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

Endpoint summary

Description of key information

Repeated dose toxicity: oral

The test substance was considered to have a NOAEL of 3.55 mg/kg/day in male rats and 4.10 mg/kg/day in female rats after 90-Days of feeding.

The test chemical is not likely to classify as a toxicant upon repeated application by the oral route of exposure.

Repeated dose toxicity: inhalation

According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance 3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one, which is reported as 0.22 Pa, thus exposure to inhalable dust, mist and vapour of the chemical 3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one is highly unlikely. Also it is a fragrance ingredient found in a variety of consumer products, humans have the potential to be exposed to low but continuous levels, primarily via the dermal route. Therefore this study is considered for waiver.

Repeated dose toxicity: dermal

On the basis of the review of the kidney histopathology data and considering the dermal inflammation and infection in the rats, the results of this study are concluded to show a systemic NOAEL of topical alpha-isomethyl ionone of 50 mg/kg. The test chemical α- isomethylionone is not likely to classify as a toxicant upon repeated application by the dermal route of exposure.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Data is from a peer-reviewed publication

Qualifier:

according to guideline

Guideline:

other: see Principles below

Principles of method if other than guideline:

A repeated dose study investigating the effect of test substance in rats..

GLP compliance:

not specified

Species:

rat

Strain:

other: FDRL

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data available
- Age at study initiation: No data available
- Weight at study initiation: Males: 59.5 ±1.5 g; Females: 58.0 ± 1.6 g
- Fasting period before study: No data available
- Housing: Animals were housed individually in wire mesh cages.
- Diet (e.g. ad libitum): Purina Laboratory Chow, ad libitum
- Water (e.g. ad libitum): Fresh water, ad libitum
- Acclimatization period: No data available

ENVIRONMENTAL CONDITIONS
- Temperature (°C):No data available
- Humidity (%):No data available
- Air changes (per hr):No data available
- Photoperiod (hrs dark / hrs light):No data available

Route of administration:

oral: feed

Vehicle:

cotton seed oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The test substance was diluted in cotton-seed oil in a concentration sufficient to provide the predetermined dosage in 2% of the diet. The oil solutions were incorporated into a nutritionally adequate basal ration (Purina Laboratory Chow).

DIET PREPARATION
- Rate of preparation of diet (frequency): Biweekly
- Mixing appropriate amounts with (Type of food): Purina Laboratory Chow
- Storage temperature of food: No data available

VEHICLE
- Justification for use and choice of vehicle (if other than water): Cotton-seed oil
- Concentration in vehicle: 2% of the diet.
- Amount of vehicle (if gavage):No data available
- Lot/batch no. (if required):No data available
- Purity:No data available

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data available

Duration of treatment / exposure:

90 days

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations: 3.66 mk/kg (measured conc. 3.55 mg/kg (males) and 4.10 mg/kg (females))

No. of animals per sex per dose:

Total: 60 rats
Control: 15 males, 15 females
3.66 mg/kg: 15 males, 15 females

Control animals:

yes

Details on study design:

- Dose selection rationale: Single dosage levels for each substance were derived from the total estimated daily intake, calculated on a mg/kg body weight basis assuming 50 kg as the average body weight, and multiplying by 100.

Positive control:

No data available

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No data available

DETAILED CLINICAL OBSERVATIONS: No data available

BODY WEIGHT: Yes
- Time schedule for examinations: Not specified

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data available

FOOD EFFICIENCY: No data available

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data available

OPHTHALMOSCOPIC EXAMINATION: No data available

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 6 week and 12 week
- Anaesthetic used for blood collection: No data available
- Animals fasted: No data available
- How many animals: 8 rats of each sex at 6 week period and all rats at 12 week period
- Parameters examined: Hematocrit, hemoglobin, red blood cells white blood cells, neutrophils and lymphocytes.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 6 week and 12 week
- Anaesthetic used for blood collection: No data available
- Animals fasted: No data available
- How many animals: 8 rats of each sex at 6 week period and all rats at 12 week period
- Parameters examined: Blood urea nitrogen

URINALYSIS: No data available

NEUROBEHAVIOURAL EXAMINATION: No data available

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
At autopsy, liver and kidney weights were recorded.

