1,3,5-triisopropylbenzene

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Apr 22 to Jul 16, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Version / remarks:

Version not specified

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:

1,3,5-triisopropylbenzene

EC Number:

211-941-3

EC Name:

1,3,5-triisopropylbenzene

Cas Number:

717-74-8

Molecular formula:

C15H24

IUPAC Name:

1,3,5-tris(propan-2-yl)benzene

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Eastman Chemical Company, Batch No. 6F11027000
- Expiration date of the lot/batch: 17/11/2016
- Purity: 96%

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 (Barcelona, Spain)
- Females nulliparous and non-pregnant: Yes
- Age at study initiation: 8 wks
- Weight at study initiation: males: ca. 286 - 278 g; females: ca. 212 - 238 g
- Housing: Bedding material: Capsumlab Lecho_10 (autoclavable)
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 8 days (Acclimatisation to the nose-only restraining tubes was performed for 35 minutes immediately before the exposure)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16.4-23.7ºC
- Humidity (%): 21-52%
- Photoperiod (hrs dark / hrs light): 12:12, 07.00 to 19.00 CET

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

clean air

Mass median aerodynamic diameter (MMAD):

1.7 µm

Remark on MMAD/GSD:

Geometric Standard Deviation (GSD) on the two PSD determinations (PSD #1 and PSD #2) were 4.3 and 5.4 respectively, which are above the target range (1.5 to 3). Single outliers during weighing may have contributed to these high values. Nevertheless, these values were considered to be acceptable taking into account that more than 89% and 67% of particles were below upper limit of 4µm in PSD #1 and PSD #2 respectively. Hence, the particle size distributions obtained were considered to be respirable to rats and these incidents are considered to have no impact on the quality / integrity of the study.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: flow-past, nose-only; Exposure chambers type EC-FPC-232 (anodised aluminium) equipped with glass exposure tubes
- Exposure chamber volume: 3L
- Method of holding animals in test chamber: restraint tubes which were positioned radially around the exposure chamber
- Source and rate of air: filtered air from a compressor; 0.5-1.0 L/min through each inhalation tube
- System of generating particulates/aerosols: Nebulizer
- Method of particle size determination: Mean Mass Median Aerodynamic Diameter (MMAD) of particle size distribution during exposure was calculated from two gravimetric measurements
- Temperature, humidity, pressure in air chamber: temperature and relative humidity of the test atmosphere in the exposure chamber was maintained as required by experimental conditions. Air flow was monitored regularly.

TEST ATMOSPHERE
- Brief description of analytical method used:
1. The test item usage determined once per exposure by weighing the amount of the test item before/after exposure to determine the quantity of test item used;
2. Aerosol concentration was determined by gravimetric analysis at least once during each hour of exposure. Test aerosol samples were collected onto a Whatman filter (grade F319-04) using a filter sampling device;
3. Particle size distribution was determined gravimetrically twice during exposure;
4. Temperature and relative humidity in the chamber was measured continuously during exposure; and
5. Actual air flow rate monitored hourly in each group during exposure.
- Samples taken from breathing zone: Not specified; but the exposure system ensured a uniform distribution

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: Several tests were performed to establish the highest stable aerosol concentration achievable that could be maintained at least for 4 hours. Aerosol starting dose of 5 mg/L air was selected as no toxic effects were expected based on the available data.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Remarks on duration:

4 consecutive hours

Concentrations:

mean concentration of 5.0 mg/L air during 4 hours

No. of animals per sex per dose:

3 males and 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Examined daily for mortality and morbidity. Clinical observations made hourly during exposure and immediately and 1hr following exposure then once daily thereafter for remainder of observation period. Weights were taken just before the start of the inhalation period, daily from days 2 to 5, then on days 8, 10, 11 and immediately before sacrifice on day 15 of study.
- Necropsy of survivors performed: Yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: clinical signs, body weight, post-mortem gross necropsy of abdominal and thoracic cavities and contents. Special attention paid to any change in respiratory tract

Results and discussion

Effect levels

Key result

Sex:

not specified

Dose descriptor:

LC50

Effect level:

> 5 mg/L air (nominal)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

All animals survived the scheduled observation period.

Clinical signs:

other: Transient clinical signs of toxicity (reduced mobility, absence of turning reflex, weakness, respiratory crackles)

Body weight:

Body weight stagnation in both sexes, but with a longer duration in females

Gross pathology:

No macroscopic findings were observed during necropsy.

Other findings:

Dirty fur was observed in all animals 1 hour after exposure. In addition, chromodacryorrhea (1 out of 3 males) and mild piloerection (1 out o 3 males and 2 out of 3 females) were recorded 1 hour after exposure. Chromodacryorrhea was not longer observed from day 2 of study onwards but dirty fur (all females) and mild piloerection (1 out o 3 males and 2 out of 3 females) were still present at day 2 of study. These clinical signs were not longer present at day 3 of study

Any other information on results incl. tables

3 deviations from the study plan were reported:

(1)   Geometric Standard Deviation (GSD) on the two PSD determinations (PSD #1 and PSD #2) were 4.3 and 5.4 respectively, which are above the target range (1.5 to 3). Single outliers during weighing may have contributed to these high values. These values were considered to be acceptable taking into account that more than 89% and 67% of particles were below upper limit of 4µm in PSD #1 and PSD #2 respectively. These incidents are considered to have no impact on the quality / integrity of the study.

(2)   Relative humidity and temperature in the husbandry room were sporadically below the optimal ranges during the study. This incident is considered not to have any impact on the quality/integrity of the study, since the relative humidity and temperature decreases were minor and no related clinical signs were recorded due to this incident.

(3)   Coefficient of variation (%CV) in the high level of the exposure chamber was 6.17 %, which is slightly above the acceptance criteria (5%). Nevertheless, this incident is considered not to have an impact on the quality / integrity of the study, since all air flow values were in the range of 0.8-1.0 L/min which is within the airflow range required for inhalation studies to guarantee sufficient air flow supply to the animals during the exposure (0.5-1.0 L/min).

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

according to EC 1278/2008 as amended

Conclusions:

LC50 of 1,3,5-Triisopropylbenzene was greater than 5.0 mg/L air (gravimetrically determined mean aerosol concentration).

Executive summary:

The acute inhalation toxicity of 1,3,5-triisopropylbenzene was tested according to the acute toxic class method with Sprague-Dawley rats according to OECD TG 436. Treatment of animals with 1,3,5-triisopropylbenzene aerosol resulted in no deaths. However, a toxic effect was observed. This toxic effect was characterized by transient clinical signs of toxicity (reduced mobility, absence of turning reflex, weakness, respiratory crackles) and body weight stagnation in both sexes, but with a longer duration in females.

It was concluded that, under the experimental conditions:

LC50 of 1,3,5-Triisopropylbenzene was greater than 5.0 mg/L air (gravimetrically determined mean aerosol concentration).