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Diss Factsheets

Administrative data

Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
17 January 2006 to 11 April 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report date:
2006

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
Version / remarks:
draft guideline
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
470-780-9
EC Name:
-
Cas Number:
55312-97-5
Molecular formula:
C10 H11 Cl O
IUPAC Name:
2-(2,5-dimethylphenyl)acetyl chloride

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Justification for test system used:
The methods used for this protocol have already been described in the literature and relevant guidelines or guideline drafts. Unless internationally recognised standardised reference values or validation tests are available, the method used here must be viewed with this in mind.
The draft guideline was approved after conduction of the test, hence, it is a standard method according to Regulation (EU) No. 1907/2008.
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: The experiment was carried out on a reconstructed human epidermis EST-1000 (CellSystems, St. Katharinen, Germany).
- Tissue batch number(s): Kit contents EST-1000; CellSystems, Cat.-No.CS-1001).

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 3 min at roomtemperature and 60 min at 37°C, 5% CO2, maximum humidity

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: with PBS three times, volume not reported
- Observable damage in the tissue due to washing: not reported

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 2h
- Spectrophotometer: automatic reader (EL808, Bio-Tek; 96 well format, 200 µL).
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: triplicate


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

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:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50µL
- Concentration (if solution): 100%

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50µL
- Concentration (if solution): 0.9% NaCl solution
Duration of treatment / exposure:
3 min at room temperature and 60 min at 37°C
Number of replicates:
triplicates

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean or three runs, negative control, 3 min
Value:
100
Vehicle controls validity:
not examined
Negative controls validity:
valid
Remarks:
100%, mean OD 1.39
Positive controls validity:
not examined
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean of three runs, 3 min
Value:
20.28
Vehicle controls validity:
not examined
Negative controls validity:
valid
Remarks:
100%
Positive controls validity:
not examined
Remarks on result:
other: mean OD 0.28
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean of three runs, negative control, 60 min
Value:
100
Vehicle controls validity:
not examined
Negative controls validity:
valid
Remarks:
100% viability, mean OD 1.12
Positive controls validity:
not examined
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean of three runs, 60 min
Value:
0.74
Vehicle controls validity:
not examined
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
other: mean OD 0.01

Any other information on results incl. tables

Summary of results:

















































Sample No.



Test item



Time [min]



OD mean*



StdDev



% Viability



1-3



control NaCl 0.9%



60



1.12



0.05



100.0



4-6



Test item



60



0.01



0.01



0.74



16-18



control NaCl 0.9%



3



1.39



0.05



100.0



19-21



Test item



3



0.28



0.01



20.28



* 6 values


Applicant's summary and conclusion

Interpretation of results:
Category 1A (corrosive) based on GHS criteria
Conclusions:
The test item was characterised by a significant impact on cell viability after the 3 min and after the 60 min period. Thus, the test item should be labelled as corrosive to skin.
Executive summary:

In a dermal irritation/corrosion study performed in accordance with OECD Guideline 431 (In Vitro Skin Irritation) (draft guideline (2006)), 2,5-dimethylphenylacetyl chloride(100% a.i.) was applied to the three-dimensional human epidermis model tissue for an exposure period of 3 min and 60 min, respectively, in triplicates. 50 μL of the undiluted test item were topically applied to the epidermal surface.


 


After 3 min or 60 min exposure at room temperature and at 37°C, respectively, the tissues were washed with phosphate buffered saline to remove any residual test material. Subsequently the cytotoxicity (irritancy) was determined by means of a MTT-viability test expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT at the end of the treatment.


 


The negative (0.9 % NaCl) control gave responses that were within the acceptance criteria and as such demonstrated the validity of the study.


The relative mean tissue viability obtained after 3 min and 60 min treatment with 2,5-dimethylphenylacetyl chloride compared to the negative control tissues was 20.28% and 0.74%. Since the mean relative tissue viability for the test substance was below 50% after 3 min and below 15% after 60 min exposure, 2,5-dimethylphenylacetyl chloride is identified to be corrosive.