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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No guideline followed, GLP, test method sufficiently described

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
no information given
GLP compliance:
yes
Test type:
other: no data
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): dimethylamine, anhydrous
- Physical state: gas
- Analytical purity: 99.95%
- Stability under test conditions: chemically stable and insensitive to light
- Storage condition of test material: normal indoor ambient condition

Test animals

Species:
rat
Strain:
other: Charles River Crl:cd BR VAF/Plus; Sprague-Dawley derived
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Inc., Portage, Michigan
- Age at study initiation: approx. 49-63 days
- Weight at study initiation: males 208-292 and females 158-220 grams on day of exposure
- Fasting period before study: Diet and water freely available except during exposure
- Housing: individual stainless steel wire mesh cages
- Diet (e.g. ad libitum): certified pelleted rodent chow #5002, Purina Mills, Inc, St-Louis, Missouri. Diet and water freely available except during exposure
- Water (e.g. ad libitum): ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C), Humidity (%), Photoperiod (hrs dark / hrs light): maintained in accordance with the recommendations contained in the D.H.E.W. Publication entitled "Guide for the care and use of Laboratory animals"

Administration / exposure

Route of administration:
inhalation: gas
Type of inhalation exposure:
whole body
Vehicle:
other: no data
Details on inhalation exposure:
not reported but figure 1 shows the schematic diagram of generation and exposure system, for more information see study trimethylamine



Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
6 min
Remarks on duration:
6, 20, 60 min
Concentrations:
6 min exposure: 13,700; 15,400; 17,400; 17,500 and 19,900 ppm
20 min exposure were conducted at concentrations of 4,620; 5,940; 7,860; 7,740 and 8,860 ppm
60 min exposure were conducted at concentrations of 4,900; 5,040; 5,080; 5,120; and 5,920 ppm
No. of animals per sex per dose:
5 male and 5 female albino rats
Control animals:
not specified
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: at 7 and 14 days post-exposure
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:
Statistics:
no data

Results and discussion

Effect levelsopen allclose all
Sex:
not specified
Dose descriptor:
LC50
Effect level:
17 600 ppm
95% CL:
15 400 - 20 300
Exp. duration:
6 min
Sex:
not specified
Dose descriptor:
LC50
Effect level:
7 340 ppm
95% CL:
6 550 - 8 230
Exp. duration:
20 min
Sex:
not specified
Dose descriptor:
LC50
Effect level:
5 290 ppm
95% CL:
5 050 - 5 530
Exp. duration:
60 min
Mortality:
6 min exposure: concentrations of 13,700; 15,400; 17,400; 17,500; and 19,900 ppm resulted in deaths of 20, 40, 50, 50, 60%, respectively
20 min exposure: concentrations of 4,620; 5,940; 7,740; 7,860; and 8,860 ppm resulted in deaths of 0, 40, 50, 50, 80%, respectively
60 min exposure: concentrations of 4,900; 5,040; 5,080; 5,120; and 5,920 ppm resulted in deaths of 20, 10, 40, 70, 80%, respectively
Clinical signs:
The significant pharmacotoxic signs noted either immediately after the exposures or during the 14 day post-exposure period were: death, laborated breathing, gasping, rales, and corneal opacities. Most deaths occured on post-exposure days 1 and 2, with one animal dying as late as post-exposure day 7. For the 6 and 20 min-exposures there were no apparent differences in mortality between males and females. However, for the 60 min-exposure there was some suggestion that females might be less sensitive than males.
Body weight:
For all three exposure durations body weight gain for surviving animals was generally depressed during the first post-exposure week, but recovered during the second post-exposure week.
Gross pathology:
At necropsy, eye abnormalities (usually corneal opacities) and lung congestion (red discoloration) were the significant macroscopic findings. There were no significant differences between three exposure durations.

Applicant's summary and conclusion

Interpretation of results:
moderately toxic
Remarks:
Migrated information H332: Harmful if inhaled, H335: May cause respiratory irritation Criteria used for interpretation of results: OECD GHS
Executive summary:

The International Research and Developmental Corporation tested in 1992 the acute toxicity by inhalation of dimethylamine with rats (strain: Charles River Crl:cd BR VAF/Plus; Sprague-Dawley derived). The route of exposure was inhalation by whole body exposure. The exposure times were 6 - 60 minutes with different concentrations (ranging from 4,620 to 19,900 ppm). Different clinical signs, changes in body weight and also mortality (20, 40, 50, 50, 60% deaths (6 min exposure), 0, 40, 50, 50, 80 % death (20 min exposure), or 20, 10, 40, 70 and 80 % death (60 min exposures)) was reported. So 3 different LC50 were determined: LC50(6min) = 17600 ppm (32.9 g/m³/6 min), LC50(20min) = 7340 ppm (13.7 g/m³/20 min) and LC50(60min) = 5290 ppm (9.9 g/m³/60 min).