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Administrative data

Description of key information

Oral LD50 930 mg/kg in the rat (worst case result from a weight of evidence) (according to OECD TG 401)
Dermal LD50 > 3100 mg/kg in the rabbit (similar to OECD TG 402)
Inhalation LC50 (4h) 1.34 mg/L in the rat (according to OECD TG 403)

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
Reference
Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards with acceptable restrictions
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
not specified
GLP compliance:
no
Remarks:
Study predates GLP
Test type:
acute toxic class method
Limit test:
no
Species:
rat
Strain:
not specified
Sex:
male/female
Details on test animals or test system and environmental conditions:
No data
Route of administration:
oral: unspecified
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
Single doses of test material were administered to 5 groups of 10 rats
Doses:
Preliminary Study
709, 795, 892 and 1001 mg/kg

Main study
795, 1001, 1260, 1980 and 2000 mg/kg
No. of animals per sex per dose:
5 males and 5 females
Control animals:
no
Details on study design:
The rats were observed for 14 days post dose. At termination, all surviving animals were killed and necropsied to allow reporting of gross findings.
Statistics:
LD50 values were calculated from the percentages via the method of Litchfield and Wilcoxon
Preliminary study:
See below
Sex:
male/female
Dose descriptor:
LD50
Effect level:
930 mg/kg bw
95% CL:
>= 750 - <= 1 153
Remarks on result:
other: Calculated from the extended range of dosages used in main study
Mortality:
See table below
Clinical signs:
other: No data
Gross pathology:
See table below

Necropsy results for preliminary study

Dose mg/kg

Necropsy Data

709

No gross abnormalities were noted at 14 day necropsies

795

Slight irritation of the GI tract was noted in one rat which died on day 2. No gross abnormalities were noted in other rats.

892

Moderate irritation of GI tract was noted in 4 dead rats at 24 hours. No gross abnormalities were noted in other rats.

1001

Moderate GI tract irritation was noted in all rats

An LD50 value calculated from these data was reported as 880 mg/kg with 95% confidence limits of 779 -994 mg/kg

Mortality results for main study

Dose mg/kg

Day of Death

Total Dead/Total Tested

1

2

795

2/10

1/10

3/10

1001

4/10

2/10

6/10

1260

6/10

2/10

8/10

1980

8/10

-

8/10

2000

10/10

-

10/10

Necropsy results for main study

Dose mg/kg

Necropsy Data

795

Very slight irritation of the GI tract in the 3 animals which died. No gross abnormalities were found in the animals necropsied at 14 days

1001

Very slight irritation of the GI tract in the 6 animlas which died. No gross abnormalities were found in the animals necropsied at 14 days

1260

Slight irritation of the GI tract was noted in the 8 animals which died. No gross abnormalities were noted in the animals necropsied at 14 days.

1580

Slight irritation of the GI tract was noted in the 8 animals which died. No gross abnormalities were noted in the other rats.

2000

Moderate irritation of the GI tract was noted in all animals.
Conclusions:
The LD50 value was 930 mg/kg with 95% confidence limits of 750-1150 mg/kg
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
930 mg/kg bw
Quality of whole database:
A set reliable studies on the acute oral toxicity of the substance is available. All studies show consistently that the acute oral toxicity of the substance is in the range leading to classification into Acute Category 4.

Acute toxicity: via inhalation route

Link to relevant study records
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP Guideline study, no deficiencies
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1300 (Acute inhalation toxicity)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:
no
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Stated in report
- Age at study initiation: 7-9 weeks (m) 10-13 (f)
- Weight at study initiation: 212 - 288g (m) 191 - 216g (f)
- Fasting period before study: Not stated
- Housing: Individually Type DK III cages
- Diet (e.g. ad libitum): KLIBA mouse/rat laboratory diet
- Water (e.g. ad libitum): ad libitum
- Acclimation period: At least one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%):30-70%
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: To:03 Feb 2005 - 02 Mar 2005
Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: INA 20
- Exposure chamber volume: 55L
- Method of holding animals in test chamber: Glass tubes
- Source and rate of air: compressed air, 1.5 m3/hr
- System of generating particulates/aerosols: Continuous infusion pump Perfusor VII, Two component atomizer Mod. 970
- Method of particle size determination: Stack Sampler Mark III

