Registration Dossier

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:
comparable to guideline study with acceptable restrictions
Remarks:
The study predates the appropriate OECD test guideline and GLP. However, the study was conducted similar to the OECD test guideline 403 with acceptable restrictions. The restrictions were that no details were given on the test material purity and the animals were kept in groups during whole-body inhalation exposure.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1978
Report Date:
1978

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
yes
Remarks:
(no details on test material purity given, the animals were kept in groups during whole-body inhalation exposure)
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS- Age at study initiation: 7-9 weeksNo further details are given in the study report.

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION- Exposure apparatus: For the 6 hour exposure experiment 4 cages (9" x 9" x 14", with 5 animals each sex per cage) were closely grouped in the center of the chamber on the top shelf. Since this apparatus was too large for the target concentrations tested in the 1 hour exposure experiment a much smaller Rochester-type inhalation chamber was used. This is why the experiment was run twice with two cages with 5 males each, and two cages with 5 females each, respectively, placed on the top shelf of the exposure chamber.- Exposure chamber volume: 4.3 m³ (6 h exposure), 0.15 m³ (1 h exposure)- Method of holding animals in test chamber: in cages, grouped to 5 animals each sex per cage- System of generating vapour: Air was passed through a perforated plate distillation column (15 plates) while liquid test material was continously recirculated from the flask below the column to the top of the column, so that each plate in the column had a small layer of liquid on it. Each stage of the column, once steady state operation was reached, exhibited a good frothing action, and it was thus assumed that air leaving the column was saturated with the test item. Calculations from vapour pressure data supplied by Thermal Lab showed that, at 23 °C saturated air contains 250 ppm of the test compound. Air exiting from the distillation column was immediately diluted into the main air flow into the chamber, at a dilution factor appropriate for the given exposure. Any deviations from the target concentrations noted during analysis of the chamber atmosphere were corrected as soon as possible by appropriate adjustment of the air flowing through the distillation column. TEST ATMOSPHERE- Brief description of analytical method used: Analytical verification of the test atmosphere during the 6h exposure experiment was determined by placing a line, which sampled chamber air, with its opening in the center of the group of four cages; presumably what was then measured was the concentration of the test material in the air just before it reached the rats, since the air flow in the chamber was from top to bottom. The analysis of the chamber air was made at least once every half hour, and as often as every 3 min during start-up. During the 1 hour exposure experiments the line for sampling chamber air was placed with its opening between the two cages, just at the top of the cages; presumably what was then measured was the concentration of the test material in the air just before it reached the rats. Analyses were made every 2 min throughout each exposure. The analysis of the test item was determined by using gas chromatography. - Samples taken from breathing zone: no
Analytical verification of test atmosphere concentrations:
yes
Remarks:
gas chromatography
Duration of exposure:
>= 1 - <= 6 h
Remarks on duration:
Two experiments were carried out, whereas in the first experiment the exposure duration was 6 hours and in the second expriment 1 hour.
Concentrations:
6 h exposure experiment (males and females): 7, 4, and 2 ppm (nominal, equal to 0.0443, 0.0253, and 0.0127 mg/L); 6.82, 3.96, and 2.03 ppm (time weighted average based on analytical analysis)1 h exposure experiment (males): 40, 20, and 10 ppm (nominal, equal to 0.2533, 0.1267, and 0.0633 mg/L); 36.32 ± 2.48, 20.39 ± 0.78, and 9.74 ± 0.56 ppm (time weighted average based on analytical analysis)1 h exposure experiment (females): 40, 20, and 10 ppm (nominal, equal to 0.2533, 0.1267, and 0.0633 mg/L); 36.57 ± 1.67, 19.77 ± 1.09, and 9.71 ± 0.42 ppm (time weighted average based on analytical analysis)The values in mg/L were calculated on the basis of c (mg/L) = (((155.1513 g/mol / 24.5 L) x concentration in ppm) / 1000)
No. of animals per sex per dose:
10
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days- Frequency of weighing: just prior to exposure, and approx. 3 times/week thereafter- Necropsy of survivors performed: yes (gross pathology)

