Acetic acid, 2-[(5-chloro-8-quinolinyl)oxy]-

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 August 2013 - 14 November 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

September 2009

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

1998

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

May 2008

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: JMAFF 2-1-3

Version / remarks:

March 2005

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

[(5-chloroquinolin-8-yl)oxy]acetic acid

Cas Number:

88349-88-6

Molecular formula:

C11H8ClNO3

IUPAC Name:

[(5-chloroquinolin-8-yl)oxy]acetic acid

Test material form:

solid: particulate/powder

Remarks:

powder

Specific details on test material used for the study:

- Name of test material (as cited in study report): X204558
- Physical state: Tan solid
- Analytical purity: 98.3% ± 0.03% wt/wt
- Purity test date: 14 September 2014
- Lot/batch No.: 2GHB0002
- Storage condition of test material: in its original container at ambient condition

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Animal Breeding Facility, Jai Research Foundation
- Age at study initiation: 8 to 9 weeks
- Weight at study initiation: 200.1 - 256.2 g for male, 159.2 - 212.8 g for female
- Fasting period before study: not applicable
- Housing: Five rats/cage in polypropylene rat cages covered with stainless steel grid top
- Diet ad libitum Teklad certified Global High Fiber Rat/Mice Feed
- Water ad libitum UV sterilized water filtered through Kent Reverse Osmosis water filtration system
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 23
- Humidity (%): 65 to 67
- Air changes (per hr): 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light

IN-LIFE DATES: From: 4 September 2013 To: 24 September 2013

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Remarks:

The solid test material was pre-mixed with iron grit.

Mass median aerodynamic diameter (MMAD):

2.37 µm

Geometric standard deviation (GSD):

2.42

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: A dynamic inhalation exposure system consisting of a flow-past head/nose-only inhalation exposure chamber with Perspex rat exposure/restraint tubes, air compressor, flow meter, 2” fluidized bed dust (dry powder) aerosol generator, cascade impactor, temperature and humidity probe (thermo-hygrometer), oxygen monitor, carbon dioxide monitor, and open-face gravimetric filter sampler.
- Exposure chamber volume: The total capacity of the chamber is 63.5 litres. The dynamic inhalation equipment has 3 main parts namely inlet, exposure and outlet chambers. Each part is 30 cm in height and 30 cm in internal diameter. The inlet unit (upper) consists of a glass cylinder with facility for the attachment of a dust inlet tube. The exposure unit (middle) is made of stainless steel with 20 portholes to accommodate transparent perspex rat exposure tubes. The outlet unit (lower) is made up of stainless steel with an outlet provision connected to a suction pump.
- Method of holding animals in test chamber: Rat exposure tubes which are provided with orifices to eliminate excreta and urine, which are collected in a dropping tray. These exposure tubes are accommodated in the portholes of the inhalation chamber. The adjustable unit of the exposure tube is set in such a way that rats breathe the test item aerosol through the window panel of the exposure tube.
- Source and rate of air: dynamic air flow rate of 51 to 52 air changes per hour
- Method of conditioning air: The exposure system designed to sustain a dynamic air flow rate of 51 to 52 air changes per hour, ensure an adequate oxygen content of at least 19% and a homogeneous, evenly distributed, respirable test aerosol with a mass median aerodynamic diameter (MMAD) particle size ranging between 1 and 4 microns. The pressure inside the exposure chamber was maintained slightly negative to the atmospheric pressure of the room to prevent leakage of the test aerosol into the surrounding area. Exposure atmosphere CO2 levels were less than 1%.
- System of generating particulates/aerosols: The dust generator system works on the principle of fluidized bed dispersion. The fluid bed is a long assembly of tubing having several tube fittings attached. The feed system consists of a hopper and small diameter tubing with valve attached that is connected to the upper part of the bed chamber and an overflow that is near the bottom of the bed chamber. The flow of air into the tubing leading from the hopper facilitates the uniform flow of test item into the bed chamber. The flow of air into the bed plenum generates the aerosol of the test item, dispersing it into the test atmosphere and carrying it to the exposure chamber.
- Method of particle size determination: Seven Stage Cascade Impactor. Aerosols from the chamber are drawn into the cascade impactor with pre-weighed stainless steel collection plates using a vacuum pump. At the end of the sampling period, the collection plates with test item are disassembled and weighed. The increase in the weight of each collection plate is the mass of particles in the size range of that impact stage. The total mass of particles and the percent mass of particles in each size range is calculated. Mass median aerodynamic diameter (MMAD) is calculated directly from percent particle size distribution.
- Treatment of exhaust air: The outgoing air from the chamber passes through an impinger containing 1.0% sodium hydroxide solutions and moisture traps.
- Temperature, humidity, pressure in air chamber: The chamber temperature during the exposure period was 21.3 to 21.5 °C, while the relative humidity was 63.0 to 67.3%. The chamber oxygen concentration recorded during the exposure period was 20.7 to 20.9%. The chamber carbon dioxide concentration recorded during the exposure period was 0.03 to 0.05%.

TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric samples were collected and analyzed to determine the chamber aerosol concentration. The concentration of aerosol present in the chamber was determined gravimetrically three times during the four-hour exposure period. The aerosol particles were collected on pre-weighed glass fibre filters using an open-face filter sampler. After each exposure atmosphere sampling, the filter was reweighed to obtain the total weight of the particles collected. The time-weighted average (TWA) exposure concentration was calculated from the aerosol
gravimetric measurements. After the target aerosol concentration (> 5 mg/L air) was verified, the test animals loaded to the exposure chamber. On the day of the acute 4-hour inhalation exposure, the time-weighted average (TWA) exposure concentration was calculated (6.11 mg/L air) from the combined aerosol.
- Samples taken from breathing zone: yes. Each sample was taken by drawing chamber atmosphere from the animal breathing zone at a set rate using a constant flow air sampling pump.

VEHICLE
- Composition of vehicle (if applicable): air, 360 g of the test substance was pre-mixed with 7200 mL inert bed material (Iron grit) to provide a test item stock of uniform concentration 50 mg/mL (mass cloquintocet acid/volume of inert bed material)

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Gravimetric

Duration of exposure:

4 h

Concentrations:

The time-weighted average (TWA) exposure concentration was 6.11 mg/L air.

No. of animals per sex per dose:

5 males and 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All rats were observed for any signs of toxicity and mortality at hourly intervals during the 4 hour exposure period and at 1 and 2 hours after the exposure. Subsequently, the surviving rats were observed twice a day for morbidity and mortality. The clinical signs were recorded once a day.
- Necropsy of survivors performed: yes, the necropsy consisted of an external examination and the opening of the nasal passage, abdominal and thoracic cavities.
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: Body weights were recorded prior to exposure on day 0 and on post-exposure days 1, 3, 7 and 14.

Statistics:

No statistical analysis was required.

Results and discussion

Preliminary study:

Not applicable

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 6.11 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality was observed.

Clinical signs:

other: No treatment-related clinical signs were observed.

Body weight:

There were no apparent effects on body weight.

Gross pathology:

External examination of terminally sacrificed male and female rats did not reveal any abnormalities of pathological significance.
Visceral examination of terminally sacrificed male and female rats did not reveal any abnormal lesions.

Other findings:

No further data

Any other information on results incl. tables

Particle Size Range (μm)	ECD (μm)	Particle Size During Exposure		Mean Percent Size	Cumulative Percent Size
		1 Hour %	3 Hour %
> 6.35	6.35	17.33	17.39	17.36	99.99
4.25 – 6.35	4.25	7.67	7.73	7.70	82.63
2.85 – 4.25	2.85	10.00	10.79	10.39	74.93
1.95 – 2.85	1.95	16.83	17.39	17.11	64.54
1.45 – 1.95	1.45	24.67	23.03	23.85	47.43
0.97 – 1.45	0.97	13.50	13.85	13.67	23.58
0.64 – 0.97	0.64	6.50	6.76	6.63	9.91
0 – 0.64	-	3.50	3.06	3.28	3.28
Total mass in 8.85 litres		100.00	100.00	-	-

Applicant's summary and conclusion

Interpretation of results:

Category 5 based on GHS criteria

Conclusions:

Under the conditions of this study, the 4 hour acute inhalation LC50 of X204558 in male and female Wistar rats was found to be greater than 6.11 mg/L air. Classification according to the CLP Regulation is not required.

Executive summary:

An acute inhalation toxicity study was conducted with X204558 (cloquintocet acid), according to OECD 423. A group of 5 male and 5 female Wistar rats were exposed to a time-weighted average (TWA) concentration of 6.11 mg X204558/L air (limit test) using a nose-only inhalation exposure system. The solid test material was pre-mixed with iron grit. The rats were exposed for 4 hours followed by a 14-day post-exposure observation period.

The mass median aerodynamic diameter (MMAD) of aerosolized X204558 was determined to be 2.37 μm with an average geometric standard deviation (GSD) of 2.42. There was no treatment-related mortality, no clinical signs of toxicity, no effects on body weight changes, and no abnormalities observed at necropsy. The 4 hour acute LC50 of X204558 (cloquintocet acid) in male and female Wistar rats was found to be greater than 6.11 mg/L air. Based on the results of this study, cloquintocet acid is not classified for acute inhalation toxicity according to the CLP Regulation.