Oxacycloheptadecan-2-one

Endpoint summary

Description of key information

In the GLP-compliant OECD guideline 422 study with rats, no adverse effects were observed at the highest tested dose of 1000 mg/kg bw/day.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6 September 2016 - 5 December 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

March 1996

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3650, Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test

Version / remarks:

July 2000

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Version / remarks:

May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Version / remarks:

October 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3010, Repeated dose 28-day oral toxicity study in rodents

Version / remarks:

July 2000

Deviations:

no

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: In refrigerator (2-8°C)
- Stability at higher temperatures: yes, maximum temperature: 40°C, maximum duration: 20 minutes
- Solubility and stability of the test substance in the solvent/vehicle: stability in corn oil for at least 6 hours at room temperature, under normal laboratory light conditions is confirmed over the concentration range 1 to 200 mg/mL in a separate study
- Specific gravity 0.977 g/mL at 20 °C
- No correction for purity required


FORM AS APPLIED IN THE TEST (if different from that of starting material)

The test item was heated up to a maximum of 39ºC for a maximum of 23 minutes during the preparation of formulations.

Species:

rat

Strain:

other: Crl:WI(Han)

Details on species / strain selection:

This species and strain of rat has been recognized as appropriate for general and reproduction toxicity studies. Charles River Den Bosch has general and reproduction/developmental historical data in this species from the same strain and source. This animal model has been proven to be susceptible to the effects of reproductive toxicants.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: Approximately 10-11 weeks
- Weight at study initiation: males 272-321 g, females 179-228 g
- Fasting period before study: no
- Housing: Sterilized sawdust as bedding material and paper as cage-enrichment/nesting material were supplied, except during locomotor activity measurements.
Pre-mating: in groups of 5 animals/sex/cage in Macrolon plastic cages MIV type
Mating: on 1:1 basis m:f in MIII type Macrolon cages
Post-mating: males in their home cages with a maximum of 5 animals/cage, females individually in MIII type Macrolon cages
Lactation: pups with the dam in Macrolon MIII type cages, except during locomotor activity monitoring of the dams the pups were kept warm in their home cage using bottles filled with warm water. In order to avoid hypothermia of pups, pups were not left without their dam or a bottle filled with warm water for longer than 30-40 minutes.
Locomotor activity measurements: individually in polycarbonate cages without cage-enrichment, bedding material, food and water.
- Diet: pelleted rodent diet (SM R/M-Z from SSNIFF®), ad libitum, except during locomotor measurements
- Water: tap water, ad libitum, except during locomotor measurements, when animals did not have access to water for a maximum 1 hour and 23 minutes.
- Acclimation period: At least 5 days prior to start of treatment

DETAILS OF FOOD AND WATER QUALITY: Diet, water, bedding and cage-enrichment/nesting material evaluation for contaminants and/or nutrients was performed according to facility standard procedures. There were no findings that could interfere with the study.

ENVIRONMENTAL CONDITIONS (set to maintain)
- Temperature (°C): 18-24
- Humidity (%): 40-70
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 06 Sepmeber 2016 To: 05 December 2016

Route of administration:

oral: gavage

Details on route of administration:

This study should provide part of a rational basis for toxicological risk assessment in man. The oral route was selected as it is a possible route of human exposure during manufacture, handling or use of the test item.

Vehicle:

corn oil

Details on oral exposure:

- PREPARATION OF DOSING SOLUTIONS:
Adjustment was made for specific gravity of the vehicle. No correction was made for the purity/composition of the test item.
Formulations (w/w) were prepared daily within 6 hours prior to dosing and were homogenized to a visually acceptable level. The test item was heated up to a maximum of 39 ºC for a maximum of 23 minutes. In order to obtain homogeneity, the test item in vehicle was heated up to a maximum temperature of 42 ºC for a maximum of 35 minutes. The formulations were allowed to cool down to a temperature of maximally 40 ºC prior to dosing.

