undecan-2-one; methyl nonyl ketone

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

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 publication

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Commercial-Grade Methyl Heptyl Ketone (5-Methyl-2-octanone) Neurotoxicity: Contribution-of 5Nonanone’

Author:

JOHN L. DONOGHUE

Year:

1982

Bibliographic source:

TOXlCOLOGY AND APPLIED PHARMACOLOGY, (1982)

Reference 2

Reference Type:

other: study report

Title:

Repeated Oral Administration of Five Ketones to Rats

Author:

Walter J. Krasavage

Year:

1994

Bibliographic source:

EASTMAN KODAK CO-Company report

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Principles of method if other than guideline:

Chronic repeated dose toxicity study particularly the neurotoxic potential of methyl heptyl ketone was studied orally in CD, COBS rats.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Nonan-2-one

EC Number:

212-480-0

EC Name:

Nonan-2-one

Cas Number:

821-55-6

Molecular formula:

C9H18O

IUPAC Name:

nonan-2-one

Constituent 2

Reference substance name:

Methyl heptyl ketone

IUPAC Name:

Methyl heptyl ketone

Test material form:

other: colorless to pale yellow clear oily liquid

Details on test material:

- Name of test material (as cited in study report): Methyl heptyl ketone
- Molecular formula (if other than submission substance): C9H18O
- Molecular weight (if other than submission substance): 142.24g/mol
- Substance type: Organic
- Physical state: colorless to pale yellow clear oily liquid
- Impurities (identity and concentrations): 27.7 %

Specific details on test material used for the study:

- Name of test material: Methyl heptyl ketone
- IUPAC name: nonan-2-one
- Molecular formula: C9H18O
- Molecular weight: 142.24g/mol
- Substance type: Organic
- Physical state: No data
- Impurities (identity and concentrations): 27.7 %

Test animals

Species:

rat

Strain:

other: CD, COBS

Details on species / strain selection:

No data

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Lab; Wilmington, Mass
- Age at study initiation: No data available.
- Weight at study initiation: No data available.
- Fasting period before study: No data available.
- Housing: They were singly housed in solid
floor cages covered by Ab-Sorb-Dri bedding to reduce the likelihood of wire mesh-induced pressure neuropathy.
- Diet (e.g. ad libitum): Purina Rodent Laboratory Chow 5001 was available ad libitum.
- Water (e.g. ad libitum): Water was available ad libitum.

- Acclimation 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.

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

Administration / exposure

Route of administration:

oral: gavage

Details on route of administration:

No data

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: Methyl heptyl ketone was dissolved in water to give a dose level of 0 or 2000 mg/Kg/day

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

VEHICLE
- Justification for use and choice of vehicle (if other than water): Water
- Concentration in vehicle: 0 and 2000 mg/kg
- 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

Duration of treatment / exposure:

90 days

Frequency of treatment:

Once a day, 5 days per week

Doses / concentrations

Remarks:

0 or 2000mg/kg

No. of animals per sex per dose:

Total animals -16 male rats
0 mg/kg: 8 male rats
2000 mg/kg: 8male rats

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Doses were select on the basis of 3 weeks range finding study. 0, 1000, 2000 and 4000 mg/kg doseof Methyl heptyl ketone were given to male rats orally by gavage once a day, 5 days per week for 3 weeks. At 4000 mg/kg/day dose group, after two to four doses animals with sevear depression were died and significant decrease in body weight gain were observed. Vascular congestion and hemorrhage in major organ and Moderate hepatocyte hypertrophy with minimal focal hepatic necrosis and enlarged hepatocytes impinged on sinusoidal spaces reducing their volume and severe central nervous system depression and consequent failure to maintain normal pulmonary ventilation and perfusion were observed at 4000 mg/kg/day dose group. Therefore, 2000 mg/kg/day dose group were selected for present study.

- Rationale for animal assignment (if not random): No data available
- Rationale for selecting satellite groups: No data available
- Post-exposure recovery period in satellite groups: No data available
- Section schedule rationale (if not random): No data available

Positive control:

No data

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: No data available
- Cage side observations checked in table [No.?] were included. No data available

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly.

