3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from peer reviewed journal

Data source

Reference

Reference Type:

publication

Title:

Evaluation of the Developmental Toxicity of Alpha-iso-methylionone in Rats

Author:

Valerie T. Politano, Elise M. Lewis, Alan M. Hoberman, Mildred S. Christian, Robert M. Diener and Anne Marie Api

Year:

2007

Bibliographic source:

International Journal of Toxicology, 26:271–276, 2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as below

Principles of method if other than guideline:

Test material was evaluated for developmental toxicity in presumed pregnant Sprague-Dawley rats.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one

EC Number:

204-846-3

EC Name:

3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one

Cas Number:

127-51-5

Molecular formula:

C14H22O

IUPAC Name:

3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one

Test material form:

liquid

Details on test material:

- Name of test material : 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one
- Common name : alpha-isomethyl ionone
- Molecular formula : C14H22O
- Molecular weight : 206.327 g/mol
- Smiles notation : C1([C@@H](\C=C(\C(C)=O)C)C(=CCC1)C)(C)C
- InChl : 1S/C14H22O/c1-10-7-6-8-14(4,5)13(10)9-11(2)12(3)15/h7,9,13H,6,8H2,1-5H3/b11-9+
- Substance type : Organic
- Physical state : Liquid

Test animals

Species:

rat

Strain:

other: Crl:CD® (SD) IGS BR VAF®/Plus

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, NC
- Age at study initiation: 6-8 weeks old
- Weight at study initiation: Females: 213 to 241 g,
- Fasting period before study: No data available
- Housing: Animals were housed individually in cage.
- Diet (e.g. ad libitum): Certified Rodent DietR 5002 (PMI Nutrition International, St. Louis, MO), ad libitum
- Water (e.g. ad libitum): reverse osmosis deionized water (with chlorine added to the processed water as a bacteriostat), ad libitum
- Acclimation period: acclimatizated for short period.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17.7 ± 26.11°C
- Humidity (%): 30% to 70%
- Air changes (per hr):at least 10 changes per hour of 100% fresh air passed through 99.97% HEPA filters.
- Photoperiod (hrs dark / hrs light): 12:12-h light-dark lighting cycle was used

IN-LIFE DATES: From: To: No data available

Administration / exposure

Route of administration:

oral: gavage

Type of inhalation exposure (if applicable):

not specified

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Dosing formulations were prepared daily from bulk materials. Samples from each concentration of the dosing suspensions (first and last days of treatment) were analyzed for AIM content.3 mg/ml conc.level was found to be stable for 10 days when stored at ambient conditions and protected from light.
DIET PREPARATION
- Rate of preparation of diet (frequency):Not applicable
- Mixing appropriate amounts with (Type of food): Not applicable
- Storage temperature of food: Not applicable
VEHICLE
- Justification for use and choice of vehicle (if other than water): corn oil
- Concentration in vehicle: 0, 3, 10 and 30 mg/kg/day
- Amount of vehicle (if gavage): 10 ml/kg
- Lot/batch no. (if required): 103K0107 and 074K0025
- Purity: Not available

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- M/F ratio per cage:1:1
- Length of cohabitation:5 days
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility:Not available
- Further matings after two unsuccessful attempts:Not available
- Verification of same strain and source of both sexes:Not available
- Proof of pregnancy: The presence of spermatozoa and/or a copulatory plug in situ was designated as gestational day 0 (GD 0).
- Any other deviations from standard protocol:Not available

Duration of treatment / exposure:

11 days (gestational days 7 to 17)

Frequency of treatment:

Daily

Duration of test:

gestational day 21

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 3, 10, or 30 mg/kg/day
Basis:
no data

No. of animals per sex per dose:

Total:100
Control(0)-25 female pregnant rats
3 mg/kg/day-25 female pregnant rats
10 mg/kg/day-25 female pregnant rats
30 mg/kg/day-25 female pregnant rats

