5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione

Endpoint summary

Description of key information

5,5'-Dithiodi-1,3,4-Dithiazole-2(3H)-thione is not irritating to the skin and the eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: 40 CFR, Part 163, Section 163.81-5, Federal Register, August 22, 1978.

Deviations:

not specified

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

Exposure duration of 24 hours

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Animals were housed and maintained according to the Animal Welfare Act (Pub. L-94-279) 9 C.F.R. Part 3.

Animal husbandry conditions:
Temperature - 70ºF ±5ºF
Relative humidity - 45% ± 5%
Light - 12 hour light/dark cycle
Diet - Wayne 15% rabbit ration and tap water provided ad libitum.
Caging - Stainless steel with elevated wire mesh flooring 1 rabbit per cage.
Weight - weighing between 2.0 and 3.0 kg.
Age - approximately 9-10 weeks of age.
Acclimatisation - for at least 5 days prior to study.

Type of coverage:

semiocclusive

Preparation of test site:

other: abraded or intact

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

A 0.5 gram sample of 5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione was dosed as supplied and applied to two abraded and two intact skin sites on the same animal.

Duration of treatment / exposure:

Exposure of the material over a period of 24 hours, at the end of which the sites were wiped but not washed and the treated areas examined.

Observation period:

Readings were taken after 24 hours and again made after 72 hours.
The Draize method of scoring was employed. All lesions observed were recorded.

Number of animals:

six

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

The Primary Irritation score was 0 and the average combined irritation score was 0 for Erythema and Eschar formation and Edema formation in all animals over 72 hours on both abraded and intact skin.

Interpretation of results:

GHS criteria not met

Remarks:

Not skin irritating

Conclusions:

5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione is not classified as a primary skin irritant to the skin of albino rabbits.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: 40 CFR, Section 163.81-1 (b) (4) (ii), Federal Register, August 22, 1978.

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

no

Remarks:

Prior to GLP

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

A group of nine New Zealand white rabbits (albino) were employed in this study.
Animal weight: 2.0 - 3.0 kg
Animal age: 9-10 weeks of age.
Animals housed and maintained in compliance with the Animal Welfare Act (Pub. L-94-279) 9 CFR Part 3.
Acclimatisation was at least 5 days prior to the study taking place.
Animal husbandry conditions:
Temperature 70 ± 2ºC
Relative humidity 45% ±5%
Light - 12 hour light/dark cycle
Diet - Wayne 15% Rabbit ration and tap water were provided ad libitum.
Caging - Stainless steel with elevated wire mesh flooring 1 rabbit/cage.

Animals were uniquely identified by ear tag.

Vehicle:

unchanged (no vehicle)

Controls:

other: The left eye of each animal served as control.

Amount / concentration applied:

The sample was dosed as supplied. A 0.1 gm sample of material was instilled into the right eye of each test animal with the other eye remaining untreated and to serve as the controls.

Duration of treatment / exposure:

The first six rabbits did not have their eyes washed subsequent to instillation. The remaining three rabbits had the treated eyes washed after 30 seconds for 1 minute with gently flowing tepid tap water (1000 ml/ minute).

Observation period (in vivo):

The treated eyes were examined at 1, 2, 3, 4 & 7 days following instillation. The readings of the eyes were made in accordance with the Draize technique for scoring occular lesions.

Number of animals or in vitro replicates:

Total number of animals = 9.
The treated eyes of six animals remained unwashed and a mean score determined. The treated eyes of three animals were washed and a mean score determined.

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

--unwashed eyes

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

mean

Remarks:

-- unwashed eyes

Time point:

24/48/72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Remarks:

Redness

Basis:

mean

Remarks:

--unwashed eyes

Time point:

24/48/72 h

Score:

0.4

Max. score:

2

Reversibility:

fully reversible within: 4 days

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

--unwashed eye

Time point:

24/48/72 h

Score:

0.3

Max. score:

3

Reversibility:

fully reversible within: 7 days

Irritant / corrosive response data:

Unwashed eye animals (1 through 6):
No corneal opacity or iritis was noted in animals 1 through 6 at 24 hours through post-exposure day 7. Conjunctival redness was noted in all animals at 24 hours post-exposure observation.
Animal 2 exhibited a positive response for conjunctival chemosis with a maximum score of 3, fully reversible within 7 days.
Washed eye animals (Animals 7 through 9):
No corneal opacity, iritis or conjunctival chemosis was noted in animals 7 through 9 at 24 hours through post-exposure day 7.
Conjunctival redness was noted in animals 7 and 9 at 24 hours post exposure, but was fully reversible within 48 hours.
Based on the data, the test substance does not appear to be an occular irritant in the unwashed eye. Washing does not appear to alter this conclusion. The minimal conjunctival irritation observed cleared up within 7 days.

Interpretation of results:

GHS criteria not met

Remarks:

Not eye irritating

Conclusions:

5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione is not irritating to the eye.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin Irritation

In a study equivalent or similar to OECD 404, not conducted according to GLP, 6 rabbits exposed to the test substance.

A mean irritation score of 0 was obtained.

5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione is, therefore, not irritating to the skin.

Eye Irritation

In a study equivalent or similar to OECD 405, not conducted according to GLP, 9 rabbits exposed to the test substance. 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione showed a mean irritation score for cornea and iris of 0, and a mean irritation score for conjunctivae redness, cornea and discharge of 1 fully reversible in 48 hours (maximum 2), 0.3 fully reversible in 7 days (maximum 3) and 0.3 fully reversible in 4 days (maximum 2) respectively.

5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione is, therefore, not irritating to the eyes.

Justification for classification or non-classification

Based on the available data, no classification for irritation is required for 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione according to the Regulation EC°1272/2008.