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:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data available.
WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water studies): No data available.


OPHTHALMOSCOPIC EXAMINATION: No data available.


HAEMATOLOGY: Yes
HAEMATOLOGY: Yes
- Time schedule for collection of blood: At the termination of study
- Anaesthetic used for blood collection: Yes, carbon dioxide were used
- Animals fasted: No data available.
- How many animals: All 16 rats were examined.
- Parameters checked in table [No.?] were examined: Total and relative white blood cell counts were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At the termination of study
- Anaesthetic used for blood collection: Yes, carbon dioxide were used
- Animals fasted: No data available.
- How many animals: All 16 rats were examined.
Parameters checked in table [No.?] were examined: Glucose level were examined.

URINALYSIS: No data available.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: weekly
- Dose groups that were examined: 2000 mg/kg/day
- Battery of functions tested: sensory activity / grip strength / motor activity / other: Yes, posture, gait, and strength were observed.


OTHER:
Organ weight:
Liver, kidneys, brain, adrenal glands, testes, heart, and spleen weight were recorded.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Gross abnormalities were examined.

Tissues were fixed in 10% buffered formalin (pH 7.0), embedded in paraffin, sectioned at 5 pm, stained with hematoxylin-eosin, and examined by light microscopy.

Eyes were fixed in a modified Zenker’s (Russell’s) fixative.

Spinal cord, sciatic-plantar nerves, and dorsal root ganglia were collected in formalin. Plantar interosseous muscles of the hindpaw were collected in Bouin’s fixative. Portions of the medulla oblongata and the cerebellum and an entire sciatic-plantar nerve were fixed with 5% glutaraldehyde in 0.1 M phosphate buffer, pH 7.4, at O”C, postfixed in Dalton’s chrome-osmium solution, dehydrated in a series of ethanol solutions and propylene oxide, and embedded in epoxy resin.

Sections cut at 1 pm were stained with toluidine blue and examined by light microscopy.

HISTOPATHOLOGY: Yes,

Organ examined:
Trachea, lungs, thymus, heart, tongue, salivary glands, esophagus, stomach, small intestine, large intestine, kidneys, urinary bladder, adrenal glands, pituitary, thyroids, parathyroids, pancreas, testes, epididymides, accessory sex glands, spleen, mesenteric lymph nodes, bone marrow, Spinal cord, medulla oblongata, pons, cerebellum, cerebral cortex, sciatic-plantar nerves, and dorsal root ganglia, thalamus, basal ganglia and eyes , Quadriceps femoris muscle, calf musculature, and plantar interosseous muscles of the hindpaw were examined.

Other examinations:

No data

Statistics:

Statistical analyses included Bartlett’s test, one-way analysis of variance (ANOVA), and Duncan’s multiple range test as a significance level of 5%.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

not specified

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

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

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not specified

Behaviour (functional findings):

effects observed, treatment-related

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

Clinical signs and mortality:
Mortality:
No data available

Clinical signs:
Peripheral neuropathy, Hind limb weakness, reduction in extension of the hind limbs and a tendency toward a base-wide stance and low or droop tail, dragging of at least one hindpaw were observed in treated rats as compared to control.

The observed sign were considered to be neurotoxic signs.

Body weight and weight gain: Minor differences in mean weekly body weight were observed in treated rats during the first 3 weeks of exposure, but the differences did not reach statistical significance until the fourth week as compared to control.

Food consumption and compound intake: Food consumption:
Minor decreases in food consumption were observed in treated rats as compared to control.

Compound intake:
No data available

Food efficiency: No data

Water consumption and compound intake: No data

Opthalmoscopic examination: No data

Haematology: Minor decrease in total white blood cell count was observed in treated rats as compared to control.

Clinical chemistry: Decrease in glucose level was observed in treated rats as compared to control.

Urinanalysis: No data

Neurobehaviour: Depression, weakness and numbness were observed in treated animals as compare to control.

Clinical neuropathy was also observed in treated rats.

Organ weights: Significant increase in absolute and relative liver weight and absolute brain, adrenal and testes weight and relative kidney weight and decrease in relative heart weight were observed in treated rats as compared to control.