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dosages were selected on the basis of range-finding study. dosages of 0, 1.25, 2.5, 5, or 10 mg/kg/day were administered
daily to 8 rats/group on GDs 7 to 17. No adverse AIM related clinical signs and food consumption observed. During the postdosage period, the
body weight gains remained increased. All rats were pregnant and all caesarean sectioning and litter observations were comparable among the five groups. No fetal gross external alterations were observed. Based on these data, a dosage greater than 10 mg/kg/day AIM was recommended for the definitive developmental toxicity study in rats.
- Rationale for animal assignment (if not random): The healthy, mated female rats, weighing 213 to 241 g, were assigned to four dosage groups, 25 rats/group, using a computer-generated (weight-ordered) randomization procedure based on body weights recorded on initiation of study.
- Rationale for selecting satellite groups:No data avaiable
- Post-exposure recovery period in satellite groups: No data avaiable
- Section schedule rationale (if not random):No data avaiable

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: yes, survival observed
DETAILED CLINICAL OBSERVATIONS: Yes
BODY WEIGHT: Yes
FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day: On gestational day 21.
OTHER:abortions and premature deliveries-Yes, Organ weight and gross pathology were examined.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes
- Soft tissue examinations: Yes
- Skeletal examinations: Yes
- Head examinations: No data

Statistics:

Continuous data were analyzed by using Bartlett’s test of homogeneity of variances and the analysis of variance. Dunnett’s test was used to identify statistical significance of individual groups. If the analysis of variance was not appropriate, the Kruskal-Wallis test or Dunn’s method of multiple comparisons was used to identify the statistical significance of the individual groups. If there were greater than 75% ties, Fisher’s exact test was used to analyze the data.

Indices:

Dead or resorbed conceptuses indice and live male fetuses indice were examined.

Historical control data:

No data avaialble

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Chromorhinorrhea, excess salivation, sparse hair coat, localized alopecia, urine-stained abdominal fur, soft or liquid feces, or decreased activities were observed in a few animals from each group of rats. None of these clinical signs were attributed to treatment because the number of affected rats was not dosage related and did not significantly differ between control and treated groups.

Dermal irritation (if dermal study):

not specified

Mortality:

no mortality observed

Description (incidence):

No effect was observed on survival of treated female rats as compared to control.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No effects were observed on body weight and body weight gain of treated female rat during dosing and post dosage period (GDs 18 to 21).

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Absolute feed consumption was 101.0%, 102.1%, and 102.6% of the control value for 3, 10, and 30 mg/kg/day dose group.
No effect was observed on food consumption of treated female rats as compared to control.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Description (incidence and severity):

No alterations were observed on litters with fetuses and % fetuses/litter in treated female rats as compared to control.

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Maternal developmental toxicity

Number of abortions:

not specified

Pre- and post-implantation loss:

not specified

Total litter losses by resorption:

no effects observed

Description (incidence and severity):

No significant effect were observed litter sizes, live fetuses, resorptions

Early or late resorptions:

no effects observed

Description (incidence and severity):

No significant effect were observed

Dead fetuses:

no effects observed

Description (incidence and severity):

No significant effect were observed percentage of live male fetuses of treated female rats as compared to control.

Changes in pregnancy duration:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Changes in number of pregnant:

not specified

Other effects:

not specified

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
Mortality: No effect was observed on survival of treated female rats as compared to control.

Clinical sing: Chromorhinorrhea, excess salivation, sparse hair coat, localized alopecia, urine-stained abdominal fur, soft or liquid feces, or decreased activities were observed in a few animals from each group of rats.

None of these clinical signs were attributed to treatment because the number of affected rats was not dosage related and did not significantly differ between control and treated groups.

Body weight and body weight gain: No effects were observed on body weight and body weight gain of treated female rat during dosing and post dosage period (GDs 18 to 21).

Food consumption: Absolute feed consumption was 101.0%, 102.1%, and 102.6% of the control value for 3, 10, and 30 mg/kg/day dose group.

No effect was observed on food consumption of treated female rats as compared to control.

Reproductive performence: No significant effect were observed on corpora lutea, implantations, litter sizes, live fetuses, resorptions, percentage of dead or resorbed conceptuses and percentage of live male fetuses of treated female rats as compared to control.

Gross pathology: No alterations were observed on litters with fetuses and % fetuses/litter in treated female rats as compared to control.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

>= 30 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

body weight and weight gain

clinical signs

food efficiency

gross pathology

maternal abnormalities

mortality

Remarks on result:

other: No toxic effects were observed

Maternal abnormalities

Abnormalities:

not specified

Localisation:

not specified

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

No effect was observed on fetus weight in treated groups as compared to control.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): No effect was observed on fetus weight in treated groups as compared to control.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

No effect was observed on number of live fetuses in treated groups as compared to control.

