N-ethyl-2-(isopropyl)-5-methylcyclohexanecarboxamide

Endpoint summary

Description of key information

Repeated dose toxicity: Oral

In a 22-week study, groups of 15 Sprague-Dawley (CFY) rats of each sex were given the test chemical by gavage at a dose of 0, 100, 300 or 725 mg/kg bw. The parameters examined were mortality, Clinical signs, body weight, food efficiency, Urinalysis, Haematology, Biochemistry, organ weight, Opthalmoscopy, Gross pathology and histopathology. After initial dosing, but not thereafter, several males were lethargic and had mild hypothermia, ataxia and lachrymation, and two females at the highest dose were semi-comatose. Throughout the study, mild transient salivation was noted in rats at the highest dose and to a lesser extent in those at 300 mg/kg bw per day. At the end of the second week and for the remainder of the study, rats at the highest dose and a few at the intermediate dose showed reduced grooming activity. Several rats had mild sialodacryoadenitis during weeks 8-12. One male and one female at the highest dose died at week 4; however, the deaths were probably the result of an intubation error. Another male at the highest dose was killed because of ocular haemorrhage after orbital blood sampling. One male at the intermediate dose was found dead during week 12 with signs of lung congestion. An additional 11 treated rats died during the last 3 weeks of the study, probably due to blood sampling error. Significantly reduced body-weight gain was also reported in females at the highest dose, and rats at the highest dose continued to show lower weight gain during the last 9 weeks. No significant variations were found in food consumption between test and control rats; however, during the first 3 months, males at the two higher doses had a dose-related reduction in growth rate. The reduced body-weight gain observed at the highest dose was accompanied by a reduction in feed use efficiency from week 5 of the study. The only variations in haematological parameters reported were in males at weeks 12, 13, 15 and 22, which showed increased blood clotting times in thrombo tests in comparison with controls; however, this effect was thought to be a result of tissue fluid contamination, and therefore additional blood samples were collected by cardiac puncture at weeks 21 and 22. At week 21, the thrombo test values for rats at the two lower doses were below the upper normal limit; although the values for animals at the highest dose remained above the normal limits of variation, the values were markedly reduced from previous weeks. At week 22, a further improvement was noted in thrombotest values in blood collected by cardiac puncture in comparison with values in blood obtained from the orbital sinus. Statistically significant variations in clinical chemistry at week 6 were limited to a reduction in serum alkaline phosphatase activity in animals at the highest dose in comparison with controls; however, the values were within the normal limits of variation. Clinical chemistry parameters examined at week 12 revealed the following statistically significant changes: increased plasma glucose and serum sodium levels, decreased serum alkaline phosphatase activity in males at the highest dose and increased total serum protein levels in both sexes. In an extension of the study, serum protein was also increased in rats of each sex at the two lower doses. At weeks 6 and 7, urine samples from controls and animals at the two higher doses contained leukocytes; however, none were seen at week 12. Epithelial cells were reported in urine samples taken at weeks 6 and 7, but not at week 12. Females at the highest dose had a dose-related increase in specific gravity with no change in urine volume at weeks 7 and 12, whereas males had an increase in volume output with no change in specific gravity. An increased urinary volume was observed in males at the intermediate dose at week 13. Additionally, reducing substances were found in the urine of females with increasing frequency over the test period. Dose-related variations in organ weights were limited to significant increases in the absolute and relative liver weights of females in all test groups in comparison with controls ,and significantly elevated relative liver weights in males at the highest dose. All other variations in organ weights were considered to be incidental or to reflect body weight differences and, as such, were not deemed to be toxicologically significant. The results of gross examinations were unremarkable. Although histopathological examination revealed some changes in cardiac and pulmonary tissues and in the livers in all groups of animals, the changes were typical of this strain of laboratory rat and considered not to be related to treatment. Based on the observations made, no observed adverse effect level (NOAEL) for the test chemical to Sprague Dawley male rat was considered to be 300 mg/kg bw/day while to female rat it was considered to be <100 mg/kg bw/day after repeated exposure via oral route.

