Ethanone, 2,2-dichloro-1-(2,3-dihydro-3-methyl-4H-1,4-benzoxazin-4-yl)-

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 February 1986 to 6 March 1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant, guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 81-3 (Acute inhalation toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,2-dichloro-1-[(3R)-3-methyl-3,4-dihydro-2H-1,4-benzoxazin-4-yl]ethan-1-one; 2,2-dichloro-1-[(3S)-3-methyl-3,4-dihydro-2H-1,4-benzoxazin-4-yl]ethan-1-one

EC Number:

619-372-6

Cas Number:

98730-04-2

Molecular formula:

C11H11Cl2NO2

IUPAC Name:

2,2-dichloro-1-[(3R)-3-methyl-3,4-dihydro-2H-1,4-benzoxazin-4-yl]ethan-1-one; 2,2-dichloro-1-[(3S)-3-methyl-3,4-dihydro-2H-1,4-benzoxazin-4-yl]ethan-1-one

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Two groups of 8 to 10 week old Sprague Dawley rats (5 animals/sex).

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

The test material was supplied as a powder and tested as received. The test atmosphere was generated using a Teost Air Mill fed via a revolving disc driven by a Sage motor. The chamber concentration was controlled by adjusting generator conditions.

The gravimetric chamber concentrationd of the test substance was determined hourly from samples collected by means of an
open-faced filter placed near the breathing zone of the animals. The nominal chamber concentratione was also calculated. Particle size analyses were conducted on hourly samples taken from the chamber using a Sierra cascade impactor. The mass median diameter and its geometric standard deviation were derived from a log-normal plot of cumulative mass of test substance deposited on each successive stage of the impactor against the stage's effective cut-off size diameter.

The hourly gravimetric chamber concentrations for Group 2 ranged from 1.9 to 2.1 mg/L with a 4-hour average value of 2.0 mg/L.

The hourly mass median diameter (MMD) and geometric standard deviation for the test atmosphere ranged from from 7.2 to 13.0 µm. (geometric SD = 2.2 to 2.6). Approximately 51% of the particles collected had an equivalent aerodynamic diameter of less than or equal to 9 µm.

Animals were exposed to control air or to 2000 mg/m3 CGA 154281 for 4 consecutive hours.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

measured every hour and ranged from 1.9 to 2.1 mg/L.

Duration of exposure:

4 h

Concentrations:

2000 mg/m3

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

14 days observation period with observations of mortality, clinical signs and bodyweight. Gross pathology examination of animals at termination.

Statistics:

Not applicable.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2 000 mg/m³ air (analytical)

Exp. duration:

4 h

Remarks on result:

other: based on 100% survival at the highest dose tested

Mortality:

No mortality was observed during the 14-day observation period.

Clinical signs:

other: Control animals were asymptomatic. In treated animals lacrimation, chromodacryorrhea, rhinorrhea, chromorhinorrhea, red stains around the facial area, salivation, dehydration, anorexia and few feces were observed. All rats recovered within 7 days.

Body weight:

Body weight gain was comparable between the groups.

Gross pathology:

At necropsy, no treatment-related findings were recorded. Mean lung weights of treated animals were comparable to the control values.

Any other information on results incl. tables

All rats survived treatment and only mild clinical signs were observed.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on the results of the study the inhalation LC50 for a 4 hour exposure period was determined to be greater than 2000 mg/m3.

Executive summary:

Male and female rats were exposed, whole body, for 4 hours to an atmosphere containing benoxacor (CGA154281 Technical) at a concentration of 2.0 mg/L (MMD = 9.0 µm, GSD = 2.3). All rats survived treatment. Clinical signs were observed.

Based on the absence of signs of toxicity in the limit exposure conditions, benoxacor is considered to be of low acute inhalation toxicity and the median lethal dose was found to exceed 2 mg/L air.