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LC50
Effect level:
24.2 ppm
Based on:
test mat.
95% CL:
17.8 - 33.4
Exp. duration:
1 h
Sex:
male
Dose descriptor:
LC50
Effect level:
0.153 mg/L air
Based on:
test mat.
95% CL:
0.113 - 0.211
Exp. duration:
1 h
Sex:
female
Dose descriptor:
LC50
Effect level:
ca. 36 ppm
Based on:
test mat.
Exp. duration:
1 h
Remarks on result:
other: insufficient data for statistical treatment
Sex:
female
Dose descriptor:
LC50
Effect level:
0.228 mg/L air
Based on:
test mat.
Exp. duration:
1 h
Remarks on result:
other: insufficiant data for statistical treatment
Sex:
male
Dose descriptor:
LC50
Effect level:
4.44 ppm
Based on:
test mat.
95% CL:
3.21 - 6.53
Exp. duration:
6 h
Sex:
male
Dose descriptor:
LC50
Effect level:
0.028 mg/L air
Based on:
test mat.
95% CL:
0.02 - 0.041
Exp. duration:
6 h
Sex:
female
Dose descriptor:
LC50
Effect level:
5.27 ppm
Based on:
test mat.
95% CL:
3.98 - 7.99
Exp. duration:
6 h
Sex:
female
Dose descriptor:
LC50
Effect level:
0.033 mg/L air
Based on:
test mat.
95% CL:
0.025 - 0.051
Exp. duration:
6 h
Mortality:
6 h exposure experiment: 7 ppm: Of 10 male rats exposed, 2 died between 24 and 32 hours post exposure, 4 died between 32 and 48 hours post exposure. A seventh rat was found to be clearly moribund 72 hours post exposure and was sacrificed. The remaining 3 rats survived 14 days until sacrifice and necropsy. Of the 10 females, 4 died between 24 and 32 hours post exposure, 3 more by 48 hours post exposure. The remaining 3 rats survived 14 days until sacrifice. 4 ppm: Of the 10 males exposed, 6 died between 32 and 48 hours post-exposure. Of the 10 female rats exposed, 3 died between 24 and 32 hours post-exposure, the rest surviving until sacrifice. 2 ppm: None of the rats, either male or female, died post exposure up to sacrifice 14 days later. 1h exposure experiment: 40 ppm: Of the 10 males exposed, 2 died within 24 hours post exposure, 2 more died within 100 hours post exposure. 4 more males dying in the 11th and 13th day post exposure due to rapid weight loss. Of the 10 females, 2 died 4 days post exposure, 3 more died in the 11th and 12th days post exposure. 20 ppm: 4 of 10 males died on the 10th and 11th days post exposure after their rapid weight loss from day 7 on.
Clinical signs:
6 h exposure experiment: 7 ppm: During exposure, all rats showed progressively increased signs of eye and nasal irritation and respiratory difficulties. Just after exposure there were signs of eye irritation, and dried dark red-brown exudate on the noses; respiratory difficulties appeared to have diminished, only slight rales being observable in a few rats. 16 hours later there was evidence of severe respiratory distress in all animals exposed. 4 ppm: Signs of the rats post-exposure were essentially the same as in the 7 ppm exposure, but slightly less pronounced. The surviving females showered severe weight loss, whereas 6 of the 7 rats regained weight and were at normal levels at sacrifice, but the seventh female showed essentially monotonous weight loss to sacrifice. 2 ppm: Signs in the rats during exposure were slight, and just after 30 min venting period post-exposure they appeared normal. 1h exposure experiment: 40 ppm: Signs in the animals developed much more quickly than in the 6 hour exposure experiment. During exposures, all rats showed signs of eye and nasal irritation and respiratory difficulties. After exposure and a 30 min venting period, both male and female rats, showed diminished signs of respiratory difficulties, but did show laboured breathing, stains on their noses, and appeared lethargic. The two male rats surviving to necropsy at day 14 post exposure showed laboured breathing and were extremely lethargic. The five surviving females did not show abnormal signs.20 ppm: Signs during and post exposure were similar to those seen in rats exposed to 40 ppm, but to lesser extent. The females apparently tolerated the exposure better than the males. Five of the six survivors showed laboured breathing and extreme lethargy, the sixth, however, appeared normal. At the end of the 14 days all females appeared normal. 10 ppm: Signs during exposure were slight; females showed no signs post exposure, only few males showed slight stains on the noses.
Body weight:
6 h exposure experiment: 7 ppm: The surviving 3 male rats showed severe and monotonous weight loss until sacrifice. One of the 3 surviving females showed essentially monotonous weight loss, whereas the two others, after severe weight loss, eventually began to gain weight and reached normal weight levels.4 ppm: The surviving males showed essentially monotonous weight loss until sacrifice14 days later, but appeared to be stabilising at that time, with 2 rats showing weight gains just prior to sacrifice. 2 ppm: All animals suffered a severe initial weight loss (more severe in males than in females), but then began to gain weight and had reached normal levels by sacrifice. 1h exposure experiment: 40 ppm: The six male survivors, after having shown severe initial weight losses, appeared to be stabilised in weight after 1 week post exposure, but shortly thereafter lost weight rapidly and steadily, within 4 more dying in the 11th and 13th day post exposure. The two rats surviving to necropsy at day 14 post exposure continued to lose weight. The five surviving females appeared to have stabilised in weight prior to necropsy. 20 ppm: The 10 males exposed showed severe weight losses, then appeared to stabilise at about 7 days post exposure, but then 9 of 10 lost weight rapidly, 4 of them died on days 10 and 11. Five of the six survivors continued to lose weight rapidly throughout the 14 day post exposure period, the sixth , however, was gaining weight. The 10 females showed severe temporary weight losses, but 4-5 days post exposure their weights stabilised, and at the end of the 14 days all their weights were near normal. 10 ppm: All males and most of the females showed weight losses post exposure, but in only one male and one female was the loss severe, and all rats of both sex were gaining weight and apparently in normal condition 14 days post exposure.

