Registration Dossier

Administrative data

Description of key information

The oral administration of 2-[2-(4-methylpentan-2-ylideneamino)ethoxy]ethanol to rats for a period of up to eight weeks (including two weeks pre-pairing, gestation and early lactation for females) at dose levels 100, 300 and 1000 mg/kg bw/day (reduced to 600 mg/kg bw/day on Day 24), resulted in the early termination of three females treated at the high dosage group and treatment related microscopic effects in animals of either sex treated with 1000/ 600 mg/kg bw/day. A No Observed Effect Level (NOEL) for systemic toxicity was considered to be 300 mg/kg bw/day for either sex.

The organ weight changes detected in the liver of males treated with 1000/600 mg/kg bw/day and the microscopic liver changes evident in these males were considered to be an adaptive response to treatment. Although the kidney findings of tubular basophilia (degenerating/ regenerating tubules) in male kidneys could be considered an adverse effect, this finding was considered to be associated with alpha 2u-globulin and formation of hyaline droplets, an effect recognized as being both species and sex specific and not relevant for humans. In terms of risk assessment, these findings observed on this study would suggest that a No Observed Adverse Effect Level (NOAEL) can be established at 1000/600 mg/kg bw/day for males because the findings do not reflect true systemic toxicity.

The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be 300 mg/kg bw/day based on slight decreased values observed at the high dose level for which statistical significance was not achieved and may have been the result of one female which performed particularly poorly during lactation.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records
Reference
Endpoint:
repeated dose toxicity: oral, other
Type of information:
experimental study
Adequacy of study:
key study
Study period:
The study was performed between 24 July 2015 and 08 April 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Version / remarks:
22 March 1996
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
no
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL- Source and lot/batch No.of test material: BBD02083V1ZK- Expiration date of the lot/batch: 07 September 2017STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL- Storage condition of test material: Room temperature, in the darkOTHER SPECIFICS:
Species:
rat
Strain:
other: Wistar Han™:RccHan™:WIST
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS- Source: Envigo RMS (UK) Limited, Blackthorn, Bicester, Oxon, UK- Females (if applicable) nulliparous and non-pregnant: [yes/no]- Age at study initiation: (P) 12 wks; - Weight at study initiation: (P) Males: 294-330 g; Females: 184-221 g; - Fasting period before study:- Housing: in groups of three in solid floor polypropylene cages with stainless steel mesh lids and softwood flake bedding (Datesand Ltd., Cheshire, UK).- Diet (e.g. ad libitum): ad libitum- Water (e.g. ad libitum): ad libitum- Acclimation period: 7 daysENVIRONMENTAL CONDITIONS- Temperature (°C): 22±3 ”C- Humidity (%): 50±20%- Air changes (per hr):- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
polyethylene glycol
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS: Prepared daily and dosed within 2 hours - Concentration in vehicle: 0, 25, 75, 250/150 mg/mL - Amount of vehicle (if gavage): 4 mL/kg - Lot/batch no. (if required): - Purity:y:
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The test item concentration in the test samples was determined by gas chromatography with external standardisation. The test item used in the main study was used as the analytical standard and gave a chromatographic profile consisting of a single peak.On receipt the formulations were diluted with tetrahydrofuran (THF). An aliquot of the test item formulation was accurately weighed into a volumetric flask and brought to volume with THF. Where necessary the sample solutions were further diluted with THF to achieve the working concentration. Instrumental details:GC System Agilent Technologies 5890, incorporating autosampler and workstationColumnDB-5 (30m x 0.25mm i.d. x 0.25µm film)Oven temperature40”C for 0 mins with 15”C/min increase to 320”C fo 8 mins.Injection temperature300”CFlame ionisation detector300”CInjection volume1µLRetention time ~6 minsLinearity0 - 0.18 mg/mLAccuracy±10%Test item formulations88 - 111% nominal
Duration of treatment / exposure:
up to 8 weeks (including 2 weeks pre-pairing, gestation (22-23.5 days) and early lactation (Day 4 post partum)
Frequency of treatment:
Once daily
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
300 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
Remarks:
Reduced to 600 mg/kg bw/day from Day 24
No. of animals per sex per dose:
12
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The dose levels were chosen based on the results of previous toxicity work (Envigo Research Limited Study Number 41501074). - Rationale for animal assignment (if not random): - Other:
