Dimethyl(octyl)amine

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-01-11 to 2016-06-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dimethyl(octyl)amine

EC Number:

230-939-3

EC Name:

Dimethyl(octyl)amine

Cas Number:

7378-99-6

Molecular formula:

C10H23N

IUPAC Name:

dimethyl(octyl)amine

Test material form:

other: liquid

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Housing: The animals were singly housed in suspended stainless steel caging, which conforms to the size recommendations in the most recent
Guide for the Care and Use of Laboratory Animals (Natl. Res. Council, 2011). Enrichment (e.g., toy) was placed in each cage. Litter paper was
placed beneath the cage and was changed at least three times per week.
Animal Room Temperature and Relative Humidity Ranges: 20-23ºC and 41-58%, respectively.
Animal Room Air Changes/Hour: 12. Airflow measurements are evaluated regularly and the records are kept on file at Product Safety Labs.
Photoperiod: 12-hour light/dark cycle
Acclimation Period: 6 or 14 days
Food: Envigo Teklad Global 16% Protein Rodent Diet® #2016. The diet was available ad libitum, except during the exposure.
Water: Filtered tap water was supplied ad libitum, except during the exposure.
Contaminants: There were no known contaminants reasonably expected to be found in the food or water at levels which would have interfered with
the results of this study. Analyses of the food and water are conducted regularly and the records are kept on file at Product Safety Labs.

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

For each exposure, the exposure chamber, air supply, and equipment used to measure particle size distribution, airflow, and chamber concentration were the same as used during the respective pre-test trials and are described generally below.
Nose-Only Exposure Chamber: A nose-only inhalation chamber was used for exposure. Animals were individually housed in polycarbonate holding
tubes which seal to the chamber with an “O” ring during exposure. The base unit terminates the chamber with a 0.5-inch diameter tube for
discharged air.
Air Supply: Filtered generator air was supplied to the spray atomization nozzle by an air compressor, and measured with a Mass Flow Controller. Additional filtered mixing air from the same air compressor, measured with a Mass Flow Controller, was introduced into the chamber to help uniformly distribute the test atmosphere by creating a vortex at the chamber inlet. Chamber airflow was monitored throughout the exposure period and recorded periodically. The exposure was conducted under slight negative pressure.

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

>= 4 h

Remarks on duration:

The animals were exposed to the targeted chamber concentration for at least 4 hours. The exposure period was extended beyond 4 hours to allow the chamber to reach equilibrium.

Concentrations:

Gravimetric samples were withdrawn at 6 intervals from the breathing zone of the animals. Samples were collected using 37 mm glass fiber filters
(Whatman™ GF/B) in a filter holder attached by ¼ inch Tygon® tubing to a vacuum pump. Filter papers were weighed before and after collection to
determine the mass collected. This value was divided by the total volume of air sampled to determine the chamber concentration. Sample airflows
were measured using a Mass Flow Controller.

No. of animals per sex per dose:

Number of Animals: 18
Sex: 9 Males and 9 Females. Females assigned to test were nulliparous and non-pregnant.
Number of Animals/Exposure Level: 3 Males and 3 Females

Control animals:

no

Details on study design:

Preparation of Test Substance
The test substance was aerosolized as received and kept on a magnetic stirrer during aerosolization, with the exception of the trials performed for the third level.
Pre-Test Trials
Prior to initiation of the full inhalation study, pre-test trials were conducted to establish generation procedures to achieve, to the extent possible,
the desired chamber concentration and desired particle size distribution (mass median aerodynamic diameter between 1 and 4 µm). In these trials, the following adjustments were made in an attempt to achieve these objectives:
Air Pressure: varied
Compressed Generator Airflow: varied
Compressed Mixing Airflow: varied
Total Airflow: varied
Liquid Pump Setting: varied
Liquid Pump Type: varied
Tubing Size: constant
Atomization System: constant
Clean-Out Needle and Fluid Cap: constant
Air Cap: constant
Vacuum Pump: constant
Concentration Sampling Time: varied
The procedures and aerosolization equipment used in the full test were based on the results of pre-test trial numbers 3, 12, and 17. In each
instance, the conditions of generation were modified to achieve the targeted chamber concentration with a desirable particle size distribution.

Selection of Animals
On the day of and prior to exposure, the rats were examined for health and weighed. Six healthy, naive rats (three males and three females;
not previously tested) were selected for each exposure.

