Benzenepropanal, 2-methyl-4-(2-methylpropyl)-

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From September 27, 2016 to October 26, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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:

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

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-[2-methyl-4-(2-methylpropyl)phenyl]propanal

EC Number:

811-285-3

Cas Number:

1637294-12-2

Molecular formula:

C14H20O

IUPAC Name:

3-[2-methyl-4-(2-methylpropyl)phenyl]propanal

Test material form:

liquid

Specific details on test material used for the study:

Appearance: Colourless to pale yellow liquid
Batch: SC00018060
Purity/Composition: 98,3% (sum of isomers)
Test item storage: At room temperature protected from light
Stable under storage conditions until: 28 April 2017 (expiry date)

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Crl:WI(Han) (outbred, SPF-Quality)

Sex:

male/female

Details on test animals or test system and environmental conditions:

Number of animals: 5 males and 5 females (females were nulliparous and nonpregnant) per exposure level. Two exposure levels
Age and body weight: Young adult animals were selected (approximately 10-11 weeks old). Animals used within the study were of approximately the same age and body weight variation did not exceed +/- 20% of the sex mean.
Identification: Individual unique number by tattoo on hind leg.
Conditions: Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, at least 10 air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study. Health inspection: At least prior to exposure. It was ensured that the animals were healthy and without any abnormality that might affect the study integrity.
Accommodation: Group housing of five animals per sex per cage in labelled Makrolon cages (type IV; height 18 cm) containing sterilized sawdust as bedding material (Lignocel S 8-15, JRS -J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) and paper as cageenrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom). Acclimatization period was at least 5 days before start of treatment under laboratory conditions.
Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany) except during exposure to the test item.
Water: Free access to tap water except during exposure to the test item.
Animal husbandry on the day of exposure.
The animals were moved to the inhalation area to in order to perform the exposure. During the exposure, there was no access to food and water. After exposure, the animals were returned to their cages which were placed in a fume cupboard for a short time period to allow test item remnants to evaporate. A sheet of filter paper was used to cover the bedding material to prevent suffocation in case of bad health condition and in order to recover and to aid the clinical observations. The sheet was removed and before the end of the exposure day, the surviving animals were returned to the animal room. Diet, water, bedding and cage enrichment evaluation for contaminants and/or nutrients was performed according to facility standard procedures. There were no findings that could interfere with the study.

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Remarks:

pressurized air

Mass median aerodynamic diameter (MMAD):

>= 2.6 - <= 3 µm

Geometric standard deviation (GSD):

>= 1.9 - <= 2.1

Remark on MMAD/GSD:

The Mass Median Aerodynamic Diameter (MMAD) and geometric standard deviation (gsd) were determined twice during the exposure period. At 5 mg/L, the MMAD was 3.0 μm (gsd 1.9) at both measurements.
At 1 mg/L, the MMAD was 2.6 μm (gsd 2.0) and 2.9 μm (gsd 2.1).

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Tested concentrations: 5 mg/L and 1 mg/L.
For the 5 mg/L exposure group, the time-weighted mean actual concentration was 5.3 ± 0.2 mg/L. The nominal concentration (amount of test item used divided by the volume of pressurized air used) was 6.2 mg/L. The generation efficiency (ratio of actual and nominal concentration) was 85%. For the 1 mg/L exposure group, the time-weighted mean actual concentration was 1.0 ± 0.03 mg/L. The nominal concentration was 1.5 mg/L and the generation efficiency was 70%. The concentration measurements equally distributed over time showed that the item was sufficiently stable.

No. of animals per sex per dose:

Five animals of each sex were exposed for 4 hours to a target concentration of the test item of 5 mg/L.
Based on the results, five animals of each sex were exposed to a target concentration of 1 mg/L.

Control animals:

no

Details on study design:

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 on the day of death or after terminal sacrifice (Day 15).

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

>= 1 - <= 5 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

All animals exposed to 5 mg/L were sacrificed for ethical reasons on Day 2 and one male exposed to 1 mg/L was sacrificed on Day 10. No further mortality occurred.

Clinical signs:

other: At 5 mg/L, slow breathing was seen during exposure (not presented in the table). After exposure, lethargy, hunched posture, laboured respiration, gasping, piloerection, chromodacryorrhoea on the nose, ptosis and hypothermia were noted for the animals. At

Body weight:

Overall body weight gain in surviving 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:

Macroscopic post mortem examination of the animals that were sacrificed for ethical reasons during the study revealed abnormalities of the lungs (several reddish foci in the lungs of one male and one female exposed to 5 mg/L and foamy contents for the male exposed to 1 mg/L) and the spleen (reduced in size for one male exposed to 5 mg/L).

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The inhalation LC50, 4h value of NYMPHEAL in Wistar rats was established to be within the range of 1 – 5 mg/L, based on animals sacrificed for ethical reasons.
It is to be noted that during macroscopic examination no abnormalities were found in the sacrificed animals except for one male and one female at 5mg/L and one male at 1mg/L.

Executive summary:

Assessment of acute inhalation toxicity with NYMPHEAL in the rat (nose-only).

The study was carried out based on the guidelines described in:

- OECD Guidelines, Section 4, Health Effects. No.403, "Acute Inhalation Toxicity", Sep 2009.

- Commission Regulation (EC) No 440/2008, B.2. Acute Toxicity (inhalation), L142, May 2008.

- EPA OPPTS 870.1300, Acute inhalation Toxicity. EPA 712-C-98-193, August 1998.

- JMAFF Guidelines (2000), including the most recent revisions.

NYMPHEAL was administered as an aerosol by nose-only inhalation for 4 hours to two groups of five male and five female Wistar rats. 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 on the day of death or after terminal sacrifice (Day 15).

For the 5 mg/L exposure group, the time-weighted mean actual concentration was 5.3 ± 0.2 mg/L. The nominal concentration (amount of test item used divided by the volume of pressurized air used) was 6.2 mg/L. The generation efficiency (ratio of actual and nominal concentration) was 85%. For the 1 mg/L exposure group, the time-weighted mean actual concentration was 1.0 ± 0.03 mg/L. The nominal concentration was 1.5 mg/L and the generation efficiency was 70%. The concentration measurements equally distributed over time showed that the item was sufficiently stable.

The Mass Median Aerodynamic Diameter (MMAD) and geometric standard deviation (gsd) were determined twice during the exposure period. At 5 mg/L, the MMAD was 3.0 μm (gsd 1.9) at both measurements. At 1 mg/L, the MMAD was 2.6 μm (gsd 2.0) and 2.9 μm (gsd 2.1).

All animals exposed to 5 mg/L were sacrificed for ethical reasons on Day 2 and one male exposed to 1 mg/L was sacrificed on Day 10. No further mortality occurred.

At 5 mg/L, slow breathing was seen during exposure. After exposure, lethargy, hunched posture, labored respiration, gasping, piloerection, chromodacryorrhoea on the nose, ptosis and hypothermia were noted for the animals. At 1 mg/L, slow breathing was seen during exposure in one animal. After exposure, lethargy, hunched posture, labored respiration and rales were seen for the animals. The surviving animals had recovered from the clinical signs by Day 3.

Overall body weight gain in surviving 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.

Macroscopic post mortem examination of the animals that were sacrificed for ethical reasons during the study revealed abnormalities of the lungs (several reddish foci in the lungs of one male and one female exposed to 5 mg/L and foamy contents for the male exposed to 1 mg/L) and the spleen (reduced in size for one male exposed to 5 mg/L).

The inhalation LC50, 4h value of NYMPHEAL in Wistar rats was established to be within the range of 1 – 5 mg/L.