Registration Dossier

Administrative data

Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16 September 2016 - 21 October 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP compliant

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report Date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
Version / remarks:
Adopted 29 July 2016
Deviations:
no
Qualifier:
according to
Guideline:
other: EU Method B.40 BIS (In Vitro Skin Corrosion: Human Skin Model Test)
Version / remarks:
31 May 2008
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Inspection dates: 7 - 11, 14 and 16 September 2015. Date of the certificate: 03 November 2015.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Details on test material:
- Appearence: colourless liquid
- Test substance storage: at room temperature

For further details, see section "confidential details on test material"
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL:
- At room temperature

FORM AS APPLIED IN THE TEST
- The liquid test item was applied undiluted (400 µl; excess amount) directly on top of the tissue.
- Since the test item is highly volatile for the 1-hour exposure an excess amount (400 µl) of the test item was applied every 15 minutes.

OTHER SPECIFICS:
- No correction was made for the purity/composition of the test item.

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Details on animal used as source of test system:
Not applicable
Justification for test system used:
Recommended test system in international guidelines (OECD and EC).
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm Skin Model EPI-200
- Tissue batch number(s): 24364 Kit M and L
- Source: MatTek Corporation, Ashland, MA, USA

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: All incubations, with the exception of the test item incubation of 3 minutes at room temperature, were carried out at 37.0 ± 1.0°C (actual range 35.6 - 37.3°C).

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT concentrate (5 mg/ml) diluted (1:5) with MTT diluent (supplemented DMEM)
- Incubation time: 3 hours (37°C)
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: OD (540-570) = 1.496+/-0.034 [1.0 - 3.0]
- Barrier function: ET-50 = 6.52 hrs [4.77 - 8.72 hrs]
- Morphology: Functional stratum corneum, viable basal cell layer, and intermediate spinous and granular layers
- Contamination: No contamination (absence of bacteria, fungus and mycoplasma)

NUMBER OF REPLICATE TISSUES: 4 tissues per test item together with a negative control and positive control (2 tissues were used for a 3-minute exposure to test item and two for a 1-hour exposure)

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

PREDICTION MODEL / DECISION CRITERIA
A test item is considered corrosive in the skin corrosion test if:
a) The relative mean tissue viability obtained after 3-minute treatment compared to the negative control tissues is decreased below 50%.
b) In addition, a test item considered non-corrosive (viability >= 50%) after the 3-minute treatment is considered corrosive if the relative tissue viability after 1-hour treatment with the test item is decreased below 15%.
A test item is considered non corrosive in the in vitro skin corrosion test if:
a) The relative mean tissue viability obtained after the 3-minute treatment compared to the negative control tissues is not decreased below 50%.
b) In addition, the relative tissue viability after the 1-hour treatment is not decreased below 15%.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Due to the high volatility of the test item an excess amount (400 µl) of the undiluted test item was added into the 6-well plates on top of the skin tissues for the 3-minute exposure. For the one hour incubation, the tissues were re-treated every 15 minutes with an excess amount (400 µl) of the undiluted test item.

NEGATIVE CONTROL
- Amount applied: 50 µl Milli-Q water

POSITIVE CONTROL
- Amount applied: 50 µl KOH
- Concentration: 8N
Duration of treatment / exposure:
3-minute and 1-hour exposures
Number of replicates:
4 tissues per test item together with a negative control and positive control (2 tissues were used for a 3-minute exposure to Test item and two for a 1-hour exposure)

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Remarks:
Mean values
Run / experiment:
3-minute application
Value:
90
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Remarks:
100%
Positive controls validity:
valid
Remarks:
11%
Remarks on result:
no indication of irritation
Irritation / corrosion parameter:
% tissue viability
Remarks:
Mean values
Run / experiment:
1-hour application
Value:
7
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Remarks:
100%
Positive controls validity:
valid
Remarks:
11%
Remarks on result:
other: Corrosive
Other effects / acceptance of results:
OTHER EFFECTS:
- Visible damage on test system: Not specified
- Direct-MTT reduction: No
- Colour interference with MTT: No

DEMONSTRATION OF TECHNICAL PROFICIENCY: Yes

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes, mean OD570 (3-minute exposure): 1.556 and mean OD570 (1-hour exposure): 1.679.
- Acceptance criteria met for positive control: Yes, mean relative tissue viability following 1-hour exposure: 11%.
- Acceptance criteria met for variability between replicate measurements: Yes, all coefficients of variation between tissue replicates were below 30%.
- Range of historical values if different from the ones specified in the test guideline: see section "Any other information on results incl. tables".