Gross pathology: Generalized adipose tissue and hindlimb musculature atrophy evident in affected muscles by flaccidity, pallor, and reduction in total muscle mass were observed in treated rats as compared to control.

Histopathology: Hepatocyte hypertrophy and increased hyalin droplet formation in the proximal renal tubular epithelium, higher degree of regenerating renal tubular epithelium and tubular dilation with casts, muscle fiber atrophy of tongue, quadriceps femoris, calf and hindpaw interosseous muscles were observed in treated rats.

Atrophic changes were characterized by increased
numbers of central myofiber nuclei, increased angular myofibers, foci of small
myofibers, and coalescence of atrophic foci into large areas. “Giant” axons and degenerating axons were located in intramuscular nerves.

Sites of axonal damage in increasing order of severity were the cerebellum, medulla oblongata, spinal cord, and peripheral nerves.

Effect levels

Dose descriptor:

LOAEL

Effect level:

2 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Effect on clinical sign, gross pathology, histopathology and neurotoxicity

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table: TERMINAL BODY AND ORGAN WEIGHTS FOR RATS DOSED WITH COMMERCIAL-GRADE METHYL HEPTYL KETONE

90- day study	Terminal body weight (g)	Liver		Kidneys		Brain		Adrenal gland		Testes		Heart
		g	% body weight	g	% body weight	g	% body weight	g	% body weight	g	% body weight	g	% body weight
2000 mg/Kg	337 ab	16.48	4.87b	3.48	1.04b	1.79b	0.54b	0.057	0.017b	3.40	1.02b	1.14b	0.39
n: 8	50.0	3.066b	0.341	0.541	0.100	0.071	0.0074	0.0053	0.0032	0.264	0.112	0.153	0.039
Control	495	13.33	270	3.10	0.63	2.05	0.42	0.053	0.011	3.16	0.64	1.74	0.35
n: 8	40.3	1.336	0.126	0.276	0.030	0.070	0.034	0.0054	0.0009	0.690	0.157	0.427	0.071

a Values are listed as X + SD.

b Indicates a statistically significant difference from control p ≤ 0.05, one-way ANOVA.

Applicant's summary and conclusion

Conclusions:

The Low Observed Adverse Effect Level (LOAEL) was considered to be 2000 mg /kg for Methyl heptyl ketone (MHK) in Charles River CD, COBS male rats for 90 days study.

Executive summary:

Chronic repeated dose toxicity study particularly the neurotoxic potential was performed, CD, COBS male rats were treated with Methyl heptyl ketone in the concentration of 0 and 2000 mg/kg/day orally by gavage for 90 days. Peripheral neuropathy, Hind limb weakness, reduction in extension of the hind limbs and a tendency toward a base-wide stance and low or droop tail, dragging of at least one hindpaw were observed. Observed sign were considered to be neurotoxic signs. Minor differences in mean weekly body weight were observed in treated rats during the first 3 weeks of exposure, but the differences did not reach statistical significance until the fourth week as compared to control. Similarly, minor decreases in food consumption, total white blood cell count and decrease in glucose level were observed in treated rats. In addition, Depression, weakness, numbness and clinical neuropathy were observed. Significant increase in absolute and relative liver weight and absolute brain, adrenal and testes weight and relative kidney weight and decrease in relative heart weight,generalized adipose tissue and hindlimb musculature atrophy evident in affected muscles by flaccidity, pallor, and reduction in total muscle mass and Hepatocyte hypertrophy and increased hyalin droplet formation in the proximal renal tubular epithelium, higher degree of regenerating renal tubular epithelium and tubular dilation with casts, muscle fiber atrophy of tongue, quadriceps femoris, calf and hindpaw interosseous muscles were observed in treated rats. Atrophic changes were characterized by increased numbers of central myofiber nuclei, increased angular myofibers, foci of small myofibers, and coalescence of atrophic foci into large areas. “Giant” axons and degenerating axons were located in intramuscular nerves. Therefore, Low Observed Adverse Effect Level (LOAEL) was considered to be 2000 mg /kg for Methyl heptyl ketone (MHK) in Charles River CD, COBS male rats for 90 days study.