A mixture of: O,O-di(1-methylethyl)trithio-bis-thioformate; O,O-di(1-methylethyl)tetrathio-bis-thioformate; O,O-di(1-methylethyl)pentathio-bis-thioformate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Study period:

The study was performed between 14 February 2011 and 15 March 2011.

Reliability:

3 (not reliable)

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 relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Di-isopropyl xanthogen polysulphid

IUPAC Name:

Di-isopropyl xanthogen polysulphid

Details on test material:

Sponsor's identification : AS 100 (Di-isopropyl xanthogen polysulphide)
Batch number : 246041112001
Content of the test item : Polysulphide 98.46%
Disulphide 0.68%
Volatiles <0.01%
Description : Yellow liquid
Date received : 11 February 2011
Expiry Date : 10 February 2012
Storage conditions : Room temperature, in the dark

Test animals

Species:

rat

Strain:

other: RccHanTM : WIST

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK
Ltd, Oxon, UK
- Age at study initiation: 8 to 12 weeks
- Weight at study initiation: 200g to 350 g
- Fasting period before study: 2 hours
- Housing: The animals were housed in groups of up to five by sex in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes.
- Diet: With the exception of the exposure period, free access to food (Harlan 2014C Rodent Diet, Harlan Laboratories UK Ltd, Oxon, UK) was allowed throughout the study.
- Water (e.g. ad libitum): With the exception of the exposure period, free access to mains drinking water was allowed throughout the study
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25 deg C
- Humidity (%): between 30 and 70%
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): the
lighting was controlled to give twelve hours continuous light and twelve hours darkness.

IN-LIFE DATES: From: Day 0 To: End of Study

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The test item was aerosolised using a glass concentric jet nebuliser (Radleys, Saffron Walden, Essex, UK) located at the top of the exposure chamber.
- Exposure chamber volume: The cylindrical exposure chamber had a volume of approximately 30 litres (dimensions: 28 cm diameter x 50 cm high).
- Exposure Chamber Oxygen Concentration: Oxygen levels within the exposure chamber were measured by an electronic oxygen analyser (Servomex (UK) Ltd, Crowborough, East Sussex) located in a sampling port in the animals breathing zone during each exposure period. The test atmosphere was generated to contain at least 19% oxygen.

- Source and rate of air: Compressed air was supplied by means of an oil free compressor and passed through a water trap and respiratory quality filters before it was introduced to the nebuliser.
air flow (L/MIN): 60


The chamber was maintained under negative pressure, the temperature and humidity were measured by an electronic thermometer/humidity meter. The temperature and humidity were recorded every 30 minutes throughout the four hour exposure period.

TEST ATMOSPHERE
Exposure Chamber Atmosphere Concentration
Prior to the start of the study, the non-volatile component of the test item was determined by adding a small, known amount of test item to glass fibre filters and recording their weights. The filters were then dried in a desiccator between 19 and 20°C for approximately 24 hours and then weighed again. The difference in the two weights was taken as the volatile content of the test item and the non-volatile component was calculated as a percentage. The mean non-volatile component of the batch used during the study was found to be 98.48% (n=10).

The test atmosphere was sampled at regular intervals during the exposure period. A weighed glass fibre filter was placed in a filter holder and temporarily sealed in a vacant port of the exposure chamber in the animals’ breathing zone. A known quantity of the exposure chamber atmosphere was drawn through the filter using a vacuum pump. After sampling, the filter was dried, under similar conditions as those previously described, and weighed again 24 hours later. The difference in the pre and post sampling weights, divided by the volume of atmosphere sampled, was the chamber concentration in terms of non-volatile component.

Based on the results of the preliminary work, these figures were adjusted to obtain a true figure for the test item concentration in the chamber. The nominal chamber concentration was calculated by dividing the mass of test item disseminated into the chamber by the total volume of air that flowed through the chamber during the exposure.


