Registration Dossier

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Administrative data

Description of key information

Three acute studies are available on DPTH : one by oral route (LD0> 2000 mg/kg in rats), one by dermal route (LD0> 2000 mg/kg in rats) and one by inhalation (LC0> 2.83 mg/L). No mortality was observed in these acute studies, DPTH is not to be considered as harmful by these all three routes of exposure.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
Reference
Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
02 November 2011 - 21 June 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
acute toxic class method
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Breeder: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: on the day of treatment, the females were approximately 8-week old
- Mean body weight at study initiation: a mean body weight of 213 g (range: 196 g to 221 g)
- Fasting period before study: yes, during the night before treatment
- Housing: polycarbonate cages with stainless steel lids
- Diet: SSNIFF R/M-H pelleted diet (free access)
- Water: tap water filtered with a 0.22 µm filter (free access)
- Acclimation period: at least 5 days before the beginning of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): approximately 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h.

IN-LIFE DATES: 02 November 2011 to 07 December 2011.
Route of administration:
oral: gavage
Vehicle:
other: 0.5% methylcellulose aqueous solution
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 30, 100 or 200 mg/mL
- Justification for choice of vehicle:
The vehicle used in this study was selected from the results of solubility assays performed by the CIT Pharmacy. In the absence of recommendation from the Sponsor, the solubility assay first started at the concentration of 200 mg/mL, and the first choice vehicle was drinking water treated by reverse osmosis, using an ELIX 5 apparatus (Millipore SA, Saint-Quentin-en-Yvelines, France). As unsatisfactory solubility of the test item was obtained in this vehicle, 0.5% methylcellulose aqueous solution, batch No. 066K0129, was used. A homogenous suspension was obtained at the concentration of 200 mg/mL in this vehicle, which was retained for the study.
Nevertheless, unsatisfactory chemical results were obtained in the homogeneity and stability study at 200 mg/mL. In this study, the test item dosage forms in 0.5% methylcellulose were found to be homogeneous at 4 mg/mL and 100 mg/mL. The preparation of dosage forms was not validated at 200 mg/mL. Therefore, the dosage volume was increased from 10 to 20 mL/kg in order to divide the concentration of the dose formulations by two.
- Maximum dose-volume applied: 20 mL/kg.

DOSAGE PREPARATION:
The test item was administered as a suspension in the vehicle. The test item was ground to a fine powder, using a mortar and pestle, and then mixed with the required quantity of vehicle.
In the second complementary assay after mixing of the test item with the vehicle, the dose formulation was magnetically stirred for at least 1 hour before using.
Dosage forms were prepared by the CIT Pharmacy extemporaneously on the day of each administration, stored at room temperature and delivered to the study room in brown flasks.
The dosage forms were stored at room temperature and delivered to the study room in brown flasks.

CLASS METHOD:
- Rationale for the selection of the starting dose:
Since no relevant toxicity data were available for the estimation of a lethal dose-level, the starting dose level was 300 mg/kg for animal welfare reasons.
Doses:
300 and 2000 mg/kg.
Following unsatisfactory chemical results obtained in the stability study at 200 mg/mL in 0.5% methylcellulose aqueous solution, the dosage volume was increased from 10 to 20 mL/kg and therefore a new administration was performed at 2000 mg/kg (second complementary assay).
No. of animals per sex per dose:
Groups 1 to 3: 3 females per treatment step,
Group 4: 6 females.
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Clinical observations: frequently during the hours following treatment; then, at least once a day.
- Body weight: just before treatment on day 1; then on days 8 and 15.
- Necropsy of survivors performed: yes (macroscopic).
Statistics:
no
Sex:
female
Dose descriptor:
LD0
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No unscheduled deaths occurred during the study.
Clinical signs:
No clinical signs were observed in any animals, except for hypoactivity seen transiently on day 1 in 1/6 females given 2000 mg/kg (concentration of 200 mg/mL and dosage-volume of 10 mL/kg; first confirmatory assay).
No clinical signs were observed in six females treated at 2000 mg/kg (concentration of 100 mg/mL and dosage-volume of 20 mL/kg) of the second confirmatory assay.
Body weight:
Body weight was unaffected by the test item treatment, when compared to CIT historical control data.
Gross pathology:
There were no macroscopic post-mortem findings in animals given 300 mg/kg.
In the second confirmatory assay, dilated uterus was noted in 3/6 females given 2000 mg/kg. This macroscopic finding is commonly recorded in the Sprague-Dawley rat, is considered to be related to the estrous cycle, not to the test item administration.
Other findings:
no
Interpretation of results:
GHS criteria not met
Conclusions:
The oral LD50 of the test item was higher than 2000 mg/kg in rats.
Executive summary:

The objective of this study was to evaluate the potential acute toxicity of the test item following a single oral administration (gavage) to rats.

