(E)-1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From December 19, 1978 to March 28, 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The study was performed prior to the OECD Test Guideline No. 401 but the protocol is similar to that guidance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

environmental conditions not reported

Principles of method if other than guideline:

Acute gavage administration to rats.

GLP compliance:

no

Remarks:

pre-GLP

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(E)-1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one

EC Number:

246-430-4

EC Name:

(E)-1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one

Cas Number:

24720-09-0

Molecular formula:

C13H20O

IUPAC Name:

1-(2,6,6-trimethylcyclohex-2-en-1-yl)but-2-en-1-one

Test material form:

liquid

Details on test material:

- Name of test material (as cited in study report): 78-057-01
- Physical state: Light yellow colored liquid
- Storage condition of test material: Stored at 5 °C in the glass bottle.
- Other: Specific gravity: 0.8703 at room temperature.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Wilmington, Massachusetts.
- Weight at study initiation: 135-219 g (range-finding study); 136-202 g (main study).
- Fasting period before study: Prior to dosing all animals were fasted overnight. After dosing, food was withheld for one hour after which it was available ad libitum.
- Housing: Animals were housed individually in suspended stainless steel cages.
- Diet: Purina Rodent Laboratory Chow®#5001, ad libitum
- Water: Water, ad libitum
- Acclimation period: 7 days

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

DOSAGE PREPARATION (if unusual): Based on a specific gravity of 0.8703 appropriate amounts of test material was admixed with corn oil to achieve required dose levels. Dosing solutions were agitated prior to administration to each animal.

Doses:

Main study: 1000, 1470, 2150, 3160, 4640 mg/kg bw

No. of animals per sex per dose:

5 animals/sex/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Animals were observed for mortality and signs of toxicity at 1, 3, 6 and 24 h after dosing and daily thereafter for 14 days. Individual body weights were recorded prior to dosing and at time of death or sacrifice on Day 14.
- Necropsy of survivors performed: Yes, all surviving animals were sacrificed using T-61®Euthanasia Solution (National Laboratories Corporation, Somerville, N. J.) on Day 14 and necropsies were performed on all animals at the time of death or sacrifice.

Statistics:

Litchfield and Wilcoxon (1949).

Results and discussion

Preliminary study:

Not applicable

Effect levels

Effect levels 1

Sex:

female

Dose descriptor:

LD50

Effect level:

1 500 mg/kg bw

Based on:

test mat.

95% CL:

940 - 2 450

Remarks on result:

other: 1/5, 3/5, 3/5, 5/5 and 5/5 females died at 1000, 1470, 2150, 3160 and 4640 mg/kg bw, respectively.

Effect levels 2

Sex:

male

Dose descriptor:

LD50

Effect level:

1 800 mg/kg bw

Based on:

test mat.

95% CL:

1 200 - 2 700

Remarks on result:

other: 1/5, 1/5, 3/5, 5/5 and 5/5 males died at 1000, 1470, 2150, 3160 and 4640 mg/kg bw, respectively.

Effect levels 3

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

1 670 mg/kg bw

Based on:

test mat.

95% CL:

970 - 2 900

Remarks on result:

other: 2/10, 4/10, 6/10, 10/10 and 10/10 animals died at 1000, 1470, 2150, 3160 and 4640 mg/kg bw, respectively.

Mortality:

2/10 (1 male + 1 female), 4/10 (1 male + 3 females), 6/10 (3 males + 3 females), 10/10 (5 females + 5 males) and 10/10 (5 females + 5 males) animals were died at 1000, 1470, 2150, 3160 and 4640 mg/kg bw, respectively.

Clinical signs:

other: Soft, mucoid feces were frequently observed in animals at all dose levels between 1 h and 4 days after dosing. A roughening of the coat was also observed on Days 2 through 4 in two females dosed with 2150 mg/kg bw and on Day 2 in one female dosed with 316

Gross pathology:

Gross pathology findings were similar in all of the found-dead animals. No gross tissue alterations attributable to treatment were observed in any of the animals. Presence of the compound was observed in the stomach of all of the found dead animals and the cecum was found to be full of fecal matter. Other frequent observations were a wet, fecal stained anal region and a crust on the nose, mouth and or forepaws. Sacrifice of the animals surviving on Day 14 revealed only mottled lungs which are believed to be an artefact of euthanasia with T-61® Euthanasia Solution.

Other findings:

None

Any other information on results incl. tables

Range-finding study:

- Mortality: Two male animals dosed with 1600 mg/kg bw and four animals (2 males + 2 females) dosed with 5000 mg/kg bw died within 3 days after dosing.

- Clinical signs: All animals were observed to have soft feces antemortem. Except for occasional soft feces, no signs of toxicity were observed in animals dosed with 50, 160 or 500 mg/kg bw.

- Gross pathology: Gross pathology revealed the presence of the compound in the stomach of all of the found dead animals and generally the cecum contained soft stool.

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

Under the test conditions, the oral LD50(Combined) is 1670 mg/kg bw, therefore the test material is classified to ‘Category 4’ according to the annex VI of the Regulation EC No. 1272/2008 (CLP) and to the GHS.

Executive summary:

In an acute oral toxicity study, groups of CD® Sprague-Dawley outbred albino rats (5/sex/dose) were administered a single oral (gavage) dose of test material diluted in corn oil at 1000, 1470, 2150, 3160 and 4640 mg/kg bw. Animals were then observed for mortality, clinical signs and bodyweights for 14 days and at the end of the study the surviving animals were sacrificed for macroscopic examination. A range finding study was conducted at the dose levels of 50, 160, 500, 1600 and 5000 mg/kg bw (2/sex/dose) to determine the dose levels for main study.

In the range-finding study, mortality was observed at 1600 and 5000 mg/kg bw in two males and four animals (2 males + 2 females), respectively. In the main study, 2/10 (1 male + 1 female), 4/10 (1 male + 3 females), 6/10 (3 males + 3 females), 10/10 (5 females + 5 males) and 10/10 (5 females + 5 males) animals were died at 1000, 1470, 2150, 3160 and 4640 mg/kg bw, respectively. Soft, mucoid feces were frequently observed in animals at all dose levels between 1 h and 4 days after dosing. A roughening of the coat was also observed on Days 2 through 4 in two females dosed with 2150 mg/kg bw and on Day 2 in one female dosed with 3160 mg/kg bw. All surviving animals dosed with 1000, 1470 and 2150 mg/kg bw appeared normal by Day 6 after dosing. An increase in body weight was noted in all animals surviving to Day 14. Conversely, a decrease in body weight was found in all animals dying prior to Day 14. No gross tissue alterations attributable to treatment were observed in any of the animals.

Oral LD50 Combined = 1670 mg/kg bw (95 % confidence limits of 970-2900 mg/kg bw).

Under the test conditions, the test material is classified to ‘Category 4’ according to the annex VI of the Regulation EC No. 1272/2008 (CLP) and to the GHS.

This study is considered as acceptable and satisfies the requirement for acute oral toxicity endpoint.