing the bio-barrier matrix was prepared. 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 2 – 8 °C until further use.

WAS THE COMPATIBILITY TEST PERFORMED: yes
In order to test whether the test system is suitable for the test item, approximately 100 mg of the test item were applied into the “Qualify Test Vial”. The vial was shaken until the solution appeared homogenous, and incubated for 1 minute. Afterwards, the colour change was noted.
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 next step.

WAS THE TIMESCALE CATEGORY TEST PERFORMED: yes
In the categorisation test the observation period of the test item after application to the bio-barrier was determined:
- Category 1: observation period after application is 4 hours
- Category 2: observation period after application is 1 hour
Approximately 100 mg of the 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 1 minute the colour change was monitored.
Based on the observed colour change, 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 (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.
The test item induced a change in colour in the Category A vial and in the Category B vial after 1 minute of incubation. According to the colour scheme the test item does not appear to be a strong acid or base and was assigned to category 2. It was concluded that the required duration of the classification test was up to 60 minutes.

TEMPERATURE USED DURING TREATMENT: room temperature

METHOD OF DETECTION
- Chemical or electrochemical detection system: chemical detection system

METHOD OF APPLICATION (CLASSIFICATION TEST):
8 vials containing the CDS were pre-warmed to room temperature (test item: 4 vials; negative control: 1 vial; positive control (sulfuric acid): 1 vial; positive control (sodium hydroxide): 1 vial; colour reference for CDS: 1 vial).
The prepared bio-barriers were placed atop the CDS vials (not longer than 2 minutes prior to application) and the test item or the respective controls were applied per bio-barrier for 1 hour, depending on the results of the categorisation test. The time interval of the possible colour change or precipitation in the CDS solution was recorded.

INTERPRETATION OF THE RESULTS:
For each vial the period until observable change in CDS solution was determined. The mean of the quadruplicate measurement was calculated. The test item was classified according to the criteria in table 1 as presented in the field "Any other information on materials and methods incl. tables" below.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): approx. 500 mg of the neat test item

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 500 µL of citric acid (10 % (w/v) solution in deionised water)

POSITIVE CONTROL (two positive controls were used)
- Amount(s) applied (volume or weight):
1) 500 µL of sulfuric acid 95 - 97 %
2) 110 ± 15 mg of sodium hydroxide
Duration of treatment / exposure:
60 minutes
Duration of post-treatment incubation (if applicable):
not applicable
Number of replicates:
Test item: quadruplicates
Negative control: single measurement
Positive control: single measurement

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
penetration time (in minutes)
Value:
0
Vehicle controls validity:
not examined
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: Colour change was not observed up to 60 minutes (treatment period)
Other effects / acceptance of results:
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 next step.

CATEGORISATION TEST:
The test item induced a change in colour in the Category A vial and in the Category B vial after 1 minute of incubation. According to the colour scheme the test item does not appear to be a strong acid or base and was assigned to category 2. It was concluded that the required duration of the classification test was up to 60 min.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: negative control did not induce a change in the colour of CDS reagent after 60 minutes (acceptability criteria: negative control does not induce a physical change (colour or precipitation) up to 60 minutes in the CDS solution in the classification test).

- Acceptance criteria met for positive control: the positive control sulfuric acid showed a distinct change in the colour of the CDS reagent in the time interval of 0 – 3 minutes. The positive control sodium hydroxide induced a change in the colour of the CDS reagent after 3 – 60 minutes (acceptability criteria: positive control (Sulfuric acid) induces a physical change (colour or precipitation) in the CDS solution in the classification test after 0 – 3 minutes. Sodium hydroxide induces a physical change (colour or precipitation) in the CDS solution in the classification test after > 3 – 60 minutes (subcategory 1B)).

Please also refer to the field "Any other information on results incl. tables" below.

Any other information on results incl. tables

CLASSIFICATION TEST:


Test Group

Time Interval of Colour Change

UN GHS

Negative Control

Colour change was not observed up to 60 minutes

Non corrosive

Positive Control

Sulfuric acid

1 minute 22 seconds

Corrosive

subcategory 1A

Positive Control

Sodium Hydroxide

12 minutes 05 seconds

Corrosive

subcategory 1B

Test Item

Up to 60 minutes

Non corrosive

HISTORICAL DATA

H2SO4

NaOH

Mean time till colour change of positive control [min]

01:03

18:46

Standard Deviation [min]

00:14

12:53

Range of mean times

00:46—01:35

06:30—60:00

mean ± 3 standard deviations

00:20—01:46

00:00—57:24

Data of 25 Experiments shared between 33 studies performed from March 2015 to January 2018.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item is not corrosive to the skin.
According to the Regulation (EC) No 1272/2008 and subsequent regulations, cobalt(II) sulfamate tetrahydrate does not require classification and labelling as being corrosive to skin.