Inhalation Procedures
For each exposure, the exposure chamber, air supply, and equipment used to measure particle size distribution, airflow, and chamber concentration were the same as used during the respective pre-test trials and are described generally below.
Nose-Only Exposure Chamber: A nose-only inhalation chamber was used for exposure. Animals were individually housed in polycarbonate holding
tubes which seal to the chamber with an “O” ring during exposure. The base unit terminates the chamber with a 0.5-inch diameter tube for
discharged air.
Air Supply: Filtered generator air was supplied to the spray atomization nozzle by an air compressor, and measured with a Mass Flow Controller.
Additional filtered mixing air from the same air compressor, measured with a Mass Flow Controller, was introduced into the chamber to help
uniformly distribute the test atmosphere by creating a vortex at the chamber inlet. Chamber airflow was monitored throughout the exposure period and recorded periodically. The exposure was conducted under slight negative pressure.
Ambient Conditions: The temperature and relative humidity within the exposure chamber as well as the room were monitored continuously during
exposure, and were measured with a temperature-humidity monitor. Temperature and relative humidity values were recorded every 15 minutes for
the first hour of exposure and approximately every 15 or 30 minutes thereafter.
Atmosphere Generation: The test atmosphere was generated using a nebulizer. The test substance was metered to the atomization nozzle through
PharMed BPT tubing, using a peristaltic pump.
Chamber Concentration Measurements: Gravimetric samples were withdrawn at 6 intervals from the breathing zone of the animals. Samples were
collected using 37 mm glass fiber filters (Whatman™ GF/B) in a filter holder attached by ¼ inch Tygon® tubing to a vacuum pump. Filter papers were weighed before and after collection to determine the mass collected. This value was divided by the total volume of air sampled to determine the
chamber concentration. Sample airflows were measured using a Mass Flow Controller.
Particle Size Distribution: An eight-stage 1 ACFM Andersen Ambient Particle Sizing Sampler was used to assess the particle size distribution of the
test atmosphere. Samples were withdrawn from the breathing zone of the animals at two intervals. The filter paper collection stages were weighed
before and after sampling to determine the mass collected upon each stage. The mass median aerodynamic diameter (MMAD) and geometric
standard deviation (GSD) were calculated using two-cycle logarithmic probit axes.
Exposure Period: The animals were exposed to the targeted chamber concentration for at least 4 hours. The exposure period was extended beyond 4 hours to allow the chamber to reach equilibrium. At the end of the exposure period, the generation was terminated and the chamber was operated
for at least 15 minutes further with clean air to allow the test atmosphere to fully dissipate. At the end of this period the animals were removed from
the exposure tubes. Prior to being returned to their cages, excess test substance was removed from the fur of each animal by rinsing with tap water and wiping with clean paper towels.

Body Weights
Individual body weights of the animals were recorded prior to test substance exposure (initial) and again on Days 1, 3, 7, and 14 (terminal) or after
death.

Cage-Side Observations
All animals were observed for mortality during the exposure period. The animals were examined for signs of gross toxicity, and behavioral changes upon removal from the exposure tube and at least once daily thereafter for 14 days or until death occurred. Observations included gross evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behavior
pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhea, and coma.

Necropsy
Surviving rats were euthanized via CO2 inhalation on Day 14. Gross necropsies were performed on all decedents and euthanized animals. Tissues
and organs of the thoracic and abdominal cavities were examined.

Statistics:

Statistical analysis was limited to the calculation of the mean and standard deviation.

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

male

Dose descriptor:

LC50

Effect level:

0.59 mg/L air

Based on:

test mat.

95% CL:

> 0.39 - < 0.9

Exp. duration:

4 h

Effect levels 2

Key result

Sex:

female

Dose descriptor:

LC50

Effect level:

>= 0.052 - <= 0.55 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

0.052 mg/L
All animals survived exposure to the test atmosphere.

0.55 mg/L
One male and three females died within one hour of exposure to the test atmosphere.

1.12 mg/L
All animals died following chamber removal.

Clinical signs:

other: 0.052 mg/L Following exposure, all rats exhibited irregular respiration. In addition, two females were noted as having ano-genital staining, tremors, and/or ataxia. However, all animals recovered from these symptoms by Day 3 and appeared active and h

Body weight:

0.052 mg/L
All animals gained body weight during the study.

0.55 mg/L
The survuving animals gained body weight during the study.

Gross pathology:

0.052 mg/L
No gross abnormalities were noted for any of the animals when necropsied at the conclusion of the 14-day observation period.

0.55 mg/L
Gross necropsy of the decedents revealed discoloration of the lungs and liver and/or distention of the stomach. No gross abnormalities were
noted for any of the animals when necropsied at the conclusion of the 14-day observation period.

1.12 mg/L
Gross necropsy of the decedents revealed discoloration of the lungs, liver, stomach, and/or intestines and/or distention of the stomach.