The study was performed according to the international guidelines (OECD No. 423 and Council Regulation No. 440/2008 of 30 May 2008, Part B.1tris) andin compliance with the principles of Good Laboratory Practice.

 

Methods

The test item was administered once by the oral route (gavage) to three groups of three fasted female Sprague-Dawley rats under a dosage-volume of 10 mL/kg. The test item was prepared in a 0.5% solution of methylcellulose.

Since no relevant toxicity data were available for the estimation of a lethal dose-level, the starting dose-level was 300 mg/kg for animal welfare reasons. After the first assay and as no toxicity was observed, the next higher dose-level of 2000 mg/kg was tested. Then, as no toxicity was observed at this higher dose-level, the results were confirmed in other females.

Nevertheless, as unsatisfactory chemical results were obtained in the stability study at the concentration of 200 mg/mL, a new dose formulation was prepared at the concentration of 100 mg/mL and the test item was administered once by the oral route (gavage) to one additional group of six fasted female Sprague-Dawley rats at dose-level of 2000 mg/kg under a dosage-volume of 20 mL/kg and a concentration of 100 mg/mL.

Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on days 1, 8 and 15.

On completion of the observation period, the animals were sacrificed and submitted for a macroscopic post-mortem examination. No tissues were preserved as no macroscopic lesions were observed.

 

Results

No unscheduled deaths were observed. No clinical signs were observed in any animals, except for hypoactivity seen transiently on day 1 in 1/6 females given 2000 mg/kg (first confirmatory assay).

Body weight was unaffected by the test item treatment.

The test item administration at 300 or 2000 mg/kg did not induce any macroscopic changes.

 

Conclusion

The oral LD50 of the test item was higher than 2000 mg/kg in rats.

Therefore, the test item is not classified as toxic or harmful by oral route according to the criteria of CLP Regulation.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
Value:
2 000 mg/kg bw
Quality of whole database:
Rokh's study is reliable with a klimisch score of 1 (GLP guideline study).

Acute toxicity: via inhalation route

Link to relevant study records
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
17 January to 31 January 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1300 (Acute inhalation toxicity)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
other: CRL:(WI) rats
Sex:
male/female
Details on test animals or test system and environmental conditions:
Species and strain: CRL:(WI) rats
Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld
Hygienic level at arrival: SPF
Hygienic level during the study: Standard housing conditions
Justification of strain: Recognized by international guidelines as a recommended test system
Number of animals: 10
Sex: Male and Female rats, nulliparous and non-pregnant
Age when treated: Young adult rats, 9 weeks old
Body weight (at dosing): 194 to 351 g (M: 311-351g; F: 194-214g)
Randomization: Selected based on the bodyweight prior to the exposure
Acclimatization time: 14 days.

Husbandry
Animal health: Only healthy animals were used for the test. The health status was certified by the veterinarian
Animal room: 245/7
Housing: Group of 5 (by sex)
Cage type: Type III solid floor cages with stainless steel mesh lids
Bedding: Lignocel Bedding for Laboratory Animals was available to animals during the study
Light: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 22 ± 3°C
Relative humidity: 30 – 70 %
Ventilation: 15-20 air exchanges/hour
Enrichment: Rodents were housed with deep wood sawdust bedding to allow digging and other normal rodent activities.

Diet and Water : The animals were provided with ssniff SM R/M-Z+H “Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance” (ssniff Spezialdiäten GmbH, D-59494 Soest Germany; Batch: 445 8440, Expiry: May 2013) and tap water fit for human consumption, ad libitum.
The diet and drinking water are routinely analysed and are considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study. Copies of the relevant Certificates of Analysis are retained in the archive of CiToxLAB Hungary Ltd.
Water quality control analysis is performed once every 3 months and microbiological assessment is performed monthly, by Veszprém County Institute of State Public Health and Medical Officer Service (ÁNTSZ, H-8201 Veszprém, József A.u.36, Hungary). The quality control results are retained in the archive of CiToxLAB Hungary Ltd.