HISTOPATHOLOGY: Yes
The following organs from half the animals in each group were taken for histological examination: liver, kidneys, stomach,small and large intestines, spleen,pancreas, heart, lungs, bone marrow, muscle, brain, spinal cord, bladder, adrenals, thyroid, pituitary, gonads, salivary glands, and lymph nodes.

Other examinations:

No data available

Statistics:

Statistical limits (P=0.05) for the controls.

Clinical signs:

not specified

Mortality:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

The males showed a slightly reduced haemoglobin level but the haematocrit and erythrocyte counts were within the control ranges.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

The males also had a mean blood urea nitrogen level somewhat below that of the composite controls.. However, the male control rats showed a mean blood urea nitrogen at 12 wk of 9.2 mg/100 ml; the value at 6 wk was 10.8 compared with 9.9 mg/100 ml for the controls.

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

Liver and kidney weights were normal throughout the study.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No significant gross pathological change was observed at autopsy in any of the rats in this study.

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

3.55 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

clinical biochemistry

gross pathology

haematology

Remarks on result:

other: No toxiceffect were observed

Key result

Dose descriptor:

NOAEL

Effect level:

4.1 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

clinical biochemistry

gross pathology

haematology

Remarks on result:

other: No toxic effect were observed

Critical effects observed:

not specified

Conclusions:

The test substance was considered to have a NOAEL of 3.55 mg/kg/day in male rats and 4.10 mg/kg/day in female rats after 90-Days of feeding.

Executive summary:

The activity of test substance was studied in a 90-day feeding studies in rats. The test material was given orally in diet to male and female FDRL rats at a dose concentration of 3.66 mg/kg (actual dose received: 3.55 mg/Kg bw/day for males and 4.10 mg/Kg bw/day for females). No significant gross pathological change was observed at autopsy in any of the rats, and only mino effects were seen on hemoglobin and blood urea nitrogen in male rats. The 90-day feeding study corresponded to at least 100 times the maximum estimated human dietary levels, and revealed no evidence of adverse toxic effects. Therefore, NOAEL was considered to be 3.55 mg/bg bw/day in male rats and 4.10 mg/kg bw/day in female rats.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

3.55 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Data is from K2 publication

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Data is from peer reviewed publication

Qualifier:

according to guideline

Guideline:

other: see Principles below

Principles of method if other than guideline:

A 90 days Subchronic dermal toxicity study was conducted on rats to evaluate the toxic nature of test substance.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

No data available

Type of coverage:

open

Vehicle:

not specified

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: No data available

TEST SITE
- Area of exposure: Clipped backs
- % coverage: No data available
- Type of wrap if used: No data available
- Time intervals for shavings or clipplings: No detailed data available

REMOVAL OF TEST SUBSTANCE
- Washing (if done): No data available
- Time after start of exposure: No data available

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): No data available
- Concentration (if solution): 0, 50, 170, 580 or 2000 mg/kg/day
- Constant volume or concentration used: No data available
- For solids, paste formed: No data available

VEHICLE
- Justification for use and choice of vehicle (if other than water): No data available
- Amount(s) applied (volume or weight with unit): No data available
- Concentration (if solution): No data available
- Lot/batch no. (if required): No data available
- Purity: No data available

USE OF RESTRAINERS FOR PREVENTING INGESTION: No data available

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data available

Duration of treatment / exposure:

90 days

Frequency of treatment:

daily

Remarks:

Doses / Concentrations: 0, 50, 170, 580 or 2000 mg/kg/day

No. of animals per sex per dose:

15/sex/dose

Control animals:

yes

Details on study design:

No data available

Positive control:

No data available

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No data available

DETAILED CLINICAL OBSERVATIONS: No data available

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: No data available

BODY WEIGHT: Yes

FOOD CONSUMPTION: Yes

FOOD EFFICIENCY: Yes

WATER CONSUMPTION: No data available

OPHTHALMOSCOPIC EXAMINATION: No data available

HAEMATOLOGY: Yes

CLINICAL CHEMISTRY: Yes

URINALYSIS: Yes

NEUROBEHAVIOURAL EXAMINATION: No data available

OTHER: Organ weight

Sacrifice and pathology:

GROSS PATHOLOGY: No data

HISTOPATHOLOGY: Yes

Other examinations:

No data available

Statistics:

No data available

Clinical signs:

not specified

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

Erythema, edema, and eschar formation was observed in all dosage groups

Mortality:

not specified

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

580 and 2000 mg/kg: Reduced body weight gain in females and in males.

