N-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)-phenyl-aminocarbonyl]-2,6-difluorobenzamide

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 Mar 1988 to 12 Apr 1988

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

May 1981

GLP compliance:

yes

Test type:

traditional method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)-phenyl-aminocarbonyl]-2,6-difluorobenzamide

EC Number:

410-690-9

EC Name:

N-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)-phenyl-aminocarbonyl]-2,6-difluorobenzamide

Cas Number:

103055-07-8

Molecular formula:

C17 H8 Cl2 F8 N2 O3

IUPAC Name:

1-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)phenyl]-3-(2,6-difluorobenzoyl)urea

Test animals

Species:

rat

Strain:

other: Tif: RAI f (SPF) hybrids of RII/1 x RII/2

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: age 7 - 8 weeks
- Weight at study initiation: 178 to 331 g
- Housing: Group of 5 (by sex); Macrolon cages, Type 4 with standardised soft wood bedding
- Diet: Rat diet, ad libitum.
- Water: ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 55 ± 10
- Air changes (per hr): approximately 15
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: From: 22 Mar 1988 To: 12 Apr 1988

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

>= 1.9 - <= 2.8 µm

Geometric standard deviation (GSD):

>= 2.2 - <= 2.5

Remark on MMAD/GSD:

In of the vicinity of the animals, 84 to 95 % (weight) of the airborne particles had a diameter smaller than 7 μm during the exposure.

Details on inhalation exposure:

INHALATION EXPOSURE CHAMBER
All exposures were conducted in a nose-only exposure. The chamber was designed to ensure a rapid equilibration (internal active volume less than one litre) and a uniform exposure of all animals in the system. In order to avoid rebreathing of the exhaled air, "fresh" test substance (in first—pass chamber air) was supplied to each animal via individual delivery and exhaust tubes. In addition to the necessary animal and sampling ports, identical "void" outlets were opened in proportion to the total air flow through the chamber. Thus the flow in any individual aerosol delivery tube was standardized to 2 L/min (velocity 1.25 m/s).
For the inhalation period, the rats were placed in Macrolon animal holders positioned radially around the exposure chamber, so that only the snouts and nostrils of the animals were exposed to the aerosol. The chamber was maintained at an exactly balanced pressure to prevent leakage of the test atmosphere from the system, as well as dilution with outside air. The exhaust air was decontaminated by subsequent passage through an absolute filter. The aerosol concentration in the chamber was determined gravimetrically 5 times during the exposure period. Samples of the test atmosphere (1 L) were passed through a GP 92 filter. The air flow rate for the sample collection was kept constant (2 L/min) by means of a Sierra Series 110 constant flow air sampler, regardless of filter loading. The mean and standard deviation of the aerosol concentrations for the exposure was calculated. Particle size analysis was conducted with an APS-33 Aerodynamic Particle Sizer, equipped with appropriate dilution systems to avoid coincidence counts. The number distribution in the 48 size classes was converted to a mass distribution, based on the bulk density of the test substance, which was determined separately. The following environmental parameters inside the inhalation chamber were monitored at approximately the same intervals as the concentration determinations:
- Temperature
- Relative humidity
- Oxygen content

AEROSOL
The aerosol was generated from the solid test material by means of a brush-feed micronizing jet mill. The aerosol generation system consists of a dual flexible brush dust-feed mechanism, modified from a design by Milliman, and a jet mill, to be aerodynamically compatible with the brush feed and the exposure system. In this instrument, powders are transferred from a hopper brush through a slit interface to the aspiration tube of the jet mill by means of a spiral feed brush driven by a stepping motor. In the mill, the material is micronized by impaction of particle against particle in two opposing air streams. A cyclone type classifier ensures that only particles of the desired diameter leave the jet mill, while the larger ones are re-entrained into the air stream for further milling. In a preliminary experiment, the appropriate interface slit size, brush speeds, and air pressures and flows were determined for the desired concentration. The dust generator was operated at a total airflow (through the aspiration tube and the two milling jets) of 37 L/min (input pressure 210/210 kPa), and the aerosol was diluted with filtered humidified air to yield a total flow of 48 L/min. Secondary agglomerates were removed from the aerosol by means of a glass cyclone. The throughput of the solid test material was determined by weighing the dust genera tor and the cyclone before and after aerosol generation. The control animals were exposed to filtered humidified air (32 L/min) under the same conditions as described above.

ANALYSIS OF INHALATION ATMOSPHERES
The air flow through the chamber was measured with flow meters. Adjustments to maintain a total flow of 48 L/min could be made with needle valves. However, no deviations were observed in any of the exposures, once the equilibrium was reached (within the first 10 minutes after beginning of exposure).

