Registration Dossier

Administrative data

Endpoint:
skin irritation / corrosion
Remarks:
in vitro
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study conducted in compliance with GLP regulations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
BASF AG, Department of Experimental Toxicology and Ecology

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 4-Aminoazobenzol
- Analytical purity: 97% (analytical report No.: 07L00179)
- Test-substance No.: 07/0429-1

Test animals

Species:
other: EpiDerm™
Strain:
other: in vitro: Human Skin Model Test
Details on test animals and environmental conditions:
- Tissue model: Epi-200
- Source: MatTek Corporation, Ashland MA, USA

Test system

Type of coverage:
open
Preparation of test site:
other: On day of receipt EpiDerm tissues were kept in the refrigerator. At least 1 hour but not more than 1.5 hours before test-substance application, tissues were transferred to 6-well plates with 0.9 mL assay medium and preconditioned in the incubator at 37°C.
Vehicle:
other: doubly distilled water
Controls:
other: Control tissues were concurrently applied with 50 μL of doubly distilled water (negative control, NC) and with 50 μL of 8 n potassium hydroxide (positive control, PC) respectively.
Amount / concentration applied:
25 μL (about 18 mg)
Duration of treatment / exposure:
3 minutes at room temperature and 1 hour in the incubator
Observation period:
after 3 minutes and after 1 hour
Number of animals:
two pieces of tissue
Details on study design:
HUMAN EPIDERMIS MODEL:
The EpiDerm model consists of normal, human-derived epidermal keratinocytes which have been cultured to form a multi layered, highly differentiated model of the human epidermis. It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo. The EpiDerm tissues (surface 0.6 cm²) are cultured on specially prepared cell culture inserts (MILLICELLs®, 10 mm Ø).

EXPERIMENTAL PROCEDURE:
On day of receipt EpiDerm tissues were kept in the refrigerator. At least 1 hour but not more than 1.5 hours before test-substance application, tissues were transferred to 6-well plates with 0.9 mL assay medium and preconditioned in the incubator at 37°C. The preincubation medium was replaced with fresh medium immediately before application.
Two tissues per exposure time (3 minutes at room temperature and 1 hour in the incubator) and test group (test material, negative control and positive control) were used.
A bulk volume of 25 μL of the test material was applied with a sharp spoon. Thereafter 25 μL doubly distilled water were added and homogeneously distributed together with the test substance.
Control tissues were concurrently applied with 50 μL of doubly distilled water (negative control, NC) and with 50 μL of 8 n potassium hydroxide (positive control, PC) respectively.
The tissues were washed with PBS to remove residual test material 3 minutes and 1 hour, respectively, after start of treatment. Rinsed tissues were kept in 24-well plates (holding plates) at room temperature on assay medium until all tissues per application time are dosed and rinsed. The assay medium was then replaced by MTT solution and tissues were incubated for 3 hours. After incubation, tissues were washed again with PBS and the formazan produced by the tissues was extracted with Isopropanol over night at room temperature. The optical density at a wavelength of 570 nm (OD570) of the extracts was determined spectrophotometrically. Blank values were established of 3 microtiter wells filled with Isopropanol for each microtiter plate.

EVALUATINON OF RESULTS:
Corrosivity potential of the test materials is predicted from the mean relative tissue viabilities obtained after 3 min treatment compared to the negative control tissues concurrently treated with doubly distilled water. A chemical is considered as "corrosive", if the mean relative tissue viability after 3 min treatment with a test material is decreased below 50%. In addition, those materials with a viability of ≥ 50% after 3 min treatment are considered as "corrosive" if the mean relative tissue viability after 1 hour treatment with a test material is decreased below 15%.

Results and discussion

Any other information on results incl. tables

Exposure time

Test article

Optical density at 570nm (mean)

Viability

[% of negative control]

3 minutes

Negative control

1.671

100

4-Aminoazobenzol

1.764

106

Positive control

0.233

14

1 hour

Negative control

1.662

100

4-Aminoazobenzol

1.818

109

Positive control

0.258

15

Based on the observed results and applying the evaluation criteria it was concluded, that 4-Aminoazobenzol, CAS 60-09-3 does not show a corrosive potential in the EpiDerm skin corrosivity test under the test conditions chosen.

Applicant's summary and conclusion