2-(6-methoxybenzofuran-2-yl)-1,3-dimethyl-5-(methylsulphonyl)1H-benzimidazolium acetate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1977

Report date:

1977

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

no

Test type:

traditional method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Fluorescent Brightener 363

IUPAC Name:

Fluorescent Brightener 363

Test animals

Species:

rat

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Rats: Tif: RAIf (SPF)
- Weight at study initiation: ranged from 170 to 185 grams.
- Housing: animals were segregated and kept in Macrolon cages, type 4 (10 animals to a cage).
- Diet: rat food - NAFAG, Gossau SG -, ad libitum.
- Water: ad libitum.
- Acclimation period: animals were adapted to our laboratoriesfor a minimum of 4 days.

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 1 °C
- Relative humidity: 55 ± 5 %
- Photoperiod: 10 hours light cycle day.

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Remark on MMAD/GSD:

Though MMAD/GSD were not determined, particle size distribution (> 40 % particles were of 1-3 µm, >30 % particles were of 0-1 µm for the concentration of 1505 mg/m³, while for the concentration of 2130 mg/m³, >70 % particles were of 0-1 µm size), indicated good respirability.

Details on inhalation exposure:

DUST PRODUCTION
The dust was generated by injecting the test material with the help of a "Grafix Exaktomat Injector" into an air stream which was discharged into the exposure chamber through a nozzle under a pressure of 2 atm. at a rate of 20 l/min. The concentration and the particle size distribution of the dust in the vicinity of the animals was monitored at 1 hour intervals throughout the dust exposure. The concentration was determined gravimetrically by sampling the test atmosphere through a selectron filter of 50 mm diameter and with a pore size of 0.2 µm (Schleicher and Schuell, Feldbach, Switzerland) at an air flow rate of 10 l/min. The size distribution of the dust particles was measured with a Cascade Impactor with selectron filters of 25 mm diameter and with a pore size of 0.2 µm (Schleicher and Schuell) at an air flow rate of 17.5 l/min.

TESTING PROCEDURE
For inhalation the rats were kept on separate PVC tubes positioned radially around the exposure chamber such that snout and nostrils of the animals only were exposed to the dust. The exposure was started 15 minutes after onset of the dust production, when the dust had reached an even dispersal throughout the chamber. During the exposure period the relative humidity inside thechamber was between 48 and 52 % RH. After a 4 hour inhalation the rats were returned to their cages. Physical condition and incidence of death were monitored throughout an observation period of 14 days.

Duration of exposure:

4 h

Concentrations:

1505 and 2130 mg/m³

No. of animals per sex per dose:

10 males and 10 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days.
- Physical condition and incidence of death were monitored throughout an observation period of 14 days.
- Necropsy of survivors performed: yes

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2 130 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

not determinable due to absence of adverse toxic effects

Mortality:

No mortality occurred through out the observation period.

Clinical signs:

other: During the 4-hour exposure period and the following 14 observation days, no toxic symptoms were observed.

Gross pathology:

No substance related gross organ changes were seen.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

LC50 (rat M/F) > 2130 mg/m³

Executive summary:

Acute inhalation toxicity of the test substance was evaluated in a study conducted according to a methodology described by Sachsse et al (1973). Two groups each consisting of 10 males and 10 females were exposed to the dust of the test substance at the concentrations of 1505 and 2130 mg/m³. Though MMAD/GSD were not determined, particle size distribution (>40 % particles were of 1-3 µm, >30 % particles were of 0-1 µm for the concentration of 1505 mg/m³, while for the concentration of 2130 mg/m³, >70 % particles were of 0-1 µm size), indicated good respirability. No mortality occurred through out the observation period. The animals were sacrificed and autopsied after an observation period of 14 days. No substance related gross organ changes were seen. Hence, based on the findings of the study, it can be concluded that the LC50 of the test substance in rats of both sexes observed over a period of 14 days is greater than 2130 mg/m³.

Conclusion

LC50 (rat M/F) > 2130 mg/m³