Benzamide, N-[[4-[(cyclopropylamino)carbonyl]phenyl]sulfonyl]-2-methoxy-

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Apr - 28 Apr 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

adopted 12 May 1981

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

adopted 7 Sep 2009

Deviations:

yes

Remarks:

Animals weren't acclimatised to the test apparatus prior to testing. Animals weren't group housed during the non-exposure periods.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

485-320-2

EC Name:

-

Cas Number:

221667-31-8

Molecular formula:

C18H18N205S

IUPAC Name:

N-[4-(cyclopropylcarbamoyl)benzenesulfonyl]-2-methoxybenzamide

Test animals

Species:

rat

Strain:

other: Wistar Hsd Cpb:WU (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan-Winkelmann GmbH, Borchen (Germany).
- Age at study initiation: Approx. 2 months.
- Weight at study initiation: 180 - 199 g for males and 164 - 179 g for females.
- Housing: Individually in conventional Makrolon® cages.
- Diet: Standard fixed formula diet (KLIBA 3883 = NAFAG 9441 pellets, PROVIMI KLIBA SA, Switzerland), ad libitum.
- Water: Drinking quality municipality tap-water, ad libitum.
- Acclimation period: At least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 40 - 60
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 / 12; artificial light from 6.00 a.m to 6.00 p.m.

IN-LIFE DATES: From: 2004-04-14 to: 2004-04-28

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

3.24 µm

Geometric standard deviation (GSD):

1.82

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: See figure 1 for a diagram of the exposure chamber (attached background material). Animals were exposed to the aerosolized test substance in Plexiglas exposure tubes applying a directed-flow nose-only exposure principle. Under dynamic conditions the test substance was aerosolized into the inlet of the cylindrical inhalation chamber. The cyclone was used to prevent larger particles from entering the inhalation chamber. The cyclone was designed so that particles larger than 10 µm are retained in the cyclone.
- Exposure chamber volume: The aluminium inhalation chamber has the following dimensions: inner diameter = 14 cm, outer diameter = 35 cm (two-chamber system), height = 25 cm (internal volume - about 3.8 L).
- Method of holding animals in test chamber: Restrained in the exposure tubes.
- Source and rate of air (airflow): Compressed air was supplied by Boge compressors. At each exposure port a minimal air flow rate of 0.75 l/min was provided.
- Method of conditioning air: Air was conditioned (i.e. freed from water, dust, and oil) automatically by a VIA compressed air dryer.
- System of generating particulates/aerosols: The test substance was aerosolized using a Wright-Dust-Feeder {BGI Inc., Waltham, MA, USA).
- Method of particle size determination: The particle-size distribution was analysed using an ANDERSEN cascade impactor (Hauke, Gmunden, Austria).
- Treatment of exhaust air: Purified via cotton-wool/HEPA filters.
- Temperature and humidity air chamber: 21 °C. Relative humidity < 7%. (Temperature and humidity measurements were made using a computerized system (Hydra, Fluke-Philips)).

TEST ATMOSPHERE
- Brief description of analytical method and equipment used: The test-substance concentration was determined by gravimetrical analysis (filter: glass fibre filters, Sartorius, Gottingen, Germany; digital balance). The number of samples taken was sufficient to characterize the test atmosphere and was adjusted so as to accommodate the sampling duration and/or the need to confirm specific concentration values. Optimally, samples were collected on an hourly basis. All analytical concentrations reported refer to mg of test substance/m3 air. Nominal concentrations were not calculated since this would have required a derangement of the dust generating system and in doing so this may had caused an increase in the temporal (day-to-day) variability of test concentrations.
- Samples taken from breathing zone: Yes (chamber samples were taken in the vicinity of the breathing zone).
- Time needed for equilibrium of exposure concentration before animal exposure: 5 minutes

- Particle size distribution:

Measurement I:

Respirability (percent < 1.0 µm):
Mass related: 2.3% (measured)
Number related: 38.7% (extrapolated)

Respirability (percent < 3.0 µm):
Mass related: 43.7% (measured)
Number related: 94.5% (extrapolated)

Respirability (percent < 5.0 µm):
Mass related: 76.3% (measured)
Number related: 99.3% (extrapolated)

Measurement II:

Respirability (percent < 1.0 µm):
Mass related: 2.3% (measured)
Number related: 38.7% (extrapolated)

