4,4'-methylenebis[N-sec-butylaniline]

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 February 2018 - 20 March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

December 2001

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Version / remarks:

May 2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Version / remarks:

December 2002

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nousan, Notification No 8147, November 2000, including the most recent partial revisions.

Version / remarks:

November 2000

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4,4'-methylenebis[N-sec-butylaniline]

EC Number:

226-122-6

EC Name:

4,4'-methylenebis[N-sec-butylaniline]

Cas Number:

5285-60-9

Molecular formula:

C21H30N2

IUPAC Name:

4,4'-methylenebis[N-sec-butylaniline]

Test material form:

liquid

Details on test material:

Appearance: Slight yellow liquid
Storage conditions: At room temperature protected from light

Specific details on test material used for the study:

Adjustment was made for specific gravity of the test item.
Specific density: 0.99 g/cm3

Test animals

Species:

rat

Strain:

other: Crl:WI (Han)

Sex:

female

Details on test animals or test system and environmental conditions:

- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: Young adult animals (approx. 8-10 weeks old)
- Weight at study initiation: 139 to 187 g.
- Fasting period before study: yes
- Housing: Group housing of 3 animals per cage in labeled polycarbonate Macrolon cages containing sterilized sawdust as bedding material. For psychological/environmental enrichment, animals were provided with paper (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd).
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water: Free access to tap water.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 – 21
- Humidity (%): 26 - 51%
- Air changes (per hr): ten or more
- Photoperiod (hrs dark / hrs light): 12/12

Deviations from the minimum level of daily mean target humidity occurred (lowest value 26%). This study plan deviation is considered not to have affected the integrity of the study because it did not noticeably affect the clinical condition of the animals or the outcome of the study.

IN-LIFE DATES: From: 13 february 2018 to 20 March 2018

Administration / exposure

Route of administration:

oral: gavage

Details on oral exposure:

GAVAGE METHOD: syringe with a plastic gavage cannula

Frequency: single dosage, on day 1.

MAXIMUM DOSE VOLUME APPLIED:
2000 mg/kg body weight.

- Rationale for the selection of the starting dose: maximum recommended dose according to OECD 423.

Doses:

2000 mg/kg body weight
300 mg/kg body weight

No. of animals per sex per dose:

2000 mg/kg: 6 (2 groups of three females in a stepwise manner)
300 mg/kg: 6 (2 groups of three females)

Control animals:

no

Details on study design:

The toxicity of the test item was assessed by stepwise treatment of groups of 3 females. The absence or presence of mortality of animals dosed at one step determined the next step, based on the test procedure defined in the guidelines. The onset, duration and severity of the signs of toxicity were taken into account for determination of the time interval between the dose groups. The first group was treated at a dose level of 2000 mg/kg. Based on the results, three additional groups were dosed at 2000, 300 and 300 mg/kg.

Animals were deprived of food overnight prior to dosing and until 3-4 hours after administration of the test substance. Water was available ad libitum.

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Postdose observations were performed at periodic intervals on the day of dosing (at least three times) and once daily thereafter.

Mortality/Viability: Throughout the study, animals were observed for general health/mortality and moribundity twice daily, in the morning and at the end of the working day.

Body weights: Animals were weighed individually on day 1 (predose), 8 and 15.

Clinical signs: At periodic intervals on the day of dosing (day 1) and once daily thereafter, until Day 15.

- Necropsy of survivors performed: All moribund animals and animals surviving to the end of the observation period were sacrificed by oxygen/carbon dioxide procedure. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities were recorded.

- Other examinations performed: none.

Results and discussion

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 - < 2 000 mg/kg bw

Based on:

test mat.

Mortality:

At 2000 mg/kg, all animals were sacrificed for humane reasons between days 8 and 11.
At 300 mg/kg, no mortality occurred.

Clinical signs:

other: At 2000 mg/kg, in the first dose group, hunched posture and piloerection were noted on day 1 and ventro-lateral recumbency, hunched posture, decreased locomotor activity, piloerection, lean appearance and/or ptosis were noted from day 5 onwards. At 2000 m

Gross pathology:

At 2000 mg/kg, abnormalities of the thymus (reduced in size), liver (discolouration, pale) and stomach (irregular surface of the forestomach) and general emaciation were found for the animals that were sacrificed for humane reasons during the study, at macroscopic examination.

At 300 mg/kg abnormalities of the thymus (many tan foci) were noted for one animal. Macroscopic post mortem examination of the other animals did not reveal any abnormalities.

Any other information on results incl. tables

According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 500 mg/kg body weight.

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

In an acute oral toxicity test, the oral LD50 of 4,4’-methylenebis-N-sec-butylaniline was found to be > 300 mg/kg bodyweight and < 2000 mg/kg bodyweight.

Executive summary:

An acute oral toxicity test was performed according to OECD guideline 423 and GLP principles. Three female Wistar rats were exposed to 2000 mg/kg body weight 4,4’-methylenebis-N-sec-butylaniline.  In a stepwise procedure three additional groups of three females were dosed at 2000, 300 and 300 mg/kg body weight. At 2000 mg/kg, in the first dose group, hunched posture and piloerection were noted on day 1 and ventro-lateral recumbency, hunched posture, decreased locomotor activity, piloerection, lean appearance and/or ptosis were noted from day 5 onwards. At 2000 mg/kg, in the second dose group, hunched posture, uncoordinated movements, decreased locomotor activity and/or piloerection were noted from day 1 onwards. At 300 mg/kg, hunched posture, uncoordinated movements and/or piloerection were noted for the animals between days 1 and 2. In addition, quick breathing and chromodacryorrhoea (nose) were noted for one animal on day 1. At 2000 mg/kg, all animals were sacrificed for humane reasons between days 8 and 11. At 300 mg/kg, no mortality occurred. No abnormalities in weight were observed in all dose groups. Necroscopy performed on 2000 mg/kg dose groups showed abnormalities at the thymus (reduced in size), liver (discolouration, pale) and stomach (irregular surface of the forestomach) and general emaciation were found for the animals that were sacrificed for humane reasons during the study, at macroscopic examination. At 300 mg/kg, abnormalities of the thymus (many tan foci) were noted for one animal. Macroscopic post mortem examination of the other animals did not reveal any abnormalities.

Based on these results, the oral LD50 of 4,4’-methylenebis-N-sec-butylaniline was found to be > 300 mg/kg bodyweight and therefore  according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2017) (including all amendments) and  according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments), 4,4’-methylenebis-N-sec-butylaniline should be classified as Category 4 and should be labeled as H302: Harmful if swallowed.