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Description of key information

In an acute oral toxicity study (fixed dose procedure, OECD 420), fasted, 8-9 weeks old female Wistar rats (1 at step 1 and 4 at step 2) were given a single oral dose of the test item (99.1% purity) in DMSO at the limit dose of 2000 mg/kg by gavage and were observed for 14 days. Based on the results from this study, the oral LD50 in rats can considered to be greater than 2000 mg/kg bw.

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:
2018-01-03 to 2018-03-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)
Version / remarks:
Adopted, 17th December, 2001
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test type:
fixed dose procedure
Limit test:
yes
Specific details on test material used for the study:
- Batch No.: 018964K19K
- CAS No.:17696-62-7
- Storage: room temperature
- Form: powder
- Expiry date: August 2018
- Colour: white
- Purity: 99.1%
Species:
rat
Strain:
Sprague-Dawley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Elevage JANVIER LABS (53940 Le Genest St Isle, France)
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: 8 or 9 weeks
- Housing: Animals 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.
- Diet (e.g. ad libitum): ad libitum, foodstuff ENVIGO - 2016; Food was removed on day 1 and then redistributed 4 hours after the test item administration.
- Water (e.g. ad libitum): ad libitum; tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
DMSO
Details on oral exposure:
VEHICLE
- Amount of vehicle (if gavage): 5 mL in the first step and 10 mL in the second step
- Justification for choice of vehicle: Dimethyl sulfoxide (DMSO) was chosen as it produced the most suitable formulation at the requested concentrations.

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg body weight

DOSAGE PREPARATION (if unusual): In the first and second step of the study, 1.0007 g and 2.0003 g of the test item were weighed and DMSO was added to a 5 mL volumetric flask and to a 10 mL volumetric flask respectively. Just before the administration, the preparations were stirred by vortex to obtain yellowish solutions.
Doses:
2000 mg/kg body weight
No. of animals per sex per dose:
Control: 4 females
Treatment: 1 female rat (step 1); 4 female rats (step 2)
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations: 30 minutes, 1 hour, 3 hours, 4 hours, on day 1 and day 2 and during 14 days
- Frequency of weighing: day 0 (just before administering the test item) then on day 2, day 7, and day 14
- Necropsy of survivors performed: yes
Statistics:
n.a.
Preliminary study:
n.a.
Key result
Sex:
female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
One mortality was noted in animals treated at the dose of 2000 mg/kg body weight, at 48 hours post dose during the step 2.
Clinical signs:
In one animal, the mortality was preceded by an absence or a decrease of spontaneous activity, Preyer’s reflex, muscle tones, righting reflex associated with hypothermia, eyes partly closed and piloerection, at 24 hours post dose.
In the surviving animals (4/5), an absence or a decrease in spontaneous activity (1/4) and righting reflex (1/4), associated with an increase of salivation (1/4) were noted during the first hours of the test. The animal recovered a normal activity on day 2.
Gross pathology:
The macroscopic examination of the mortal animal revealed black spots on the corpus. Rigor mortis was noted before the necropsy. No other changes were noted.
The macroscopic examination of the surviving animals at the end of the study did not reveal treatment related changes.
Interpretation of results:
GHS criteria not met
Conclusions:
In an acute oral toxicity study in rats conducted according to OECD 420 one out of four female rat died at the limit dose of 2000 mg/kg bw at 48 hours post dose during the step 2. The LD50 value was determined to be greater than 2000 mg/kg bw.
Executive summary:

In an acute oral toxicity study (fixed dose procedure, OECD 420), fasted, 8-9 weeks old female Wistar rats (1 at step 1 and 4 at step 2) were given a single oral dose of the test item (99.1% purity) in DMSO at the limit dose of 2000 mg/kg by gavage and were observed for 14 days. One animal died at 48 hours post dose during the step 2. The mortality was preceded by an absence or a decrease of spontaneous activity, Preyer’s reflex, muscle tones, righting reflex associated with hypothermia, eyes partly closed and piloerection, at 24 hours post dose. Rigor mortis was noted before the necropsy. The macroscopic examination of the animal revealed black spots on the corpus. No other change was noted. In the surviving animals an absence or a decrease in spontaneous activity (1/4) and righting reflex, associated with an increase of salivation were noted during the first hours of the test. The animal recovered a normal activity on day 2. The macroscopic examination of the animals at the end of the study did not reveal treatment related changes. Based on the results from this study, the oral LD50 in rats can considered to be greater than 2000 mg/kg bw.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
GLP guideline study

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

In an acute oral toxicity study (fixed dose procedure, OECD 420), fasted, 8-9 weeks old female Wistar rats (1 at step 1 and 4 at step 2) were given a single oral dose of the test item (99.1% purity) in DMSO at the limit dose of 2000 mg/kg by gavage and were observed for 14 days. One animal died at 48 hours post dose during the step 2. The mortality was preceded by an absence or a decrease of spontaneous activity, Preyer’s reflex, muscle tones, righting reflex associated with hypothermia, eyes partly closed and piloerection, at 24 hours post dose. Rigor mortis was noted before the necropsy. The macroscopic examination of the animal revealed black spots on the corpus. No other change was noted. In the surviving animals an absence or a decrease in spontaneous activity (1/4) and righting reflex, associated with an increase of salivation were noted during the first hours of the test. The animal recovered a normal activity on day 2. The macroscopic examination of the animals at the end of the study did not reveal treatment related changes. Based on the results from this study, the oral LD50 in rats can considered to be greater than 2000 mg/kg bw.

Justification for classification or non-classification

Based on the available data, Phenyl 4-hydroxybenzoate does not warrant classification for acute toxicity. LD50 values for the oral route are above the limit values of the relevant OECD guidelines. The LD50 value received from an acute oral toxicity study was greater than 2000 mg / kg bw.