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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:
14 Nov 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-Guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
other: OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
Deviations:
yes
Remarks:
no positive control used
Qualifier:
according to guideline
Guideline:
other: EU Method B.40 bis (In Vitro Skin Corrosion: Human Skin Model Test)
Deviations:
yes
Remarks:
no positive control used
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
Dodecanoic acid, ester with 1,2,3-propanetriol, acetylated
EC Number:
294-597-7
EC Name:
Dodecanoic acid, ester with 1,2,3-propanetriol, acetylated
Cas Number:
91744-35-3
IUPAC Name:
91744-35-3
Details on test material:
- Name of test material (as cited in study report): only trade name given
- Chemical name: Acetylided glyceride-mixture
- Physical state: light yellow liquid
- Analytical purity: 99.7%
- Composition of test material, percentage of components: triacetin, 0.2%; glycerol monolaurate, diacetylated, 73%; glycerol dilaurate, acetylated, 24%; glycerol trilaurate, 2.5%; unknown ingredients, 0.3%
- Lot/batch No.: CH70920C
- Expiration date of the lot/batch: 20 Sep 2008
- Storage condition of test material: at room temperature

Test animals

Species:
human
Strain:
other: reconstructed human epidermis EST-1000
Details on test animals or test system and environmental conditions:
TEST SKIN MODEL
- Source: CellSystems, St. Katharinen, Germany
- Adaptation to cell culture conditions: inserts with EST-1000 reconstructed human epidermis (0.6 cm²) were packed under sterile conditions and were shipped refrigerated on supplemented Agarose. Upon arrival, 6-well culture plates were pre-filled with 1 mL of fresh and cool maintenance medium. The reconstructed tissues were placed into the prepared cell culture plates (1 insert/well) and were adapted to the recommended tissue culture conditions (5% CO2, 37 °C, max humidity) afterwards for at least 6 h before use. In case of cultivation of the skin equivalents for more than 24 h, a daily medium change is required by aspirating the medium and replacing it by 1 mL new maintenance medium (37 °C) for each well.

ENVIRONMENTAL CONDITIONS (Incubator)
- Temperature (°C): 37 ± 2
- CO2 gas concentration (%): 5
- Humidity: maximum

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 0.9% NaCl
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 with PBS.
- Time after start of exposure: 3 min and 1 h

CELL VIABILITY MEASUREMENTS
- Method: MTT assay
- Details on method used: for viability testing, the inserts were placed in new 24-well plates containing 300 µL of MTT solution (37 °C, 1 mg/mL in MTT-assay medium delivered by CellSystems®). The tissues were incubated for about 2 h under cell culture conditions (5% CO2, 37 °C, max humidity). The extraction of blue formazan was performed in isopropanol (24-well plates, 2 mL per insert) on a vertical shaker (at least 60 min). For determination of cell viability, the absorption of the isopropanol extracts was measured in duplicates at 570 nm in an automatic reader (EL808, Bio-Tek; 96-well format, 200 µL). Data acquisition and evaluation were done with "KC4" (software by Bio-Tek).
- Reliability check: Reliability of the test was confirmed before by interlaboratory validation.

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
other: other: cell viability (% of negative control)
Value:
100
Remarks on result:
other:
Remarks:
Basis: other: negative control (0.9% NaCl). Time point: 3 min. (migrated information)
Irritation / corrosion parameter:
other: other: cell viability (% of negative control)
Value:
103.35
Remarks on result:
other:
Remarks:
Basis: other: test material. Time point: 3 min. (migrated information)
Irritation / corrosion parameter:
other: other: cell viability (% of negative control)
Value:
100
Remarks on result:
other:
Remarks:
Basis: other: negative control (0.9% NaCl). Time point: 60 min. (migrated information)
Irritation / corrosion parameter:
other: other: cell viability (% of negative control)
Value:
93.78
Remarks on result:
other:
Remarks:
Basis: other: test material. Time point: 60 min. (migrated information)

In vivo

Irritant / corrosive response data:
The cell viability after 3 min exposure was greater than 50% and the cell viability after 1 h exposure was greater than 15%.
Other effects:
No further effects were reported.

Any other information on results incl. tables

Table 1. Summary of results of the MTT assay.

 

Sample No.

Test item

Time (min)

OD mean (n = 6)

SD

% Viability

1-3

Control NaCl 0.9%

60

1.73

0.15

100.00

7-9

Test substance

60

1.62

0.05

93.78

10-12

Control NaCl 0.9%

3

1.81

0.10

100.00

16-18

Test substance

3

1.87

0.14

103.35

 

OD: Absorption at 570 nm

SD: Standard deviation

Applicant's summary and conclusion

Interpretation of results:
other: non-corrosive
Remarks:
Criteria used for interpretation of results: EU
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.
CLP: inconclusive
DSD: inconclusive