α,α-dichlorotoluene

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental study based on guideline OECD 431

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

29th July 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

α,α-dichlorotoluene

EC Number:

202-709-2

EC Name:

α,α-dichlorotoluene

Cas Number:

98-87-3

Molecular formula:

C7H6Cl2

IUPAC Name:

(dichloromethyl)benzene

Constituent 2

Reference substance name:

Dichloromethylbenzene

EC Number:

249-854-8

EC Name:

Dichloromethylbenzene

Cas Number:

29797-40-8

IUPAC Name:

(dichloromethyl)benzene

Details on test material:

- Name of test material (as cited in study report): Benzylidenchlorid
No more data available

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Not specified

Source strain:

not specified

Details on animal used as source of test system:

The test was carried out with the reconstituted three-dimensional human skin model EpiDerm (MatTek). This skin model consists of normal (non-cancerous), human-derived epidermal keratinocytes (NHEK) which have been cultured to form a multilayered, highly differentiated model of the human epidermis. The NHEK are cultured on chemically modified, collagen-coated cell culture inserts (Millicell). The EpiDerm skin model exhibits in vivo-like morphological and growth characteristics which are uniform and highly reproducible. It consists of organised basal, spinous, granular and cornified layers analogous to those found in vivo.

Vehicle:

other: The NHEK are cultured on chemically modified, collagen-coated cell culture inserts (Millicell).

Control samples:

yes, concurrent negative control

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

6-well plates containing 0.9 mL pre-warmed assay medium per well. The 6-well plates were pre-incubated in a humidified incubator at 37 ± 1°C, 5.0% CO2 / 95% air for at least 1 h. Then the medium was replaced by 0.9 mL fresh assay medium and the surface was dried using a sterile cotton tip.

Duration of treatment / exposure:

60min experiment and 3 min experiment

Duration of post-treatment incubation (if applicable):

3h

Number of replicates:

6

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 min experiment

Value:

> 0.2 - < 1.3

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item showed no corrosive effects. The test item is classified as “non-corrosive“.

Executive summary:

In the present study the skin corrosivity potential of Benzal chloride was analysed. Since corrosive chemicals are cytotoxic after a short time exposure to the stratum corneum of the epidermis the cytotoxic effects of the test item on EpiDerm, a reconstituted three-dimensional human epidermis model, were determined. Hereby, the test item was applied topically. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after a 3 min and 60 min exposure period and compared to those of the concurrent negative controls.

The mixture of 50 μL test item per 1 mL MTT medium showed no reduction of MTT as compared to the solvent. The mixture did not turn blue/purple. Therefore, NSMTT equaled 0%.

The mixture of 50 μL test item per 300 μL Aqua dest. and per 90 μL isopropanol showed no colouring as compared to the solvent. Therefore NSC equaled 0%.

The test item showed no non-specific reduction of MTT and no relevant colouring potential after mixture with aqua dest. and with isopropanol. Therefore, no additional controls for correction of possible false-negative results were necessary.

The test item showed no corrosive effects. The mean relative tissue viability (% negative control) was ≥ 50% (101.5%) after 3 min treatment and ≥ 15% (91.6%) after 60 min treatment.