Identification : Each animal was identified by a unique number marked on the tail. The animal number was assigned on the basis of the CiToxLAB Hungary Ltd. master file.
Cages were identified by cage card, giving details of study code, sex, dose-group, cage number and individual animal numbers.
Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
air
Details on inhalation exposure:
Technical Trials: Prior to animal exposures, test material atmospheres were generated within the exposure chamber. During these technical trials, air-flow settings and test material input rates were varied to achieve the required atmospheric characteristics.

Atmosphere Generation: The test item was aerosolised using two Wright’s Dust Feed Systems (TSE Systems GmbH, Bad Homburg, Germany) located at the top of the exposure chamber. Compressed air was supplied by means of an oil-free compressor and passed through a suitable filter system prior to introduction to the dust generator.

Animal Exposure System: The animals were exposed, nose-only, to an atmosphere of the test item using a TSE Rodent Exposure System (TSE Systems GmbH, Bad Homburg, Germany). This system comprises of two, concentric anodised aluminium chambers and a computer control system incorporating pressure detectors and mass flow controllers.
Fresh aerosol from the generation system was constantly supplied to the inner plenum (distribution chamber) of the exposure system from where, under positive pressure, it was distributed to the individual exposure ports. The animals were held in polycarbonate restraint tubes located around the chamber which allowed only the animal’s nares to enter the exposure port. After passing through the animal’s breathing zone, used aerosol entered the outer cylinder from where it was exhausted through a suitable filter system. Atmosphere generation was therefore dynamic.
Airflows and relative pressures within the system were constantly monitored and controlled by the computer system thus ensuring a uniform distribution and constant flow of fresh aerosol to each exposure port (breathing zone). The flow of air through each port was at least 0.7 L/min. This flow rate was considered adequate to minimise re-breathing of the test atmosphere as it is about twice the respiratory minute volume of a rat.
Homogeneity of the test atmosphere within the test chamber and amongst the exposure ports was not specifically determined during this study. However, chambers of this design have been fully validated and have shown to produce evenly distributed atmospheres in the animals’ breathing zones (Pauluhn, 1994).

Exposure Procedure: Each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber. Only the nose of each animal was exposed to the test atmosphere.
Following an equilibration period of at least the theoretical chamber equilibration time (T99) (Silver, 1946), a group of ten rats (five male and five female) was exposed to an atmosphere of the test material for a period of four hours. The maximum attainable concentration was used for the exposure as a target. As no deaths occurred at the maximum attainable concentration, no further data were required.
Analytical verification of test atmosphere concentrations:
no
Remarks:
nominal
Duration of exposure:
4 h
Concentrations:
2.83 mg/l
No. of animals per sex per dose:
10 animals (5 males/5 females).
Control animals:
no
Details on study design:
Test Atmosphere Concentrations: The test atmosphere was sampled at regular intervals during each exposure period. Samples were taken from an unoccupied exposure port (representing the animal’s breathing zone) by pulling a suitable, known volume of test atmosphere through weighed GF10 glass fibre filters (Whatman GmbH, Hahnestraße 3 – D-37586 Dassel, Germany). The difference in the pre- and post-sampling weights, divided by the volume of atmosphere sampled, was equal to the actual achieved test atmosphere concentration.
The nominal concentration was calculated by dividing the mass of test material disseminated into the chamber by the total volume of air that went through the chamber during the same period.

Particle Size Analysis: The particle size of the test atmosphere was determined three times during the exposure period using a 7-stage impactor of Mercer style (TSE Systems GmbH, Bad Homburg, Germany). Such devices employ an inertial separation technique to isolate particles in the discrete aerodynamic size ranges. Samples were taken from an unoccupied exposure port (representing the animal’s breathing zone).
The collection substrates and the backup filter were weighed before and after sampling and the weight of test item, collected at each stage, calculated by this difference.
The total amount collected for each stage was used to determine the cumulative amount below each cut-off point size. In this way, the proportion (%) of aerosol less than 0.55, 0.96, 1.55, 2.11, 3.56, 6.66 and 10.55 µm was calculated.
From these data, using software supplied with the impactor (TSE Systems GmbH, Bad Homburg, Germany), the Mass Median Aerodynamic Diameter (MMAD), and Geometric Standard Deviation (GSD) were calculated. In addition, the proportion (%) of aerosol less than 4µm (considered to be the inhalable portion) was determined.

