2-ethylhexyl 2-([1,1'-biphenyl]-4-ylcarbonyl)benzoate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 February 2021 to 18 June 2021

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

August 1998

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

September 2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexyl 2-([1,1'-biphenyl]-4-ylcarbonyl)benzoate

EC Number:

278-051-5

EC Name:

2-ethylhexyl 2-([1,1'-biphenyl]-4-ylcarbonyl)benzoate

Cas Number:

75005-95-7

Molecular formula:

C28H30O3

IUPAC Name:

2-ethylhexyl 2-{[1,1'-biphenyl]-4-carbonyl}benzoate

Test material form:

liquid

Details on test material:

Purity/Composition: 96.27%
Storage Conditions: At room temperature
Test Facility test item number: 210244/A
Test item handling: No specific handling conditions required
CAS number: 75005-95-7
EC Number: 278-051-5
Substance Name: 2-ethylhexyl 2-([1,1'-biphenyl]-4-ylcarbonyl)benzoate

Specific details on test material used for the study:

Physical Description: Colourless to pale yellow liquid (determined by Charles River Den Bosch)
Purity/Composition: 96.27%
Storage Conditions: At room temperature
Purity/Composition correction factor: No correction factor required
Test item handling: No specific handling conditions required

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Rationale for alternative/additional species to rat (if applicable)
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: [yes]
- Rationale for use of males (if applicable)
- Age at study initiation: approximately 9 weeks old
- Weight at study initiation: Males: 237 to 247 g, Females: 157 to 177 g
- Fasting period before study: not reported
- Housing: polycarbonate cages (Makrolon MIV type; height 18 cm.)
- Historical data: not reported
- Diet (e.g. ad libitum): Pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany) was provided ad libitum throughout the study, except during designated procedures.
- Water (e.g. ad libitum): Municipal tap-water was freely available to each animal via water bottles, except during designated procedures.
- Acclimation period: 5 days
- Microbiological status when known: not reported
- Method of randomisation in assigning animals to test and control groups: Animals were assigned to the study at the discretion of the coordinating biotechnician.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 21 °C
- Humidity (%): 42 to 63%
- Air changes (per hr): Ten or greater air changes per hour with 100% fresh air
- Photoperiod (hrs dark / hrs light): 12-hour light/12-hour dark cycle

IN-LIFE DATES: From: 15 February 2021 To: 17 March 2021

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

>= 2.4 - <= 2.5 µm

Geometric standard deviation (GSD):

>= 1.9 - <= 2.1

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The animals were placed in polycarbonate restraining tubes, which were connected to the exposure chamber.
- Exposure chamber volume: not reported
- Method of holding animals in test chamber: polycarbonate restraining tubes
- Source and rate of air (airflow): An aerosol was generated by means of a Collison nebulizer and pressurized air. The mean total airflow was 18 L/min.
- Method of conditioning air: The nebulizer was placed in a water bath (temperature approximately 65 degrees Celsius)
- System of generating particulates/aerosols: Collison nebulizer
- Method of particle size determination: The samples were collected with an 8 stage Marple personal cascade impactor containing fiber glass filters (TE-290-GF. Tisch Environmental, Cleves, Ohio, USA) and a fiber glass back-up filter (SEC-290-F1, Westech, Upper Stondon, Bedfordshire, England). Amounts of test item collected were measured gravimetrically. Subsequently the Mass Median Aerodynamic Diameter (MMAD) and the Geometric Standard Deviation (GSD) were determined based on OECD guidance document No 39.
- Treatment of exhaust air: From the exposure chamber the test atmosphere was passed through a filter before it was released to the exhaust of the fume hood.
- Temperature, humidity, pressure in air chamber: 21.1 and 22.3 °C, daily mean relative humidity of 6 and 8%, pressure not reported.