Any other information on results incl. tables

6 h exposure experiment:

2 ppm: No grossly visible lesions were noted in any of the male rats. 5 of 10 females showed focal pneumonia in the lungs and one female showed focal atelectasis (collapse) in the lung. These minimal lesion were considered to be due to exposure to vapours of the test material since similar lesions were observed only infrequently in control animals.

4 ppm: In general, the rats that died had porphyrin-containing secretions on the facial regions adjacent to the eyes, nose, and/or mouth. This was considered to be an indication of irritation of the ocular and nasal mucous membranes. Corneal or conjunctival alterations indicative of eye irritation were observed in 4 of 6 males that died, but not in the females. Examination of the internal organs and tissues of rats that died revealed variable evidence of upper respiratory irritation such as inflammation of the nasal mucosa (rhinitis), and excess quantities of gaseous material in the gastrointestinal tract. Congestion of the lungs which was observed in some rats may have been indicative of an effect on this organ. Congestion of the liver and kidneys which was observed in rats that died was considered to be an agonal event and not a primary effect of treatment. All male rats killed at the end of the 14 day observation period had patchy areas of pneumonia usually accompanied by inflammatory exudate in the trachea and/or bronchi; decreased quantities of ingesta within the gastrointestinal tract; decreased deposits of adipose tissue, and a shrunken, atrophic appearance of the thymus. In the surviving females 2 out of 7 had focal pneumonia, 4 of 7 had decreased deposits of adipose tissue, and one had a shrunken, atrophic thymus. The focal pneumonia observed in the surviving rats was considered to be indicative of probable irritation to the lungs, whereas the observations of decreased deposits of adipose tissue and thymic atrophy were interpreted to be secondary effects related to stress incurred as a result of primary effects of the test material on the respiratory system.

7 ppm: Most males and females that died had accumulations of prophyrin-containing secretions on the facial regions (eyes, nose, and/or mouth); decreased ingesta and/or increased quantities of gaseous material in the gastrointestinal tract; congestion of the livers, kidneys, and several had alterations of the cornea and/or conjunctiva. Of rats that survived the 14 day post exposure period: 3/3 males and 1/3 females had focal pneumonia and thymic atrophy, and 3/3 males and 2/3 females had decreased deposits of adipose tissue. Thus, the lesions in the rats exposed to 7 ppm were similar to those exposed to 4 ppm. The toxicological significance of the lesions was similar to that discussed above.

 

1h exposure experiment:

10 ppm: 4 males and 4 females were examined and had no lesions that could be attributed to the treatment with the test material.

20 ppm: 10 male and 3 females were subjected to gross pathologic examination. Focal cloudiness of the cornea of one eye was observed in the females that was considered to be possibly related to treatment. Males had lesions of the respiratory system, i. e. congestion of the nasal mucosa, focal pneumonia and failure of the lungs to collapse normally upon opening of the trachea and bronchi that were considered to be primary effects of treatment with the test material. Cloudiness or opacity of the cornea of one or both eyes was observed in 4/10 males and was also considered to be treatment related. In addition, decreased deposits of adipose tissue and/or dehydration of the tissues was observed in most of the males. These were considered to be secondary effects incurred as a result of the failure of the rats to consume normal quantities of food and water, which, in turn, can be attributed to the pneumonia observed in these rats.

40 ppm: Macroscopic evaluation of all 20 rats revealed a variety of grossly visible lesions that were indicative of irritation of the upper and lower respiratory passages. Lesions observed that were considered to be indicative of respiratory irritation were: exudative material around the external nares in 8/10 males and 4/10 females, congestion of the nasal turbinate mucosa in 7/10 males and 2/10 females, inflammatory exudate in the nasal passageways in 6/10 males and 2/10 females, focal pneumonia in 6/10 males and 3/10 females, failure of the lungs to collapse normally to opening the trachea and bronchi in 3/10 males and 3/10 females, areas of congestion and oedema of the lungs in 1/10 males, diffuse congestion of the lungs with focal atelectasis in 1/10 females, and distension of the stomach with air which is indicative of upper respiratory obstruction in 5/10 males and 2/10 females. Cloudiness of the cornea of one or both eyes was observed in 2/10 males which was considered to be a probable effect of treatment. A variety of other pathologic alterations such as dehydration, decreased deposits of adipose tissue, thymic atrophy, congestion of the abdominal viscera or liver, and a roughened appearance of the haircoat were observed which were considered to be secondary effects that were incurred as a result of inflammatory lesions of the respiratory system.

Applicant's summary and conclusion

Interpretation of results:
other: CLP/EU GHS Category 1 (H330) according to Regulation (EC) No 1272/2008