Chamber Environmental Conditions: The following variables were monitored continuously and recorded every minute during each exposure period by the TSE-DACO monitoring system integrated into the exposure system:
Chamber airflow rates
Test Atmosphere temperature
Test atmosphere relative humidity
Test atmosphere carbon dioxide concentration
Test atmosphere oxygen concentration

OBSERVATIONS
Morbidity/Mortality: Animals were checked hourly during exposure, one hour after exposure and twice daily (early and late in the working day) during the 14-day observation period for morbidity and/or mortality.
Clinical Signs: All animals were observed for clinical signs at hourly intervals during exposure, as soon as practically possible following removal from restraint at the end of exposure, one hour after exposure and subsequently once daily for fourteen days.
Bodyweight: Individual bodyweights were recorded prior to treatment on the day of exposure (Day 0) and on Days 1, 3, 7 and 14.
Necropsy: At the end of the fourteen day observation period, the animals were euthanised by exsanguination under anaesthesia (RELEASE 300mg/ml injekció A.U.V.; Lot No.: 063012; Expiry: 01-2015; Produced by Wirtschaftsgenossenschaft deutscher Tierartze eG, Siemensstr. 14, 30827 Garbsen, Germany) and gross macroscopic examination was performed. All animals were subject to a gross necropsy which included a detailed examination of the abdominal and thoracic cavities. Special attention was given to the respiratory tract for macroscopic signs of irritancy or local toxicity.
Statistics:
No
Sex:
male/female
Dose descriptor:
LC0
Effect level:
> 2.83 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No animals died during the study.
Clinical signs:
other: Wet fur and fur staining were commonly recorded on the day of exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, were considered not to be biologically significant. Laboured respiration w
Body weight:
Normal bodyweight gain was noted during the observation period for all animals.
Gross pathology:
A single four hours nose-only exposure of Dipentamethylenethiuram hexasulfide to Wistar CRL: (WI) rats dosed at the maximum attainable concentration of 2.83 mg/L followed by a 14 day of observation period, was not associated with any macroscopic findings.
Other findings:
no
Interpretation of results:
GHS criteria not met
Conclusions:
Under the experimental conditions of this study, no death occurred in a group of ten rats exposed to the maximum attainable concentration of 2.83 mg/L for four hours. The acute inhalation median lethal concentration (4hr LC50) of Dipentamethylenethiuram hexasulfide, in CRL: (WI) Wistar strain rats, was therefore considered to be greater than 2.83 mg/L.
Executive summary:

Introduction: This study was performed to assess the acute inhalation toxicity of Dipentamethylenethiuram hexasulfide. The method used followed that described in the US Environmental Protection Agency (EPA) Health Effects Test Guidelines, OPPTS 870.1300, Acute Inhalation Toxicity, August 1998. The method was also designed to meet OECD guideline 403 (07 September 2009), Council Regulation (EC) No 440/2008, Annex Part B, B.2: "Acute Toxicity (Inhalation)", Official Journal of the European Union No. L 142, dated May 31st, 2008, in line with the Sponsor requirements.

 

Study Design: A group of ten CRL: (WI) Wistar strain rats (five male and five female) was exposed to the maximum attainable concentration of Dipentamethylenethiuram hexasulfide. The animals were exposed for four hours using a nose-only exposure system, followed by a fourteen day observation period. The day of exposure was designated Day 0. Aerosol concentrations were measured gravimetrically 17 times during the animal exposure. The particle size distribution of the test aerosol was determined regularly (3 times) during the exposure period.

Clinical observations and bodyweights were recorded throughout the study. At the end of the scheduled period the animals were sacrificed and subjected to a gross examination post mortem.

No control group was used in this study.

 

Results

The mean achieved atmosphere concentration was as follows:

Mean Achieved Concentration (Maximum attainable)

(mg/l)

Standard Deviation

Nominal Concentration

(mg/l)

2.83

0.40

5.32

 

The characteristics of the test atmosphere were as follows:

Mean Achieved

(mg/l)

Mean Mass Median Aerodynamic Diameter

(MMAD) (µm)

Geometric Standard Deviation

Inhalable Fraction

(% <4µm)

2.83

3.96

2.34

50.4

 

The mortality data were summarised as follows:

Mean Achieved

 (mg/l)

Male Deaths

Female Deaths

Total Deaths

2.83

0/5

0/5

0/10

 

Clinical Observations: Wet fur and fur staining were commonly recorded on the day of exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, were considered not to be biologically significant.