Food consumption and compound intake (if feeding study):

not specified

Description (incidence and severity):

580 and 2000 mg/kg: Food consumption elevations in females, lower efficiency food utilization in both male and females.

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

580 and 2000 mg/kg: lower efficiency food utilization in both male and females.

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

170 mg/kg: Changes in hematology parameters in both sexes.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

580 and 2000 mg/kg: Serum glucose levels were depressed in males at week 7 and in both sexes at termination. BUN levels increased with dose in males.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

170, 580 and 2000 mg/kg: Urine albumin levels were significantly increased in male groups at termination.

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

50 mg/kg: Dose related increase in liver weight and.
170, 580 and 2000 mg/kg: Increases in the absolute and relative weights in the liver and kidneys in both sexes.

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Severe tissue destruction and infection in the skin may have combined to elicit increased kidney weight at higher doses and epithelial eosinophilic globules in the convoluted tubules of the outer cortex. To determine if these effects were specific to male rat nephropathy, a review of the histopathology of kidney from rats in this study was conducted. This lesion occurred in a dose-responsive fashion in males only and was seen
also in male control rats. It was accompanied by interstitial nephritis in control and treated rats. The findings suggest an endogenous disease process which was exacerbated by the application of the irritating test material and marked skin necrosis.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

On the basis of the review of the kidney histopathology data and considering the dermal inflammation and infection in these animals, the results of this study are concluded to show a systemic NOAEL of topical alpha-isomethyl ionone of 50 mg/kg. Since erythema and eschar formation
occurred in all treatment groups, a NOAEL for this effect could not be established

Key result

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day

Based on:

test mat.

Sex:

not specified

Basis for effect level:

histopathology: non-neoplastic

other: On the basis of the review of the kidney histopathology data and considering the dermal inflammation and infection in the animals

Remarks on result:

other: No toxic effects were observed

Critical effects observed:

not specified

Conclusions:

On the basis of the review of the kidney histopathology data and considering the dermal inflammation and infection in the rats, the results of this study are concluded to show a systemic NOAEL of topical test substance of 50 mg/kg.

Executive summary:

A dermal subchronic study was conducted on Sprague-Dawley rats (15/sex/dose). An open application of test substance at a dose of 50, 170, 580 or 2000 mg/kg was made to the clipped backs, once daily for 90 days. The controls (60 rats/sex) were not treated with the test material. Observations for signs of toxicity including erythema and eschar formation, were performed daily. Body weight and food consumption data were measured weekly. Selective hematology, clinical chemistry and urinalysis assessment were conducted at weeks 7 and 13 of the study. A complete gross necropsy on all animals and a microscopic examination of tissues in the control and high dose animals were conducted at sacrifice. No treatment related deaths occurred. On the skin at the application site there was a dose-dependent increase in the severity of erythema, and eschar formation. At 50 mg/kg: Dose related increase in liver weight and changes in urinalysis parameters at this dose . At 170 mg/kg: Changes in hematology parameters in both sexes. BUN levels increased with dose in males. Urine albumin levels were significantly increased in male groups at termination. Increases in the absolute and relative weights in the liver and kidneys in both sexes. At 580 and 2000 mg/kg: Reduced body weight gain in females and in males. Food consumption elevations in females, lower efficiency food utilization in both male and females. Serum glucose levels were depressed in males at week 7 and in both sexes at termination. BUN levels increased with dose in males. Urine albumin levels were significantly increased in male groups at termination. Increases in the absolute and relative weights in the liver and kidneys in both sexes Moderate to severe erythema and eschar formation was observed in all test groups and increased with increasing levels of test material. Severe tissue destruction and infection on doses above 50 mg/kg may have combined to elicit increased kidney weight at higher doses. Since erythema and eschar formation occurred in all treatment groups, a NOAEL for this effect could not be established. On the basis of the review of the kidney histopathology data and considering the dermal inflammation and infection in these animals, the results of this study are concluded to show a systemic NOAEL of topical test substance of 50 mg/kg.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

50 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

Data is from K2 publication

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The data available for the test chemical was reviewed to determine the toxic nature of 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one (CAS no 127-51-5) repeated exposure by oral route. The study is as mentioned below:

 

