2-cyano-2-[2,3-dihydro-3-(tetrahydro-2,4,6-trioxo-5(2H)-pyrimidinylidene)-1H-isoindol-1-ylidene]-N-methylacetamide

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03.11.1981 - 17.11.1981

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

comparable to Guideline 403, non GLP, but comparable reporting details

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-cyano-2-[2,3-dihydro-3-(tetrahydro-2,4,6-trioxo-5(2H)-pyrimidinylidene)-1H-isoindol-1-ylidene]-N-methylacetamide

EC Number:

278-388-8

EC Name:

2-cyano-2-[2,3-dihydro-3-(tetrahydro-2,4,6-trioxo-5(2H)-pyrimidinylidene)-1H-isoindol-1-ylidene]-N-methylacetamide

Cas Number:

76199-85-4

Molecular formula:

C16H11N5O4

IUPAC Name:

2-cyano-N-methyl-2-[3-(2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)-2,3-dihydro-1H-isoindol-1-ylidene]acetamide

Test material form:

solid

Details on test material:

- Physical state: solid, yellow
- Analytical purity: 88 %
- Stability: At least 2 years under normal conditions

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: WIGA Versuchstierzuchtanstalt, Sulzfeld, Germany, outbred strain: CAW-ICO-Wiga
- Age at study initiation: about 8 - 10 weeks
- Weight at study initiation: male animais 318 +/- 27 g, female animals 228 +/- 19 g
- Housing: five per cage, cages of Becker, type D III, without bedding.
- Diet: SSNIFF R complete diet for rats and mice, manufacturer: SSNIFF-Versuchstierdiaeten GmbH, Soest, Germany, ad libitum
- Water: tap water ad libitum during the observation period

ENVIRONMENTAL CONDITIONS
- Temperature (°C): temperature 22 +/- 2
- Humidity (%): 55 +/- 5
- Photoperiod (hrs dark / hrs light): 12 h/12 h

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose/head only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

1.7 µm

Geometric standard deviation (GSD):

4

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Read-nose inhalation system INA 20 (glass-steel construction, BASF AG)
- Exposure chamber volume: 55 L
- Method of holding animals in test chamber: The animals are restrained in tubes and their snouts project into the inhalation chamber.
- Source and rate of air: 1500 L/h compressed air by the injector and 1500 L/h ventilator air as dilution air.
- System of generating particulates/aerosols: A mixture of dust and air was generated by means of dust metering equipment (BASF).
By means of a dust generator the substance to be tested was generated into a dust aerosol, which was passed into the inhalation system.
An automatic vibrator was used for dust generation. The concentration was adjusted by varying the apertural width and varying the amplitude of oscillations of the metering beaker.
- Method of particle size determination: Andersen Stack Sampler Mark III Millipore vacuum compressed air pump XX 60 220 50, limiting orifice 3 L/min, Millipore sampling probe, internal diameter 6.9 mm, 30 minutes after the beginning of the test at the earliest, one sample was taken for the particle size analysis. Before the sampling, the impactor was equipped with glass-fiber collecting discs and a backup particle filter.
The impactor was connected to the pump and the test apparatus, and one sample (9 L) was removed.
The impactor was taken apart, and the collecting discs and the backup particle filter were weighed. The contents of the pre-impactor were determined gravimetrically.
- Pressure in air chamber: 1500 L/h compressed air by the injector and 1500 L/h ventilator air as dilution air
- To ensure, that the mixture of the test substance and air was not diluted with fresh air, the air suction system was reduced about 10 % compared to the supply air system (excess pressure).