TEST ATMOSPHERE
- Brief description of analytical method used: Air sampler GS 312 (DESAGA), Gas Chromatography
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
ca. 4 h
Concentrations:
0.74, 1.35, 5.2 mg/L
Mass median aerodynamic diameter between 1.8 and 3.5 µm
No. of animals per sex per dose:
5/sex/dose
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Week days, twice daily. Weekend, daily. Weight, weekly
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, gross pathology
Statistics:
Probit analysis
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 1.34 mg/L air (analytical)
Based on:
test mat.
95% CL:
ca. 0.99 - ca. 4.34
Exp. duration:
4 h
Sex:
male
Dose descriptor:
LC50
Effect level:
ca. 1.38 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Sex:
female
Dose descriptor:
LC50
Effect level:
ca. 1.16 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Mortality:
All male and female animals died at 5.2 mg/l, two of five males and three of five females died at 1.35 mg/l and one of five females but no males died at 0.74 mg/l, respectively. The lethality's occurred until study day 3
Clinical signs:
other: Clinical signs of toxicity in animals exposed to 0.74 mg/l comprised visually accelerated respiration, pulmonary respiration sounds, squatting posture, piloerection and contaminated fur. Findings were observed from h0 of exposure until including study day
Body weight:
The mean body weights of the animals increased throughout the study period
Gross pathology:
Test group 1 (0.74 mg/l)
No gross pathological abnormalities were noted in the female animal that died 1 day after exposure. However, necropsy findings of 2 males sacrificed at termination of the study comprised diffuse red discoloration and edema of all lung lobes and diffuse red discoloration of all lung lobes in 3 males and 4 females.

Test group 2 (1.35 mg/l)
No gross pathological abnormalities were noted in the animals necropsied at termination of the post exposure observation period and in 2 female animals that died during exposure and 1 male and 1 female animal that died 1 day after exposure.
The following gross pathological abnormality was detected in 1 male animal that died 2 days after exposure: diffuse red discoloration of all lung lobes.

Test group 3 (5.2 mg/l)
Necropsy findings of the animals that died during exposure (4 males and 4 females) comprised diffuse red discoloration of all lung lobes with partly sunken surface. The animal body showed wet fur and white contamination in the region of the head.
Necropsy findings of the 2 animals (1 male and 1 female) that died after exposure (d2; d3) comprised red discoloration of all lung lobes, partly focal. The animals showed slight red discoloration of content of the small intestine and moderate dilatation was seen in the small intestine or in the large intestine of the male animal, additionally.

Clinical signs of toxicity in animals exposed to 1.35 mg/l comprised visually accelerated respiration, pulmonary respiration sounds, squatting posture, piloerection, exsiccosis, reduced general state and smeared and contaminated fur. Findings were observed from h0 of exposure until including study day 14. The mean body weights of the surviving male animals increased throughout the study period. The mean body weights of the surviving female animals decreased during the first post exposure observation week but increased during the second week. No gross pathological abnormalities were noted in the animals necropsied at termination of the post exposure observation period, in two female animals that died during exposure and 1 male and 1 female animal that died 1 day after exposure. The following gross pathological abnormality was noted in 1 male animal that died 2 days after exposure: diffuse red discoloration of all lung lobes. The clinical signs of toxicity in animals exposed to 5.2 mg/l were comparable to test group 2 (1.35 mg/l). Gasping, formation of nasal crusts and apathy in 1 male and 1 female animal were observed additionally. Findings were observed from hour 0 of exposure until including study day 1.

No body weight development of the male and female animals could be determined because all animals died within 3 days after exposure. Necropsy findings of the animals that died during exposure (4 males and 4 females) comprised diffuse red discoloration of all lung lobes with partly sunken surface. The animal body showed wet fur and white contamination in the region of the head. Necropsy findings of the 2 animals (1 male and 1 female) that died after exposure (d2; d3) comprised red discoloration of all lung lobes, partly focal. The animals showed slight red discoloration of content of the small intestine and moderate dilatation was seen in the small intestine or in the large intestine of the male animal, additionally. Under the conditions of this study the LC50 for male and female rats after liquid aerosol inhalation was calculated to be 1.34 mg/l.

 

Mean body weights (g)

 

Test concentration mg/L

Day 0 

Day 7 

Day 14 

 Male

0.74 

241.6

250.3 

287.0 

 Female

0.74

216.7 

224.8

245.4 

 Male

1.35

212.6

22.3 

262.6 

 Female

1.35 

191.7 

179.9 

196.4 

 Male

5.2

288.3 

-

- 

 Female

5.2 

211.3 

- 

- 

 

Mortality

Concentration (mg/L)

0.74

1.35

5.2

Mortality

 Male

0

2

5

 Female

1

3

5
Interpretation of results:
Toxicity Category IV
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The combined LC50 is 1.34 mg/L
The LC50 was found to be 1.16 mg/L for female animals and 1.38 mg/L for male animals
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LC50
Value:
1 340 mg/m³ air
Quality of whole database:
Three studies on the acute inhalation toxicity of the substance are available, two of which used whole-body exposure systems. Only one reliable study is available exposing animals in a nose-only system. This study resulted in LC50 values above 1 mg/L in male and female animals (combined LC50 value of 1.34 mg/L) leading to classification into Acute Category 4.

