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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09 Dec 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
human
Strain:
other: reconstructed human epidermis EST-200
Details on test animals and environmental conditions:
TEST SKIN MODEL
- Source: MatTek Corporation, Ashland, USA
- Before the start of the test, the skin models were pre-incubated for 1 h under culture conditions (5% CO2, 37 °C) with assay medium. The medium was changed and the test and reference substances were applicated (50 µL/insert) onto the skin model.

ENVIRONMENTAL CONDITIONS (Incubator)
- Temperature (°C): 37
- CO2 gas concentration (%): 5

Test system

Type of coverage:
open
Preparation of test site:
other: intact reconstructed human epidermis
Vehicle:
unchanged (no vehicle)
Controls:
other: concurrent negative control tissue treated with distilled water
Amount / concentration applied:
TEST MATERIAL
- Amount applied: 0.05 mL (ca. 83 µL/cm²)
Duration of treatment / exposure:
3 min and 1 h
Observation period:
Not applicable
Number of animals:
Not applicable. Tests were performed in triplets for each treatment duration.
Details on study design:
TEST SITE
- Area of exposure: 0.6 cm²

REMOVAL OF TEST SUBSTANCE
- Washing (if done): after the incubation periods, the inserts were washed carefully
- Time after start of exposure: 3 min and 1 h

CELL VIABILITY MEASUREMENTS
- Method: MTT assay
- Details on method used: after exposure to the test substance, the skin model was incubated with MTT solution for 3 h. Thereafter, the inserts were washed 3 times with PBS. For viability testing, the inserts were placed in new 24-well plates and the extraction of blue formazan was performed in the extraction solution on a shaker for 120 min (120 U/min) at room temperature. For determination of cell viability, the solution was homogenized and 3 x 200 µL were inserted into a 96 well plate. The absorption was measured in duplicates at 570 nm in a plate reader.

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
other:
Value:
100
Remarks on result:
other: Basis:
Irritation / corrosion parameter:
other:
Value:
72
Remarks on result:
other: Basis:
Irritation / corrosion parameter:
other:
Value:
24
Remarks on result:
other: Basis:
Irritation / corrosion parameter:
other:
Value:
100
Remarks on result:
other: Basis:
Irritation / corrosion parameter:
other:
Value:
25
Remarks on result:
other: Basis:
Irritation / corrosion parameter:
other:
Value:
12
Remarks on result:
other: Basis:

Any other information on results incl. tables

Table 1. Results of the MTT assay.

Test substance

Tissue

OD

Cell viability

(% of negative control)

Value 1

Value 2

Value 3

Mean

Mean

(tissue 1+2)

Incubation time 3 min

Negative control

1

2.007

1.993

2.010

2.003

2.031

100

2

2.067

2.032

2.074

2.058

Test substance

1

1.263

1.250

1.292

1.268

1.454

72

2

1.638

1.635

1.648

1.640

Positive control

1

0.545

0.527

0.533

0.535

0.485

24

2

0.438

0.431

0.436

0.435

Incubation time 60 min

Negative control

1

1.841

1.848

1.853

1.847

1.755

100

2

1.687

1.640

1.658

1.662

Test substance

1

0.481

0.457

0.461

0.466

0.445

25

2

0.426

0.422

0.421

0.423

Positive control

1

0.168

0.163

0.191

0.174

0.213

12

2

0.251

0.250

0.252

0.251

OD: optical density

Applicant's summary and conclusion

Interpretation of results:
other: non-corrosive
Conclusions:
Under the conditions of this in vitro study, the test material is non-corrosive to reconstructed human epidermis. However, this study does not provide adequate information on skin irritation for classification purposes.