Benzeneacetyl chloride, 2,5-dimethyl-

Endpoint summary

Description of key information

study according to OECD test guideline 431; result: corrosive

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

draft guideline

GLP compliance:

yes

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

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

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

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.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin corrosion:

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.

Justification for classification or non-classification

Based on the avilable data 2,5-dimethylphenylacetyl chloride is classiefied according to Regulation (EU) No. 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemicals (GHS) as skin corrosive Category 1A 'Causes severe skin burns and eye damage'. Although no eye corrosion test was conducted and in accordance to CLP Regulation the substance is also considered to cause severe eye damage and is classified as Category 1 'causes serious eye damage' for precutionary reasons.