The activity of test substance was studied by a short-term (90 days) feeding studies in rats. Single dosage level was derived from the total estimated daily intake, calculated on mg/kg body weight basis assuming 50 kg as the average body weight, and multiplying by 100. The test material was given orally through diet to 15/sex FDRL strain rats at a dose concentration of 3.55 mg/Kg bw/day for males and 4.10 mg/Kg bw/day for females. No significant gross pathological change was observed at autopsy in any of the rats, with the exception of occasional pulmonary alterations associated with a respiratory infection. None of the deviations shown for the test groups can be regarded as pathological even though they fall somewhat outside the statistical limits (P=0.05) for the controls and were not dose related. 90-Day feeding studies in groups of rats receiving dietary doses of test substance at levels corresponding to at least 100 times the maximum estimated human dietary levels, revealed no evidence of adverse toxic effects. Various observations were conducted and the No Observed Adverse Effect Level (NOAEL) was found to be 3.55 mg/Kg bw/day in males and 4.10 mg/Kg bw/day in females.

 

In a repeated dose toxicity study, the toxic effcts of test substance was evaluated in male and female Sprague Dawley rats at a concentration of 0, 5, 30 or 500 mg/kg/day. Body weight, organ weight, hematological, blood biochemistry and histopathological examinations were performed. Treatment with 30 or 500 mg/kg/day resulted in globular accumulations of eosinophilic material in the tubular epithelium in kidneys of male rats. Rats, especially male rats, treated with 500 mg/kg/day showed a statistically significant increase in liver and kidney weights, both absolute and relative to terminal body weight. Males from this group also showed statistically significant increases in absolute and relative spleen weight. In addition, blood chemistry evaluation revealed a statistically significant increase in plasma creatinine, total protein, and cholesterol in rats treated with 500 mg/kg/day when compared to controls. Based on the results, test substance is considered to have a NOAEL of 30 mg/kg/day in male rats and a NOAEL of 500 mg/kg/day in female rats.

 

Test substance, a widely used fragrance ingredient, was evaluated for its subacute toxic nature in presumed pregnant Sprague-Dawley rats. The test compound was administered orally via gavage at a dosage level of0, 3, 10, or 30 mg/kg/day in corn oil to 25/grouppregnant Sprague-Dawley rats on GDs 7-17. Rats were observed for viability, clinical signs, body weights, and feed consumption. Caesarean sectioning and necropsy occurred on gestational day 21. Uteri were examined for number and distribution of implantations, live and dead fetuses, and early and late resorptions. Numbers of corpora lutea were also recorded. Fetuses were weighed and examined for gender, gross external changes, and soft tissue or skeletal alterations. No maternal or fetal deaths occurred. No fragrance ingredient–related clinical signs were observed. Feed consumption, body weight gains, gross tissue changes at necropsy, and caesarean section or litter parameters, as well as fetal developmental morphology, were unaffected by dosages of test substance as high as 30 mg/kg/day. The observations in the pregnant female rats did not significantly differ from the vehicle control group values and were within the ranges observed historically. All fetal gross external, soft tissue, or skeletal alterations were considered unrelated to AIM because neither the fetal nor litter incidences were dosage dependent; the incidences did not significantly differ from the control group values; and/or the incidences were within the ranges observed historically at the Testing Facility. The No Observed Adverse Effect Level (NOAEL) for the test substance is ≥ 30 mg/kg/day in pregnant female Sprague-Dawley rats and their fetuses.

 

In a repeated dose oral toxicological study , male and female FDRL rats were fed diet containing 0 or 10.6 mg/kg/day test substance ,a concentration that was reported by conducted measurement to provide an average intake of 11.8 mg/kg/day for males and 11.1 mg/kg/day for females for 90 days. No exposure-related effects were observed based on evaluations of body weight, food intake, hematology, blood chemistry (endpoints not specified), liver and kidney weights and histopathology. Therefore, the No Observed Adverse Effect Level (NOAEL) for male FDRL rats was considered to be 11.8 mg/kg/day while NOAEL for female FDRL rats was considered to be 11.1 mg/kg/day when exposed to test substance.

 

In the same study, male and female FDRL rats were fed diet containing 0 or 11.4 mg/kg/day test substance , a concentration that was reported by conducted measurement to provide an average intake of 11.6 mg/kg/day for males and 13.1 mg/kg/day for females for 90 days. No exposure-related effects were observed based on evaluations of body weight, food intake, hematology, blood chemistry (endpoints not specified), liver and kidney weights and histopathology. Therefore, NOAEL for male FDRL rats was considered to be 11.6 mg/kg/day while NOAEL for female FDRL rats was considered to be 13.1 mg/kg/day when exposed to test substance.