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes - Time schedule: before dosing, soon after dosing, and one hour after dosing (except for femalesduring parturition where applicable) - Cage side observations included overt signs of toxicity, ill-health and behavioral change DETAILED CLINICAL OBSERVATIONS: Yes - Time schedule: Hematological and blood chemical investigations were performed on five males and five females selected from each test and control group prior to termination (Day 42 for males and Day 4 post partum for females) BODY WEIGHT: Yes - Time schedule for examinations: Individual body weights were recorded on Day 1 (prior to dosing) and then weekly for males until termination and weekly for females until pairing. During pairing phase females were weighed daily until mating was confirmed. Body weights were then recorded for females on Days 0, 7, 14 and 20 post coitum, and on Days 1 and 4 post partum. Body weights were also recorded at terminal kill. FOOD CONSUMPTION During the pre-pairing period, weekly food consumption was recorded for each cage of adults. This was continued for males after the mating phase. For females showing evidence of mating, food consumption was recorded for the periods covering post coitum Days 0-7, 7-14 and 14-20. For females with live litters, food consumption was recorded on Days 1 and 4 post partum.
Sacrifice and pathology:
SACRIFICE - Male animals: All surviving animals on Day 43/44 - Maternal animals: All surviving animals on Day 5 post partum GROSS NECROPSY - Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera HISTOPATHOLOGY / ORGAN WEIGHTS The tissues indicated belowfrom 5 selected males and 5 selected females form each does group, were prepared for microscopic examination and weighed, respectively: Adrenals Pituitary (post-fixation)Brain Prostate and Seminal VesiclesEpididymides SpleenHeart TestesKidneysThymusLiver Thyroid (weighed post-fixation with Parathyroid)Ovaries Uterus (weighed with Cervix)
Statistics:
See Below
Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Animals of both sexes treated with 1000/600 mg/kg bw/day showed incidences of increased salivation from Day 4 until termination. Increased salivation was also evident, to a lesser extent, in animals of either sex treated with 300 mg/kg bw/day from Day 23 (females) and Day 29 (males) until termination. Episodes of noisy respiration were evident in all males and four terminal kill females treated with 1000/600 mg/kg bw/day between Days 1-25 (males) and Day 3-28 (females) and in one female treated with 300 mg/kg bw/day on Day 23 only. An isolated incident of pilo-erection and a stained snout were also evident in one female treated with 1000/600 mg/kg bw/day on Day 16 and stained fur was also evident in one male treated with 300 mg/kg bw/day on Day 13 only.The females from the 1000/600 mg/kg bw/day dose group that were killed in extremis showed respiratory pattern changes, increased salivation and/or hunched posture, tiptoe gait and ptosis.No such effects were evident in animals of either sex treated with 100 mg/kg bw/day.One control male showed an isolated incident of noisy respiration on Day 15 only. This was considered to be an incidental finding.
Mortality:
mortality observed, treatment-related
Description (incidence):
Two females treated with 1000 mg/kg bw/day were killed in extremis due to clinical signs of toxicity on Days 22 and 23. Following the reduction of the high dose level to 600 mg/kg bw/day from Day 24, a further female from this dose group was killed in extremis on Day 25. Female 85 had agonal congestion in the liver which correlated with the dark discolouration at necropsy. Centrilobular necrosis was also present but due to the lack of any reactive response to this it was considered to be agonal and associated with the congestion. There was inflammatory cell infiltration in the peribronchial area of the lungs which may have contributed to the clinical signs noted although it was only a mild change. There were no other notable findings in the animal. Female 90 had minimal atrophy in the liver (inactive, shrunken cells) and reduced cellularity in the bone marrow. There was inflammatory cell infiltration in the peribronchial area of the lungs and in the trachea, both mild although these may have contributed to the clinical signs. Female 92 had mild atrophy in the liver (mainly periportal) with minimal centriolobular hypertrophy in a few lobules. Inflammatory changes, again mild were present in the lungs. There was increased fat (decreased cellularity) in the bone marrow.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
There were no treatment-related effects detected in body weight development for males treated with 100, 300 or 1000/600 mg/kg bw/day.There were no treatment-related effects detected in body weight development for females treated with 100, 300 or 1000/600 mg/kg bw/day during maturation, gestation or lactation.Statistical analysis of the data did not reveal any significant intergroup differences.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
There were no treatment-related effects detected in food consumption for males treated with 100, 300 or 1000/600 mg/kg bw/day.There were no treatment-related effects detected in food consumption for females treated with 100, 300 or 1000/600 mg/kg bw/day during maturation, gestation or lactation.
Food efficiency:
no effects observed
Description (incidence and severity):
There were no treatment-related effects detected in food efficiency for males treated with 100, 300 or 1000/600 mg/kg bw/day.There were no treatment-related effects detected in food efficiency for females treated with 100, 300 or 1000/600 mg/kg bw/day during maturation, gestation orlactation.
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