TEST ATMOSPHERE
- Brief description of analytical method and equipment used: A total of 21 representative samples were taken for determination of the actual concentration during exposure at 5 mg/L. Samples were drawn from the test atmosphere through a tube mounted in one of the free animal ports of the exposure chamber. Samples were drawn through a glass fiber filter (type APFC04700, Millipore, Billerica, MA, USA). Sample volumes were measured by means of a dry gas meter (type G 1.6, Actaris Meterfabriek B.V., Dordrecht, The Netherlands).
- Samples taken from breathing zone: yes
- Time needed for equilibrium of exposure concentration before animal exposure: Due to the small volume of the exposure chamber the equilibrium time was negligible.

VEHICLE
- Composition of vehicle (if applicable): not reported
- Concentration of test material in vehicle (if applicable): 7.9 mg/L
- Justification of choice of vehicle: The inhalation route of administration was selected because this route was defined as a possible route of human exposure. Nose only exposure was used since this was the most applicable method of exposure for the test model while minimizing concurrent exposure by the oral and dermal routes. Exposure levels were selected based on the EC and UN classification guidelines.
- Lot/batch no. (if required):
- Purity: 96.27

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: The particle size distribution was characterized twice during each exposure period.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The MMAD was 2.5 µm (gsd 2.1) and 2.4 µm (gsd 1.9).

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: The starting exposure level was selected based on the available test item data and was one expected not to cause mortality.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

The time-weighted mean actual concentration was 5.2 ± 0.1 mg/L. The nominal concentration (amount of test item used divided by the volume of pressurized air used) was 7.9 mg/L.

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: Post exposure observations were performed at periodic intervals on the day of exposure (at least two times) and once daily thereafter. Animals were weighed individually on Day 1 (pre exposure), 2, 4 and 8 and 15.
- Necropsy of survivors performed: yes
- Clinical signs including body weight: yes
- Other examinations performed:

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

7.9 mg/L air (nominal)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

not determinable due to absence of adverse toxic effects

Mortality:

No mortality occurred.

Clinical signs:

other: During exposure,decreased respiratory rate was seen for all animals.After exposure, decreased respiratory rate, hunched posture and increased activity were seen for all animals on Day 1. Three males and two females also showed partly closed eyes on Day 1.

Body weight:

Overall body weight gain in males and females was within the range expected for rats of this strain and age used in this type of study and were therefore considered not indicative of toxicity.

Gross pathology:

No abnormalities were found at macroscopic postmortem examination of the animals.

Any other information on results incl. tables

The time-weighted mean actual concentration was 5.2 ± 0.1 mg/L. The nominal concentration (amount of test item used divided by the volume of pressurized air used) was 7.9 mg/L. This resulted in a generation efficiency (ratio of actual and nominal concentration) of 65%.

The concentration was measured at time points (n=21) that were equally distributed over the exposure period, which demonstrated that the item was sufficiently stable. The variation in concentration was caused by adjustments to the generation equipment. The generation was interrupted on one occasion to adjust the set-up as the concentration was too high. To compensate for this interruption, the generation time was elongated by 4 minutes in order to achieve an actual exposure time of 240 minutes. By calculating the time-weighted mean concentration, effects of interruptions and variations were taken into account resulting in an actual reflection of the mean exposure concentration over time.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The inhalation LC50, 4h value of C991 in Wistar Han rats was established to exceed 5 mg/L.

Based on these results the test item does not have to be classified and has no obligatory labelling requirement for acute inhalation toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2017) (including all amendments) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Executive summary:

The test item was administered as an aerosol by nose only inhalation for 4 hours to one group of five male and five female Wistar Han rats at a target concentration of 5 mg/L. Mortality and clinical signs were observed daily during the observation period and body weights were determined on Days 1, 2, 4, 8 and 15. Macroscopic examination was performed after terminal sacrifice (Day 15).

The time-weighted mean actual concentration was 5.2 ± 0.1 mg/L. The nominal concentration (amount of test item used divided by the volume of pressurized air used) was 7.9 mg/L. This resulted in a generation efficiency (ratio of actual and nominal concentration) of 65%.

The MMAD was 2.5 µm (gsd 2.1) and 2.4 µm (gsd 1.9).