5,7-di-tert-butyl-3-[4-(2-hydroxyethoxy)phenyl]-1-heteropolycycl-2(3H)-one

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 February 2012 - 8 March 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Exception to GLP: No analysis was carried out to determine the homogeneity, concentration or stability of the test item formulation. The test item was formulated within two hours of being applied to the test system; it is assumed that the formulation was stable for this duration. This exception is considered not to affect the purpose or integrity of the study.

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Test material

Test material information

Constituent 1

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Test animals

Species:

rat

Strain:

other: Wistar (RccHanTM:WIST)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK.
- Age at study initiation: 8 - 12 weeks.
- Weight at study initiation: The bodyweight variation did not exceed ± 20 % of the bodyweight of the initially dosed animal.
- Fasting period before study: Overnight fast immediately before dosing and for approximately three to four hours after dosing.
- Housing: The animals were housed in groups of up to four in suspended solid-floor polypropylene cages furnished with woodflakes.
- Diet (e.g. ad libitum): ad libitum 2014C Teklad Global Rodent diet (supplied by Harlan Laboratories UK Ltd., Oxon, UK)
- Water (e.g. ad libitum): free access to mains drinking water.
- Acclimation period: At least 5 days.

The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that would reasonably be expected to affect the purpose or integrity of the study.

The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): At least 15 per hour.
- Photoperiod (hrs dark / hrs light): The lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

IN-LIFE DATES: From: To: 2 February 2012 - 8 March 2012

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

Experimental Preparation
For the purpose of the study the test item was freshly prepared, as required, as a suspension in arachis oil BP. Arachis oil BP was used because the test item did not dissolve/suspend in distilled water.

Procedure
In the absence of data regarding the toxicity of the test item, 300 mg/kg was chosen as the starting dose.

A single animal was treated at a dose level of 300 mg/kg (concentration of 30 mg/mL and dose volume of 10 mL/kg).
In the absence of mortality or evident toxicity at a dose level of 300 mg/kg, an additional animal was treated at a dose level of 2000 mg/kg (concentration of 200 mg/mL and dose volume of 10 mL/kg).

In the absence of mortality or evident toxicity at a dose level of 2000 mg/kg, an additional group of 4 animals was treated at a dose level of 2000 mg/kg (concentration of 200 mg/mL and dose volume of 10 mL/kg).

All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe. The volume administered to each animal was calculated according to the fasted bodyweight at the time of dosing. Treatment of animals was sequential. Sufficient time was allowed between each dose level to confirm the survival of the previously dosed animals.

Doses:

Sighting test of 300 mg/kg bw
Limit test of 2000 mg/kg bw

No. of animals per sex per dose:

1 female in the sighting test
5 females in the limit test

Control animals:

no

Details on study design:

Clinical observations were made 0.5, 1, 2, and 4 hours after dosing and then daily for fourteen days.
Morbidity and mortality checks were made twice daily.

Individual bodyweights were recorded on Day 0 (the day of dosing) and on Days 7 and 14.

At the end of the observation period the 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.

Evaluation of Data:
Data evaluations included the relationship, if any, between the animals' exposure to the test item and the incidence and severity of all abnormalities including behavioural and clinical observations, gross lesions, bodyweight changes, mortality and any other toxicological effects. If possible the signs of evident toxicity were also identified. Evident toxicity is defined as the toxic effects which are of a severity such that administration at the next highest level could result in mortality.

Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD50) of the test item was made.

Results and discussion

Preliminary study:

Mortality
There was no mortality.

Clinical Observations
No signs of systemic toxicity were noted during the observation period.

Bodyweight
The animal showed expected gains in bodyweight over the observation period.

Necropsy
No abnormalities were noted at necropsy.

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

There were no deaths.

Clinical signs:

other: No signs of systemic toxicity were noted during the observation period.

Gross pathology:

No abnormalities were noted at necropsy.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The LD50 of the test item in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bodyweight.

Executive summary:

The LD50 of the test item in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bodyweight. The test was conducted in accordance with OECD Guidelines for Testing of Chemicals No 420 "Acute Oral Toxicity - Fixed Dose Method" (2001) and Method B1 bis Acute Toxicity (Oral) of Commission Regulation (EC) No. 440/2008.