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Toxicological information

Skin irritation / corrosion

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Administrative data

skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
other: OECD test guideline, “In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method” (TG 439).
GLP compliance:

Test material

Details on test material:
As per IUCLID Sections 1.1. 1.2. and 4.1.

Test animals

other: Study was in vitro.
not specified
Details on test animals and environmental conditions:
Study was conducted in vitro.

Test system

Amount / concentration applied:
30 ul neat test substance
Duration of treatment / exposure:
60 minutes
Observation period:
42 +/- 2 hr
Number of animals:
None, study conducted in vitro.
Details on study design:
The EpiDerrn human skin model tissues were stored at 2-8°C until use. On the day prior to testing, EpiDermTM Maintenance Medium was set to room temperature prior to use. Nine-tenths mL of Maintenance Medium were aliquotted into the appropriate wells of 6-well plates. Each 6-well plate was labeled with the test article, positive control, or negative control. The EpiDermTM tissues were incubated at 37±1°C in a humidified atmosphere of 5±t% CO2 in air (standard culture conditions) for 18 ±3 hours to acclimate the tissues.

The definitive assay included a negative control and a positive control. The negative control was 30 uL of sterile, Calcium and Magnesium Free Dulbecco’s Phosphate Buffered Saline (CMF-DPBS) and the positive control was 30 uL of 5% Sodium Lauryl Sulfate (SLS). After the overnight incubation for 18 ±3 hours, the 6-well plates containing the EpiDermT’ tissues were removed from the incubator and placed at room temperature for at least 5 minutes prior to dosing.

The EpiDermTM tissues were treated in triplicate with the test substance, negative control and positive control for 60 ±1 minutes. All of plates were transferred to the incubator for 35 ± 1 minutes at standard culture conditions. After 35 minutes, all of the plates were removed from the incubator, placed into the laminar flow hood and kept at room temperature until the exposure period was completed for the first dosed tissue. After 60 ± 1 minutes of of treatment, the tissues were rinsed with sterile, CMF-DPBS.

The tissue inserts were transferred to new 6-well plates containing 0.9 mL of flesh warmed (to 37°C) Maintenance Medium. The tissue surface was carefully blotted with sterile cotton-tipped applicators to remove any excess moisture, and the tissue surface was visually observed for residual test substance using a dissecting scope. Since residual test substance was observed, sterile cotton-tipped applicators pre-moistened with CMF-DPBS were used to attempt to remove any residual test substance from the tissue surface. A minimal amount of residual test substance remained after attempting to remove with the cotton swab. The tissues were then placed into the incubator at standard culture conditions for a post-treatment expression incubation of 42 ± 2 hours.

After the total 42 ± 2 hours post-exposure expression incubation, the 6-well plates were removed from the incubator. Each tissue was blotted on a sterile paper towel and transferred to an appropriate well containing 0.3 mL of MTT (3-[4,5 - dirnethylthiazol-2-ylj - 2,5 - diphenyltetrazolium bromide)’ solution. The 24-well MTT plates were incubated at standard culture conditions for 3 +/- 0.1 hours.

After the 3 ± 0.1 hour incubation, the EpiDermTM tissues were submerged, gently swirled, and rinse media decanted in a beaker containing approximately 150 mL of CMF-DPBS three times. The tissue was then blotted on absorbent paper, and transferred to a prelabelled 24-well plate containing 2.0 mL of isopropanol in each designated well. The plates were covered with parafllm and shaken for at least 2 hours at room temperature to extract the MMT. The absorbance at 570 nm (0D570) of each extract was measured with a Molecular Devices Vmax plate reader with the AUTOMIX function selected.

Results and discussion

In vitro

Irritation / corrosion parameter:
% tissue viability
Remarks on result:
Basis: mean. Time point: One hr.. Reversibility: no data Study was conducted in vitro.. Remarks: The test substance treated EpiDerm tissue relative percent viability was 6.7%. . (migrated information)
Other effects / acceptance of results:
Mean relative test substance treated EpiDerm tissue viability was 6.7%.

Applicant's summary and conclusion

Interpretation of results:
not irritating
Migrated information Due to technical difficulties in removal of the test substance from the EpiDerm tissue the results do not support a conclusion of irritation. Criteria used for interpretation of results: other: published
The mean relative percent viability of the test substance treated EpiDerm tissue was 6.7%. However, due to technical difficulties in the removal of the test substance from the tissue the exposure was prolonged. Furthermore, physical trama to the tissues may have occured when attempting to remove test substance from the exposed tissue. These two confounding factors are likly to have contiributed to the reduced viabilty of test substance treated EpiDerm tissues. Therefore, the data are not useful for accessing the potential skin irritating potential of the test substance.
Executive summary:

The test substance, 1,2,3,6 -Tetrahydrophthalic anhydride, oligomeric reaction products with 2,2 -dimethylpropane-1,3 -diol, when tested in an O.E.C.D. test guideline 439 Human skin irritation model was reported to have a mean relative tissue viability of 6.7%. However, due to technical difficulties in the removal of test substance from the exposed tissue surface, the data are not reliable for prediciting the skin irritating potential of the test substance.