Females treated with 1000/600 mg/kg bw/day showed statistically significant reductions in hemoglobin, erythrocyte count and hematocrit. All of the individual values were within historical control ranges, however microscopic examination of the spleen revealed changes which were associated with these intergroup differences. Therefore a relationship to treatment cannot be excluded.Females treated with 300 mg/kg bw/day also showed statistically significant reductions in hemoglobin, erythrocyte count and hematocrit, with the effect on hematocrit also extending to females treated with 100 mg/kg bw/day. All of the individual values were within historical control ranges and in the absence of any associated microscopic changes in the spleen, the intergroup differences were considered not to be of toxicological significance.No such effects were detected in males treated with 1000/600, 300 or 100 mg/kg bw/day.
Clinical biochemistry findings:
no effects observed
Description (incidence and severity):
There were no treatment-related effects detected in the blood chemical parameters examined.
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Description (incidence and severity):
Behavioral AssessmentsThere were no treatment-related changes in the behavioral parameters at 100, 300 or 1000/600 mg/kg bw/day.Noisy respiration was evident in four males treated with 1000/600 mg/kg bw/day during Week 1, one male treated with 1000/600 mg/kg bw/day during Week 2 and one male and one female treated with 1000/600 mg/kg bw/day during Week 3 assessments. This correlated with the clinical signs evident in this dose group.Functional Performance TestsThere were no treatment related changes in functional performance considered to be related to treatment at 100, 300 or 1000/600 mg/kg bw/day.Statistical analysis of the data did not reveal any significant intergroup differences.Sensory Reactivity AssessmentsThere were no inter-group differences in sensory reactivity scores that were considered to be related to treatment at 100, 300 or 1000/600 mg/kg bw/day.
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Males treated with 1000/600 mg/kg bw/day showed a statistically significant increase in kidney and liver weight both absolute and relative to terminal body weight.No such effects were detected in females treated with 1000/600 mg/kg bw/day or in animals of either sex treated with 300 or 100 mg/kg bw/day.
Gross pathological findings:
no effects observed
Description (incidence and severity):
The females that were killed in extremis had gaseous distension in the gastrointestinal tract. Two of these females had gaseous distension in the stomach and one also had a dark liver whilst the other also had reddened lungs.No toxicologically significant macroscopic effects were detected in terminal kill animals.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
The following treatment related microscopic abnormalities were detected:Kidneys: An increase in hyaline droplets was evident in four males treated with 1000/600 mg/kg bw/day, associated with multifocal mild tubular basophilia (degenerating/regenerating tubules) in two males. An increase in hyaline droplets was present in two males treated with 300 mg/kg bw/day without any other associated pathology.Liver: Centrilobular hepatocellular hypertrophy was evident in two males treated with 1000/600 mg/kg bw/day only.Lungs: A minor increase in the amount of inflammatory change was evident in the lungs of high dose males, however once all males were examined it was likely that individual variation rather than a treatment related effect was seen.Spleen: Increased hematopoiesis was evident in females treated with 1000/600 mg/kg bw/day when compared to controls with two females above control limits.The premature decedent females did not have any major pathological changes which could be specifically attributed as the cause of death. All three had minor changes in the lungs which may have contributed to the clinical signs noted. The etiology of these is not clear but reflux or accidental inhalation of the test item maybe a possibility. There were also minor changes in the liver of all three and in animal 90 there was reduced cellularity in the bone marrow.
Histopathological findings: neoplastic:
no effects observed
Other effects:
no effects observed
Details on results:
MatingNo treatment-related effects were detected in mating performance.FertilityNo treatment-related effects were detected in fertility.Gestation LengthsGestation lengths were between 22 and 23½ days and the distribution of gestation lengths for treated females was essentially similar to control.Litter ResponsesOffspring Litter Size, Sex Ratio and ViabilityNo significant differences were detected for corpora lutea, implantation counts or pre andpost implantation losses for treated animals when compared to controls. Of the litters born, litter size at birth and on Days 1 and 4 post partum was comparable to controls. Sex ratio and viability was also unaffected by treatment.
Key result
Dose descriptor:
NOEL
Effect level:
300 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
Key result
Dose descriptor:
NOAEL
Effect level:
> 600 - < 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
organ weights and organ / body weight ratios
Key result
Dose descriptor:
NOEL
Effect level:
300 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: reproductive performance
Key result
Critical effects observed:
no
Lowest effective dose / conc.:
1 000 mg/kg bw/day (nominal)
System:
hepatobiliary
Organ:
liver
Treatment related:
yes
Dose response relationship:
no
Relevant for humans:
no
Key result
Critical effects observed:
no
Lowest effective dose / conc.:
1 000 mg/kg bw/day (nominal)
System:
urinary
Organ:
kidney
Treatment related:
yes
Dose response relationship:
no
Relevant for humans:
no

