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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:
2011-09-30 to 2012-01-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: aqueous solution
Details on test material:
- Name of test material (as cited in study report): N,N-dimethyldecylamine-N-oxide (solution)
- Substance type: colourless to yellowish liquid
- Analytical purity: 40.5% active
- Impurities (identity and concentrations): peroxide: 0.01%, free amine: < 0.5%
- Purity test date: 2011-11-14
- Lot/batch No.: 1108042301
- Expiration date of the lot/batch:2 years in original closed packaging
- Storage condition of test material: 10 - 25°C
- Other: pH = 7.59

In vitro test system

Test system:
human skin model
Source species:
human
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EST-1000
- Tissue batch number(s): EST-111205-001

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: not reported

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: Single washing step with Dulbecco's phosphate buffered saline (D-PBS). Volume not reported.
- Observable damage in the tissue due to washing: None reported.
- Modifications to validated SOP: None reported

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 hours at 37°C
- Spectrophotometer: not specified
- Wavelength: 540 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability/barrier function: Each batch of the epidermal model used meets defined production release criteria, set by the supplier, among which those for viability and for barrier function are the most relevant (MTT, 2 hours Triton X-100: target > 50%). The barrier properties of the tissues were verified by the supplier.
- Morphology: No. of cornified layers - 5; No. of vital cell layers - 4.
- Contamination: The skin model was free of contamination with bacteria (including mycoplasma) or fungi.

NUMBER OF REPLICATE TISSUES: 3

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 123.5 μL
- Concentration (if solution): 40.5 %

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 123.5 μL
- Concentration (if solution): 100% (deionised water)

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): 8N
Duration of treatment / exposure:
3 minutes, 1 hour
Duration of post-treatment incubation (if applicable):
3 hours
Number of replicates:
3

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
3 minutes
Value:
78.8
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: mean of 3 replicates
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
1 hour
Value:
65.9
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: mean of 3 replicates
Other effects / acceptance of results:
In comparison to the negative controls, the mean viability of cells exposed to the test item was 78.8% after a 3-minute exposure period and 65.9% after a 1-hour exposure. The OD540 values were well above the cut-off percentage cell viability values distinguishing corrosive from non-corrosive test items of <50% or <15% for a 3-minute or 1-hour treatment, respectively. Therefore, the test item was non-corrosive in this skin model and is predicted to be non-corrosive to human skin.
The mean viability of cells treated with the positive reference item 8 N KOH were 5.0% (3-minute incubation) and 1.2% (1-hour incubation) of the negative controls and were below the cut-off values. Hence, 8 N KOH caused pronounced corrosion in this skin model and is predicted to be corrosive to human skin.
All quality criteria required were fulfilled

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In comparison to the negative controls, the mean viability of cells exposed to the test item was 78.8% after a 3-minute exposure period and 65.9% after a 1-hour exposure. The OD540 values were well above the cut-off percentage cell viability values distinguishing corrosive from non-corrosive test items of <50% or <15% for a 3-minute or 1-hour treatment, respectively. Therefore, the test item was non-corrosive in this skin model and is predicted to be non-corrosive to human skin.
Executive summary:

In an in vitro skin corrosivity study performed in accordance with OECD Guideline 431 using the EST-100 model the test item, N,N-dimethyldecylamine-N-oxide (solution), was applied to the skin surface. De-ionised water was used as the negative control. 8 N KOH was used as the positive reference item. Two exposure times of 3 minutes or 1 hour were employed.

In comparison to the negative controls, the mean viability of cells exposed to the test item was 78.8% after a 3-minute exposure period and 65.9% after a 1-hour exposure. The OD540values were well above the cut-off percentage cell viability values distinguishing corrosive from non-corrosive test items of <50% or<15% for a 3-minute or 1-hour treatment, respectively. Therefore, the test item was non-corrosive in this skin model and is predicted to be non-corrosive to human skin.

The mean viability of cells treated with the positive reference item 8 N KOH were 5.0% (3-minute incubation) and 1.2% (1-hour incubation) of the negative controls and were below the cut-off values. Hence, 8 N KOH caused pronounced corrosion in this skin model and is predicted to be corrosive to human skin.

Under the present test conditions N,N-dimethyldecylamine-N-oxide (solution) tested at two exposure times of 3 minutes or 1 hour was non-corrosive to skin in vitro.