Isobutyl 4-hydroxybenzoate

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Isobutyl 4-hydroxybenzoate

EC Number:

224-208-8

EC Name:

Isobutyl 4-hydroxybenzoate

Cas Number:

4247-02-3

Molecular formula:

C11H14O3

IUPAC Name:

2-methylpropyl 4-hydroxybenzoate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Isobutylparaben
- Chemical name: Isobutyl 4-hydroxybenzoate
- Active content: 99.1 (% w/w)

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 10 -11 weeks
- Weight at study initiation:
Step 1: 173 -192 g
Step 2: 176 - 194 g
- Fasting period before study: 16 -19 h
- Housing: in groups in IVC cages, type III H, polysulphone cages on Altromin sae fibre bedding
- Diet (e.g. ad libitum): Altromin 1324 maintenance diet fro rats and mice, ad libitum
- Water (e.g. ad libitum): Tap water, ad libitum
- Acclimation period:
Step 1: 19 days
Step 2: 22 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3 °C
- Humidity (%): 55 +/- 10%
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES:
From: 1. March To: 6. April 2018

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle:
Step 1: 2.079 g/10 mL
Step 2: 2.032 g/ 10 mL
- Amount of vehicle (if gavage): 10 mL/kg bw
- Justification for choice of vehicle: due to solubility and non-toxic characteristics
- Lot/batch no. (if required): MCC0462

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
clincal examination: at least once during the first 4 h post-dose, several times on th day of dosing, thereafter once daily
Weight assessment: days 1 (prio to administration), 8 and 15
- Necropsy of survivors performed: yes

Results and discussion

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

no mortaliy observed

Clinical signs:

other: reduced spontaneous activity, prone position, moving the bedding, ataxia, hunched posture, piloerection and half eyelid closure. All symptoms recovered within 1 day post-dose.

Gross pathology:

no macroscopic findings reported

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The median lethal dose of Isobutyl 4-hydroxybenzoate after a single oral administration to female rats, observed over a period of 14 days is:
LD50 (rat): > 2000 mg/kg bw
According to the OECD 423 test guideline, the LD50 cut-off value was considered to exceed 5000 mg/kg bw.

Executive summary:

Two groups, each of three female WISTAR Crl: WI(Han) rats, were treated with the test item by oral gavage administration at a dosage of 2000 mg/kg body weight. The test item was suspended with the vehicle corn oil at a concentration of 0.2 g/mL and administered at a dose volume of 10 mL/kg.

All animals used in the study after their entrance at BSL were allowed to acclimatise to the laboratory conditions for at least 5 days. The animals were observed on delivery, on inclusion in the study and before administration for mortality/morbidity and other clinical signs. All animals were examined for clinical signs several times on the day of dosing and once daily until the end of the observation period. Their body weights were recorded on day 1 (prior to the administration) and on days 8 and 15.All animals were necropsied and examined macroscopically.

All animals survived until the end of the study showing signs of toxicity.

The most relevant clinical findings in the animals treated with the test item at a dose of 2000 mg/kg bw were reduced spontaneous activity, prone position, moving the bedding, ataxia, hunched posture, piloerection and half eyelid closure. All symptoms recovered within 1 day post-dose.

Throughout the 14-day observation period, the weight gain of the animals was within the normal range of variation for this strain.

At necropsy, no macroscopic findings were observed in any animal of any step.

LD₅₀:                                     > 2000 mg/kg bw

LD₅₀cut-off (rat):                   > 5000mg/kg bw (according to OECD 423 test guideline)