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

2350 ± 100 mg/m³

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

OBSERVATIONS
MORBIDITY/MORTALITY
The animals were examined for clinical symptoms and mortalities during the exposure at 1, 2, and 4 hours, as well as 2 hours after the exposure and daily thereafter for 14 days.

BODY WEIGHTS
Body weights were recorded immediately prior to exposure and on days 7 and 14 of the observation period.

GROSS PATHOLOGY
Examinations were performed on all animals, which were killed after 14 days by ether anaesthesia. Particular attention was given to the respiratory tract

Statistics:

Inhalation LC50 values (including their 95 % confidence limits) for a 4 hour treatment and a subsequent 14 day observation period could not be calculated, because no mortalities were elicited by the test substance at a concentration of 2350 ± 100 mg/m3 (limit test). The body weights of the treated animals and the controls were compared by analysis of variance.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2 350 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality occurred.

Clinical signs:

other: The symptoms, piloerection, hunched posture, dyspnea, were seen and in similar extent in both sexes. These findings disappeared within 2 days.

Body weight:

The males exposed to the test article exhibited a significantly higher body weight increase during the second week after exposure

Gross pathology:

No treatment-related deviations from normal morphology were detected at necropsy.

Any other information on results incl. tables

Table 1 Exposure atmospheres

Parameter	1 - Control Group (air)	2 – Exposure Group (test substance)
Exposure day	22 Mar 1988	12 April 1988
Nominal concentration (mg/m^3)	Control *	3003
Mean exposure concentration ** (mg/m^3) ± SD		2350 ± 100
Mass median aerodynamic diameter (MMAD) (mm)		1.9 – 2.8
Geometric standard deviation (GSD)		2.2 – 2.5
Particles < 7 mm (% w/w)		84 – 95
Particles < 3 mm (% w/w)		52 – 73
Air flow (L/min) through generator through chamber	32	37 48
Mean chamber temperature (ºC) *** ± SD	22.3 ± 0.1	23.0 ± 0.1
Mean relative humidity (%) *** ± SD	47 ± 1	38 ± 1
Mean oxygen content (%) *** ± SD	21.0 ± 0	21.0 ± 0

* exposed to filtered humidified air

** determined gravimetrically 5 times during exposure period

*** determined 5 times during the exposure period

Table 2 Observation of symptoms

Observations

Exp. day

Day of post exposure period

de

ae

1

2

3

4

5

6

7

8

9

>9

Control males

no effect observed in all animals

Test article exposed males

piloerection

++

+

hunched post.

+

dyspnoea

++

+

Control females

no effect observed in all animals

Test article exposed females

piloerection

++

+

hunched post.

+

dyspnoea

++

+

 Exp.day = exposure day (de = during, ae = after exposure)

+ = slight ++ moderate = +++ = severe

hunched post. = hunched posture

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute inhalation LC50 of the test substance in rats was found to be greater than 2350 mg/m3 for both males and females.

Executive summary:

The acute inhalation toxicity of the test substance was evaluated in groups of 5 male and 5 female young adult albino rats (Tif: RAI f (SPF)), rats in accordance with OECD TG 403 following GLP principles. The animals were exposed to 0 (control – purified air) or 2350 mg/m³ test article in a nose-only exposure system and were examined for clinical symptoms and mortalities during the exposure at 1, 2, and 4 hours, as well as 2 hours after the exposure and daily thereafter for 14 days. Body weights were recorded immediately prior to exposure and on days 7 and 14 of the observation period. Gross pathological examinations were performed on all animals, which were killed after 14 days by ether anaesthesia. Particular attention was given to the respiratory tract.

Upon a 4hour aerosol inhalation exposure and a 14 day post-treatment observation period, no mortalities were elicited by the test substance at a concentration of 2350 ± 100 mg/m3. Due to the properties of the test material, it was not possible to generate higher aerosol concentrations of the test substance. The mass median aerodynamic diameter (MMAD) of the particles was between 1.9 and 2.8 µm, with a geometric standard deviation (GSD) of 2.2 to 2.5. In the vicinity of the animals, 84 to 95 % of the airborne particle mass had a diameter smaller than 7 µm. The animals of both sexes exposed to the test substance experienced the symptoms piloerection, hunched posture and dyspnoea to a similar extent. They recovered within 2 days. From the absence of mortalities it can be assumed that the LC50 to male and female rats is greater than 2350 mg/m3 air.

In conclusion, the acute inhalation LC50 of the test substance in rats was found to be greater than 2350 mg/m3 for both males and females.