3-(biphenyl-4-yl)-6-(4-chlorophenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 30 April 2009 and 11 May 2009.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD TG Draft Guideline (Version 7.6)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EU Guideline Testing of Chemicals B46

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 19/08/09 Date of Signature: 04/03/09

Test material

Test material information

Constituent 1

Reference substance name:

3-{[1,1'-biphenyl]-4-yl}-6-(4-chlorophenyl)-1H,2H,4H,5H-pyrrolo[3,4-c]pyrrole-1,4-dione

EC Number:

700-341-1

Cas Number:

105194-34-1

Molecular formula:

C24H15ClN2O2

IUPAC Name:

3-{[1,1'-biphenyl]-4-yl}-6-(4-chlorophenyl)-1H,2H,4H,5H-pyrrolo[3,4-c]pyrrole-1,4-dione

Constituent 2

Reference substance name:

3-(biphenyl-4-yl)-6-(4-chlorophenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione

IUPAC Name:

3-(biphenyl-4-yl)-6-(4-chlorophenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione

Details on test material:

ESponsor's identification : PDE-28
Description : red powder
Batch number : 1RF-8017
Date received : 23 March 2009
Storage conditions : room temperature in the dark

Test animals

Species:

other: reconstituted human epidermis model

Strain:

other: reconstituted human epidermis model

Details on test animals or test system and environmental conditions:

Not applicable

Test system

Type of coverage:

other: Topical

Preparation of test site:

other: Not applicable

Vehicle:

other: No vehicle used

Controls:

no

Amount / concentration applied:

TEST MATERIAL

- Amount(s) applied (volume or weight with unit):
10 mg of the test material was applied to the epidermis surface.

- Concentration (if solution):
The test material was used as supplied.

VEHICLE
No vehicle used

Duration of treatment / exposure:

15 Minutes & 42 hour post exposure incubation

Observation period:

Not applicable

Number of animals:

Not applicable

Details on study design:

TEST SITE
- Area of exposure:
10 mg of the test material was applied to the epidermis surface..

- % coverage:
The test material was applied topically to the corresponding tissues ensuring uniform covering.

- Type of wrap if used:
None used

REMOVAL OF TEST SUBSTANCE
- Washing (if done):
At the end of the exposure period, each tissue was removed from the well using forceps and rinsed using a wash bottle containing PBS with Ca++ and Mg++. Rinsing was achieved by filling and emptying each tissue insert for approximately 40 seconds using a constant soft stream of PBS to gently remove any residual test material.

- Time after start of exposure:
15 minutes post exposure

SCORING SYSTEM:
Quantitative MTT Assessment (percentage tissue viability):
For the test material the relative mean tissue viabilities obtained after the 15 minute treatment followed by the 42 hour post-exposure incubation period were compared to the mean of the negative control treated tissues (n=3). The relative mean viabilities were calculated in the following way:

mean OD540 of test material / mean OD540 of negative control x 100

Classification of irritation potential is based upon relative tissue viability following the 15 minute exposure period followed by the 42 hour post-exposure incubation period according to the following table:
Criteria for in vitro interpretation Classification
Mean tissue viability is ≤50% Irritant (I) R38
Mean tissue viability is >50% Non-Irritant (NI)

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: other: Viability of cells

Value:

96.5

Remarks on result:

other:

Remarks:

Basis: mean Viability of cells. Time point: Day 6. Max. score: 96.5. Reversibility: other: Not applicable. Remarks: EPISKINTM RECONSTITUTED HUMAN EPIDERMIS MODEL. (migrated information)

In vivo

Irritant / corrosive response data:

Not applicable

Other effects:

No

Any other information on results incl. tables

Direct MTT Reduction:

The MTT solution containing the test material did not turn blue/purple which indicated that the test material did not directly reduce MTT.

