5-methylheptan-3-one oxime

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Remarks:

Short term data taken from the OECD 422 using the male rat data which equates to 36 days repeated dosing.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

yes

Remarks:

At arrival, the body weight range of females was 184 to 215 g instead of 175 to 200 g as specified in the Study Protocol.

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

5-methylheptan-3-one oxime

EC Number:

245-010-8

EC Name:

5-methylheptan-3-one oxime

Cas Number:

22457-23-4

Molecular formula:

C8H17NO

IUPAC Name:

5-methylheptan-3-one oxime

impurity 1

Reference substance name:

(E)-3,4-dimethylhexan-2-one oxime

IUPAC Name:

(E)-3,4-dimethylhexan-2-one oxime

impurity 2

Reference substance name:

(Z)-3,4-dimethylhexan-2-one oxime

IUPAC Name:

(Z)-3,4-dimethylhexan-2-one oxime

Test material form:

liquid

Specific details on test material used for the study:

Identity STEMONE
Batch no. PE00160768
Expiry date 02 December 2018
Storage conditions +4°C protected from light
RTC number 15272

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

A total of 122 Hsd: Sprague Dawley SD rats (57 males and 65 virgin females), 7 to 8 weeks old and weighing 200 to 225 g for males and 184 to 215 g for females, were received from Charles River Italia S.p.A., Calco (Lecco), Italy.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Italia S.p.A., Calco (Lecco), Italy.
- Age at study initiation: 7 to 8 weeks old
- Weight at study initiation: 200 to 225 g
- Fasting period before study:
- Housing: Clear polysulfone cages measuring 42.5×26.6×18.5 cm with a stainless steel mesh lid and floor (Tecniplast Gazzada S.a.r.l., Buguggiate, Varese.). Each cage tray held absorbent material.
- Diet (e.g. ad libitum): A commercially available laboratory rodent diet (4 RF 21, Mucedola S.r.l., Via G. Galilei, 4, 20019, SettimoMilanese (MI), Italy) was offered ad libitum throughout the study
- Water (e.g. ad libitum): Drinking water was supplied ad libitum to each cage via water bottles.
- Acclimation period: An acclimatisation period of 21

DETAILS OF FOOD AND WATER QUALITY:
There was no information available to indicate that any non-nutrient substance likely to influence the effect of the test item was present in the drinking water or the diet. Records of analyses of water and diet are kept on file at RTC.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C±2°C
- Humidity (%): 55%±15%
- Air changes (per hr): 15 to 20 air changes per hour
- Photoperiod (hrs dark / hrs light): Rooms were lit by artificial light for 12 hours each day.

Administration / exposure

Type of coverage:

other: Dermal application.

Vehicle:

corn oil

Details on exposure:

Before the start of treatment, fur was removed from the dorsal surfaces of the trunk over an estimated area of at least 10% of the total body surface (approximately 5 x 7 cm) using an electric clipper with a suitable blade. Care was taken to avoid any damage or abrasion to the skin. The clipping procedure was repeated as necessary during the course of the study to keep the area free of fur.

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Formulation analyses were regarded as unnecessary, the test item being used as supplied.

Duration of treatment / exposure:

Males of the main groups were treated for 2 weeks prior to pairing and during pairing with females until the day before necropsy, for a total of 34, 35 or 36 days.

As part of the OECD 422 study:
Females of the main groups were treated for 2 weeks prior to pairing, during pairing up to post coitum Day 19. Dosing for pregnant females started again on Day 4 post partum until Day 13 post partum. Non pregnant females were dosed up to Day 19 post coitum and sacrificed after Day 25 post coitum.

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

200 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

500 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

Each main group comprised 10 male and 10 female rats (Groups 1 to 4).
Two groups (control and high dose levels) included 5 animals per sex to be sacrificed after 2 weeks of recovery (Groups 5 and 6).

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes.
- Time schedule: At least once daily during the study

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Once before commencement of treatment and at least once daily during the study, each animal was observed and any clinical signs were recorded.

BODY WEIGHT: Yes
Males were weighed weekly from allocation to termination.
Females were weighed weekly from allocation to positive identification of mating and on Days 0, 7, 14 and 19 post coitum.
Dams were also weighed on Days 1, 4, 7, 13 post partum and just before necropsy.

FOOD EFFICIENCY:
The weight of food consumed by each cage ofmales and females was recorded weekly during the pre-mating period starting from allocation. Individual food consumption for the females
was measured on Days 7, 14 and 19 post coitum starting from Day 0 post coitum and on Days 4, 7 and 13 post partum starting from Day 1 post partum.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes

CLINICAL CHEMISTRY: Yes
Dosing phase:
Leucocytosis was recorded in some males from all treated groups, such as: animal nos. X0450032 (200mg/kg/day), X0450058 (500mg/kg/day), X0450064 and X0450070 (1000mg/kg/day).
Compared with mean control data, individual increases were 1.6 to 2.3 fold, with no clear dose-relation.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
Once during the study, towards the end of treatment, 5 males and 5 females were randomly selected from each group for evaluation of sensory reactivity to stimuli of different modalities
(e.g. auditory, visual and proprioceptive stimuli); and for assessment of grip strength. For the females, the tests were performed on Day 13 post partum. Measurements were performed
using a computer generated random order (for the main groups).
Once during the study, towards the end of treatment, 5 males and 5 females were randomly selected from each group and the motor activity was measured (for approximately 5 minutes)
by an automated activity recording device. For the females, the tests were performed on Day 13 post partum. Measurements were performed using a computer generated random order
(for the main groups). Once duringWeek 2 of recovery, the motor activity was also measured for all animals.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see report)

HISTOPATHOLOGY: Yes (see report)

Other examinations:

The tissues required for histopathological examination are listed in the report.

