Phenethyl phenylacetate

Endpoint summary

Description of key information

Repeated Dose Oral Toxicity:

Repeated dose oral study for test chemical was assessed for its possible toxic potential. Groups of 10 male and 10 female Osbourne-Mendel rats were provided test chemical mixed in the diet at concentrations of 0, 1000, 2500 or 10,000 ppm which corresponding to an average daily intakes of 0, 50, 250, or 500 mg/kg bw per for 17 weeks. At termination, hematological examinations revealed no effects due to administration of the test chemical. At necropsy, no differences were reported in major organ weights between test and control animals. Gross examination of tissue of all animals was unremarkable and histopathological examination of six-eight animals, equally represented by gender, for the high-dose group and the control group revealed no treatment-related lesions. Hence, the highest dose tested i.e 500 mg/kg/day can be considered as the NOAEL.

Repeated dose toxicity: Inhalation

The short term toxicity study need not be conducted because exposure to humans via inhalation route is not likely taking into account due to the low vapour pressure of the test chemical. The experimental vapour pressure was 0.0248Pa at 20 deg C. Also, the LC50 was considered to be >5500 mg/m³, when rats were exposed to the test chemical by inhalation route for 4 hours. Thus, exposure to inhalable dust, mist and vapour of the chemical is highly unlikely. Therefore, this study is considered for waiver

Repeated dose toxicity: dermal

A short-term repeated dose dermal toxicity study need not be conducted because exposure of humans via dermal route in production and/or in use is highly unlikely based on the thorough and rigorous risk assessment provided. Also, the acute dermal toxicity LD50 value for the test chemical (as provided in section 7.2.3) is >2000 mg/kg body weight. The test chemical was also found to be not sensitizing to the skin. Considering this, the end point for repeated dermal toxicity is considered as waiver.     

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

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 publication.

Qualifier:

according to guideline

Guideline:

other: As mention below

Principles of method if other than guideline:

To evaluate the toxic potential of test chemical in male and female rats by oral feed for 17 weeks.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Osborne-Mendel

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Housing: The animals were housed individually in wire cages
- Diet (e.g. ad libitum): Rodent diet ad libitum
- Water (e.g. ad libitum): water ad libitum

Route of administration:

oral: feed

Vehicle:

other: Rodent diet

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency):The test chemical was fed in the diet and fresh diets were made and distributed weekly.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Not specified.

Duration of treatment / exposure:

17 weeks

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
1000, 2500 and 10000 ppm, corresponding to an average daily intake of 0, 50, 250 or 500 mg/kg bw
Basis:
no data

No. of animals per sex per dose:

Total number of animals 80
0 mg/kg/day-10 male and 10 female
50 mg/kg/day-10 male and 10 female
250 mg/kg/day-10 male and 10 female
500 mg/kg/day-10 male and 10 female

Control animals:

yes, plain diet

Details on study design:

no data available

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

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: Not specified

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Not specified
- Time schedule for examinations:

OPHTHALMOSCOPIC EXAMINATION: Not specified
- Time schedule for examinations:
- Dose groups that were examined:

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Haematological examinations were made at termination of the subacute studies
- Parameters checked in table [No.?] were examined. These examinations included white cell counts, red cell counts, haemoglobins and haematocrits

CLINICAL CHEMISTRY: Not specified

URINALYSIS: Not specified

NEUROBEHAVIOURAL EXAMINATION: Not specified

IMMUNOLOGY: Not specified


OTHER: The viscera were removed and the liver, kidneys, spleen, heart, and testes were weighed.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes , At the termination of the experiments the rats were sacrificed and exsanguinated.

HISTOPATHOLOGY: Yes , The tissues of all the rats were examined macroscopically at the time of sacrifice. These organs, the remaining abdominal and
thoracic viscera, and one hind leg, for bone, bone marrow, and muscle, were preserved in 10 % buffered formalin-saline solution for histopathological
examination. For routine histopathology, sections were embedded in paraffin wax and stained with haematoxylin and eosin.

Other examinations:

Tissues from rats dying during the experiment were examined for gross changes and were preserved if autolysis was not advanced. Organs were not weighed but abnormalities and the suspected reason for death were noted

Statistics:

Not specified

Clinical signs:

no effects observed

Description (incidence and severity):

No significant effect were observed at doses 0, 50, 250 or 500 mg/kg bw in treated group compare to control.