Any other information on results incl. tables

0.052 mg/L

The chamber and nominal chamber concentrations were 0.052 mg/L and 1.54 mg/L, respectively. The average mass median aerodynamic diameter was estimated to be 1.76 µm based on graphic analysis of the particle size distribution as measured with a 1 ACFM Andersen Ambient Particle Sizing Sampler with an average geometric standard deviation of 2.32.
All animals survived exposure to the test atmosphere and gained body weight during the study. Following exposure, all rats exhibited irregular respiration. In addition, two females were noted as having ano-genital staining, tremors, and/or ataxia. However, all animals recovered from these symptoms by Day 3 and appeared active and healthy for the remainder of the 14-day observation period. No gross abnormalities were noted for any of the animals when necropsied at the conclusion of the 14-day observation period.

0.55 mg/L

The chamber and nominal chamber concentrations were 0.55 mg/L and 6.48 mg/L, respectively. The average mass median aerodynamic diameter was estimated to be 1.70 µm based on graphic analysis of the particle size distribution as measured with a 1 ACFM Andersen Ambient Particle Sizing Sampler with an average geometric standard deviation of 2.17. One male and three females died within one hour of exposure to the test atmosphere. Prior to death, one female was hypoactive and exhibited irregular respiration and prone posture. There were no adverse clinical effects observed for the remaining one male and two females prior to death. Following exposure, the two surviving males exhibited abnormal respiration, ano-genital staining, tremors, and/or were hypoactive. However, the two surviving animals recovered by Day 4 and appeared active and healthy for the remainder of the 14-day observation period. Gross necropsy of the decedents revealed discoloration of the lungs and liver and/or distention of the stomach. No gross abnormalities were noted for any of the animals when necropsied at the conclusion of the 14-day observation period.

1.12 mg/L

The chamber and nominal chamber concentrations were 1.12 mg/L and 9.10 mg/L, respectively. The average mass median aerodynamic diameter was estimated to be 2.28 µm based on graphic analysis of the particle size distribution as measured with a 1 ACFM Andersen Ambient Particle Sizing Sampler with an average geometric standard deviation of 2.65.

All animals died following chamber removal. There were no adverse clinical effects observed for any of the animals prior to death. Gross necropsy of the decedents revealed discoloration of the lungs, liver, stomach, and/or intestines and/or distention of the stomach.

Applicant's summary and conclusion

Interpretation of results:

Toxicity Category II

Remarks:

Migrated information fatal if inhaled Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of this study, the acute inhalation defined LC50 of the test substance calculated by Probit Analysis was 0.59 mg/L in males with 95% confidence limits of 0.39 mg/L (lower) and 0.9 mg/L (upper). The data does not permit calculation of the LC50 for females by Probit Analysis.
The LC50 for females is greater than 0.052 mg/L and less than 0.55 mg/L. Based on an LC100 of 0.55 mg/L and an LC50 range of 0.052 to
0.55 mg/L in females, AD-1 may be classified according to Regulation 1272/2008 as Acute Toxicity Category 2; H330 fatal if inhaled.

Executive summary:

An acute inhalation toxicity test was conducted with rats to determine the potential for AD-1 to produce toxicity from a single exposure via the inhalation (nose-only exposure) route. Under the conditions of this study, the acute inhalation defined LC₅₀of the test substance calculated by Probit Analysis was 0.59 mg/L in males with 95% confidence limits of 0.39 mg/L (lower) and 0.9 mg/L (upper). The data does not permit calculation of the LC₅₀for females by Probit Analysis.  The LC₅₀for females is greater than0.052mg/L and less than 0.55 mg/L. 

Based on an LC₁₀₀of 0.55 mg/L and an LC₅₀range of 0.052 to 0.55 mg/L in females,  AD1 may be classified according to Regulation 1272/2008 as Acute Toxicity Category 2; H330 fatal if inhaled.

After establishing the desired generation procedures during the pre-test trials,eighteenhealthy rats were selected for test and equally distributed into three exposure groups(3 males and 3 females per exposure). Exposure levels of1.0, 0.5 and 0.05 mg/L were selected for testing. Each group of animals was exposed to the test atmosphere for approximately 4 hours.Chamber concentration and particle size distributions of the test atmosphere were determined periodically during the exposure period. The animals were observed for mortality, signs of gross toxicity, and behavioral changes at least once daily for 14 days following exposure or until death occurred. Body weights were recorded prior to exposure (initial) and again on Days 1, 3, 7, and 14 (terminal) or after death. Necropsies were performed on all animals.

The incidence of mortality at each exposure level is summarized below:

Exposure Concentration	Mortality
(mg/L)	Males	Females	Total
1.12	3/3	3/3	6/6
0.55	1/3	3/3	4/6
0.05	0/3	0/3	0/6