N-nitro-N-(3-methyl-3,6-dihydro-2H-1,3,5-oxadiazin-4-yl)amine

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995-11-17 until 1996-03-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline-conform study under GLP without deviations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

These deviations are stated in the original study report and were not considered to have influenced the validity of the study.

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

These deviations are stated in the original study report and were not considered to have influenced the validity of the study.

GLP compliance:

yes (incl. QA statement)

Remarks:

certified by: Staatstoezicht op de Volksgezondheit, the Netherlands

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

431-060-1

EC Name:

-

Cas Number:

153719-38-1

Molecular formula:

Hill formula: C4H8N4O3 CAS formula: C4H8N4O3

IUPAC Name:

3-methyl-N-nitro-3,6-dihydro-2H-1,3,5-oxadiazin-4-amine

Details on test material:

- Name of test material (as cited in study report): CA 2343 A (Intermediate of CGA 293343)
- Substance type: mono-constituent organic substance
- Physical state: solid, fine white powder
- Analytical purity: 96.7 %
- Impurities (identity and concentrations): no data
- Purity test date: no data
- Lot/batch No.: P.503005
- Expiration date of the lot/batch: Date of reanalysis: December 1996
- Stability under test conditions: not reported
- Storage condition of test material: 4 °C

- Mass median aerodynamic diameter (for liq.+solid aerosol): MMAD 6 µm
- 67 % of the particels present at the animals breathing zone had an aerodynamic diameter of <= 8,2 µm.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga, Sulzfeld, Germany.
- Age at study initiation: 5-6 weeks
- Weight at study initiation: body weights of the male and female rats were 292 g and 193 g, respectively
- Fasting period before study: not reported
- Housing: During exposure the animals were deprived of food and water and housed individually in the holders. Immediately after the exposure, the animals were returned to their living cages, 5 males or 5 females to a cage, and were held for an observation period of 14 days. The animals were housed under conventional conditions in suspended stainless steel cages fitted with wire-mesh floor and front.
- Diet (e.g. ad libitum): All rats received the Institute's powdered, cereal-based rodent diet ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: Total duration of the acclimatization period in the animal room was 25 days.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): between 21.0 and 23.5 °C,
- Humidity (%): between 45 and 70%.
- Air changes (per hr): The number of air changes was about 10 per hour.
- Photoperiod (hrs dark / hrs light): 12-hour light and 12-hour dark cycle


IN-LIFE DATES: From: 1996-01-05 To: 1996-01-19

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose-only inhalation chamber, a modification of the chamber manufactured by ADG Developments Ltd., Codicote, Hitchin, Herts. SG4 8UB, United Kingdom (see attached)
- Exposure chamber volume: 50 l
- Method of holding animals in test chamber: The animals were secured in plastic animal holders
- Source and rate of air: The test atmosphere was generated by passing the ground test material using a dry material helix feeder (Hethon, Hengelo, the Netherlands) to a jet mill (Institute's design) (see also attached figure).
- Method of conditioning air: The jet mill was operated with dry pressurized air (less than 1% humidity); the test material was delivered using a slip stream of airconditioned room air and pressurized air. This stream accounted for about 33% of the total amount of air. The generated aerosol was passed to the inlet of the exposure unit and directed downward through the mixing chambers towards the animals. The mean amount of air passed through the exposure unit was 105.8 I/min.At the bottom of the unit the test atmosphere was exhausted.
- System of generating particulates: jet mill (see decription above)
- Method of particle size determination: Particle size distribution measurement was carried out once during exposure using a 10-stage Andersen cascade impactor with the largest cut-off size of 32 pm, of which the last stage (viz. with cut-off size 0.1 µm) was not used. The Mass Median Aerodynamic Diameter (MMAD) and the mean geometric standard deviation (gsd) were calculated (Lee, 1972).
- Treatment of exhaust air: not reported
- Temperature, humidity, pressure in air chamber: The mean temperature was 20.6 ± 0.4 °C (range 19.8-21.1 °C); relative humidity was 12 ± 1%
(range 11-14%). The oxygen concentration was 21.9%.


TEST ATMOSPHERE
- Brief description of analytical method used: The actual concentration in the test atmosphere was determined eight times (twice each hour) by gravimetric analysis. Representative samples were obtained by passing 10-l test atmospbere samples at ca. 5 I/min through fiber glass filters (Sartorius). Before sampling the filters were weighed; immediately after sampling the filters were weighed again. The actual concentration was calculated by dividing the amount of test material captured by the volume of the air sample taken.
- Samples taken from breathing zone: yes


VEHICLE: none


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: The particle size distribution is given in Table 2 of the original study report; it was shown that 67% of the particles present at the animals' breathing zone were smaller than or equal to 8.2 µm.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The MMAD was 6.0 µm; the GSD of the particles was 2.5 µm.


CLASS METHOD (not applicable)

Analytical verification of test atmosphere concentrations:

yes

Remarks:

The actual concentration of CA 2343 A (Intermediate of CGA 293'343) during the exposure based on gravimetric analyses was 6.92 ± 0.5 g/m³ (mean concentration).

Duration of exposure:

4 h

Concentrations:

The test animals were exposed to the limit concentration of at least 5 g/m³

No. of animals per sex per dose:

5 males and 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The rats were visually inspected just before exposure, for reactions to treatment during the exposure, shortly after exposure, and at least once daily during the observation period. Body weights were recorded just prior to exposure (day 0), and on days 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight: as described above

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 6.9 mg/L air (analytical)

Exp. duration:

4 h

Mortality:

no mortalities observed

Clinical signs:

other: Observation of the rats was limited during exposure due to the stay in restraining tubes; however, shallow breathing and visually decreased breathing rate were observed in all rats during the exposure period. Slight shallow breathing was seen during the s

Body weight:

One male and one female rat showed slight weight loss seven days after exposure. However, the overall body weight gain was considered to be normal for male rats and slightly reduced for female rats of this strain and age.

Gross pathology:

Abnormalities at necropsy consisted of grey discoloured lungs in one male and two female rats, and one or a few small lung haemorrhages in two males. Small haemorrhages (petechiae) are occasionally found in rats of this strain and age and are, therefore, considered not to be related lo treatment. Sparsely haired fur in various regions was observed in four female rats; this change was also considered unrelated to treatment.

Other findings:

none reported

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

Migrated information

Conclusions:

The acute inhalation (4 hour) LC-50 for CA 2343 A (Intermediate of CGA 293'343) in the rat is higher than 6.92 g/m³. Therefore the test substance is not classified as to its acute inhalation toxicity properties.

Executive summary:

A (4-hour) inhalation toxicity study with CA 2343 A (Intermediate of CGA 293'343) was carried out in rats, acc. to OECD Guideline 403. One test group consisting of each five male and female rats were exposed to the test atmosphere with a test item concentration of 6.92 + 0.5 g/m³ (nose-only exposure). Some clinical effects of the test animals were reported. Since none of the rats died at this concentration level, the 4-hour LC50 value of CA 2343 A (Intermediate of CGA 293'343) was higher than 6.92 g/m³. Therefore the test substance is not classified as to its acute inhalation toxicity properties.