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution:
The particle size of the generated atmosphere inside the exposure chamber was
determined three times during each exposure period using a Marple Personal Cascade
Impactor (Westech IS Ltd, Beds., UK).
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric):
Group 1:
Mean Mass Median Aerodynamic Diameter (MMAD) = 1.64 μm
Geometric Standard Deviation (GSD) = 2.33
Group 2:
Mean Mass Median Aerodynamic Diameter (MMAD) = 2.40 μm
Geometric Standard Deviation (GSD) = 1.98
CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration:

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Dose Group 1 –2.11 mg/L

Dose Group 2 –5.05 mg/L

No. of animals per sex per dose:

Sighting exposure: 2 rats one male and 1 female were exposed to an atmosphere concentartion of 2.06 mg/L for 4 hours.

5 males and 5 females were subjected to a single exposure to the test item for a period of 4 hours. A concentration of 2.11 mg/L was achieved for the first exposure, a target concentration of 5 mg/L was utilised for the second exposure.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: Individual bodyweights were recorded on arrival, prior to treatment on the day of
exposure and on Days 1, 3, 7 and 14 or at death.

- Necropsy of survivors performed: yes

At the end of the fourteen day observation period, the surviving animals were killed by intravenous overdose of sodium pentobarbitone. All animals, including those that died during the study, were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded. The respiratory tract was subjected to a detailed macroscopic examination for signs of irritancy or local toxicity.

- Other examinations performed: clinical signs, body weight,organ weights, histopathology, Clinical signs: All animals were observed for clinical signs at hourly intervals during exposure, immediately on removal from the restraining tubes at the end of exposure, one hour after termination of exposure and subsequently once daily for up to fourteen days. Any deaths or evidence of overt toxicity were recorded at each observation.

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.05 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Effect levels 2

Sex:

male

Dose descriptor:

LC50

Effect level:

> 5.05 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Effect levels 3

Sex:

female

Dose descriptor:

LC50

Effect level:

4.56 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

Group Number Mean Achieved Atmosphere Concentration (mg/L) Male Deaths Female Deaths Total
1 2.11 1/5 0/5 1/10
2 5.05 2/5 3/5 5/10

Clinical signs:

other: Signs of hunched posture and pilo-erection are commonly seen in animals for short periods on removal from the chamber following 4-hour inhalation studies. Wet fur is commonly recorded both during and for a short period after exposure. These observations a

Body weight:

Group 1 – All surviving animals exhibited a bodyweight loss on Day 1, one surviving male and three females exhibited a bodyweight loss or showed no bodyweight gain from Days 1 to 3. Weight gains were noted in all surviving animals for the remainder of the recovery period.

Group 2 – All surviving animals exhibited a bodyweight loss on Day 1, two surviving male animals and all surviving females exhibited a bodyweight loss or exhibited no bodyweight gain from Days 1 to 3. Reasonable bodyweight development was noted in all surviving animals during the remainder of the recovery period.

Gross pathology:

With the exception of one instance of dark patches on the lungs no macroscopic abnormalities were detected at necropsy for animals that survived until the end of the recovery period.

Haemorrhagic or abnormally dark lungs were detected at necropsy amongst animals that died during the course of the study. Due to lung observations noted in the animals it is considered that the deaths noted during this study may have been attributable to local toxicity caused by the test item.

Any other information on results incl. tables

Exposure Chamber Concentration

The actual concentration of the test item was measured seventeen times during each exposure period. The mean values obtained were:

Group number	Atmospheric concentration
	Mean Achieved (mg/L)	Standard deviation	Nominal (mg/L)
1	2.11	0.05	5.72
2	5.05	0.16	20.9

Chamber flow rate was maintained at 60 L/min providing 120 air changes per hour.