 

Considering all the available data for target as well as its read across substance it can be considered that the substance 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one did not cause any significant changes. Also it did not showed any specific target organ toxicity, hence the substance 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one is not likely to classify as a toxicant upon repeated application by the oral route of exposure.

 

Repeated dose toxicity: inhalation According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance 3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one (127-51-5), which is reported as 0.0016501357 at 20 C, thus exposure to inhalable dust, mist and vapour of the chemical 3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one is highly unlikely. Also it is a fragrance ingredient found in a variety of consumer products, humans have the potential to be exposed to low but continuous levels, primarily via the dermal route. Therefore this study is considered for waiver.

 

Repeated dose toxicity:Dermal Two different studies were reviewed for evaluating the toxic nature of test compound 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one upon repeated application by the dermal route of exposure. The same is summarized is below as weight of evidence:

 

A dermal subchronic study was conducted on Sprague-Dawley rats (15/sex/dose). An open application of test substance at a dose of 50, 170, 580 or 2000 mg/kg was made to the clipped backs, once daily for 90 days. The controls (60 rats/sex) were not treated with the test material. Observations for signs of toxicity including erythema and eschar formation, were performed daily. Body weight and food consumption data were measured weekly. Selective hematology, clinical chemistry and urinalysis assessment were conducted at weeks 7 and 13 of the study. A complete gross necropsy on all animals and a microscopic examination of tissues in the control and high dose animals were conducted at sacrifice. No treatment related deaths occurred. On the skin at the application site there was a dose-dependent increase in the severity of erythema, and eschar formation. At 50 mg/kg: Dose related increase in liver weight and changes in urinalysis parameters at this dose. At 170 mg/kg: Changes in hematology parameters in both sexes. BUN levels increased with dose in males. Urine albumin levels were significantly increased in male groups at termination. Increases in the absolute and relative weights in the liver and kidneys in both sexes. At 580 and 2000 mg/kg: Reduced body weight gain in females and in males. Food consumption elevations in females, lower efficiency food utilization in both male and females. Serum glucose levels were depressed in males at week 7 and in both sexes at termination. BUN levels increased with dose in males. Urine albumin levels were significantly increased in male groups at termination. Increases in the absolute and relative weights in the liver and kidneys in both sexes Moderate to severe erythema and eschar formation was observed in all test groups and increased with increasing levels of test material. Severe tissue destruction and infection on doses above 50 mg/kg may have combined to elicit increased kidney weight at higher doses. Since erythema and eschar formation occurred in all treatment groups, a NOAEL for this effect could not be established. On the basis of the review of the kidney histopathology data and considering the dermal inflammation and infection in these animals, the results of this study are concluded to show a systemic NOAEL of topical test substance of 50 mg/kg.

 

 Test substance was tested in a 90-day dermal toxicity study on rats. Ten Sprague-Dawley albino male and female rats (5/sex) received a dermal application of 1% test substance in phenethyl alcohol (PEA), at a dose of 10 mg/kg, once daily for 90 days. A control group of ten rats (5/sex) received applications of 1 mg/kg PEA. All animals were observed daily and skin reactions were recorded. Body weights were recorded weekly. At the study’s termination, selected hematology, clinical chemistry and urinalysis parameters were evaluated. Necropsy was conducted on all animals. Gross observations were normal in all animals. The hematology, clinical chemistry and urinalysis parameters evaluated were comparable to the controls. Dermal reactions were normal for all animals. Thus, the NOEL after dermal application of alpha-isomethyl ionone for 90 days was considered to be 10 mg/kg on the basis of no effects on Dermal irritation, Haematology, Clinical biochemistry, Urinalysis and Gross pathology.

 

Considering the available data for target substance it can be considered that the substance 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one (CAS no 127-51-5) did not cause any significant changes. Also it did not showed any specific target organ toxicity, hence the substance 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one (CAS no 127-51-5) is not likely to classify as a toxicant upon repeated application by the dermal route of exposure.

Justification for classification or non-classification

Based on the available data summarized and CLP criteria ,the test chemical 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one is not likely to classify as a toxicant upon repeated application by the oral and dermal route of exposure.