Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

EC Number:

247-556-2

EC Name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

Cas Number:

26264-05-1

Molecular formula:

C18H30O3S.C3H9N

IUPAC Name:

sodium dodecylbenzenesulfonate

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: All cells used to produce EpiDERM are purchased or derived from tissue obtained by MatTek Corporation from accredited institutions.

Source strain:

not specified

Details on animal used as source of test system:

Cells purchased or derived from suitable human tissues. The cells used were screened for potential biological contaminants.

Justification for test system used:

Standard as per OECD guideline

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDERM Reconstructed Human Epidermis
- Tissue batch number(s): 27636
- Production date: Not specified
- Shipping date: Not specified
- Delivery date: Not specified

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 36.2 to 37.3°C
- Temperature of post-treatment incubation (if applicable): 36.2 to 37.3°C

Test for colour interferance:
The test substance was checked for possible color interference before the study was started. Some non-colored test items may change into colored items in aqueous conditions and thus stain the skin tissues during the 1-hour exposure. To assess the color interference, 50 μl of the test item or 50 μl Milli-Q water as a negative control were added to 0.3 ml Milli-Q water. The mixture was incubated for approximately 1 hour at 37.0 ± 1.0°C in the dark. At the end of the exposure time the mixture was shaken and it was checked if a blue / purple color change was observed.

Test for reduction of MTT by the test substance:
The test substance was checked for possible direct MTT reduction before the study was started. To assess the ability of the test item to reduce MTT, 50 μl of the test item or 50 μl Milli-Q water as a negative control were added to 1 ml MTT solution (1 mg/mL) in phosphate buffered saline. The mixture was incubated for approximately 1 hour at 37.0 ± 1.0ºC. At the end of the exposure time it was checked if a blue / purple color change or a blue / purple precipitate was observed.

NUMBER OF REPLICATE TISSUES: Two tissues were used for a 3-minute exposure to the test substance and two for a 1-hour exposure. For the negative and positive controls, 2 tissues were treated with 50 μl Milli-Q water (negative control) and 2 tissues were treated with 50 μl 8N KOH (positive control) for both the 3-minute and 1-hour time point.

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

Amount/concentration applied:

50μl of the undiluted test item was added into the 6-well plates on top of the skin tissues.

Duration of treatment / exposure:

3 minutes and 1 hour of exposure

Duration of post-treatment incubation (if applicable):

Incubated for 3 hours with 300 µL MTT-medium.

Number of replicates:

Two tissues were used for a 3-minute exposure to the test substance and two for a 1-hour exposure

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minute application

Value:

93

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 hour application

Value:

78

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

The test substance was checked for color interference in aqueous conditions and possible direct MTT reduction by adding the test item to MTT medium. Because the solutions did not turn blue / purple nor a blue / purple precipitate was observed it was concluded that the test item did not interfere with the MTT endpoint.

The relative mean tissue viability obtained after the 3-minute and 1-hour treatments with the substance compared to the negative control tissues was 93% and 78% respectively. Because the mean relative tissue viability for the substance was not below 50% after 3 minutes treatment and not below 15% after 1 hour treatment the substance is considered to be not corrosive.

The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the acceptance limits of OECD 431 (lower acceptance limit ≥0.8 and upper acceptance limit
In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was < 8% for the negative control. The Coefficient of Variation between tissues replicates treated with the test item was 33% after the 1-hour treatment exposure. However, both viabilities were in the same category, indicating that the test system functioned properly.

Any other information on results incl. tables

Mean Tissue Viability in the in vitro Skin Corrosion Test with the test substance

	3-minute application viability (percentage of control)	1-hour application viability (percentage of control)
Negative control	100	100
Test substance	93	78
Positive control	7.6	13

Mean Absorption in thein vitro Skin Corrosion Test with the test substance

	3-minute application					1-hour application
	A (OD570)	B (OD570)	Mean (OD570)		SD	A (OD570)	B (OD570)	Mean (OD570)		SD
Negative control	2.060	1.911	1.985	±	0.105	1.966	1.939	1.953	±	0.019
Test substance	1.943	1.755	1.849	±	0.133	1.825	1.230	1.528	±	0.421
Positive control	0.167	0.134	0.150	±	0.023	0.298	0.199	0.249	±	0.070

SD = Standard deviation

Duplicate exposures are indicated by A and B.

In this table the values are corrected for background absorption (0.0427). Isopropanol was used to measure the background absorption.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, the test substance is not corrosive in the in vitro skin corrosion test under the experimental conditions described.