- VEHICLE
- Justification for use and choice of vehicle: based on trial formulations performed at Charles River Den Bosch
- Amount of vehicle (if gavage): 5 mL/kg bw
- Specific gravity: 0.92

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were conducted on a single occasion during the treatment phase according to a validated method. Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations).
The accuracy of preparation was considered acceptable if the mean measured concentrations were 90-110% of the target concentration. Homogeneity was demonstrated if the coefficient of variation was ≤ 10%.

Duration of treatment / exposure:

Males: 31 days, i.e. 2 weeks prior to mating, during mating, and up to the day prior to scheduled necropsy.
Females that delivered: 41-52 days, i.e. during 2 weeks prior to mating (with the objective of covering at least two complete estrous cycles), the variable time to conception, the duration of the pregnancy and at least 4 days after delivery up to and including the day before scheduled necropsy.
Two females that failed to deliver (low- and high-dose groups): 40 and 42 days, respectively

Frequency of treatment:

Once daily for 7 days per week, approximately the same time each day with a maximum of 6 hours difference between the earliest and latest dose.

Dose / conc.:

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

Remarks:

Concurrent vehicle controls (Group 1)

Dose / conc.:

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

Remarks:

Group 2

Dose / conc.:

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

Remarks:

Group 3

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

Remarks:

Group 4

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on results of a 10-day dose range finding study
- Section schedule rationale:
Males: Following completion of the mating period (a minimum of 28 days of dose administration).
Females that delivered: PND 5-7
Females that failed to deliver: Post-coitum Days 25 or 27 (females with evidence of mating).
Females with total litter loss: Two days after litter loss
One female euthanized in extremis: day 24 post-coitum

Positive control:

Not applicable

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least twice daily for mortality and viability

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once daily from start of treatment onwards up to the day prior to necropsy after dosing at no specific time point, but within a similar time period after dosing for the respective animals. Once prior to start of treatment and at weekly intervals during the treatment period this was also performed outside the home cage in a standard arena.

BODY WEIGHT: Yes
- Time schedule for examinations: prior to first dosing and weekly thereafter. Mated females were weighed on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum and during lactation on PND 1 and 4. In addition, for the females for which mating was overlooked one additional body weight measurement was performed.

FOOD CONSUMPTION AND COMPOUND INTAKE: yes
- Time schedule for examinations: Weekly, except for males and females which were housed together for mating and for females without evidence of mating. Food consumption of mated females was measured on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum and during lactation on PND 1 and 4.

FOOD EFFICIENCY: no

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Subjective appraisal was maintained during the study, but no quantitative investigation was introduced, as no treatment related effect was suspected.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the treatment period on the day of scheduled necropsy
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes, overnight for maximum 24 hours; water was available.
- How many animals: selected 5 animals/sex/group
- Parameters examined: WBC, differential leucocyte count (neutrophils, lymphocytes, monocytes, eosinophils, basophils), RBC, reticulocytes, RDW, haemoglobin, haematocrit, MCV, MCH, MCHC, platelets; PT, APTT

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at the end of the treatment period on the day of scheduled necropsy
- Animals fasted: Yes, overnight for maximum 24 hours; water was available.
- How many animals: selected 5 animals/sex/group
- Parameters examined: ALAT, ASAT, ALP, total protein, albumin, total bilirubin, bile acids, urea, creatinine, glucose, cholesterol, sodium, potassium , chloride, calcium, inorganic phosphate

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: selected males during week 4, selected females towards the end of the scheduled lactation period (from lactation Day 4 onwards)
- Dose groups that were examined: all dose levels, selected 5 animals/sex/group
- Battery of functions tested: sensory activity (hearing, pupillary reflex, static rightling reflex, fore- and hind limb grip strength, motor activity (total movements and ambulations)

IMMUNOLOGY: No


OTHER: for details on reproductive and developmental toxicity examinations see sections 7.8.1 and 7.8.2 (cross-references)

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, full post mortem necropsy, with special attention being paid to the reproductive organs.
The following organ weights were recorded:
Selected 5 animals/sex/group: adrenal glands, brain, epididymides, heart, kidneys, liver, ovaries, prostate, seminal vesicles including coagulating glands, spleen, testes, thymus, thyroid including parathyroid, uterus including cervix.
All other animals: epididymides, testes