Acute toxicity: via dermal route

Link to relevant study records
Reference
Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards with acceptable restrictions
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
yes
Remarks:
skin was abraded in some animals and an occlusive dressing was applied
GLP compliance:
no
Remarks:
study predates GLP
Test type:
standard acute method
Limit test:
no
Species:
rabbit
Strain:
other: New Zealand albino
Sex:
not specified
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Skippack Farms
- Housing: Individually in suspended cages
- Diet: Purina rabbit pellets ad libitum
- Water: Tap water ad libitum
- Acclimation period: Brief (exact period not stated)
Type of coverage:
occlusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
Treatment consisted of a single dermal application of m-xylenediamine (MXDA) to the skin. The test site was completely occluded with an impervious dam. After 24 hours, the wrapping was removed and the residue gently washed off.
Doses:
1260, 1580, 2000 and 2510 mg/kg
No. of animals per sex per dose:
Four
Control animals:
no
Details on study design:
Prior to treatment, the backs of all rabbits were clipped free of fur and the animals were assigned to four treatment groups. Two rabbits in each group were abraded with a burred needle and two remained intact.

The following laboratory observations were made:
1. Animals were examined daily for abnormal behaviour or mortality.
2. Skin reactions of erythema and edema were scored at 24 hours and daily thereafter for 14 days according to the method of Draize (see Appendix 1, attached).
3. Body weights were recorded on Days 0, 7 and 14.
4. At termination or death, each animal was subjected to a gross examination of the viscera, except in cases of advanced autolysis of the tissue.
Statistics:
No data
Preliminary study:
No data
Sex:
not specified
Dose descriptor:
LD50
Effect level:
2 000 mg/kg bw
95% CL:
>= 1 562 - <= 2 560
Mortality:
Mortality took place in the first six days after exposure:
Treatment with 2510 mg/kg: 3 out of 4 rabbits died
Treatment with 2000 mg/kg: 3 out of 4 rabbits died
Treatment with 1580 mg/kg: 1 out of 4 rabbits died
Treatment with 1260 mg/kg: 0 out of 4 rabbits died
Clinical signs:
other: Vocalisation and hyperactivity were noted in all rabbits soon after application of MXDA. However, no other systemic reactions or unusual behaviour were noted. After 24 hours exposure, all rabbits (intact and abraded) exhibited severe erythema and oedema.
Gross pathology:
Gross pathological findings were not remarkable in those survivors necropsied at Day 14. Advanced autolysis prevented examination in those animals found dead.
Conclusions:
The dermal LD50 was calculated to be 2000 mg/kg bw and the associated confidence limits were 1562-2560 mg/kg bw
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
3 100 mg/kg bw
Quality of whole database:
Only pre-GLP studies on the acute dermal toxicity are available. Both studies show that the substance exhibits low acute systemic toxicity via the skin.

Additional information

The only GLP study (Allen, 1998) describing oral toxicity is a limit test reporting LD50 in the rat to be > 200 mg/kg and < 2000 mg/kg. However, a pre-GLP study (Iesaka, 1980) showed the oral LD50 in the rat to be 1090 mg/kg for males and 980 mg/kg for females and a second pre-GLP study reported the oral LD50 of male/female rats as 930 mg/kg (Moore, 1973). Supporting evidence showed the oral LD50 of male mice to be 1180 mg/kg (Iesaka, 1980). The available studies show consistently that the substance exhibits oral acute toxicity in a range making necessary the classification into Acute Category 4 according to CLP Regulation.

Dermal toxicity is reported in one non-GLP study (Upman, 1975) as an LD50 of 2000 mg/kg in the rabbit. However there is evidence to suggest that the corrosive nature of the test substance caused death due to local tissue damage and fluid loss. A further non-GLP study (Sachesse & Bathe, 1975) found the acute dermal LD50 to be > 3100 mg/kg in rats of both sexes. Both studies together give evidence that the LD50 value tends to be greater than 2000 mg/kg bw making classification for acute dermal toxicity not necessary.