Mortality:

no mortality observed

Description (incidence):

No mortality were observed at doses 0, 50, 250 or 500 mg/kg bw in treated group compare to control.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Weekly measurement of body weight showed no significant difference between test and control animals.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Weekly measurement of food intake showed no significant difference between test and control animals.

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Description (incidence and severity):

At termination, haematological examination revealed no effects due to treatment. No significant effect were observed at doses 0, 50, 250 or 500 mg/kg bw in treated group compare to control.

Clinical biochemistry findings:

not specified

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):

At necropsy, no difference between test and control animals in the weights of major organs was reported.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No significant effect were observed at doses 0, 50, 250 or 500 mg/kg bw in treated group compare to control.

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

Gross examination of tissues from all animals revealed no remarkable changes, and histological examination of three to four animals of each sex at the high dose and from the control group revealed no treatment-related lesions.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

food consumption and compound intake

gross pathology

haematology

histopathology: non-neoplastic

mortality

Critical effects observed:

no

Conclusions:

At termination, hematological examinations revealed no effects due to administration of the test chemical. At necropsy, no differences were reported in major organ weights between test and control animals. Gross examination of tissue of all animals was unremarkable and histopathological examination of six-eight animals, equally represented by gender, for the high-dose group and the control group revealed no treatment-related lesions. Hence, the highest dose tested i.e 500 mg/kg/day can be considered as the NOAEL.

Executive summary:

Repeated dose oral study for test chemical was assessed for its possible toxic potential. Groups of 10 male and 10 female Osbourne-Mendel rats were provided test chemical mixed in the diet at concentrations of 0, 1000, 2500 or 10,000 ppm which corresponding to an average daily intakes of 0, 50, 250, or 500 mg/kg bw per for 17 weeks. The animal’s weight, food intake and general condition were recorded every week. Haematological examinations were made at termination of the subacute studies. These examinations included white cell counts, red cell counts, haemoglobins and haematocrits. At the termination of the experiments the rats were sacrificed and exsanguinated. The tissues of all the rats were examined macroscopically at the time of sacrifice. The viscera were removed and the liver, kidneys, spleen, heart, and testes were weighed. These organs, the remaining abdominal and thoracic viscera, and one hind leg, for bone, bone marrow, and muscle, were preserved in 10% buffered formalin-saline solution for histopathological examination. For routine histopathology, sections were embedded in paraffin wax and stained with haematoxylin and eosin. Measurement of body weight and food intake recorded weekly showed no significant difference between test and control animals at any intake level. At termination, hematological examinations revealed no effects due to administration of the test chemical. At necropsy, no differences were reported in major organ weights between test and control animals. Gross examination of tissue of all animals was unremarkable and histopathological examination of six-eight animals, equally represented by gender, for the high-dose group and the control group revealed no treatment-related lesions. Hence, the highest dose tested i.e 500 mg/kg/day can be considered as the NOAEL.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

500 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Data waiving:

exposure considerations

Justification for data waiving:

a short-term toxicity study does not need to be conducted because exposure of humans via inhalation in production and/or use is not likely as based on the provided thorough and rigorous exposure assessment

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

exposure considerations

Justification for data waiving:

a short-term toxicity study does not need to be conducted because exposure of humans via the dermal route in production and/or use is not likely as based on the provided thorough and rigorous exposure assessment

Critical effects observed:

not specified

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated Dose Oral Toxicity:

Various studies have been reviewed to determine the toxic effect of the test chemical when exposed repeatedly via oral route. These include in vivo experimental studies performed on rats for the test chemical. The results are mentioned below:

 

Repeated dose oral study for test chemical was assessed for its possible toxic potential. Groups of 10 male and 10 female Osbourne-Mendel rats were provided test chemical mixed in the diet at concentrations of 0, 1000, 2500 or 10,000 ppm which corresponding to an average daily intakes of 0, 50, 250, or 500 mg/kg bw per for 17 weeks. The animal’s weight, food intake and general condition were recorded every week. Haematological examinations were made at termination of the subacute studies. These examinations included white cell counts, red cell counts, haemoglobins and haematocrits. At the termination of the experiments the rats were sacrificed and exsanguinated. The tissues of all the rats were examined macroscopically at the time of sacrifice. The viscera were removed and the liver, kidneys, spleen, heart, and testes were weighed. These organs, the remaining abdominal and thoracic viscera, and one hind leg, for bone, bone marrow, and muscle, were preserved in 10% buffered formalin-saline solution for histopathological examination. For routine histopathology, sections were embedded in paraffin wax and stained with haematoxylin and eosin. Measurement of body weight and food intake recorded weekly showed no significant difference between test and control animals at any intake level. At termination, hematological examinations revealed no effects due to administration of the test chemical. At necropsy, no differences were reported in major organ weights between test and control animals. Gross examination of tissue of all animals was unremarkable and histopathological examination of six-eight animals, equally represented by gender, for the high-dose group and the control group revealed no treatment-related lesions. Hence, the highest dose tested i.e 500 mg/kg/day can be considered as the NOAEL.