Laboured respiration was only noted for the exposed animals on day of exposure. No abnormalities were detected in any animal from Day 2 of the observation period.

Bodyweights: Normal bodyweight gain was noted during the observation period for all animals.

Necropsy: A single four hours nose-only exposure of Dipentamethylenethiuram hexasulfide to Wistar CRL: (WI) rats dosed at the maximum attainable concentration of 2.83 mg/L followed by a 14 day of observation period, was not associated with any macroscopic findings.

 

Conclusion: Under the experimental conditions of this study, no death occurred in a group of ten rats exposed to the maximum attainable concentration of 2.83 mg/L for four hours. The acute inhalation median lethal concentration (4hr LC50) of Dipentamethylenethiuram hexasulfide, in CRL: (WI) Wistar strain rats, was therefore considered to be greater than 2.83 mg/L.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating conc.
Value:
2 830 mg/m³
Quality of whole database:
Inhalation study is reliable with a klimisch score of 1 (GLP guideline study).

Acute toxicity: via dermal route

Link to relevant study records
Reference
Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
03 November 2011 - 02 December 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
yes
Remarks:
filtered drinking water was used to moisten the gauze pad for administration and to remove any residual test item (instead of drinking water treated by reverse osmosis).
Qualifier:
according to guideline
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Deviations:
no
Remarks:
idem above
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: breeder: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: on the day of treatment, the animals were approximately 8 weeks old
- Mean body weight at study initiation: the males had a mean body weight of 274 g (range: 268 g to 278 g) and the females had a mean body weight of 216 g (range: 208 g to 224 g)
- Fasting period before study: yes, during the night before treatment
- Housing: polycarbonate cages with stainless steel lid
- Diet: SSNIFF R/M-H pelleted diet (free access)
- Water: tap water filtered with a 0.22 µm filter (free access)
- Acclimation period: at least 5 days before the beginning of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): approximately 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h (7:00 - 19:00)

IN-LIFE DATES: 03 November 2011 to 02 December 2011.
Type of coverage:
semiocclusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
TEST SITE
- Area of exposure: 10% of body surface, dorsal site
- Type of wrap if used: hydrophilic gauze pad + adhesive hypoallergenic aerated semi-occlusive dressing + restraining bandage

REMOVAL OF TEST SUBSTANCE
- Removal of dressing: 24h post-exposure
- Washing: at 24h post-exposure, with a moistened cotton pad

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): ----
- Constant volume: no
- For solids, paste formed: ----yes/no----
Duration of exposure:
single exposure (24h)
Doses:
2000 mg/kg
No. of animals per sex per dose:
5 male and 5 females.
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Clinical observations: frequently during the hours following treatment; then, at least once a day.
- Body weight: just before treatment on day 1; then on days 8 and 15.
- Necropsy of survivors performed: yes (macroscopic).
Statistics:
no
Sex:
male/female
Dose descriptor:
LD0
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No unscheduled deaths occurred during the study.
Clinical signs:
No clinical signs indicative of systemic toxicity were observed in any animals.
No cutaneous reactions were observed in any animals.
Body weight:
Body weight was unaffected by the test item-treatment when compared to CIT historical control data.
Gross pathology:
At the end of the 14-day observation period, the spleen was enlarged in 4/5 males given the test item at 2000 mg/kg. In view of the absence of similar findings in females treated at the same dose-level, this finding was considered to be incidental and unrelated to the test item administration.
Interpretation of results:
GHS criteria not met
Conclusions:
The dermal LD50 of the test item was higher than 2000 mg/kg in rats.
Executive summary:

The objective of this study was to evaluate the potential toxicity of the test item following a single dermal application to rats.

This study was conducted in compliance with the principles of Good Laboratory Practice.

 

Methods

The test item Dipentamethylenethiuram hexasulfide was applied in its original form to the skin of five female then five male Sprague-Dawley rats at the dose-level of 2000 mg/kg. The application site was covered by a semi-occlusive dressing for 24 hours.

Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on day 1 and then on days 8 and 15.

On completion of the observation period, the animals were sacrificed and then submitted for a macroscopic post-mortem examination.Macroscopic lesions were preserved but no microscopic examination was performed.

 

Results

No unscheduled deaths occurred during the study.

No clinical signs indicative of systemic toxicity or cutaneous reactions were observed in any animals.

Body weight was unaffected by the test item treatment.

At the macroscopic examination, enlarged spleen was observed in 4/5 males but this was considered not to be related to the test item.

Conclusion

The dermal LD50of the test item was higher than 2000 mg/kg in rats.

Therefore, the test item is not classified as harmful or toxic by dermal route according to the criteria of CLP Regulation.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
Value:
2 000 mg/kg bw
Quality of whole database:
Petitpretz's study is reliable with a klimisch score of 1 (GLP guideline study).

Additional information

Oral acute toxicity study in rats (OECD 423) (2012) :

The objective of this study was to evaluate the potential acute toxicity of the test item following a single oral administration (gavage) to rats. The test item was administered once by the oral route (gavage) to six fasted female Sprague-Dawley rats at dose-level of 2000 mg/kg under a dosage-volume of 20 mL/kg and a concentration of 100 mg/mL. The test item was prepared in a 0.5% solution of methylcellulose. Each animal was observed at least once a day for mortality and clinical signs for 15 days. Body weight was recorded on days 1, 8 and 15. On completion of the observation period, the animals were sacrificed and submitted for a macroscopic post-mortem examination. No tissues were preserved as no macroscopic lesions were observed.

No unscheduled deaths were observed. No clinical signs were observed in any animals, except for hypoactivity seen transiently on day 1 in 1/6 females given 2000 mg/kg. Body weight was unaffected by the test item treatment. The test item administration did not induce any macroscopic changes.The oral LD50 of the test item was higher than 2000 mg/kg in rats.

Inhalation acute toxicity study in rats (OECD 436) (2013):

This study was performed to assess the acute inhalation toxicity of Dipentamethylenethiuram hexasulfide (OECD 403). A group of ten CRL: (WI) Wistar strain rats (five male and five female) was exposed to the maximum attainable concentration of Dipentamethylenethiuram hexasulfide. The animals were exposed for four hours using a nose-only exposure system, followed by a fourteen day observation period.

The mean achieved atmosphere concentration (maximum attainable) was 2.83 mg/l (SD 0.40) corresponding to a nominal concentration of 5.32 mg/l. No mortality was observed in this study (0/10 animals).  

Wet fur and fur staining were commonly recorded on the day of exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, were considered not to be biologically significant.  Laboured respiration was only noted for the exposed animals on day of exposure. No abnormalities were detected in any animal from Day 2 of the observation period. Normal bodyweight gain was noted during the observation period for all animals.  A single four hours nose-only exposure of Dipentamethylenethiuram hexasulfide to Wistar CRL: (WI) rats dosed at the maximum attainable concentration of 2.83 mg/L followed by a 14 day of observation period, was not associated with any macroscopic findings.  Under the experimental conditions of this study, no death occurred in a group of ten rats exposed to the maximum attainable concentration of 2.83 mg/L for four hours.The acute inhalation median lethal concentration (4hr LC50) of Dipentamethylenethiuram hexasulfide, in Wistar strain rats, was therefore considered to be greater than 2.83 mg/L.  

 

Dermal acute toxicity study in rats (OECD 402) (2012):

 The objective of this study was to evaluate the potential toxicity of the test item following a single dermal application to rats. This study was conducted in compliance with the principles of Good Laboratory Practice.  

 The test item Dipentamethylenethiuram hexasulfide was applied in its original form to the skin of five female then five male Sprague-Dawley rats at the dose-level of 2000 mg/kg. No unscheduled deaths occurred during the study. No clinical signs indicative of systemic toxicity or cutaneous reactions were observed in any animals. Body weight was unaffected by the test item treatment. At the macroscopic examination, enlarged spleen was observed in 4/5 males but this was considered not to be related to the test item. The dermal LD50 of the test item was higher than 2000 mg/kg in rats. 

Justification for classification or non-classification

Based on the available data, no classification for acute toxicity is required for Dipentamethylenethiuram hexasulfide according to the Regulation EC n°1272/2008.