HISTOPATHOLOGY: Yes
The following tissues were examined by histopathologist:

On selected 5 animals/sex/group from controls and high-dose group: adrenal glands, brain (cerebellum, mid brain, cortex (7-levels), caecum, cervix, clitoral gland, colon, coagulation gland, duodenum, epididymides, eyes with optic nerve, if detectable, and Harderian gland; female mammary gland area, femur including joint, heart, ileum, jejunum, kidneys, liver, lungs, lymph nodes (mandibular, mesenteric), ovaries, Peyers patches (jejunum, ileum) if detectable, pituitary gland, preputial gland, prostate gland, sciatic nerve, seminal vesicles, skeletal muscle, spinal cord (cervical, midthoracic, lumbar), spleen, sternum with bone marrow, stomach, testes, thymus, thyroid including parathyroid if detectable, trachea, urinary bladder, uterus, vagina, all gross lesions
On selected 5 males/group from controls and high dose group, and all males that failed to sire: additional testes slides
On the female euthanized in extremis: all preserved organs and tissues
On all males that failed to sire and all females that failed to deliver healthy pups: reproductive organs
On the female with total litter loss: mammary gland

Other examinations:

For examination of reproductive and developmental toxicity see Sections 7.8.1 and 7.8.2 (cross-references)

Statistics:

The following statistical methods were used to analyse the data:
• If the variables could be assumed to follow a normal distribution, the Dunnett-test (many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups for each sex.
• The Steel-test (many-to-one rank test) was applied if the data could not be assumed to follow a normal distribution.
• The Fisher Exact-test was applied to frequency data.
• The Kruskal-Wallis nonparametric ANOVA test was applied to motor activity data to determine intergroup differences.
All tests were two-sided and in all cases p < 0.05 was accepted as the lowest level of significance.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No clinical signs of toxicity were noted either during the daily observation for clinical signs or the weekly arena observations.
Salivation seen after dosing among animals of the 300 and 1000 mg/kg bw/day dose groups from the third week of treatment onwards was considered to be a physiological response rather than a sign of systemic toxicity considering the nature and minor severity of the effect and its time of occurrence (i.e. after dosing).
Incidental findings that were noted included rales, chromodacryorrhoea (snout), alopecia and scabbing, all at a slight degree. These findings occurred within the range of background findings to be expected for rats of this age and strain which are housed and treated under the conditions in this study. At the incidence observed, these were not considered to be signs of toxicological relevance.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

No mortality occurred during the study period that was considered to be related to treatment with the test item.
One female in the 300 mg/kg bw/day group had delivered one dead (male) fetus only. Due to this total litter loss she was euthanized two days thereafter. Histopathology of the reproductive organs of this female and the male she was mated with did not reveal any changes that could explain this total litter loss. As it was an isolated finding at the mid dose level, it was considered to be unrelated to treatment with the test item.
One control female was euthanized on Day 24 post-coitum due to complications during parturition. Signs of delivery were noted the day before. At necropsy, she had a pale appearance. In her uterus 14 dead fetuses (9 male and 5 female) were found next to reddish content. As far as their autolytic condition permitted external examination, no abnormalities were noted. The female showed marked hepatocellular necrosis in the liver (corresponding macroscopic finding: liver with many, reddish foci) which was considered to be related to the intrauterine dead of the fetuses and the cause of moribundity of this animal. Furthermore she had a gelatinous thymus (corresponding microscopic finding: marked lymphocytolysis). As this control female was treated with the vehicle alone a relation to treatment with the test item could be excluded.
All remaining animals survived until their scheduled necropsies.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Body weights and body weight gain of treated animals remained in the same range as controls over the treatment period.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Food consumption before or after allowance for body weight was similar between treated and control animals.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Haematological parameters of treated rats were not considered to be affected by treatment. The slightly, but statistically significantly, lower activated partial thromboplastin time (APPT) time recorded in males at 300 mg/kg bw/day was not considered to be test item-related as this change occurred in the absence of a treatment-related distribution and remained within the range considered normal for rats of this age and strain.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were no differences noted between control and treated rats that were considered to be test item-related.
The slightly, but statistically significantly, higher concentration of glucose and lower concentration of chloride recorded in females at 100 mg/kg bw/day and 300 mg/kg bw/day, respectively, was not considered to be test item-related as this change occurred in the absence of a treatment-related distribution and remained within the range considered normal for rats of this age and strain.

