N,N”-hexane-1,6-diylbis(N’-alkylaryl)urea

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Nov - 04 Dec 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

2009

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

1998

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nohsan, Notification No. 8147, April 2011; including the most recent partial revisions.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Health Care Inspectorate, Ministry of Health, Welfare and Sport, Den Haag, The Netherlands

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): trade name given
- Substance type: white powder
- Analytical purity: 99.5%
- Lot/batch No.: 1592ZG-076
- Expiration date of the lot/batch: Aug 2015
- Storage condition of test material: at room temperature

Test animals

Species:

rat

Strain:

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

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: approx. 9 weeks old
- Weight at study initiation: 246-300 g (males), 180-196 g (females)
- Housing: groups of 5 animals per sex per cage in Makrolon cages (type IV; height 18 cm), sterilized sawdust was used as bedding material, paper as cage-enrichment
- Diet: SM R/M-Z (SSNIFF Spezialdiäten GmbH, Soest, Germany), ad libitum except during exposure period
- Water: tap water, ad libitum except during exposure period
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 24
- Humidity (%): 40-70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 20 Nov 2014 To: 04 Dec 2014

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The design of the exposure chamber is based on the flow past nose-only inhalation chamber. The chamber consisted of three animal sections with eight animal ports each. Each animal port had its own atmosphere inlet and exhaust outlet.
- Method of holding animals in test chamber: Animals were placed in restraining tubes and connected to the animal ports.
- Source and rate of air: 1 L/min
- System of generating particulates/aerosols: The test substance was fed to a stream of pressurized air (mean air flow 22 L/min) by means of a spiral feeder and a vertically placed air mover. Vibrators were used to keep the material moving. The dust was passed through two vertical elutriators, allowing larger particles to settle, and subsequently let through the exposure chamber. The rotation speed of the feeder and air flow were varied to obtain the desired exposure concentration. The generation was interrupted eight times to remove test substance deposits from the system or to change the set-up. The generation time was elongated with 27 minutes in order to achieve an actual exposure time of 240 minutes.
- Method of particle size determination: The particle size distribution was characterized twice during the exposure period. The samples were drawn (2 L/min) from the test atmosphere through a tube mounted in one of the free animal ports of the middle section of the exposure chamber. The samples were collected with an 8 stage Marple personal cascade impactor containing fiber glass filters and a fiber glass back-up filter. Amounts of test substance collected were measured gravimetrically. Subsequently the Mass Median Aerodynamic Diameter (MMAD) and the Geometric Standard Deviation (GSD) were determined.
- 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 in air chamber: 20.0-20.2 °C, 24-28%

TEST SUBSTANCE PREPARATION: The test substance was sieved (wire mesh sieve 500 µm) and dried in a desiccator overnight prior to use.

TEST ATMOSPHERE
- Brief description of analytical method used: The actual concentration was determined sixteen times during the exposure period. Samples were drawn from the test atmosphere through a tube mounted in one of the free animal ports of the middle section of the exposure chamber. Samples were drawn through a glass fiber filter. The collected amount of the test substance in the air sample was measured gravimetrically. Sample volumes were measured by means of a dry gas meter. Subsequently the time-weighted mean concentration with the standard deviation was calculated.

TEST ATMOSPHERE
- Particle size distribution: Please refer to Table 1.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 4.0 µm / 2.4 µm (in both determination)

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetric

Duration of exposure:

4 h

Concentrations:

2.1 ± 0.06 mg/L (mean actual concentration)
38 mg/L (nominal 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: Animals were observed three times during exposure for mortality, behavioural signs of distress and effects on respiration. After exposure animals were observed on Day 1, one and three hours after exposure and once daily thereafter until Day 15. Individual body weights were determined before administration of the test substance (Day 1) and thereafter on Days 2,4,8 and 15. Observations on mortality were made twice daily.
- Necropsy of survivors performed: yes

- Other examinations performed: Clinical signs: The symptoms were graded according to fixed scales and the time of onset, degree and duration were recorded.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.1 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: maximum attainable concentration

Mortality:

No mortality occurred during the study period.

Clinical signs:

other: During exposure, no clinical signs were seen. After exposure, one female showed lethargy, hunched posture, laboured respiration and chromodacryorrhoea (eye left and right). The animal had recovered from the signs by Day 4. No clinical signs of systemic to

Body weight:

All animals gained the expected body weight over the study period.

Gross pathology:

Macroscopic post mortem examination revealed reddish discoloration of the thymus for one female. No abnormalities were noted at necropsy of the other animals that were killed at the end of the study.

Any other information on results incl. tables

Table 1. Aerodynamic particle size distribution in the test atmosphere.

Measurement 1
Stage	Cut point (µm)	Mass sampled (mg)	Relative mass (%)	Cumulative mass (% of total sampled)
1	21	0.03	1.46	98.54
2	15	0.04	1.94	96.6
3	10	0.36	17.48	79.13
4	6	0.34	16.5	62.62
5	3.5	0.36	17.48	45.15
6	2	0.41	19.9	25.24
7	0.9	0.44	21.36	3.88
8	0.5	0.08	3.88	0
Back up	0.25	0	0	0
Measurement 2
1	21	0.23	4.22	95.78
2	15	0.11	2.02	93.76
3	10	0.41	7.52	86.24
4	6	0.97	17.8	68.44
5	3.5	0.73	13.39	55.05
6	2	1.49	27.34	27.71
7	0.9	1.16	21.28	6.42
8	0.5	0.34	6.24	0.18
Back up	0.25	0.01	0.18	0

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
DSD: not classified