Respirability (percent < 3.0 µm):
Mass related: 43.7% (measured)
Number related: 94.5% (extrapolated)

Respirability (percent < 5.0 µm):
Mass related: 76.3% (measured)
Number related: 99.3% (extrapolated)

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetric analysis

Duration of exposure:

4 h

Concentrations:

5000 mg/m³ (nominal concentration), 3513 mg/m³ (analytical concentration, maximum achievable concentration)

No. of animals per sex per dose:

5

Control animals:

yes

Remarks:

Controls were exposed to an atmosphere using essentially similar exposure conditions as were used for the test substance (15 L air/min; conditioned dry air; duration of exposure = 1 x 4h; 5 males and 5 females per group).

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Body weights were measured before exposure, on Days 3 and 7, and weekly thereafter. Individual weights are also recorded at death, if applicable. The appearance and behavior of each rat were examined carefully several times on the day of exposure and at least once daily thereafter. Weekend assessments were made once a day (morning). Assessments from restraining tubes were made only if unequivocal signs occurred (e.g. spasms, abnormal movements, and severe respiratory signs). Following exposure, observations were made and recorded systematically; individual records were maintained for each animal. Cage-side observations included, but were not limited to, changes in the skin and fur, eyes, mucus membranes, respiratory, circulatory, autonomic and central nervous system, and somatomotor activity and behavior pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhea, lethargy, somnolence and prostration, The time of death was recorded as precisely as possible, if applicable. Since these signs can only be assessed adequately from freely moving animals, no specific assessment was performed during exposure while animals were restrained. Each rat was first observed in its home cage and then individually examined. The following reflexes were tested, based on recommendations made by Irwin (1968): visual placing response and grip strength on wire mesh, abdominal muscle tone, corneal and pupillary reflexes, pinna! reflex, righting reflex, tail-pinch response, startle reflex with respect to behavioral changes stimulated by sounds (finger snapping) and touch (back). rectal temperatures were measured shortly after cessation of exposure (approximately within 30 minutes after the end of exposure) using a digital thermometer with a rectal probe for rats.
- Necropsy of survivors performed: yes

Statistics:

Particle size characteristics and respirable mass fraction were determined by calculation of MMAD and GSD employing probit analysis and linear regression as necessary. Means and single standard deviations of body weights are calculated. Body weight gain was statistically evaluated for each group. For these evaluations a one-way ANOVA was used. Rectal temperature measurements were statistically evaluated using the ANOVA procedure.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 3 513 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: highest technically achievable concentration

Mortality:

There were no mortalities during the study.

Clinical signs:

other: Nonspecific clinical signs, piloerection (2/5) and ungroomed hair coat (3/5) were transiently observed in cyprosulfamide-treated female rats for 1 - 2 days.

Body weight:

There were no treatment-related differences in bodyweight gain between treated animals and controls.

Gross pathology:

No observable findings were made for both controls and treated animals including the respiratory tract.

Other findings:

Reflex measurements:
A battery of reflex measurements was made on the first post-exposure day. In comparison to the rats of the control group, none of the rats in the treated group exhibited changes in the reflex behavior.

Rectal temperature:
Statistical comparisons between the control and the exposure group revealed that there was no toxicologically significant effect on the body temperature (although a statistically significant decreased body temperature was observed).

Any other information on results incl. tables

Table 2: Summary of acute inhalation toxicity - 4 hour exposure to aerosolized testsubstance (powder)

Test Group	Measured concentration [mg/m^3]	Toxicological Result	Onset and Duration ofSigns	Onset of Mortality	Rectal Temperature (°C)
Male
Control		0 / 0 / 5	-	-	37.9
Test Substance		0 / 0 / 5	-	-	37.3*
Female
Control		0 / 0 / 5	-	-	38.5
Test Substance		0 / 3 / 5	1d – 2d	-	37.5**

* = p < 0.05, ** = p < 0.01

Toxicological Result:

First Number = Number of dead animals

Second Number = Number of animals with signs after cessation of exposure

Third Number = Number of animals exposed

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria not met, no classification required according to Regulation (EC) No 1272/2008.

Conclusions:

The study was performed in accordance to OECD TG 403 under GLP conditions and is considered reliable. The LC50 was determined to be > 3513 mg/m3.