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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May - June 1983
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1983
Report date:
1983

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.1 (Acute Toxicity (Oral))
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
4,4'-methylenebis[2,6-diethylaniline]
EC Number:
237-185-4
EC Name:
4,4'-methylenebis[2,6-diethylaniline]
Cas Number:
13680-35-8
Molecular formula:
C21H30N2
IUPAC Name:
4,4'-methylenebis(2,6-diethylaniline)
Test material form:
solid: crystalline
Details on test material:
- Physical state: see above
- Appearance: see above
Specific details on test material used for the study:
TEST MATERIAL
- Substance identification/name in the report: P5256
- Aspect: off-white crystalline solid
- Batch no.: E 29.3.83

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage conditions: Room temperature, protected from light
- Stability under test conditions: stable
- Expiry date: not given

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River (UK) Ltd., Manston Road, Margate, Kent, UK
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 6-10 weeks
- Weight at study initiation: males 143-193 g: females 127-177 g
- Fasting period before study: yes
- Housing: caged in groups of 4 by sex for the screening study and in groups of 5 by sex and dose group
- Diet (e.g. ad libitum): SQC Rat and Mouse Maintenance Diet No. 1, Expanded, Special Diets Services Ltd., Stepfield, Witham, Essex, UK
- Water (e.g. ad libitum): tap water
- Acclimation period:5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-21°C
- Humidity (%): 52-70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): Fluorescent lighting to give a cycle of 12 hours light and 12 hours darkness

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
PRETEST:
Four groups, each of 2 fasted rats (1 male, 1 female), were dosed as follows:
- Dose level 50 mg/kg (Conc. 5 mg/ml) = dose volume 10.00 ml/kg
- Dose level 250 mg/kg (Conc. 25 mg/ml) = dose volume 10.00 ml/kg
- Dose level 1250 mg/kg (Conc. 125 mg/ml) = dose volume 10.00 ml/kg
- Dose level 5000 mg/kg (Conc. 500 mg/ml) = dose volume 10.00 ml/kg

MAIN STUDY:
Five groups, each of 10 fasted rats (5 males, 5 females), were dosed as follows:
- Dose level 1000 mg/kg (Conc. 200 mg/ml) = dose volume 5.00 ml/kg
- Dose level 1410 mg/kg (Conc. 200 mg/ml) = dose volume 7.05 ml/kg
- Dose level 1680 mg/kg (Conc. 200 mg/ml) = dose volume 8.40 ml/kg
- Dose level 2000 mg/kg (Conc. 200 mg/ml) = dose volume 10.00 ml/kg
- Dose level 2830 mg/kg (Conc. 200 mg/ml) = dose volume 14.15 ml/kg
Doses:
PRETEST:
- Dose level 50 mg/kg
- Dose level 250 mg/kg
- Dose level 1250 mg/kg
- Dose level 5000 mg/kg

MAIN STUDY:
- Dose level 1000 mg/kg
- Dose level 1410 mg/kg
- Dose level 1680 mg/kg
- Dose level 2000 mg/kg
- Dose level 2830 mg/kg
No. of animals per sex per dose:
PRETEST:
Four groups, each of 2 fasted rats (1 male, 1 female)

MAIN STUDY:
Five groups, each of 10 fasted rats (5 males, 5 females)
Control animals:
no
Details on study design:
APPEARANCE, BEHAVIOUR AND GENERAL OBSERVATIONS:
All animals were observed for overt signs of toxicity or behavioural change at 0.25, 1, 2 and 4 hours after treatment and subsequently once daily for 14 days. All gross or visible toxic or pharmacological effects were recorded.

BODY WEIGHTS:
Individual body weights were recorded on the day before treatment (day -1), on the day of treatment, 7 and 14 days after treatment and at death.

NECROPSY:
All animals were subjected to a gross necropsy examination. No tissues were retained. Animals surviving the 14 day observation period were killed by
exposure to high levels of carbon dioxide.
Statistics:
The acute oral median lethal dose (LDso) for combined male and female groups were calculated using a probit analysis (Finney, D.J. (1964), Statistical Method for Biological Assay, 2nd Edition, London, Charles Griffin). Separate LDso values were calculated for male and female animals. The mortalities did not allow the calculation of 95% fiducial limits or the production of a dose response curve.

Results and discussion

Preliminary study:
Mortalities occured at dose levels of 1250 (50%) and 5000 mg/kg (100%). No mortlaity was noted at 50 and 250 mg/kg. Clinical signs were not determined.
Effect levelsopen allclose all
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
1 901 mg/kg bw
Based on:
test mat.
95% CL:
1 768 - 2 109
Key result
Sex:
male
Dose descriptor:
LD50
Effect level:
1 736 mg/kg bw
Based on:
test mat.
Key result
Sex:
female
Dose descriptor:
LD50
Effect level:
2 026 mg/kg bw
Based on:
test mat.
Mortality:
A total of 18 (11 male, 7 female) of the 50 animals died during the study period. All deaths were noted within 5 days after treatment.
Clinical signs:
other: All animals treated with 1000 mg/kg appeared normal throughout the study period. All treated animals appeared normal during the day of dosing. Major signs of toxicity noted were lethargy and/or prostration, with occasional signs of piloerection, chromodac
Gross pathology:
Major pathological findings in animals dying during the study were associated with the stomach, which appeared distended. The livers were often pale with a speckled appearance and pale kidneys were also noted. With the exception of 1 animal treated with 1000 mg/kg which had dark lungs, and 2 animals treated with 1680 mg/kg which had pale livers, no other abnormalities were noted in animals necropsied at the end of the study period.

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Conclusions:
The combined LD50 on Wistar rats was found to be 1901 mg/kg; the LD50 for males 1736 mg/kg and for females 2026 mg/kg.
Executive summary:

The acute oral toxicity was determined in a standard acute toxicity study according to OECD 401 and EC B.1 on male and female Wistar rats. Vehicle was corn oil. The appropriate dose levels were determined in a screening test on one male and female each, using doses of 50, 250, 1250 and 5000 mg/kg. Based on the pretest results, doses of 1000, 1410, 1680, 2000 and 2830 mg/kg were applied to 5 males and 5 females per group in the main study. A total of 18 (11 male, 7 female) of the 50 animals died during the study period. All deaths were noted within 5 days after treatment. All animals treated with 1000 mg/kg appeared normal throughout the study period. All treated animals appeared normal during the day of dosing. Major signs of toxicity noted were lethargy and/or prostration, with occasional signs of piloerection, chromodacryorrhoea, hunched posture and staining around nose and mouth. With the exception of 1 animal treated with 1680 mg/kg all surviving animals showed body weight gains at the end of the study period. Animal 41 lost 36 g at termination. Major pathological findings in animals dying during the study were associated with the stomach, which appeared distended. The livers were often pale with a speckled appearance and pale kidneys were also noted. With the exception of 1 animal treated with 1000 mg/kg which had dark lungs, and 2 animals treated with 1680 mg/kg which had pale livers, no other abnormalities were noted in animals necropsied at the end of the study period.

In conclusion, the combined LD50 on Wistar rats was found to be 1901 mg/kg; the LD50 for males 1736 mg/kg and for females 2026 mg/kg.