Amines, C14-16 (even numbered)-alkyldimethyl, N-oxides

Skin irritation / corrosion

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

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N-dimethyldecylamine N-oxide

EC Number:

220-020-5

EC Name:

N,N-dimethyldecylamine N-oxide

Cas Number:

2605-79-0

Molecular formula:

C12H27NO

IUPAC Name:

decyl(dimethyl)amine oxide

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

Results

Results 1

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

Results 2

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.