Particle Size Distribution

The particle size analysis of the atmosphere drawn from the animals breathing zone, was as follows:

Group number	Mean Achieved Atmosphere Concentration (mg/L)	Mean Mass Median Aerodynamic Diameter (µm)	Inhalable Fraction (% < 4 µm)	Geometric Standard Deviation
1	2.11	1.64	85.6	2.33
2	5.05	2.40	77.5	1.98

Applicant's summary and conclusion

Interpretation of results:

Toxicity Category IV

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute inhalation median lethal concentrations (LC50) (it was not possible to calculate 95% confidence limits as only two groups were exposed) of AS 100 (Di-isopropyl xanthogen polysulphide) in the RccHanTM : WIST strain rat, were calculated to be:
All animals : >5.05 mg/L
Males only : >5.05 mg/L
Females only : 4.56 mg/L

Executive summary:

Introduction.

A study was performed to assess the acute inhalation toxicity of the test item. The method used was compatible with that described in the OECD Guidelines for Testing of Chemicals (2009) No. 403 “Acute Inhalation Toxicity” and was designed to be compatible with Method B2 (Inhalation) of Commission Regulation (EC) No. 440/2008 with the exception that only two groups were exposed to atmospheres of the test item.

Methods.

Groups of ten RccHanTM : WIST strain rats (five males and five females) were exposed to an aerosol atmosphere. The animals were exposed for four hours using a nose only exposure system, followed by a fourteen day observation period.

Results:

The mena achieved atmosphere concentrations were as follows:

Group number	Atmospheric concentration
	Mean Achieved (mg/L)	Standard deviation	Nominal (mg/L)
1	2.11	0.05	5.72
2	5.05	0.16	20.9

The characteristics of the achieved atmospheres were as follows:

Group number	Mean Achieved Atmosphere Concentration (mg/L)	Mean Mass Median Aerodynamic Diameter (µm)	Inhalable Fraction (% < 4 µm)	Geometric Standard Deviation
1	2.11	1.64	85.6	2.33
2	5.05	2.40	77.5	1.98

The mortality data were summarised as follows:

Group Number	Mean Achieved Atmosphere Concentration (mg/L)	Deaths
		Male	Female	Total
1	2.11	1/5	0/5	1/10
2	5.05	2/5	3/5	5/10

Clinical Observations.

Common abnormalities noted during the study included increased respiratory rate, ataxia, hunched posture, pilo-erection and wet fur. There were frequent instances of a heightened sensitivity to audio stimuli and occasional instances of decreased respiratory rate, isolated instances of laboured respiration, noisy respiration, gasping respiration and prostration were also noted. Surviving animals from Group 1 appeared normal from Days 5 to 6 post-exposure, surviving Group 2 animals appeared normal from Days 6 to 7 post-exposure.

Bodyweight.

Group 1 – All surviving animals exhibited a bodyweight loss on Day 1, one surviving male and three females exhibited a bodyweight loss or showed no bodyweight gain from Days 1 to 3. Weight gains were noted in all surviving animals for the remainder of the recovery period.

Group 2 – All surviving animals exhibited a bodyweight loss on Day 1, two surviving male animals and all surviving females exhibited a bodyweight loss or exhibited no bodyweight gain from Days 1 to 3. Reasonable bodyweight development was noted in all surviving animals during the remainder of the recovery period.

Necropsy.

With the exception of one instance of dark patches on the lungs no macroscopic abnormalities were detected at necropsy for animals that survived until the end of the recovery period. Haemorrhagic or abnormally dark lungs were detected at necropsy amongst animals that died during the course of the study. Due to lung observations noted in the animals it is considered that the deaths noted during this study may have been attributable to local toxicity caused by the test item.

Conclusion:

The acute inhalation median lethal concentrations (LC50) (it was not possible to calculate 95% confidence limits as only two groups were exposed) of AS 100 (Di-isopropyl xanthogen polysulphide) in the RccHanTM : WIST strain rat, were calculated to be:

All animals : >5.05 mg/L

Males only : >5.05 mg/L

Females only : 4.56 mg/L