Test Material, Positive Control Material and Negative Control Material:

The individual and mean OD₅₄₀ values, standard deviations and tissue viabilities for the test material, negative control material and positive control material are given in Table 1. The mean viabilities and standard deviations of the test material and positive control, relative to the negative control are also given in Table 1.

The relative mean viability of the test material treated tissues was 96.5% after a 15‑minute exposure.

The qualitative evaluation of tissue viability is given in Table 2.

Following the 15-minute exposure the test material treated tissues appeared blue which was considered indicative of viable tissue.

Quality Criteria:

The relative mean tissue viability for the positive control treated tissues was≤ 40% relative to the negative control treated tissues and the Standard Deviation (SD) value of the % viability was ≤ 20%. The positive control acceptance criterion was therefore satisfied.

The mean OD₅₄₀ for the negative control treated tissues was ≥ 0.6 and the SD value of the % viability was ≤ 20%. The negative control acceptance criterion was therefore satisfied.

Table1:              Mean OD₅₄₀ Values and % Viabilities for the Negative Control Material, Positive Control Material and Test Material

Material	OD540 of tissues	Mean OD540 of triplicate tissues	± SD of OD540	Relative individual tissue viability %	Relative mean % viability	± SD of % viability
Negative Control Material	0.910	0.878	0.03	103.6	100*	3.4
	0.875			99.7
	0.850			96.8
Positive Control Material	0.242	0.238	0.03	27.6	27.1	2.9
	0.211			24.0
	0.261			29.7
Test Material	0.853	0.847	0.03	97.2	96.5	3.5
	0.814			92.7
	0.875			99.7

 

*= The mean viability of the negative control tissues is set at 100%

Table2              Qualitative Evaluation of Tissue Viability (MTT uptake visual evaluation)

Material	Tissue 1	Tissue 2	Tissue 3
Negative Control Material	-	-	-
Positive Control Material	++	++	++
Test Material	-	-	-

MTT visual scoring scheme
-          =         blue tissue (viable)
+         =         blue/white tissue (semi-viable)
++       =         tissue is completely white (dead)

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

The test material was considered to be Non-Irritant to the skin.

Executive summary:

Introduction: The purpose of this test was to evaluate the skin irritation potential of the test material using the EPISKIN^TM reconstituted human epidermis model after a treatment period of 15 minutes followed by a post-exposure incubation period of 42 hours. The principle of the assay was based on the measurement of cytotoxicity in reconstituted human epidermal cultures following topical exposure to the test material by means of the colourimetric MTT reduction assay. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt (3‑[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to a blue formazan salt (within the mitochondria of viable cells) in the test material treated tissues relative to the negative controls. The concentration of the inflammatory mediator IL-1α in the culture medium retained following the 42 hour post-exposure incubation period is also determined for test materials which are found to be borderline non-irritant based upon the MTT reduction endpoint. This complimentary end‑point will be used to either confirm a non-irritant result or will be used to override the non‑irritant result.

Triplicate tissues were treated with the test material for an exposure period of 15 minutes. At the end of the exposure period each tissue was rinsed before incubating for approximately 42 hours. At the end of the post-exposure incubation period each tissue was taken for MTT-loading. The maintenance medium from beneath each tissue was transferred to pre‑labelled micro tubes and stored in a freezer for possible inflammatory mediator determination. After MTT loading a total biopsy of each epidermis was made and placed into micro tubes containing acidified isopropanol for extraction of formazan crystals out of the MTT‑loaded tissues. 

At the end of the formazan extraction period each tube was mixed thoroughly and duplicate 200 µl samples were transferred to the appropriate wells of a pre-labelled 96‑well plate. The optical density was measured at 540 nm.

Data are presented in the form of % viability (MTT reduction in the test material treated tissues relative to negative control tissues).

Results: The relative mean viability of the test material treated tissues was 96.5% after a 15‑minute exposure.

Quality criteria:  The quality criteria required for acceptance of results in the test were satisfied.

Conclusion: The test material was considered to be non-irritant to the skin.