The oral administration of 2-[2-(4-methylpentan-2-ylideneamino)ethoxy]ethanol to rats for a period of up to eight weeks (including two weeks pre-pairing, gestation and early lactation for females) at dose levels 100, 300 and 1000 mg/kg bw/day (reduced to 600 mg/kg bw/day on Day 24), resulted in the early termination of three females treated at the high dosage group and treatment related microscopic effects in animals of either sex treated with 1000/ 600 mg/kg bw/day. A No Observed Effect Level (NOEL) for systemic toxicity was considered to be 300 mg/kg bw/day for either sex.

The organ weight changes detected in the liver of males treated with 1000/600 mg/kg bw/day and the microscopic liver changes evident in these males were considered to be an adaptive response to treatment. Although the kidney findings of tubular basophilia (degenerating/ regenerating tubules) in male kidneys could be considered an adverse effect, this finding was considered to be associated with alpha 2u-globulin and formation of hyaline droplets, an effect recognized as being both species and sex specific and not relevant for humans. In terms of risk assessment, these findings observed on this study would suggest that a No Observed Adverse Effect Level (NOAEL) can be established at 1000/600 mg/kg bw/day for males because the findings do not reflect true systemic toxicity.

The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be 300 mg/kg bw/day based on slight decreased values observed at the high dose level for which statistical significance was not achieved and may have been the result of one female which performed particularly poorly during lactation.

Conclusions:
The oral administration of 2-[2-(4-methylpentan-2-ylideneamino)ethoxy]ethanol to rats for a period of up to eight weeks (including two weeks pre-pairing, gestation and early lactation for females) at dose levels 100, 300 and 1000 mg/kg bw/day (reduced to 600 mg/kg bw/day on Day 24), resulted in the early termination of three females treated at the high dosage group and treatment related microscopic effects in animals of either sex treated with 1000/600 mg/kg bw/day. A No Observed Effect Level (NOEL) for systemic toxicity was considered to be 300 mg/kg bw/day for either sex.The organ weight changes detected in the liver of males treated with 1000/600 mg/kg bw/day and the microscopic liver changes evident in these males were considered to be an adaptive response to treatment. Although the kidney findings of tubular basophilia (degenerating/regenerating tubules) in male kidneys could be considered an adverse effect, this finding was considered to be associated with alpha 2u-globulin and formation of hyaline droplets, an effect recognized as being both species and sex specific and not relevant for humans. In terms of risk assessment, these findings observed on this study would suggest that a No Observed Adverse Effect Level (NOAEL) can be established at 1000/600 mg/kg bw/day for males because the findings do not reflect true systemic toxicity.The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be 300 mg/kg bw/day based on slight decreased values observed at the high dose level for which statistical significance was not achieved and may have been the result of one female which performed particularly poorly during lactation.
Executive summary:

The study was designed to investigate the systemic toxicity and potential adverse effects of the test item on reproduction (including offspring development) and is designed to be compatible with the requirements of the OECD Guidelines for Testing of Chemicals No. 422 “Combined Repeated Dose Toxicity Study with the Reproduction/ Developmental Toxicity Screening Test” (adopted 22 March 1996). This study was also designed to be compatible with Commission Regulation (EC) No 440/2008 of 30 May 2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).