Any other information on results incl. tables

Preliminary tests

1,1,1-trifluoroacetone was checked for colour 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 1,1,1-trifluoroacetone did not interfere with the MTT endpoint.

Main test

The mean absorption at 570 nm measured after treatment with 1,1,1-trifluoroacetone and controls are presented in the following Table. The individual OD570 measurements are presented in an other Table below.

Mean absorption in the in vitro skin corrosion test with 1,1,1-trifluoroacetone

  3 -minute application              1 -hour application             

 A (OD570)

 B (OD570)

 Mean (OD570)

 

 SD

 A (OD570)

 B (OD570)

 Mean (OD570)

 

 SD

 Negative control

 1.526

1.586 

1.556 

 +/-

0.042 

 1.770

1.588 

 1.679

 +/-

 0.129

 Lithium

Trifluoromethanesulfonate

 1.417

 1.393

 1.405

 +/-

 0.016

 0.137

 0.108

 0.122

 +/-

 0.021

 Positive control

 0.180

 0.155

 0.167

 +/-

 0.018

 0.205

 0.163

 0.184

 +/-

 0.030

SD= Standard deviation

Duplicate exposures are indicated by A and B

In this table the values are corrected for background absorption (0.0420). Isopropanol was used to measure the background absorption.

The following Table shows the mean tissue viability obtained after 3-minute and 1-hour treatments with 1,1,1-trifluoroacetone compared to the negative control tissues.

 

3-minute application

Viability, percentage of control

1 -hour application

Viability, percentage of control 

 Negative control

100 / SD: 3.8 

100 / SD: 10.3 

 Lithium Trifluoromethanesulfonate

90 / SD: 1.6 

7 / SD: 21.4 

 Positive control

11 / SD: 13.9 

11 / SD: 20.6 

SD= Standard deviation

Skin corrosion is expressed as the remaining cell viability after exposure to the test item.

Historical control data for in vitro skin corrosion studies

      Negative control     Positive control     Positive control
 

 3 -minute treatment

(OD570)

 1 -hour treatment

(OD570)

 3 -minute treatment

(OD570) 

 1 -hour treatment

(OD570)

 3 -minute treatment

(% viability) 

 1 -hour treatment

(% viability)

 Range  1.324 - 2.615  1.361 - 2.352  0.172 - 0.56  0.057 - 0.277  6 - 22  3 - 12
 Mean  1.86  1.86  0.18  0.13  10.67  7.17
 SD  0.24  0.22  0.10  0.05  3.9  2.36
 n  65  67  64  61  30  30

SD= Standard deviation

n= Number of observations

The above mentioned historical control data range of the controls were obtained by collecting all data over the period of December 2012 to December 2015.

Applicant's summary and conclusion

Interpretation of results:
Category 1B (corrosive) based on GHS criteria
Conclusions:
1,1,1-trifluoroacetone is corrosive in the in vitro skin corrosion test (OECD Guideline No. 431, adopted 29 July 2016) under the experimental conditions described in this report.
The substance should be classified as corrosive to skin subcategories 1B and 1C according to UN GHS criteria.
Executive summary:

The assessment of the corrosive potential to skin of 1,1,1-trifluoroacetone was carried out, under GLP compliance, using an in vitro skin corrosive test based on the guidelines described in: OECD No. 431 (adopted 29 July 2016) and EU Method B.40 BIS.

The test consisted of topical application of 1,1,1-trifluoroacetone ( 400 µl; excess amount, every 15 minutes for the 1 -hour exposure) on the skin tissue for 3-minute and 1-hour. After exposure the skin tissue was thoroughly rinsed to remove the test item followed by immediate determination of the cytotoxic (corrosive) effect.

Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) at the end of the treatment.

The relative mean tissue viability obtained after the 3-minute and 1-hour treatments with 1,1,1-trifluoroacetone compared to the negative control tissues was 90% and 7% respectively.

Because the mean relative tissue viability for 1,1,1-trifluoroacetone was not below 50% after 3 minutes treatment but was below 15% after 1 hour treatment, 1,1,1-trifluoroacetone is considered to be corrosive. The substance should be classified as corrosive to skin subcategories 1B and 1C according to UN GHS criteria.