TEST ATMOSPHERE
- Brief description of analytical method used:
• Vacuum compressed air pump (Millipore) XX 60 220 50,
• Filtration equipment with probe (Millipore) (internal diameter: 4 mm),
• Filter: MN 85/90 Bf (d = 4.7 cm),
• Balance: Cahn 26
Gravimetric determination of the concentration: the preweighed filter was placed into a filtration equipment. By means of a vaccuum compressed air pump a volume of the dust aerosol characterized by a limiting orifice was drawn through the filter.
The dust concentration in mg/L was calculated from the difference between the preweight of the filter and the weight of the filter after sampling with reference to the sample volume.
- Samples taken from breathing zone: yes,
• Sampling: Velocity: 1.25 m/s, amount: 1 L, probe diameter: 4 mmm, frequency: half-hourly, in the immediate vicinity of the animal noses


- Particle size distribution: EACD 50% (effective aerodynamic cutoff diameter 50%);
Stage: Pre-impactor / EACD 50 % (µm): 26.6
Stage: Cascade impactor: Backup filter / EACD 50 % (µm): <1.2 / Percentage distribution (%): 41.14
Stage: Cascade impactor: 7 / EACD 50 % (µm): 1.2 / Percentage distribution (%): 18.69 / Cumulative distribution (%): 41.14
Stage: Cascade impactor: 5 / EACD 50 % (µm): 2.8 / Percentage distribution (%): 22.28 / Cumulative distribution (%): 59.83
Stage: Cascade impactor: 4 / EACD 50 % (µm): 5.5 / Percentage distribution (%): 8.40 / Cumulative distribution (%): 82.11
Stage: Cascade impactor: 3 / EACD 50 % (µm): 8.5 / Percentage distribution (%): 5.22 / Cumulative distribution (%): 90.51
Stage: Cascade impactor: 1 / EACD 50 % (µm): 18.2 / Percentage distribution (%): 2.14 / Cumulative distribution (%): 95.73
Stage: Cascade impactor: 0 / EACD 50 % (µm): 29.5 / Percentage distribution (%): 2.13 / Cumulative distribution (%): 97.87

A respirable dust fraction of 90.5% was obtained from the results of the particle size analysis.

- MMAD (Mass median aerodynamic diameter) 50 % = 1.7 µm/ GSD (Geometric st. dev.): 4.0

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5.42 mg/l (analytical), 19.7 mg/l (nominal)

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: daily observation, weighing; before start of application, then on day 7 and day 14,
- Necropsy of survivors performed: yes, with grosspathological examination.
- Other examinations performed: body weight

Statistics:

The statistical evaluation of the concentrations-response relationship was carried out in accordance with the binomial test (Wittig, H.: Mathematische Statistik 1974, pp.32 - 35) using tables of the BASF Computer Center.
The particle size was determined in accordance with mathematical and graphical methods of evaluating particle measurements (Silverman, L.: Particle Size Analysis in Industrial Hygiene, 1971, pp. 235-259).

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.42 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: No mortality and no toxicity observed.

Mortality:

no mortality

Clinical signs:

other: During exposure: no abnormalities; After exposure: fur discolored by the test substance, particularly the region of the head; otherwise no abnormalities.

Body weight:

The body weight of the animals showed no adverse effects in comparison with that of the control.
Mean body weight (male / female)
- Before the study
Treatment group: 318 / 228
Control: 307 / 230
- After 7 days
Treatment group: 345 / 242
Control: 340 / 240
- After 14 days
Treatment group: 368 / 251
Control: 367 / 249

Gross pathology:

No abnormalities detected.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study the median lethal concentration of the test substance after inhalative exposure was found to be greater than 5.42 mg dust/L air for male and female animals.

Executive summary:

In an Industrial Hygiene Orientating Investigation study evaluating acute toxicity following inhalative administration, Sprague-Dawley rats were exposed to the test substance similar to OECD guideline 403. Five male and female animals were exposed to 5.42 mg/l (analytical) test substance in a read-nose inhalation system for 4 hours. The MMAD 50% (mass median aerodynamic diameter 50%) is 1.7 µm, calculated from the results of the particle size analysis and the respirable dust fraction was calculated to be 90.5%. During the observation period of 14 days, the animals were examined for clinical signs daily and at the end of the study necropsied with gross pathological examination. All animals survived until the end of the study period. No clinical signs were observed during the study period. Only the fur was discolored by the test substance, particularly the region of the head.

Under the conditions of this study the median lethal concentration of the test substance after inhalative exposure was found to be greater than 5.42 mg dust/L air for male and female animals.