4-methylbenzothiazol-2-ylamine

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-01-10 - 2017-02-15 (Experimental)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Version / remarks:

2001

Deviations:

yes

Remarks:

see "Principles of method if other than guideline" for information on deviation

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)

Version / remarks:

2008

Deviations:

yes

Remarks:

see "Principles of method if other than guideline" for information on deviation

Principles of method if other than guideline:

Animal number 2-0 was outside the ±20% body weight range (25.5%) of the first treated animal;further, due to a technician error, animal number 2-0 was fed approx. 2 hours after dosing (guideline: approx. 3 to 4 hours).
Although animal 2-0 showed a slightly different spectrum of clinical signs to the other animals treated at a dose level of 50 mg/kg, the difference cannot definitely be attributed to a higher starting weight or an early cessation of fasting. Indeed, the early cessation of feeding did not impact the clinical signs present as they were present at all observations during the day of dosing and did not change once the animal had been fed. The difference was more likely due to natural variation within the species and therefore these deviations were considered not have affected the integrity or validity of the study.

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

no

Test material

Test material information

1

Reference substance name:

4-methylbenzothiazol-2-ylamine

EC Number:

216-028-3

EC Name:

4-methylbenzothiazol-2-ylamine

Cas Number:

1477-42-5

Molecular formula:

C8H8N2S

IUPAC Name:

4-methyl-1,3-benzothiazol-2-amine

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Envigo RMS (UK) Limited, Oxon, UK
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 149 - 187 g
- Fasting period before study: over night
- Housing: The animals were housed in groups of up to four in suspended solid-floor polypropylene cages furnished with woodflakes.
- Diet & Water (e.g. ad libitum): With the exception of an overnight fast immediately before dosing and for approximately 3 to 4 hours after dosing, free access to mains drinking water and food (2014C Teklad Global Rodent diet supplied by Envigo RMS (UK) Limited, Oxon, UK) was allowed throughout the study. The diet, drinking water and bedding were routinely analyzed and were considered not to contain any contaminants that would reasonably be expected to affect the purpose or integrity of the study.
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 °C
- Humidity (%): 30-70%
- Air changes (per hr): 15 changes/hour
- Photoperiod (hrs dark / hrs light): 12 hrs dark / 12 hrs light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 30 resp 5 mg/mL
- Justification for choice of vehicle: Arachis oil BP was used because the test item did not dissolve/suspend in distilled water.

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Since no data were available, the preliminary experiment started with the administration of the test item at a dose of 300 mg/kg b.w. to one animal.

Doses:

50 or 300 mg/kg bw

No. of animals per sex per dose:

1 (300 mg/kg), 5 (50 mg/kg)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Clinical observations were made 30 minutes, 1, 2, and 4 hours after dosing and then daily for up to 14 days. Morbidity and mortality checks were made twice daily, early and late during normal working days, and once daily at weekends and public holidays.
Individual body weights were recorded on Day 0 (the day of dosing) and on Days 7 and 14 or at death.
At the end of the observation period the surviving animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight.

Results and discussion

Preliminary study:

Dose Level - 300 mg/kg:
- Mortality: The animal was found dead 1 day after dosing.
- Clinical Observations: Pilo-erection and increased respiratory rate were noted at all observation time points on the day of dosing.
- Body Weight: Body weight loss was noted during the observation period.
Necropsy: Macroscopic abnormalities noted at necropsy were abnormally red lungs, dark liver and dark kidneys.

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

>= 30 - <= 500 mg/kg bw

Based on:

test mat.

Mortality:

Dose Level - 50 mg/kg: There were no premature deaths.

Clinical signs:

other: Dose Level - 50 mg/kg: Hunched posture was noted in all animals. Lethargy and/or pilo-erection were also noted in all animals. Ataxia was noted in the initial treated animal. With the presence of ataxia, animal 2-0 showed a slightly different spectrum of

Gross pathology:

Dose Level - 50 mg/kg: No macroscopic abnormalities were noted at necropsy.

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The study was conducted under GLP according to OECD guideline 420 and EU method B1 bis on the registered substance itself. The method is to be considered scientifically reasonable with only slight deviations (body weight and feeding after dosing of one animal) not affecting the integrity or validity of the study. The acute oral median lethal dose (LD50) of the test item in the female Wistar strain rat was estimated to be in the range of 50 - 300 mg/kg body weight.

Executive summary:

The study according to OECD 420 and EU method B1 bis (GLP) was performed to assess the acute oral toxicity of the test item in the Wistar strain rat using the fixed dose method.

The test item was formulated as a suspension in arachis oil BP. A sighting test in a single fasted animal was performed at dose levels of 300 mg/kg and 50 mg/kg. Subsequently, a further group of four fasted females was given a single oral dose of test item, as a suspension in arachis oil BP, at a dose level of 50 mg/kg body weight. Clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy.

The animal treated at a dose level of 300 mg/kg was found dead 1 day after dosing. There were no premature deaths at a dose level of 50 mg/kg.

Pilo-erection and increased respiratory rate were noted in the animal treated at a dose level of 300 mg/kg. Signs of toxicity noted at a dose level of 50 mg/kg were hunched posture, lethargy, ataxia and pilo-erection. All animals treated at a dose level of 50 mg/kg appeared normal 1 day after dosing.

Surviving animals showed expected gains in body weight, except for one animal which showed body weight loss during the first week but expected gain in body weight during the second week.

Abnormalities noted at necropsy of the animal treated at a dose level of 300 mg/kg were abnormally red lungs, dark liver and dark kidneys. No macroscopic abnormalities were noted at necropsy of the animals treated at a dose level of 50 mg/kg.

The acute oral median lethal dose (LD50) of the test item in the female Wistar strain rat was estimated to be in the range of 50 - 300 mg/kg body weight (Globally Harmonized Classification System - Category 3).