 

This result is supported by a Combined repeated dose repro-developmental toxicity study performed to provide evaluations of general and reproduction/ developmental toxicity endpoints associated with administration of repeated doses of test substance in Wistar rats. The animals were randomly allocated to the four main groups (13/sex/group) and two recovery groups (5/sex/group). The doses selected for main groups were; 0 (G1-control),308 mg/kg body weight (G2), 556 mg/kg body weight (G3) and 1000 mg/kg body weight (G4) daily for 64 days. The recovery groups G1-R and G4-R were dosed with similar doses of respective main groups. Vehicle corn oil to G1 and G1-R and test item to G2, G3, G4 and G4-R animals were administered by oral gavage route each day during the dosing period. No mortality and morbidity were observed any of the groups of animals throughout the study period. Animals of all dose groups were observed for Clinical signs/ symptoms daily once during the experimental period. No apparent treatment related clinical signs were observed in any of the animals throughout the treatment and recovery period. All hematological and clinical chemistry parameters in animals of different treated groups of both the sexes were comparable to their respective control groups. No treatment related changes were observed in any of the treatment groups.  At the end of treatment and recovery period, absolute and relative weight of organs of treated group rats of either sex did not differ significantly when compared to the respective control group rats. External and visceral examination of all male and female rats of control and all treated groups including recovery groups did not reveal any abnormality of pathological significance. Terminally sacrificed pups of all treated groups did not reveal any lesion of pathological significance in any of the group when compared with control group. Pups that died among the control and treated groups during the course of study, revealed various lesions when examined externally and internally but the observations were not considered treatment related. From the patho-morphological results presented, it was concluded that, the treatment of test chemical at 308, 556 and 1000 mg/kg body weight in male and female rats did not affect adversely and no alteration of pathological significance was observed in any of the organs and reproductive organs of high dose treated group rats are well comparable with respective control group rats and exhibited no dose relationship. Further these observed lesions are common in occurrence in rodents during toxicological studies. Hence, occurrence of these lesions could be considered as spontaneous or incidental in nature and not to be attributed to the administration of the test chemical. Based on the findings of Repeated Dose Oral Toxicity Study in combination with Reproduction/ Developmental Toxicity of test chemical in Wistar Rats with 14 days recovery, where in 0, 308, 556 and 1000 mg/kg body weight, doses were tested; no test item related changes were observed at any of the dose level, hence the general No Observed Adverse Effect Level (NOAEL) of test chemical was considered to be more than 1000 mg / kg body weight.

 