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

Hearing ability, pupillary reflex, static righting reflex and grip strength were normal in all selected animals.
The variation in motor activity did not indicate a relation with treatment. All groups showed a similar habituation profile with very high activity in the first interval that decreased over the duration of the test period.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

Organ weights and organ to body weight ratios of treated animals were unaffected by treatment with the test item.
The slightly, but statistically significantly, higher kidney weight (absolute and relative to body weight) recorded in females at 300 mg/kg bw/day was not considered to be test item-related as this change occurred in the absence of a treatment-related distribution and remained within the range considered normal for rats of this age and strain.

Gross pathological findings:

no effects observed

Description (incidence and severity):

Macroscopic observations at necropsy did not reveal any alterations that were considered to have arisen as a result of treatment.
The incidence of all findings among control and treated animals was within the background range of findings that are encountered among rats of this age and strain, and did not show a dose-related incidence trend. These necropsy findings were therefore not considered to be toxicologically relevant.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

There were no test item-related microscopic observations.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Details on results:

For details on reproductive and developmental toxicity examinations see sections 7.8.1 and 7.8.2 of this IUCLID (cross-references)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects at the highest tested dose of 1000 mg/kg bw/day

Key result

Critical effects observed:

no

Formulation analysis

The concentrations analysed in the formulations of Group 2, Group 3 and Group 4 were in agreement with target concentrations (i.e. mean accuracies 99%, 101% and 104%, respectively; n = 12 (4 samples at 105, 50% and 90% height of the vessel each), 4 (4 samples at 50% height of the vessel) and 12 ((4 samples at 105, 50% and 90% height of the vessel each), respectively.

The formulations of Group 2 and Group 4 were homogeneous (i.e. coefficient of variation 8.6%, 10% and 7.2% for low, mid- and high-dose groups, respectively).

Conclusions:

In a GLP-compliant OECD guideline 422 study, no adverse effects were observed at the highest tested dose of 1000 mg/kg bw/day, which was considered a NOAEL for general toxicity.

Executive summary:

In a GLP-compliant OECD guideline 422 study with rats, groups of 10 animals/sex/dose were treated by gavage with the test substance in corn oil at dose levels of 0 (concurrent vehicle controls), 100, 300 and 1000 mg/kg bw/day. No treatment-related toxicologically significant changes were noted in any of the parental parameters investigated in this study (i.e. viability/mortality, clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination). Based on this, the highest tested dose level of 1000 mg/kg bw/day was considered to be a NOAEL for general toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

1 (GLP-compliant guideline study)

System:

other: no adverse effects at the highest tested dose of 1000 mg/kg bw/day

Organ:

other: no adverse effects at the highest tested dose of 1000 mg/kg bw/day

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

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Mode of Action Analysis / Human Relevance Framework

No adverse toxicological effects were observed at the highest tested dose of 1000 mg/kg bw/day.

Additional information

In a GLP-compliant OECD guideline 422 study with rats, groups of 10 animals/sex/dose were treated by gavage with the test substance in corn oil at dose levels of 0 (concurrent vehicle controls), 100, 300 and 1000 mg/kg bw/day. No treatment-related toxicologically significant changes were noted in any of the parental parameters investigated in this study (i.e. viability/mortality, clinical appearance, functional observations, body weight, food consumption, clinical laboratory investigations, macroscopic examination, organ weights, and microscopic examination). Based on this, the highest tested dose level of 1000 mg/kg bw/day was considered to be a NOAEL for general toxicity.

Justification for classification or non-classification

Based on the lack of adverse effects at the highest tested dose of 1000 mg/kg bw/day, classification of oxacycloheptadecan-2-one for repeated dose toxicity is not warranted under Regulation (EC) 1272/2008.