Methanaminium, N,N,N-trimethyl-, 2,2-dimethylpropanoate (1:1)

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Study period:

From September 25, 2017 to June 14, 2018

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Justification for type of information:

The acute inhalation toxicity study on Methanaminium N,N,N-trimethyl-, salt with 2,2-dimethylpropanoic acid in the species rat was disregarded due to major methodological deficiencies of the testing procedure.

Whole-body chambers were chosen as the method of exposure instead of the recommended nose-only exposure for aerosols, without justification. The disadvantage of the whole-body chambers is, that uptake of the substance due to other routes than inhalation (oral route via preening or dermal route as described in the Guidance Document on Acute Inhalation Toxicity Testing. Environmental Health and Safety Monograph Series on Testing and Assessment No. 39) can’t be ruled out. Furthermore, the description of the testing conditions is not sufficient to ascertain whether the results could be regarded as reliable. The measurements, apart from volume of the inhalation chambers has not been described and neither the number of test animals per chamber.

The study design further deviates significantly from the OECD Guideline 403 (Acute Inhalation Toxicity) as follows:

• Age of test animals was not stated.
• Conditions of housing for the test animals was not described.
• No determination of particle size for the aerosol as strongly recommended by the OECD guideline. “The particle size distribution of aerosols should be determined at least twice during each 4 hour exposure”.
• The air flow in the testing chamber was not recorded, neither was the test atmosphere concentration as a mean to control dynamic atmosphere generation parameters.
• Relative humidity in the breathing zone was not recorded.
• Not detailed how actual concentration was measured.
• No sighting study, despite the lag of previous data.
• No observations of changes in the skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, and somatomotor activity and behaviour patterns.
• Individual animal weights not recorded on day 1 and 3 (only on day 0, 7 and 14) as recommended by Guideline.
• Missing in the description of caging conditions: number (or change in number) of animals per cage, bedding material, photoperiod, and identification of diet.
• Method of randomization not described.
• Details of food and water quality not stated.
• No description of any pre-test conditioning including diet, quarantine, and treatment for disease.
• Source and description of equipment used for the exposure of animals as well as generation of atmosphere missing.
• Equipment for measuring temperature, humidity, particle-size, and actual concentration not noted.
• Source of air and treatment of air supplied/extracted and system used for conditioning not detailed.
• Methods used for calibration of equipment to ensure a homogeneous test atmosphere not described.
• Location of animals in the system for whole-body exposure not recorded.
• No location of temperature and humidity sensors and sampling of test atmosphere in the chamber stated.
• Information about the equipment used to measure oxygen and carbon dioxide missing.
• Time required to reach inhalation chamber equilibrium (t95) not recorded.
• No tabulation of chamber temperature, humidity, and airflow.

It is not possible to get a clear understanding how the test was performed and if other routes of exposure could be ruled out. Overall the number and severity of deviations from the OECD Guideline 403 led to the Klimisch ranking of reliability 3 (not reliable) and the disregard of the study result.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

478-310-4

EC Name:

-

Cas Number:

53803-13-7

Molecular formula:

C9H21NO2

IUPAC Name:

Methanaminium N,N,N-trimethyl-, salt with 2,2-dimethylpropanoic acid

Test material form:

solid: crystalline

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Evonik Specialty Chemicals (Nanjing) Co., Ltd. , Lot Number: Ten.17.812
- Purity, including information on contaminants, isomers, etc.: 99.5%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Keep away from light at room temperature.

FORM AS APPLIED IN THE TEST (if different from that of starting material)
- Specify the relevant form characteristics if different from those in the starting material, such as state of aggregation, shape of particles or particle size distribution:
The test substance was dissolved in distilled water and tested as aerosol.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Slac JingDa Laboratory Animal Co., Ltd., Hunan Province
- Females (if applicable) nulliparous and non-pregnant: yes, 20 females
- Weight at study initiation: 189 - 224 g

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-23°C
- Humidity (%): 62-68%

Food: Supplied by TianQin biotechnology Ltd, Changsha

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

water

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Inhalation chamber
- Exposure chamber volume: 0.3m³
- Source and rate of air (airflow): dynamic air flow
- System of generating particulates/aerosols: Atomized by atomizer generator
- Temperature, humidity, pressure in air chamber: 22-23°C, humidity 62-68%

VEHICLE
- Composition of vehicle (if applicable): distilled water
- Concentration of test material in vehicle (if applicable):
200, 500, 800, 1100 mg/m³
0.875%, 2.19%, 3.5%, 4.81%

Duration of exposure:

ca. 4 h

Concentrations:

Actual exposure concentration
211, 520, 837, 1130 mg/m³

No. of animals per sex per dose:

20 males, 20 females

Control animals:

no

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

female

Dose descriptor:

LC50

Effect level:

>= 224.7 - <= 1 773.7 mg/m³ air

95% CL:

ca. 624.1

Exp. duration:

4 h

Effect levels 2

Key result

Sex:

male

Dose descriptor:

LC50

Effect level:

>= 131.3 - <= 1 373.8 mg/m³ air

95% CL:

ca. 424.7

Exp. duration:

4 h

Mortality:

Female
- 211 mg/m³ - 0 animals deceased
- 520 mg/m³ - 3 of 5 animals deceased
1 died during exposure
2 died 3.5 h after exposure
- 837 mg/m³ - 3 of 5 animals deceased
3 died 4 h after exposure
- 1130 mg/m³ - 4 of 5 animals deceased
1 died during exposure
3 died 15 h after exposure


Male
-211 mg/m³ - 1 of 5 animals deceased
1 died 4.5 h after exposure
-520 mg/m³ - 3 of 5 animals deceased
1 died during exposure
2 died 3.5 h after exposure
-837 mg/m³ - 3 of 5 animals deceased
2 died during exposure
1 died 4 h after exposure
-1130 mg/m³ - 5 of 5 animals deceased
3 died during exposure
2 died 15 h after exposure

Clinical signs:

lethargy (hypoactivity)

Remarks:

During the exposure the animals exposed to 500, 800 and 1100 mg/m³ substance were less dynamic and had a slow reaction time. They recovered 23.5-72 hrs after exposure. The animals exposed to 200 mg/m³ showed similar reactions and recovered after 22.5 hrs.

Body weight:

The body weight of the surviving animals increased 7 and 14 days after exposure.
Details are to be found in the attached table.

Gross pathology:

The animals that died during the 4h exposure time showed liver congestion. No abnormal necropsy finding occured in other test animals.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

The study has major methodological deficiencies.