ethyl 2-[[(1R,2S,5R)-5-methyl-2-propan-2-ylcyclohexanecarbonyl]amino]acetate

Endpoint summary

Description of key information

In a key study performed accoridng to OECD TG 423, fasted  female rats were treated with the test material at a dose level of 2000 mg/kg bodyweight. This was followed  by a further group of three fasted  females at the same dose level. The clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy.

The results showed that there were no deaths observed after the treatment. Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD50)  of the test material, WS-5, was calculated. LD50 was determined to be >2500 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:

18 March 2004 till 6 April 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: WS-5
- Description: white powder

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark.
- Solubility of the test substance in the solvent/vehicle: Arachis oil BP was used because the test material did not dissolve/suspend in distilled water.

The test material was freshly prepared, as required, as a suspension at the appropriate concentration in arachis oil BP.
Determination by analysis of the concentration, homogeneity and stability of the test material preparations was not appropriate because it was not specified in the Study Plan and is not a requirement of the Test Guideline.

Species:

rat

Strain:

Sprague-Dawley

Remarks:

CD (CRL:CD® (SD) IGS BR)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: by Charles River (UK) Ltd, Margate, Kent, UK
- Females: nulliparous and non-pregnant: [yes]
- Age at study initiation: eight to twelve weeks of age
- Weight at study initiation: bodyweights fell within an interval of± 20% of the mean initial bodyweight of the first treated group
- Fasting period before study: yes - an overnight fast immediately before dosing and for approximately" three to four hours after dosing
- Housing: in groups of three in suspended solid-floor polypropylene cages furnished with woodflakes- Diet (e.g. ad libitum):
- Water and food (e.g. ad libitum): free access to mains drinking water and food (Certified Rat and Mouse Diet (Code 5LF2) supplied by BCM IPS Limited, London, UK).
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.
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%): 30 to 70%
- Air changes (per hr): at least fifteen changes per hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (06:00 to 18 :00) and twelve hours darkness.

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 mg/ml
- Amount of vehicle (if gavage): 10ml/kg
- Justification for choice of vehicle: Arachis oil BP was used because the test material did not dissolve/suspend in distilled water.


CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Using all available information on the toxicity of the test material, 2000 mg/kg was chosen as the starting dose.

Doses:

2000 mg/kg

No. of animals per sex per dose:

10

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The animals were observed for deaths or overt signs of toxicity 1/2, 1, 2, 4 hours after dosing and subsequently once daily for fourteen days. Individual bodyweights were recorded prior to dosing and 7 and 14 days after treatment
- Necropsy of survivors performed: yes.
- Other examinations performed: All animals were subjected to gross pathological examination. This consisted of an external examination and opening of the abdominal and thoracic cavities for examination of major organs. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.
Data evaluations included the relationship, if any, between the exposure of the animal to the test material and the incidence and severity of all abnormalities including behavioural and clinical observations, gross lesions, bodyweight changes, mortality and any other toxicological effects

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 500 mg/kg bw

Based on:

other: deaths

Mortality:

No mortality observed.

Clinical signs:

There were no signs of systemic toxicity.

Body weight:

All animals showed expected gains in bodyweight over the study period.

Gross pathology:

No abnormalities were noted at necropsy.

Table 2. Mortality data
Dose level (mg/kg)	Sex	Number of animals treated	Deaths
2000	female	3	0/3
	female	3	0/3

Interpretation of results:

other: not classified according to EU CLP criteria

Conclusions:

There were no deaths observed after the treatment. LD50 was determined to be >2500 mg/kg/bw. Based on the results of this study, WS-5 is not classified as acute oral toxic accrding to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

Executive summary:

The aim of the study performed according to OECD TG 423 (Acute Oral Toxicity – Acute Toxic Class Method) was to assess the acute oral toxicity  of the test material, WS-5  following  a single oral administration  in female Sprague-Dawley CD (Crl: CD® (SD) IGS BR) strain rats.

WS-5 was administered orally as a suspension in arachis oil BP. All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe.  

Fasted  females were treated with the test material at a dose level of 2000 mg/kg bodyweight. This was followed  by a further group of three fasted  females at the same dose level. The clinical signs and body weight development were monitored during the study.  All animals were subjected to gross necropsy.

There were no deaths observed after the treatment. Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD50) of the test material was calculated. LD50 was determined to be >2500 mg/kg/bw.

Based on the results of this study, WS-5 is not classified as acute oral toxic accrding to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 500 mg/kg bw

Justification for classification or non-classification

Based on available data, WS-5 is not be classified for acute toxicty by the oral route of exposure under EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.