A new key study was chosen after re-evaluation of the existing data on the acute inhalation toxicity of the substance. The new key study by Gamer and Leibold (2005) exposed rats to the substance in a nose-only system. The substance exhibited comparable acute inhalation toxicity to female and male rats with 4-hour LC50 values > 1 mg/L. The established LC50 values make necessary the classification of the substance into Acute Category 4 according to CLP. A supporting non-GLP study with 50 female and male rats (Ulrich, 1978) gives the LC50 (1h) for males/females as 3.75 mg/L after 14 days observation and 4.49 mg/L after 48 hours observation supporting the finding that similar toxicity occurred in both sexes.

According to Jackson (1993), significant differences existed in the acute inhalation toxicity of the substance to female and male rats: the inhalation LC50 (4h) of female rats was 0.8 mg/L but was presumed to be greater than 1.42 mg/L for males. The combined LC50 for males and females was reported as 2.4 mg/L of air. However, the other two available studies show that such a sex difference in toxicity is unlikely. The findings of the study by Jackson (1993) may be accidental. Animals were exposed in a whole-body system, which appears to be inappropriate for this corrosive substance as potential ingestion of substance due to grooming and corrosive effects to skin and eyes may have occurred. The reliability rating of the study was, therefore, reduced and the study by Gamer and Leibold (2005) was used as the new key study instead.

The test substance is corrosive to rat and mouse skin and the results of all studies suggest that toxicity occurs via tissue damage at the first point of contact; digestive or respiratory organs, or the skin.


Justification for selection of acute toxicity – oral endpoint
A set of reliable studies on the acute oral toxicity of the substance was available and used in a weight-of-evidence approach. The lowest LD50 value was used for the hazard assessment.

Justification for selection of acute toxicity – inhalation endpoint
The LC50 value of 1.34 mg/L (1.16 mg/L in females, 1.38 mg/L in males) found in the study applying nose-only exposure was used for the hazard assessment.
The study by Gamer and Leibold (2005) was used as the key study because test animals were exposed in a nose-only system in this study, ensuring that the observed LC50 value was due to the acute inhalation exposure to the substance and not due to other effects. For example, it was observed in the studies applying whole-body exposure that the substance stuck to the fur. Animals may have been exposed by ingestion of substance due to grooming. In addition, the substance was found to be corrosive to the skin and whole-body exposure may have subjected animals to skin and eye corrosion during the exposure period. Finally, the study by Jackson (1993) suggested significant gender differences in the susceptibility to acute inhalation exposure, which was not seen in the key or supporting studies.

Justification for selection of acute toxicity – dermal endpoint
Two studies on the acute dermal toxicity are available showing that the substance exhibits low acute systemic toxicity via the skin. LC50 values in the rabbit of 2000 mg/kg bw and in the rat of > 3100 mg/kg bw were found in these two studies. Taking both studies together gives evidence that the LC50 tends to be > 2000 mg/kg bw making a classification for acute dermal toxicity not necessary.

Justification for classification or non-classification

Results from acute oral toxicity studies in two species indicate that the LD50 falls within the range 200-2000 mg/kg bw. It is therefore appropriate to classify the test substance as R22: harmful if swallowed under the criteria provided by Directive 67/548/EEC. It is also appropriate to classify the substance as Acute toxicity (oral) category 4, H302: Harmful if swallowed under GHS as reflected by Regulation (EC) 1272/2008.

A dermal toxicity study in the rabbit reports an LD50 value of 2000 mg/kg, which is at the extreme upper limit of the range given by Directive 67/548/EEC and by Regulation (EC) 1272/2008. There is also evidence to suggest that the animals died following tissue damage and fluid loss caused by application of a corrosive substance to the skin rather than from systemic toxicity. That conclusion is supported by a second dermal toxicity study in the rat, which determined the LD50 value as > 3100 mg/kg in both sexes. It is therefore considered unnecessary to classify the substance for acute dermal toxicity.

Classification with respect to acute inhalation toxicity is based on a GLP study (Gamer and Leibold 2005) which produced a 4-hour LC50 value of 1.34 mg/L for both sexes and LC50 values of 1.16 mg/L and 1.38 mg/L for female and males rats, respectively. The test substance should be classified as R20: harmful by inhalation using the criteria given by Directive 67/548/EEC. The appropriate classification under CLP is Acute toxicity (inhalation) category 4, H332: Harmful if inhaled under Regulation (EC) 1272/2008 (based on 4 hour exposure to dusts/mists).