Benzenesulfonamide, N-[2-[[(phenylamino)carbonyl]amino]phenyl]-

Endpoint summary

Description of key information

Acute oral and inhalation toxicity tests were conducted as these were considered the most likely routes of exposure.

Acute oral toxicity

The oral LD50 value of the test substance in Wistar rats was established to exceed 2000 mg/kg body weight.

According to the OECD 423 test guideline, the LD50 cut-off value was considered to exceed 5000 mg/kg body weight.

 

Acute inhalation toxicity

The inhalation LC50 value of the test substance in Wistar rats was established to exceed 5.23 mg/L.

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

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

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: JMAFF Guidelines, 2000

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Approximately 8 weeks old
- Weight at study initiation: Did not exceed ± 20% of sex mean. Approximately 149 g.
- Fasting period before study: Animals were deprived of food overnight prior to dosing and until 3-4 hours after dosing.
- Housing: Group housing of 3 animals per cage in labelled makrolon cages containing sterilized sawdust as bedding.
- Diet (e.g. ad libitum): Free access to pelleted rodent diet.
- Water (e.g. ad libitum): Free access to tap water
- Acclimation period: At least 5 days prior to treatment.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 - 24°C
- Humidity (%): 40 - 70%
- Air changes (per hr): 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours ligh/ 12 hours dark cycle

IN-LIFE DATES: From: To: 2014-06-17 to 2014-07-03

Route of administration:

oral: gavage

Vehicle:

propylene glycol

Details on oral exposure:

Oral gavage, using plastic feeding tubes.
Vehicle: Propylene glycol (Merck, Darmstadt, Germany) (specific gravity 1.036)
Preparation: The formulations (w/w) were prepared within 4 hours prior to dosing. Homogeneity was accomplished to a visually acceptable level.
Adjustment was made for specific gravity of the vehicle. No correction was made for purity of the test substance.

Doses:

2000 mg/kg body weight to two successive groups.

No. of animals per sex per dose:

3 (6 in total, two successive doses)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Bodyweights - Days 1 (pre-administration), 8 and 15.
Clinical signs - At periodic intervals on the day of dosing (Day 1) and once daily thereafter until Day 15.

- Necropsy of survivors performed: Yes
- Other examinations performed: Macroscopic abnormalities

Statistics:

No statistical analysis was performed.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No unscheduled mortality occured

Clinical signs:

other: Hunched posture and/or piloerection were noted for the animals between Days 1 and 3.

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Interpretation of results:

GHS criteria not met

Conclusions:

According to the study according to OECD TG 423 the LD50 value exceeds 2000 mg/kg bw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation 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:

Wistar

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: Eight to twelve weeks
- Weight at study initiation: 200 to 350g
- Housing: Housed in groups of upto 3 per sex in solid-floor polypropylene cages with stainless steel lids,
- Diet (e.g. ad libitum): Free access except during the exposure period and during acclimitization to the restraining tubes.
- Water (e.g. ad libitum): Free access except during the exposure period and during acclimitization to the restraining tubes.
- Acclimation period: At least 5 days in the detailed housing. Animals were also acclimitized for approximately 2 hours the day prior to exposure to the restraining tubes.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19°C throughout the exposure period (in the animal room; 19 to 25°C was set to be maintained).
- Humidity (%): 33-34% throughout the exposure period (in the animal room; 30 to 70% was set to be maintained).
- Air changes (per hr): At least 15 air changes per hour.
- Photoperiod (hrs dark / hrs light): 12 hours continuous light

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: acetone

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Cylindrical exposure chamber.

- Exposure chamber volume: 30L

- Method of holding animals in test chamber: Individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber 'O' ring.

- Source and rate of air: Oil free compressed air provided by a compressor at a rate of 60L/min

- Method of conditioning air: The air was passed though a water trap and respiratory quality filters before being introduced to the nebulizer.

- System of generating aerosols: The test item formulation was aerosolized using a metal concentric jet nebulizer located at the top of the exposure chamber. The nebulizer was connected to a glass syringe attached to an infusion pump, which provided a continuous supply of test item formulation under pressure, and to a metered compressed air supply.

- Method of particle size determination: The particle size of the generated atmosphere inside the exposure chamber was determined three times during the exposure period using a Marple Personal Cascade Impactor. This device consisted of six impactor stages (8.4, 7.3, 3.6, 1.3, 0.94 and 0.43 μm cut points) with stainless steel collection substrates and a backup glass fiber filter, housed in an aluminum sampler. The sampler was temporarily sealed in a sampling port in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through it using a vacuum pump. The collection substrates and backup filter were weighed before and after sampling and the weight of test item, collected at each stage, calculated by difference.

- Temperature, humidity, pressure in air chamber: The temperature, relative humidity and pressure in the air chamber was determined to be 19°C, 33-34% and negative pressure respectively.

TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric analysis was used. The test atmosphere was sampled at regular intervals during the exposure period. A weighed glass fiber 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, in a desiccator under reduced pressure between 18 and 20°C, 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. The addition of Acetone to improve aerosolization was considered not to affect the gravimetric calculation as all of the filters were dried thoroughly (for 24 hours) prior to weighing.

- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle (if applicable): Acetone

- Concentration of test material in vehicle (if applicable): A ratio of 20:80 (w/w) test material and acetone.

- Justification of choice of vehicle: The nature of the test item was such that a suitable dust atmosphere could not be generated from the test item as supplied. A formulation was, therefore, prepared with Acetone.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: No toxicity was observed in the preceding acute oral toxicity test.

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

4 h

Concentrations:

A target concentration of 5 mg/L was used for exposure.

No. of animals per sex per dose:

3 males and 3 females per sex per dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: Clinical signs were observed at hourly intervals during exposure, immeadiately on removal of the restraining tubes at the end of exposure, one hour after the end of exposure, and subsequently once daily for up to 14 days. Bodyweights were were recorded on arrival, prior to treatment on the day of exposure and on Days 1, 3, 7 and 14.

- Necropsy of survivors performed: Yes; all animals 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.

Statistics:

Not required in study design.

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.23 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No deaths occured on study in either sex.

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

Body weight:

All males and one female animal exhibited body weight losses on the first day post-exposure. With the exception of one female animal which exhibited a slight body weight loss from Days 1 to 3 post-exposure, reasonable body weight gains were noted for all 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 amongst animals at necropsy.

Interpretation of results:

GHS criteria not met

Conclusions:

No deaths occurred in a group of six rats exposed to a mean achieved atmosphere concentration of 5.23 mg/L for four hours. It was therefore considered that the acute inhalation median lethal concentration (4 hr LC50) of the test substance, in the RccHanTM : WIST strain rat, was greater than 5.23 mg/L. This results in no classification for acute toxicity via inhalation under CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 230 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No 1272/2008
The available data for acute toxicity are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. Based on this data, the substance is not considered to be classified for acute toxicity under Regulation (EC) No 1272/2008, as amended for the seventeenth time in Regulation (EU) 2021/849.