Methods

The test item was administered by gavage to three groups, each of twelve male and twelve female Wistar Han™:RccHan™:WIST strain rats, for up to eight weeks (including a two week pre-pairing phase, pairing, gestation and early lactation for females), at dose levels of 100, 300 and 1000 mg/kg bw/day (reduced to 600 mg/kg bw/day from Day 24 onwards). A control group of twelve males and twelve females was dosed with vehicle alone (Polyethylene glycol 400).

Clinical signs, behavioral assessments, body weight change and food and water consumption were monitored during the study.

Pairing of animals within each dose group was undertaken on a one male: one female basis within each treatment group on Day 15 of the study, with females subsequently being allowed to litter and rear their offspring to Day 5 of lactation.

During the lactation phase, daily clinical observations were performed on all surviving offspring, together with litter size and offspring weights and assessment of surface righting reflex.

Extensive functional observations were performed on five selected males from each dose group after the completion of the pairing phase, and for five selected parental females from each dose group on Day 4 post partum. Hematology and blood chemistry were evaluated prior to termination on five selected males and females from each dose group.

Adult males were terminated on Day 43 or 44, followed by the termination of all surviving females and offspring on Day 5 post partum. Any female which did not produce a pregnancy was terminated on or after Day 25 post coitum. All animals were subjected to a gross necropsy examination and histopathological evaluation of selected tissues was performed.

Results

Adult Responses

Mortality

Two females treated with 1000 mg/kg bw/day were killed in extremis due to excessive clinical signs of toxicity on Days 22 and 23. Following the reduction of the high dose level to 600 mg/kg bw/day on Day 24, a further female from this dose group was killed in extremis on Day 25. There were no further unscheduled deaths.

Clinical Observations

Animals of either sex treated with 1000/600 mg/kg bw/day showed incidences of increased salivation from Day 4 until termination. Increased salivation was also evident, to a lesser extent, in animals of either sex treated with 300 mg/kg bw/day. Episodes of noisy respiration were evident in all males and four surviving females treated with 1000/600 mg/kg bw/day and in one female treated with 300 mg/kg bw/day. An isolated incident of pilo-erection and a stained snout was also evident in one female treated with 1000/600 mg/kg bw/day and on one occasion, stained fur was also evident in one male treated with 300 mg/kg bw/day. The females that were killed in extremis showed respiratory pattern changes, increased salivation and/or hunched posture, tiptoe gait and ptosis. No clinical signs were evident in animals of either sex treated with 100 mg/kg bw/day.

Behavioral Assessment

There were no treatment-related changes in the behavioral parameters at 100, 300 or 1000/600 mg/kg bw/day.

Functional Performance Tests

There were no treatment related changes in functional performance considered to be related to treatment at 100, 300 or 1000/600 mg/kg bw/day.

Sensory Reactivity Assessments

There were no inter-group differences in sensory reactivity scores that were considered to be related to treatment at 100, 300 or 1000/600 mg/kg bw/day.

Body Weight

There were no treatment-related effects detected in body weight development for males treated with 100, 300 or 1000/600 mg/kg bw/day.

There were no treatment-related effects detected in body weight development for females treated with 100, 300 or 1000/600 mg/kg bw/day during maturation, gestation or lactation.

Food Consumption

There were no treatment-related effects detected in food consumption for males treated with 100, 300 or 1000/600 mg/kg bw/day. There were no treatment-related effects detected in food consumption for females treated with 100, 300 or 1000/600 mg/kg bw/day during maturation, gestation or lactation.

Water Consumption

There were no treatment related effects detected in water consumption.

Reproductive Performance Mating

No treatment-related effects were detected in mating performance.

Fertility

No treatment-related effects were detected in fertility.

Gestation Lengths

Gestation lengths were between 22 and 23½ days and the distribution of gestation lengths for treated females was essentially similar to control.

Litter Responses

Offspring Litter Size, Sex Ratio and Viability

No significant differences were detected for corpora lutea, implantation counts or pre and post implantation losses for treated animals when compared to controls. Of the litters born, litter size at birth and on Days 1 and 4 post partum was comparable to controls. Sex ratio and viability was also unaffected by treatment.