Statistics:

Standard deviationswere calculated as appropriate. For continuous variables the significance of the differences amongst group means was assessed by Dunnett’s test or a modified t test, depending on the homogeneity of data. The non-parametric Kruskal-Wallis analysis of variance (non-continuous variables) was used for the other parameters. Intergroup differences between the control and treated groups were assessed by the non-parametric version of the Williams test. Statistical analysis of histopathological findings was carried out by means of the non-parametric Kolmogorov-Smirnov test if ‘n’ was more than 5. The criterion for statistical significance was p < 0.05. The mean values, standard deviations and statistical analysis were calculated from actual values in the computer without rounding off.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

The treatment site was observed daily. During treatment, the observations were performed twice daily (at the end of the treatment period, after the removal of the bandage and approximately 24 hours after treatment start). No signs were observed in control animals of both sexes during the whole study.

Dermal irritation:

effects observed, treatment-related

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One male of the recovery group receiving 1000mg/kg/day was found dead on Day 27 of the study (no. X0450096). Macroscopically, the findings observed in this animal included: distended caecum, red colour or areas of jejunum, mesenteric lymph nodes and thymus. At histopathology, inflammatory cell foci of heart and liver or glandular dilatation of the stomach were noted. Such findings did not establish the factors contributory to the death.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Main and Recovery groups
No differences were seen in body weight of treated animals when compared to controls, both in the main and recovery groups.
The only difference noted in body weight gain of the main groups was evident in the high dose males (1000mg/kg/day) on Day 8 of the study and in low dose females (200mg/kg/day) on Day 7 post partum. The differences were considered incidental.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Main and Recovery groups
Food consumption was unaffected by treatment in both sexes during the study.

Food efficiency:

no effects observed

Description (incidence and severity):

Main and Recovery groups
Food efficiency was unaffected by treatment in both sexes during the study.

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

no effects observed

Description (incidence and severity):

Main and Recovery groups
Water consumption was unaffected by treatment in both sexes during the study.

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Dosing phase
Leucocytosis was recorded in some males from all treated groups, such as: animal nos. X0450032 (200mg/kg/day), X0450058 (500mg/kg/day), X0450064 and X0450070 (1000mg/kg/day).
Compared with mean control data, individual increases were 1.6 to 2.3 fold, with no clear dose-relation.

Recovery phase
No changes of the white blood cells were recorded in treated males, confirming complete reversibility.
The statistically significant difference of platelets recorded between controls and treated males was not recorded at the dosing phase, therefore it was considered unrelated to treatment.

Coagulation - Dosing phase
No relevant changes were recorded.

Coagulation - Recovery phase
No relevant changes were recorded.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

Main groups - Dosing phase
Phosphorus was increased in males dosed at 500 and 1000mg/kg/day. Mean group data were 16% and 19%, respectively, above controls. Since changes were of slight severity and there were no other related findings, these increases were considered of no toxicological importance. The other statistically significant differences recorded between control and treated females (decreases of creatinine and phosphorus in females) were recorded in the low and/or intermediate groups only, therefore they were considered incidental.

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, non-treatment-related

Description (incidence and severity):

Main and Recovery groups
Observation of animals at removal from the cage and in an open arena (neurotoxicity assessment) did not reveal changes attributable to the test item.

Main groups
Motor activity recorded at the end of the treatment period was comparable between control and treated main groups.
Statistically significant increase in landing foot splay measurement (individual and mean data for first and second trials) was noted in treated males of Group 4 (1000mg/kg/day) when compared to the control group. The variation was considered of no toxicological significance, since it was observed in only one sex.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

Final and recovery sacrifice
No relevant changes were observed on terminal body weight of treated animals, when compared to the controls.
No relevant changes were observed in the absolute and relative organ weights of treatment groups of both sexes, when compared to control data. The changes observed in absolute
prostate and thymus weights in high dose males, relative adrenals weight in treated males or relative brain and liver weights in high dose males could be considered without toxicological
relevance, since the histopathological evaluation of these organs was comparable to control animals.

Gross pathological findings:

no effects observed

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

An increased severity of hyaline droplets accumulation in kidneys from moderate to marked degree was observed in high dose males, when compared with controls. However, since the increase in hyaline droplets in the kidneys is not relevant for human, it was decided not to proceed with the extension of histopathological examination.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Details on results:

No relevant changes were recorded in terminal body weight and organ weights (absolute and relative) in animals of both sexes, when compared to the control group. At macroscopic observations, no treatment-related changes were noted.
At microscopic observations changes were noted in the kidneys of high dose males, when compared with controls. An increased severity of hyaline droplets accumulation in kidneys from moderate to marked degree was observed in high dose males.

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

dermal irritation

Remarks on result:

other: Based on clinical signs and skin irritation.

Target system / organ toxicity

Key result

Critical effects observed:

no

Lowest effective dose / conc.:

1 000 mg/kg bw/day (nominal)

System:

other: Whole animal model and skin irritation.

Organ:

skin

Applicant's summary and conclusion

Conclusions:

Based on the results of the present study, the NOAEL (No Observed Adverse Effect Level) for general toxicity and reproductive and developmental toxicity was considered to be 1000mg/kg/day for both males and females.

Executive summary:

The NOAEL is 1000 mg/kg/day.