ethyl 5,5-diphenyl-2-isoxazoline-3-carboxylate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 Sep - 07 Oct 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

Current version adopted in 2009

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

Guideline in place during study conduct: adopted in 1981

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPP 81-3 (Acute inhalation toxicity)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 5

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (MAFF), Testing Guidelines for Toxicology Studies, 59 NohSan No. 4200

Version / remarks:

Adopted in 1985

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The department of health of the government of the United Kingdom

Test type:

traditional method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

443-870-0

EC Name:

-

Cas Number:

163520-33-0

Molecular formula:

C18H17NO3

IUPAC Name:

ethyl 5,5-diphenyl-4,5-dihydro-1,2-oxazole-3-carboxylate

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Ltd., Margate, UK
- Age at study initiation: 8 - 10 weeks
- Weight at study initiation: males: 272 – 317 g, females: 215 – 232 g
- Fasting period before study: no
- Housing: 5 animals of the same sex per cage in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes (Datesand Ltd., Cheshire, UK), except during exposure period
- Diet: Rat and Mouse Expanded Diet No. 1 (Special Diets Services Ltd., Witham, UK), ad libitum (except during exposure period)
- Water: tap water in drinking water quality, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 55 ± 15
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Mass median aerodynamic diameter (MMAD):

1.7 µm

Geometric standard deviation (GSD):

0.55

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: cylindrical exposure chamber
- Exposure chamber volume: 30 L
- Method of holding animals in test chamber: Each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber 'O' ring. Only the nose of each animal was exposed to the test atmosphere.
- Source and rate of air (airflow): oil free compressor, 20 L/min, providing 40 air changes per hour
- Method of conditioning air: Compressed air was supplied by means of an oil free compressor and was passed through a water trap and respiratory quality filters before it was introduced to the dust feed.
- System of generating particulates/aerosols: A dust atmosphere was produced from the test substance using a 'Wright's Dust Feed' mechanism located at the top of the exposure chamber and driven by a variable speed motor. The dust feed was connected to a metered compressed air supply.
- Method of particle size determination: The particle size of the generated atmosphere of the test substance inside the exposure chamber was determined three times during the exposure period using a cascade impactor. This device consisted of six impactor stages with stainless steel collection substrates (10, 6, 3.5, 1.6, 0.9 and 0.5 µm cut-off points) and a back-up glass fibre filter housed in an aluminium sampler. The sampler was temporarily sealed in a sampling port in the animals' breathing zone. Exposure chamber air was drawn through the cascade impactor using a vacuum pump for a suitable time period. The collection substrates and back-up filter were weighed before and after sampling and the weight of test substance, collected at each stage, calculated by difference.
- Treatment of exhaust air: The extract from the exposure chamber passed through a 'scrubber' trap and was connected with a high efficiency filter to a metered exhaust system.
- Temperature and humidity in air chamber: 20 - 21 °C, 41 - 57%. The temperature and relative humidity inside the exposure chamber were measured by an electronic thermometer/humidity meter (Kane-May Ltd., Welwyn Garden City, UK) located in a vacant port in the animals' breathing zone of the chamber and recorded every 30 min throughout the 4 h exposure period.

TEST ATMOSPHERE
- Brief description of analytical method and equipment used: The chamber atmosphere was sampled once after chamber equilibration and in 15-min intervals thereafter till the end of the exposure. The method used employed glass fibre filters (Gelman type A/E 25 mm) placed in a filter holder. The holder was temporarily sealed in a vacant port in the exposure chamber in the animals' breathing zone. Exposure chamber air was drawn through the filter at a measured rate using a vacuum pump for a suitable time period. Each filter was weighed before and after sampling in order to calculate the weight of collected test substance. The difference in the two weights divided by the volume of atmosphere sampled was used for real-time monitoring of chamber concentration. At 30-min intervals a filter was placed in a pre-labelled glass container, extracted with acetonitrile, and submitted for chemical analysis by HPLC (column: Prodigy ODS (250 x 4.6 mm id), mobile phase: acetonitrile: 0.1% orthophosphoric acid:propan-2-ol (52.5:45:2.5 v/v), flow rate: 1.5 mL/min, UV detector wavelength: 230 nm, injection volume: 10 µL, retention time: ~ 15 min)
- Samples taken from breathing zone: yes
- Time needed for equilibrium of exposure concentration before animal exposure : theoretical chamber equilibration time (T99): 7 min

TEST ATMOSPHERE
- Particle size distribution: 91.8% < 4 µm

Analytical verification of test atmosphere concentrations:

yes

Remarks:

HPLC

Duration of exposure:

4 h

Concentrations:

5040 mg/m³, 5.04 mg/L

No. of animals per sex per dose:

5

Control animals:

other: not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All animals were observed for clinical signs at hourly intervals during exposure, immediately on removal from the restraining tubes at the end of exposure, 1 h after termination of exposure, and subsequently once daily till study termination. Body weights were recorded prior to treatment and weekly thereafter.
- Necropsy of survivors performed: yes
- Examinations performed: clinical signs, body weight, detailed macroscopic examination of the respiratory tract

Statistics:

Means and standard deviations were calculated.

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.04 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Effect levels 2

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5 040 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality occurred during the study period.

Clinical signs:

other: After exposure, all animals showed wet fur, hunched posture, and piloerection.

Remarks:

For details see "Other findings".

Body weight:

No effect on body weight was noted.

Gross pathology:

No abnormalities were detected at necropsy, with the exception of one male which showed dark foci on the lungs. This isolated finding was not considered to be related to treatment with the test substance.

Other findings:

- Clinical observations: During exposure, wet fur was commonly observed and in the females signs of decreased respiratory rate and an isolated incident of laboured respiration were noted. After exposure, all animals showed wet fur, hunched posture and piloerection. There were incidents of increased (2/5 males, 1/5 females) or reduced (1/5 males) respiratory rate, ptosis (2/5 males, 3/5 females) and red/brown staining around the eyes and/or snout (1/5 males, 1/5 females). 1 h post exposure, signs of wet fur had diminished. 1 day post exposure 9/10 animals showed no abnormalities while one female continued to show hunched posture. All animals had recovered on Day 2. No further abnormalities were observed.

Any other information on results incl. tables

Table 1. Table for acute inhalation toxicity.

 

Target concentration [mg/L air]	Toxicological results*	Duration of clinical signs	Time of death	Mortality (%)
Males
5.04	0/5/5	Day 0-1	---	0
Females
5.04	0/5/5	Day 0-2	---	0
LC50 > 5.04 mg/L air

                                                                                           

* first number = number of dead animals                                   

 second number = number of animals with clinical signs           

 third number = number of animals used                                 

 

Applicant's summary and conclusion

Interpretation of results:

other: CLP: not classified

Conclusions:

Based on the results of the present study, no classification for acute inhalation toxicity according to Regulation (EC) 1272/2008 is warranted.