γ-valerolactone

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-07-13 to 2020-12-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))

Version / remarks:

31 July 2019

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

18 June 2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

γ-valerolactone

EC Number:

203-569-5

EC Name:

γ-valerolactone

Cas Number:

108-29-2

Molecular formula:

C5H8O2

IUPAC Name:

5-methyloxolan-2-one

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Batch number of test material: Grosss 542
- Expiration date of the batch: 04 June 2022

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Not indicated

Justification for test system used:

OECD accepted in vitro model system as part of a turnkey test strategy to assess the skin irritation potential of chemicals

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ 200 kit (MatTek In Vitro Life Science Laboratories, Bratislava, Slovakia)
- Tissue batch number: 30881
- Date of initiation of testing: 2020-07-22 (Date of quality check)

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: Room temperature (for the 3-minutes incubation period) or at 37°C (for 1-hour incubation period)

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: Tissues were washed with sterile PBS (number and volume not indicated)
- Observable damage in the tissue due to washing: Not indicated

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mL of a 1.0 mg/mL MTT solution
- Incubation time: 3 hours
- Spectrophotometer: SunriseTM Absorbance Reader
- Wavelength: 570 nm without reference filter

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability and barrier function: MatTek determines the ET50 value following exposure to Triton X-100 (1%) for each EpiDermTM batch. The ET50 must fall within an established range based on a historical database of results (table 1)

NUMBER OF REPLICATE TISSUES: 2 tissues per incubation time

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
No direct MTT interference occured, thus no freeze-killed control tissues were used.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: One test sequence was conduced using 2 replicate tissues per time point

PREDICTION MODEL / DECISION CRITERIA
- 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 applied: 30 µL

NEGATIVE CONTROL
- Amount applied: 50 µL deionized water

POSITIVE CONTROL
- Amount applied: 50 µL 8 N potassium hydroxide solution
- Concentration: 8 N

Duration of treatment / exposure:

3 min and 1 hour treatments

Duration of post-treatment incubation (if applicable):

No post-incubation period

Number of replicates:

2 tissue replicates per time point

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Run 1 (1 hour incubation time, 2 tissue replicates)

Value:

21

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Run 1 (3 minutes incubation time, 2 tissue replicates)

Value:

86.6

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: Not indicated
- Direct-MTT reduction: No
- Colour interference with MTT: No

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes (see table 2-4)
- Acceptance criteria met for positive control: Yes (see table 2-4)
- Acceptance criteria met for variability between replicate measurements: Yes (see table 2-4)
- Range of historical values if different from the ones specified in the test guideline: No

Any other information on results incl. tables

Table 3: Individual and mean OD570 values, individual and mean viability values, standard deviations and coefficients of variation (exposure period 3 min)

Test substance identification		tissue 1	tissue 2	mean	SD	CV [%]
NC	mean OD570	2.085	2.131	2.108
	Viability [% of NC]	98.9	101.1	100.0	1.5	1.5
Test item	mean OD570	1.735	1.916	1.825
	Viability [% of NC]	82.3	90.9	86.6	6.1	7.0
PC	mean OD570	0.171	0.192	0.181
	Viability [% of NC]	8.1	9.1	8.6	0.7	8.0

 Table 4: Individual and mean OD570 values, individual and mean viability values, standard deviations and coefficients of variation (exposure period 1 hour)

Test substance identification		tissue 1	tissue 2	mean	SD	CV [%]
NC	mean OD570	2.083	1.936	2.010
	Viability [% of NC]	103.6	96.4	100.0	5.2	5.2
Test item	mean OD570	0.440	0.403	0.421
	Viability [% of NC]	21.9	20.0	21.0	1.3	6.2
PC	mean OD570	0.061	0.063	0.062
	Viability [% of NC]	3.0	3.1	3.1	0.1	2.3

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

The Skin Corrosion Test according to OECD guideline 431 showed no skin corrosive potential of gamma-Valerolacton.