Isopropylnaphthalene

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

adopted 1981

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Bis(isopropyl)naphthalene

EC Number:

254-052-6

EC Name:

Bis(isopropyl)naphthalene

Cas Number:

38640-62-9

Molecular formula:

C16H20

IUPAC Name:

Bis(isopropyl)naphthalene

Details on test material:

- Name of test material (as cited in study report): KMC
- Physical state: liquid
- Analytical purity: 98%
- Isomers composition: no data
- Stability under test conditions: stable at room temperature
- Storage condition of test material: at room temperature protected from light

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Kleintierfarm Madoerin AG, Fuellinsdorf, Switzerland
- Age at study initiation: males 11 weeks, females 13 weeks
- Weight at study initiation: males 237.5 - 255.6 g, females 218.3 - 239.7 g
- Housing: 5 per cage in makrolon cages, type IV, with standard softwood bedding
- Diet (e.g. ad libitum): pelleted standard Kliba 343 rat maintenance diet (Klingenthalmuehle AG. Kaiseraugst, Switzerland), ad libitum
- Water (e.g. ad libitum): community tap water from Geneva, ad libitum
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 40 - 70
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: From: 09.11.1987 To: 01.12.1987

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: exposure chamber according to Sachsse et al (1973, 1976): Breathing atmosphere (aerosol) is passed through a central
cylindrical tube vertically positioned to which animal confinement chambers are radially attached. From the internal active exposure chamber,
small tubes lead to the breathing zone of the attached confinement chambers. Surplus breathing air and exhaled air are discharged through
an outer cylindrical tube positioned around the internal active chamber.
- Exposure chamber volume: volume of the internal active chamber: 1 L
- Method of holding animals in test chamber: Macrolon restraint tubes of suitable size and shape vertically attached to the exposure chamber
- System of generating particulates/aerosols: The test atmosphere was generated by a constant volume reservoir feeding a Hospitak No. 950
nebulizer following dissolution with water. Following the nebulizer, a dilution system was used to dilute the test article output of the nebulizer
with clean air to the concentration required for the study. The aerosol generating system was designed to create an aerosol with a mass median
diameter of 3 µm or less. Following aerosolization, the test article was discharged into the exposure chamber.
- Method of particle size determination: separation of particles using a Mercer 7 stage cascade impactor. The sampling air flow was 1.0 L/min
and the mass content of the different stages of the impactor was assessed gravimetrically.
- Temperature, humidity, pressure in air chamber: 21°C, 12% (relative humidity), slight positive pressure in inner chamber and slight negative
pressure in outer chamber.

TEST ATMOSPHERE
- Brief description of analytical method used: Test substance was sampled by passing test atmosphere through three in line gas washing bottles
containing ice-cold acetonitrile as solvent. Aliquots of this solution were analyzed by HPLC (solvent acetonitrile/water 70/30, column RP-18).
KMC was used as external standard for calibration (see Appendix D).
- Samples taken from breathing zone: yes

VEHICLE
- no

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: 36.3% ≤4.6 and >3.0 µm, 23.3% ≤3.0 and >2.13 µm, 40.4% ≤2.13 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): no data

Analytical verification of test atmosphere concentrations:

yes

Remarks:

see above

Duration of exposure:

4 h

Concentrations:

5.64 mg/l (Limit test; mean analytical exposure concentration)

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: once per hour during exposure, once after exposure on test day 1 and twice daily thereafter,
body weight measurements at days 1 (day of exposure), 8, and 15 of test
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight; lungs from all animals were collected at necropsy and
fixed in a neutral phosphate buffered 4% formaldehyde solution.

Statistics:

No statistics

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.64 mg/L air

Based on:

test mat.

Remarks:

(aerosol)

Exp. duration:

4 h

Mortality:

2/5 females died at day 14 post exposure; no deaths among males.

Clinical signs:

other: During exposure: slight to moderate nose bleeding (epistaxis), no other significant signs. After exposure: slight to moderate signs of discomfort and physiological distress: hunched posture, piloerection, distended abdomen, tremor, impaired breathing, sa

Body weight:

Males: Mean body weight decreased from test day 1 to day 8. Until test day 15, mean body weight increased again,
but the starting value was not reached.
Females: Mean body weight decreased continuously over day 8 up to day 15 (only 3 animals at day 15).

Gross pathology:

red spots in the lung

Applicant's summary and conclusion

Conclusions:

In an acute inhalation toxicity test using only one concentration (5.64 mg/L, limit test), 5 rats/sex were exposed to KCM (diisopropylnaphthalene) as aerosol for 4 hours.Two of the female rats died at day 14 (mortality 2/10 total). The LC50 for acute inhalation toxicity can be assessed to be >5.64 mg/L based on the mortality observed.