[No public or meaningful name is available]

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

27.04.2009 - 28.08.2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

1981

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

1998

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: MAFF Japan Agricultural Chemicals Regulation Laws 2-1-3 Notification 12 Nousan 8147 and Notification 13 Seisan 1739

Version / remarks:

2000 & 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

traditional method

Test material

Test material information

Constituent 1

Reference substance name:

2-Amino-5-cyano-N,3-dimethylbenzamide

Cas Number:

890707-29-6

Molecular formula:

C10H11N3O

IUPAC Name:

2-Amino-5-cyano-N,3-dimethylbenzamide

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- The test material was milled to a fine particle size specifically for use in the inhalation study

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, NC
- Age at study initiation: Approximately 8-9 weeks old
- Weight at study initiation: 230–322 g for males; 180–234 g for females
- Housing: Animals were housed individually in solid bottom caging with bedding.
- Diet: PMI Nutrition International, LLC Certified Rodent LabDiet (#5002), ad libitum
- Water: Tap water, ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-26
- Humidity (%): 30-70
- Air changes (per hr): Not recorded
- Photoperiod (hrs dark / hrs light): 12/12

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
Chamber atmospheres were generated by suspension of the test substance in air with a Fluid Energy Processing model 00 jetmill. The test substance was metered into the jetmill with a K-Tron model T-20 Twin Screw volumetric feeder. Filtered, high-pressure air, metered into the jetmill, carried the resulting atmosphere through a 2-L glass cyclone and into the 34 L exposure chamber. The atmospheric concentration of the test substance was determined by gravimetric analysis at approximately 30-minute intervals during the exposure period. Samples to determine particle size distribution were taken during the exposure with a Sierra® Series 210 cyclone preseperator/cascade impactor and Sierra® Series 110 constant flow air sampler.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

2.2 mg/L and 5.6 mg/L of the test substance

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

Two groups of 5 male and 5 female rats each were exposed to mean aerosol concentrations of either 2.2 mg/L or 5.6 mg/L of the test substance suspended in air for a single 4-hour period. During exposure, animals were individually restrained in perforated stainless steel cylinders with conical nose pieces. The restrainers were inserted into a polymethylmethacrylate faceplate attached to the exposure chamber so that the nose of each animal extended into the exposure chamber. Animals were observed for mortality and response to alerting stimuli during the exposure and observed for mortality and clinical signs of toxicity immediately after they were removed from the restrainers following exposure. During a 14-day post exposure period, all surviving rats were observed each day for mortality, were weighed test Days 0,1, 2, 3, 4, 7 and 14 and observed for clinical signs of toxicity daily during the recovery period. At the end of the 14-day recovery period, all surviving animals were necropsied and all animals were examined for gross pathological changes.

Statistics:

The data did not warrant statistical analysis.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No animals died following the 2.2 mg/L test substance exposure. One day following the 5.6 mg/L test substance exposure one female rat was found dead and 2 days following the 5.6 mg/L exposure one male rat was found dead. All remaining animals from the 5.6 mg/L exposure survived to the 14 day post exposure recovery period.

Clinical signs:

lethargy (hypoactivity)

Remarks:

Following the 5.6 mg/L exposure, 2 females demonstrated lethargy 2 days post-exposure which resolved by 3 days post-exposure. Following the 2.2 mg/L exposure, 2 females showed hypo-activity on day one post-exposure which resolved by 2 days post-exposure.

Body weight:

One day following the exposures, male and female rats demonstrated body weight losses of up to 36.5 g and 26.9 g, respectively. All surviving animals demonstrated body weight gains by 4 days post-exposure.

Gross pathology:

No test substance-related gross lesions were observed at necropsy in either exposure group.

Any other information on results incl. tables

Table 2: Concentrations, mortality/animals treated, inhalation LC50

Concentration (mg/L)	Males (a)	Females (a)	Combined (a)
2.2	0/5	0/5	0/10
5.6	1/5	1/5	2/10
Inhalation LC50:	>5 mg/L	>5 mg/L	>5 mg/L

(a) Number of animals died/number of animals in exposure group

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the acute inhalation LC50 for the test substance in rats was >5.6 mg/L for both males and females.

Executive summary:

The acute inhalation toxicity of the test substance was investigated according to the OECD Guideline 403.

Two groups of 5 male and 5 female Crl:CD(SD) rats were exposed nose-only for a single 4-hour period to the test substance in air. The test substance is a solid/powder at room temperature and aerosol atmospheres were generated by suspending the test substance in air. Airborne concentrations of the test substance were determined by gravimetric analysis. Animals were weighed and observed for clincial signs of toxicity during a 14-day recovery period.
Rats were exposed to mean aerosol concentrations of either 2.2 ± 0.5 or 5.6 ± 1.3 mg/L test substance (mean ± standard deviation). The mean mass median aerodynaic diameters ± geometric standard devation for the 2.2 and 5.6 mg/L exposure atmospheres were 2.1 μm ± 1.9 and 2.6 μm ± 2.0, respectivley.
No mortalities were observed following the 2.2 mg/L exposure while 1 male and 1 female rat died within 2 days following the 5.6 mg/L exposoure.
One day following the exposures, male and female rats demonstrated body weight losses of up to 36.5 g and 26.9 g, respectively. All surviving animals demonstrated body weight gains by 4 days post-exposure.
Immediately following the 5.6 mg/L exposure, all rats demonstrated labored breathing, which persisted for up to 1-2 days for males and females, respectively. Also, 2 of 5 male rats demonstrated a high posture that resolved 2 days following the exposure, while 3 females demonstrated a high posture 2 days post-exposure following the 5.6 mg/L exposure. On test day 2 following the 5.6 mg/L exposure, 2 female rats demonstrated lethargy that was resolved by 3 days post-exposure. One day following the 2.2 mg/L exposure, 2 of 5 females demonstrated hypoactivity, which resolved by 3 days post-exposure.
Under the conditions of this study, the 4-hour inhalation median lethal concentration (LC50) for the test substance in male and female rats was greater than 5.6 mg/L.