These results are further supported by a Repeated Dose 28-day Oral Toxicity study designed and conducted to determine the toxicity profile of the test chemical when administered daily for 28 days to the Sprague Dawley rats. The study was performed according to OECD 407 Guidelines.A total of 48 animals (24 males + 24 females) were selected and randomly distributed into four groups with 6 animals/sex/group and 3/sex/cage. The test chemical was administered to animals at the dose levels of 250 mg/kg,500 mg/kg and 1000 mg/kg body weight. The control animals were administered with corn oil only. Rats were observed daily for Viability, Behavior, Alterations, Vocalizations, Respiration and Palpebral closure. The rats were observed for reaction to removal, reaction to handling, urination, defecation, prominence of eye, lacrimation, salivation, piloerection, examination of mucous membrane, examination of skin / fur, examination of natural orifices and animal appearance. The animals were also placed in the open field and its appearance and behavior were observed. The quantity of feed consumed by control and different treatment groups was recorded weekly until scheduled sacrifice. All the rats survived through the dosing period of 28 days and were sacrificed and gross lesions were noted. The rats were sacrificed by CO2 asphyxiation and Gross necropsy was conducted. All the animals of 0 mg/kg, 250 mg/kg, 500 mg/kg and 1000 mg/kg/bw/day group were sacrificed and gross lesions were noted. Liver, Kidneys, Adrenals, Epididymides, Prostate + Seminal Vesicle with Coagulation gland as whole, Thymus, Spleen, Brain, Heart, Lungs, Uterus, Testes/Ovaries were dissected free of fat and weighed. The paired organs were weighed together.Following tissue samples of organs from control and animals treated at different dose groups were preserved and those from control and treated at the highest dose level of 1000 mg/kg were subjected to histopathological examination.Adrenals, Aorta, Brain (cerebrum, cerebellum and pons), Caecum, Cervix, Colon, Duodenum, Epididymides, Eyes, Heart, Ileum, Jejunum, Kidneys, Liver, Lungs, Mesenteric Lymphnodes, Oesophagus, Ovaries, Pancreas, Pituitary gland, Pharyngeal Lymphnodes, Prostate, Rectum, Skeletal Muscles, Skin with Mammary Gland, Spleen, Sternum with bone marrow, Sciatic Nerve, Spinal Cord (Cervical, mid thoracic and lumbar), Stomach, Seminal Vesicles with Coagulation Gland, Testes, Thymus, Thyroid, Trachea, Vagina, Urinary Bladder, Uterus.  All the male and female animals from control and all the treateddose groups up to 1000 mg/kg survived throughout the dosing period of 28 daysMale and female animals from control and all the treated dose groups exhibited normal body weight gain at the end of the dosing period of 28 days.Male and female animals from control and all the treated dose groups exhibited normal body weight gain at the end of the dosing period of 28 days.Daily clinical observations did not reveal any signs of toxicity in male and female animals from different dose groups during the dosing period of 28 days.Towards the end of the exposure period in week 4, functional observation battery such as sensory reactivity to stimuli of different types (e.g. auditory, visual and proprioceptive stimuli) revealed no abnormalities attributable to the treatment.Grip strength values observed in male and female animals for control and different dose groups were comparable.Higher values for motor activity were observed in male animals from 500 mg/kg dose group for first interval. Lower values for motor activity were observed in female animals from 500 mg/kg dose group for first and second interval.These changes were within laboratory range and were considered to be of no toxicological importance. Haematological analysis performed on 29thday revealed statistically significant increase in the values of Hb of male rats dosed at 500 mg/kg and 1000 mg/kg, MCHC of male rats dosed at 500 mg/kg, Total WBC of male rats dosed at 1000 mg/kg and Platelets of female rats dosed at 1000 mg/kg.Organ weight data of male animals sacrificed on day 29, was found to be comparable with that of controls.Organ weight data of female animals sacrificed on day 29, revealed increased relative weights of liver, ovaries and lungs of animals from 1000 mg/kg dose group.Although significant changes in organ weights were observed in female animals from high dose group, no related gross pathological or histological changes were seen and hence considered to be of no toxicological importance.Gross pathological examination conducted in rats of all dose groups during necropsy did not reveal any abnormality attributable to the treatment. Histopathological examination conducted in rats of control and high dose groups did not reveal any abnormality attributable to the treatment. Based on these findings the No Observed Adverse Effect Level (NOAEL) of the test chemical in the Sprague Dawley rat via oral route, was considered to be 1000 mg/kg body weight in male and female animals.

 

Based on the available results, the NOAEL value for the test chemical can be considered to be >500 mg/kg/day when exposed for longer duration to test animals orally. Hence, the test chemical can be considered to be comparatively non-toxic via oral route of administration and can be classified under the category “Not Classified” as per CLP Regulation.

 

Repeated dose toxicity: Inhalation

The short term toxicity study need not be conducted because exposure to humans via inhalation route is not likely taking into account due to the low vapour pressure of the test chemical. The experimental vapour pressure was 0.0248Pa at 20 deg C. Also, the LC50 was considered to be >5500 mg/m³, when rats were exposed to the test chemical by inhalation route for 4 hours. Thus, exposure to inhalable dust, mist and vapour of the chemical is highly unlikely. Therefore, this study is considered for waiver

 

Repeated dose toxicity: dermal

A short-term repeated dose dermal toxicity study need not be conducted because exposure of humans via dermal route in production and/or in use is highly unlikely based on the thorough and rigorous risk assessment provided. Also, the acute dermal toxicity LD50 value for the test chemical (as provided in section 7.2.3) is >2000 mg/kg body weight. The test chemical was also found to be not sensitizing to the skin. Considering this, the end point for repeated dermal toxicity is considered as waiver.