Sodium salts of substituted amino acid

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:

12 Nov 2018 - 17 Dec 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

July 2015

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

July 2012

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Test material form:

liquid

Remarks:

aquous solution

Details on test material:

Sodium salts of substituted amino acid (2) solution, FC-C 13588
Appearance: clear colorless solution

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

skin obtained from plastic surgery from multiple donors

Justification for test system used:

In the interest of sound science and animal welfare, a sequential testing strategy is recommended to minimize the need of in vivo testing. One of the validated in vitro skin irritation tests is the EPISKIN test, which is recommended in international guidelines (e.g. OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN Small Model™
- Tissue batch number: 18-EKIN-050
- Surface: 0.38 cm^2
- Expiration date: 17 December 2018

TEST FOR THE INTERFERENCE OF THE TEST ITEM WITH THE MTT ENDPOINT
- The test substance was checked for possible color interference and reduction of MTT before the study. No interference was found.

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during exposure to the test item: room temperature
- Temperature of incubations(°C): 37.0 ± 1.0°C (actual range 35.9 – 37.0°C)
- Humidity(%): 80 - 100% (actual range 70 - 90%)

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: tissues were washed with phosphate buffered saline (1 washing step)
- Observable damage in the tissue due to washing: no

APPLICATION/TREATMENT OF TEST ITEM
- Number of replicate tissues: 3 for the test substance. Additionally, 3 tissues for the negative and the positive control each.
- Volume test item: 25 μL
- The positive control was re-spread after 7 minutes contact time.
- Exposure period: 15 minutes.
- Incubation period after exposure: 42 hours at 37°C.

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

MEASUREMENT OF CELL VIABILITY
- After incubation, tissues were dried and incubated with 2 mL MTT-solution (0.3 mg/mL in PBS).
- Incubation time: 3 hours at 37°C
- Formazan was extracted with 500 μL isopropanol (MatTek corporation)
- The amount of extracted formazan was determined spectrophotometrically at 570 nm in duplicate with the TECAN Infinite® M200 Pro Plate Reader.

INTERPRETATION (see Table 1)
A test item is considered irritant in the skin irritation test if:
The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
A test item is considered non-irritant in the in vitro skin irritation test if:
The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is > 50% of the mean viability of the negative controls.

ACCEPTABILITY CRITERIA
a) The absolute mean OD570 (optical density at 570 nm) of the three tissues of the negative control should reasonably be within the laboratory historical control data range and the Standard Deviation value (SD) of the % viability should be ≤ 18.
b) The mean relative tissue viability of the positive control should be ≤ 40% relative to the negative control and the Standard Deviation value (SD) of the % viability should be ≤ 18.
c) The SD calculated from individual % tissue viabilities of the three identically treated replicates should be ≤ 18.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

The liquid test item was applied undiluted (25 μL) directly on top of the tissue.

Duration of treatment / exposure:

15 ± 0.5 minutes at room temperature

Duration of post-treatment incubation (if applicable):

42 hours at 37°C +3 hours with MTT

Number of replicates:

The test was performed on a total of 3 tissues per test item together with negative and positive controls.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Value:

104

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- No visible damage on test system, no direct-MTT reduction and no colour interference with MTT was observed.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The absolute mean OD570 of the negative control tissues was within the laboratory historical control data range.
- Acceptance criteria met for positive control: The positive control had a mean cell viability after 15 ± 0.5 minutes exposure of 11%.
- Acceptance criteria met for variability between replicate measurements: The standard deviation value of the percentage viability of three tissues treated identically was < 7%, indicating that the test system functioned properly.

Any other information on results incl. tables

Table 2: Individual OD Measurements at 570 nm

	A (OD570)	B (OD570)	C (OD570)
Negative control OD570measurement 1 OD570measurement 2	1.1825 1.1440	1.1022 1.0589	1.2550 1.2064
Test item OD570measurement 1 OD570measurement 2	1.2464 1.2055	1.2406 1.1709	1.2199 1.1644
Positive control OD570measurement 1 OD570measurement 2	0.1414 0.1401	0.2036 0.2002	0.1645 0.1616

OD = Optical density

Triplicate exposures are indicated by A, B and C.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results of a skin irritation study, performed according to OECD guideline 439, Sodium salts of substituted amino acid (2) solution is non-irritant under the experimental conditions described in this report. The substance does not require classification according to GHS and according to Regulation (EC) No. 1272/2008.