Offspring Growth and Development

Female offspring body weights on Days 1 and 4 post partum were comparable to control litters however male offspring body weights on Day 4 post partum in litters from females treated with 1000/600 mg/kg bw/day were slightly reduced when compared to controls. Consequently male offspring body weight gain between Days 1 and 4 post partum and litter weight on Day 4 was slightly reduced at this dose level. A reduction in surface righting reflex was also evident in offspring in litters from females treated with 1000/600 mg/kg bw/day. Statistical significance was not achieved however, and the reductions in male weight, litter weight and surface righting may have been the result of one female which performed particularly poorly during lactation. Sex ratio for all treated litters was comparable to controls. No such effects were detected in litters from females treated with 100 or 300 mg/kg bw/day.

Laboratory Investigations

Hematology

Females treated with 1000/600 mg/kg bw/day showed statistically significant reductions in hemoglobin, erythrocytes and hematocrit. No toxicologically significant effects were detected in males treated with 1000/600 mg/kg bw/day or in animals of either sex treated with 300 or 100 mg/kg bw/day.

Blood Chemistry

There were no treatment-related effects detected in the blood chemical parameters examined.

Pathology

Necropsy

The females that were killed in extremis had gaseous distension in the gastrointestinal tract. Two of these females had gaseous distension in the stomach and one also had a dark liver whilst the other also had reddened lungs.

No toxicologically significant macroscopic effects were detected in terminal kill animals.

Organ Weights

Males treated with 1000/600 mg/kg bw/day showed a statistically significant increase in kidney and liver weight both absolute and relative to terminal body weight. No such effects were detected in females treated with 1000/600 mg/kg bw/day or in animals of either sex treated with 300 or 100 mg/kg bw/day.

Histopathology

The following treatment related microscopic abnormalities were detected:

Kidneys: An increase in hyaline droplets was evident in four males treated with 1000/ 600 mg/kg bw/day, associated with multifocal mild tubular basophilia (degenerating/ regenerating tubules) in two males. An increase in hyaline droplets was present in two males treated with 300 mg/kg bw/day without any other associated pathology.

Liver: Centrilobular hepatocellular hypertrophy was evident in two males treated with 1000/600 mg/kg bw/day only.

Lungs: A minor increase in the amount of inflammatory change was evident in the lungs of high dose males, however once all males were examined it was likely that individual variation rather than a treatment related effect was seen.

Spleen: Increased hematopoiesis was evident in females treated with 1000/600 mg/kg bw/day when compared to controls with two females above control limits.

The premature decedent females did not have any major pathological changes which could be specifically attributed as the cause of death. All three had minor changes in the lungs which may have contributed to the clinical signs noted. The etiology of these is not clear but reflux or accidental inhalation of the test item maybe a possibility. There were also minor changes in the liver of all three and in animal 90 there was reduced cellularity in the bone marrow.

Conclusion

The oral administration of 2-[2-(4-methylpentan-2-ylideneamino)ethoxy]ethanol to rats for a period of up to eight weeks (including two weeks pre-pairing, gestation and early lactation for females) at dose levels 100, 300 and 1000 mg/kg bw/day (reduced to 600 mg/kg bw/day on Day 24), resulted in the early termination of three females treated at the high dosage group and treatment related microscopic effects in animals of either sex treated with 1000/ 600 mg/kg bw/day. A No Observed Effect Level (NOEL) for systemic toxicity was considered to be 300 mg/kg bw/day for either sex.

The organ weight changes detected in the liver of males treated with 1000/600 mg/kg bw/day and the microscopic liver changes evident in these males were considered to be an adaptive response to treatment. Although the kidney findings of tubular basophilia (degenerating/ regenerating tubules) in male kidneys could be considered an adverse effect, this finding was considered to be associated with alpha 2u-globulin and formation of hyaline droplets, an effect recognized as being both species and sex specific and not relevant for humans. In terms of risk assessment, these findings observed on this study would suggest that a No Observed Adverse Effect Level (NOAEL) can be established at 1000/600 mg/kg bw/day for males because the findings do not reflect true systemic toxicity.

The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be 300 mg/kg bw/day based on slight decreased values observed at the high dose level for which statistical significance was not achieved and may have been the result of one female which performed particularly poorly during lactation.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
300 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
Study Klimisch 1 (GLP Guideline study).
Organ:
kidney
other: Although the kidney findings of tubular basophilia (degenerating/ regenerating tubules) in male kidneys could be considered an adverse effect, an effect recognized as being both species and sex specific and not relevant for humans.

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

Additional information

Justification for classification or non-classification

Based on the above mentioned results the substance does not need to be classified according to CLP regulation (Regulation EC No. 1272/2008) and DSD (Directive 67/548/EEC).