Dicopper sulphide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with Good laboratory Practice and internationally accepted guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dicopper sulphide

EC Number:

244-842-9

EC Name:

Dicopper sulphide

Cas Number:

22205-45-4

Molecular formula:

Cu2S

IUPAC Name:

Copper(I) sulphide

Details on test material:

- Name of test material (as cited in study report): Dicopper sulphide.
- Analytical purity: >99%
- Lot/batch No.: CM25005
- Storage condition of test material: room temperature in the dark.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: other: Relative mean viability

Remarks on result:

other: Reconstructed human epidermis model. Time point: 15 Minute exposure period. Remarks: The relative mean viability of the test item treated tissues was 57.6% after a 15 Minute exposure period.

Any other information on results incl. tables

RESULTS

Direct MTT Reduction

The MTT solution containing the test item did not turn blue which indicated that the test item did not directly reduce MTT. Quantitative correction of the results was therefore unnecessary.

Test Item, Positive Control Item and Negative Control Item

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

Table 1: Mean OD540 Values and Percentage Viabilities for the Negative Control Item, Positive Control Item and Test Item

Item	OD540of tissues	Mean OD540of triplicate tissues	±SDof OD540	Relative individual tissue viability (%)	Relative mean viability (%)	± SD of Relative mean viability (%)
Negative Control Item	0.976	0.829	0.129	117.7	100*	15.6
	0.734			88.5
	0.776			93.6
Positive Control Item	0.093	0.088	0.005	11.2	10.6	0.5
	0.085			10.3
	0.085			10.3
Test Item	0.542	0.477	0.068	65.4	57.6	8.2
	0.406			49.0
	0.483			58.3

SD=    Standard deviation

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

The relative mean viability of the test item treated tissues was57.6% after a 15‑Minute exposure period.

Quality Criteria

The relative mean tissue viability for the positive control treated tissues was 10.6% relative to the negative control treated tissues and the standard deviation value of the percentage viability was 0.5%. The positive control acceptance criterion was therefore satisfied.

The mean OD540 for the negative control treated tissues was 0.829 and the standard deviation value of the percentage viability was 15.6%. The negative control acceptance criterion was therefore satisfied.

The standard deviation calculated from individual percentage tissue viabilities of the three identically treated tissues was 8.2%. The test item acceptance criterion was therefore satisfied.

CONCLUSION

The test item was considered to be Non-Irritant.

 

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Dicopper sulphide was considered to be Non-Irritant.

Executive summary:

A GLP-compliant in-vitro study was conducted using the EPISKIN reconstructed human epidermis modelin accordance with the requirements of OECD Guideline 439 and EU Method B.46. Triplicate tissues were treated with the test item for an exposure period of 15 minutes.  At the end of the exposure period each tissue was rinsed before incubating for 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. The findings were assessed in terms of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

The relative mean viability of the test item treated tissues was 57.6% after the 15-Minute exposure period. The quality criteria required for acceptance of results in the test were satisfied. Dicopper sulphide was considered to be Non-Irritant.