Changes in sex ratio:

not specified

Changes in litter size and weights:

not specified

Changes in postnatal survival:

not specified

External malformations:

not specified

Skeletal malformations:

effects observed, treatment-related

Description (incidence and severity):

Limited to infrequent incidences of skeletal variations as delayed ossification at various bone ossification centers (non–dose dependent) and the presence of cervical ribs at the 7th cervical vertebra in four foetuses of 30 mg/kg/day and in control.

Visceral malformations:

not specified

Other effects:

not specified

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Mortality: No effect was observed on number of live fetuses in treated groups as compared to control.

Fetus weight: No effect was observed on fetus weight in treated groups as compared to control.

Gross pathology: No gross external fetal alterations were observed in treated rats as compared to control.

Soft tissue malformations:
Limited to infrequent incidences of skeletal variations as delayed ossification at various bone ossification centers (non–dose dependent) and the presence of cervical ribs at the 7th cervical vertebra in four foetuses of 30 mg/kg/day and in control.

Folded retinas in seven foetuses and aberrant umbilical artery in two fetuses at 10 mg/kg/day

Slight dilation of the renal pelvis in one fetus at 3 mg/kg/day was observed.

All fetal gross external, soft tissue, or skeletal alterations (malformations or variations) were considered unrelated to test material
because (1) neither the fetal nor litter incidences were dosage dependent; (2) the incidences did not significantly differ from the control group values; and/or (3) the incidences were within the ranges observed historically at the Testing Facility.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

>= 30 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reduction in number of live offspring

fetal/pup body weight changes

changes in litter size and weights

skeletal malformations

Remarks on result:

other: All fetal gross external, soft tissue, or skeletal alterations (malformations or variations) were considered unrelated to test material

Fetal abnormalities

Key result

Abnormalities:

no effects observed

Localisation:

other: not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Treatment related:

not specified

Relation to maternal toxicity:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

NOAEL was considered to be 30 mg/kg/day for F0 and F1 generation when Crl:CD® (SD) IGS BR VAF®/Plus female rats treated with test material.

Executive summary:

Developmental study was initiated to study the activity of test material . In this study, Crl:CD® (SD) IGS BR VAF®/Plus male and female rats were mated for 5 days and the presence of spermatozoa and/or a copulatory plug in situ was designated as gestational day 0 (GD 0). The test material in a corn oil vehicle was administered orally via gavage to four groups of presumed pregnant rats on GDs 7 to 17 at dosages of 0, 3, 10, or 30 mg/kg/day. No effects were observed on survival, body weight and body weight gain and food consumption of treated female rats as compared to control. Chromorhinorrhea, excess salivation, sparse hair coat, localized alopecia, urine-stained abdominal fur, soft or liquid feces, or decreased activities were observed in a few animals from each group of rats. None of these clinical signs were attributed to treatment because the number of affected rats was not dosage related and did not significantly differ between control and treated groups. Similarly, No significant effect were observed on corpora lutea, implantations, litter sizes, live fetuses, resorptions, percentage of dead or resorbed conceptuses and percentage of live male fetuses and no alterations were observed on litters with fetuses and % fetuses/litter in treated female rats as compared to control. In addition, no effects were observed on number of live fetuses, fetus weight and on gross external fetal alterations in treated rats as compared to control. Limited to infrequent incidences of skeletal variations as delayed ossification at various bone ossification centers (non–dose dependent) and the presence of cervical ribs at the 7^thcervical vertebra in four foetuses were observed in 30 mg/kg/day and in control. Folded retinas in seven foetuses and aberrant umbilical artery in two fetuses at 10 mg/kg/day and Slight dilation of the renal pelvis in one fetus at 3 mg/kg/day was observed. All fetal gross external, soft tissue, or skeletal alterations (malformations or variations) were considered unrelated to treatment because (1) neither the fetal nor litter incidences were dosage dependent; (2) the incidences did not significantly differ from the control group values; and/or (3) the incidences were within the ranges observed historically at the Testing Facility. Therefore, NOAEL was considered to be 30 mg/kg/day for F0 and F1 generation when Crl: CD® (SD) IGS BR VAF®/Plus female rats were treated with test material orally by gavge for 11 days.