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Toxicological information

Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
February - March 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: Japanese MAFF, 2000
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
fixed dose procedure
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione
EC Number:
276-763-0
EC Name:
5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione
Cas Number:
72676-55-2
Molecular formula:
C4-H2-N4-S6
IUPAC Name:
5-[(5-sulfanylidene-4,5-dihydro-1,3,4-thiadiazol-2-yl)disulfanyl]-2,3-dihydro-1,3,4-thiadiazole-2-thione
Test material form:
solid: particulate/powder

Test animals

Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals or test system and environmental conditions:
Female Wistar (RccHan™:WIST) strain rats were supplied by Harlan Laboratories UK Ltd., Oxon, UK.
The females were nulliparous and non-pregnant.
Acclimatization period of at least five days.
At the start of the study the animals were approximately nine to eleven weeks of age.
The body weight variation did not exceed ±20% of the mean weight at the start of treatment
The animals were housed in groups of up to four in suspended solid-floor polypropylene cages with stainless steel mesh lids and furnished with woodflakes.
With the exception of an overnight fast immediately before dosing and for approximately three to four hours after dosing, free access to mains drinking water and food was allowed throughout the study.

The temperature and relative humidity remained within 19 to 25 °C and 30 to 70%, respectively, during the study.
The rate of air exchange was at least fifteen changes per hour.
The lighting was controlled by a time switch to give twelve hours continuous artificial light (06:00 to 18:00) and twelve hours darkness.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
DMSO
Details on oral exposure:
All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe. The volume administered to each animal was calculated according to the fasted body weight at the time of dosing.

The test item was formulated within two hours of being applied to the test system. No analysis was conducted to determine the homogeneity, concentration or stability of the test item formulation. This is an exception with regard to GLP and has been reflected in the GLP compliance statement.
Doses:
2000 mg/kg
No. of animals per sex per dose:
Dose group 1: 1 Female
Dose group 2: 4 Females
Control animals:
no
Details on study design:
In the absence of mortality at a dose level of 2000 mg/kg in the sighting test with one female animal, an additional group of four female animals was treated. At least 24 hours was allowed between each dose group to confirm the survival of the previously dosed animals.

Clinical observations were made ½, 1, 2, and 4 hours after dosing and then daily for fourteen days.

Morbidity and mortality checks were made twice daily, early and late during normal working days and once daily on weekends and public holidays.

Individual body weights were recorded on Day 0 (the day of dosing) and on Days 7 and 14.

At the end of the observation period the animals were killed by cervical dislocation.

All animals were subjected to gross necropsy.

Results and discussion

Effect levels
Sex:
female
Dose descriptor:
LD0
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
There were no unscheduled deaths.
Clinical signs:
Hunched posture and lethargy were noted during the day of dosing.
Body weight:
All animals showed expected gains in body weight.
Gross pathology:
No abnormalities were noted.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute oral median lethal dose (LD50) of 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione in the female Wistar strain rat is greater than 2000 mg/kg body weight.
Executive summary:

The study was performed to assess the toxicity of the test item following a single oral dose to the Wistar strain rat.

Following a sighting test at a dose level of 2000 mg/kg in one fasted female, an additional four fasted female animals were given a single oral dose of test item, as a solution in dimethyl sulphoxide, at a dose level of 2000 mg/kg body weight. Clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy.

There were no unscheduled deaths. Hunched posture and lethargy were noted during the day of dosing in the initial treated animal. There were no signs of systemic toxicity noted in the additional treated animals. Based on historical data from the supplier for this strain, all animals showed expected gains in body weight over the observation period.

No abnormalities were noted at necropsy.

The acute oral median lethal dose (LD50) of the test item in the female Wistar strain rat was estimated to be greater than 2000 mg/kg body weight