Benzamide, N-(5-bromo-3-methyl-2-pyridinyl)-N-methyl-

Endpoint summary

Description of key information

Acute oral toxicity: Key study. Test method according to OECD 420, GLP study. The LD50 of the test item is higher than 2000 mg/ kg body weight by oral route in the rat.

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:

key study

Study period:

From 27-09-2022 to 12-10-2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (F-69210 Saint-Germain-Nuelles),
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8 weeks
- Weight at study initiation: 206.4 g(SD=11.9 g)
- Fasting period before study: Food was removed on Day -1 (i.e. overnight prior to treatment) and then redistributed 4 hours after the test item administration.
- Housing: Rats were housed by group of three in solid-bottomed clear polycarbonate cages with a stainless steel mesh lid. Each cage contains sawdust bedding which was changed at least 2 times a week. Each cage was installed in conventional air conditioned animal husbandry.
- Diet (e.g. ad libitum): Ad libitum. ENVIGO 2016
- Water (e.g. ad libitum):Ad libitum. Drinking water (tap-water from public distribution system). Microbiological and chemical analyses of the water were carried out once every six months by Bureau Veritas – Eurofins (FRANCE).
- Acclimation period: the animals were acclimatized for at least 5 days before treatment.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19ºC to 25ºC
- Humidity (%): 30 to 70%
- Air changes (per hr): ≥ 10 air changes/hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (07.00 to 19.00) and twelve hours darkness

Route of administration:

oral: gavage

Vehicle:

DMSO

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg bw
- Justification for choice of vehicle: Dimethyl sulfoxide (DMSO) was chosen as it produced the most suitable formulation at the requested concentration.

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

DOSAGE PREPARATION (if unusual): The preparations were stirred using a vortex and by ultraturrax to obtain yellowish solutions just before the administration.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Step 1 (2000 mg/kg bw): 1 animal
Step 2 (2000 mg/kg bw): 4 animals.

Control animals:

yes

Remarks:

Three female rats, received the control item Dimethyl sulfoxide, administered by gavage under a volume of 10 mL/kg body weight

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: At each step, the animals were observed four times on test day 0 (day of administration), i.e. at T0+30 min, T0+1h, T0+3h and T0+4h, and once daily during days 1 to 14 post administration. The body weights were recorded on test day 0 (just before administration) then on D2, D7, and D14.
- Necropsy of survivors performed: yes.
- Clinical signs including body weight: spontaneous activity, Preyer’s reflex (noise), respiratory rate, convulsions, tremors, body temperature, muscle tone, palpebral opening, pupil appearance, salivat
ion, lachrymation, righting reflex, back hair appearance. The body weight evolution of animals treated with the test item was compared with the body weight evolution of the control group.
- Other examinations performed: Macroscopic observations were entered on individual autopsy sheets. Only those organs likely to be modified in cases of acute toxicity were examined. No organ
was removed and preserved in view to microscopic examinations.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred during the study.

Clinical signs:

other: No clinical signs related to the administration of the test item were observed during the study.

Body weight:

other body weight observations

Remarks:

The body weight evolution of the animals remained normal during the study.

Gross pathology:

The macroscopic examination of the animal at the end of the study did not reveal treatment related changes.

Table 1: Body weight and weight gain in grams. Steps 1 & 2 (2000 mg/kg bw)

FEMALES	D0	D2	D2-D0	D7	D7-D0	D14	D14-D0
Rf 7044	187	198	11	209	22	228	41
Rf 7045	213	217	4	236	23	263	50
Rf 7046	203	220	17	231	28	242	39
Rf 7047	216	236	20	246	30	281	65
Rf 7048	213	-	-	-	-	-	-
MEAN	206.4	217.8	13.0	230.5	25.8	253.5	48.8
Standard deviation	11.9	15.6	7.1	15.6	3.9	23.3	11.8

Interpretation of results:

other: No category (CLP Regulation EC no. 1272/2008).

Conclusions:

The LD50 of the test item is higher than 2000 mg/ kg body weight by oral route in the rat.

Executive summary:

The acute oral toxicity of the test item has been tested in accordance with OECD Test Guideline 420, following GLP. 5 female Sprague-Dawley rats were administered by oral gavage in 2 steps with test item diluted in vehicle DMSO. The sighting study was performed at the dose of 2000 mg/kg bw in one female rat. As no effects were observed in the preliminary test, the subsequent main study was performed with 4 females administered with test item at the same dose of 2000 mg/kg bw. No mortality occurred during the study. No clinical signs related to the administration of the test item were observed during the study. The body weight evolution of the animals remained normal throughout the study. The macroscopic examination of the animals at the end of the study did not reveal treatment related changes. Based on these results, the LD50 of the test item is determined to be higher than 2000 mg/ kg bw by oral route in the rat.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Key study with Klimisch score = 1

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available data, the substance is not classified for acute toxicity (oral) according to CLP Regulation (EC) no. 1272/2008.