Repeated dose toxicity: Inhalation

N-ethyl-2-(isopropyl)-5-methylcyclohexanecarboxamide (CAS no 39711-79-0) has very low vapor pressure of 0.0072 Pa (5.4004433e-5 mm Hg), so the potential for the generation of inhalable vapours is very low, also the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be highly unlikely and therefore this end point for repeated dose toxicity by inhalation route of exposure was considered for waiver.

Repeated dose toxicity: Dermal

The acute dermal toxicity value for 3 N-ethyl-2-(isopropyl)-5-methylcyclohexanecarboxamide (CAS no 39711-79-0) (as provided in section 7.2.3) is >2000 mg/kg body weight. 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:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from WHO Food addtivies series

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

A 22 week study was carried out on groups of 15 Sprague-Dawley (CFY) male/female rats with intake of the test chemical through gavage route to measure its effect on repeated exposure.

GLP compliance:

not specified

Species:

rat

Strain:

Sprague-Dawley

Remarks:

CFY

Details on species / strain selection:

Not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

Not specified

Route of administration:

oral: gavage

Details on route of administration:

Not specifed

Vehicle:

not specified

Details on oral exposure:

Not specifed

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

Not specifed

Duration of treatment / exposure:

22 weeks

Frequency of treatment:

Not specifed

Dose / conc.:

0 other: mg/kg bw/day

Dose / conc.:

100 other: mg/kg bw/day

Dose / conc.:

300 other: mg/kg bw/day

Dose / conc.:

725 other: mg/kg bw/day

No. of animals per sex per dose:

3 groups of 15 Sprague-Dawley (CFY) rats of each sex

0 mg/Kg/day: 15 males and 15 females
100 mg/Kg/day: 15 males and 15 females
300 mg/Kg/day: 15 males and 15 females
725 mg/Kg/day: 15 males and 15 females

Control animals:

yes, concurrent vehicle

Details on study design:

Not specified

Positive control:

Not specified

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Throughout the study period
- Cage side observations checked in table [No.?] were included. Clinical signs and behavioral changes

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Throughout the study period

BODY WEIGHT: Yes
- Time schedule for examinations: Throughout the study period

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
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

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: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
- Time schedule for examinations:

OPHTHALMOSCOPIC EXAMINATION: Yes - Time schedule for examinations:
- Dose groups that were examined:

HAEMATOLOGY: Yes
- Time schedule for collection of blood: No data
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: No data
- Parameters checked in table [No.?] were examined. Blood clotting times

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: No data
- Animals fasted: No data
- How many animals: No data
- Parameters checked in table [No.?] were examined. Plasma glucose and serum sodium levels, serum alkaline phosphatase activity and total serum protein levels

URINALYSIS: Yes
- Time schedule for collection of urine: No data
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters checked in table [No.?] were examined. No data

NEUROBEHAVIOURAL EXAMINATION: No data
- Time schedule for examinations: No data
- Dose groups that were examined: No data
- Battery of functions tested: sensory activity / grip strength / motor activity / other: No data

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Other examinations:

Not specified

Statistics:

Not specified

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

After initial dosing, but not thereafter, several males were lethargic and had mild hypothermia, ataxia and lachrymation, and two females at the highest dose were semi-comatose. Throughout the study, mild transient salivation was noted in rats at the highest dose and to a lesser extent in those at 300 mg/kg bw per day. At the end of the second week and for the remainder of the study, rats at the highest dose and a few at the intermediate dose showed reduced grooming activity. Several rats had mild sialodacryoadenitis during weeks 8-12.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One male and one female at the highest dose died at week 4; however, the deaths were probably the result of an intubation error. Another male at the highest dose was killed because of ocular haemorrhage after orbital blood sampling. One male at the intermediate dose was found dead during week 12 with signs of lung congestion. An additional 11 treated rats died during the last 3 weeks of the study, probably due to blood sampling error.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Significantly reduced body-weight gain was also reported in females at the highest dose, and rats at the highest dose continued to show lower weight gain during the last 9 weeks.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No significant variations were found in food consumption between test and control rats; however, during the first 3 months, males at the two higher doses had a dose-related reduction in growth rate.

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

The reduced body-weight gain observed at the highest dose was accompanied by a reduction in feed use efficiency from week 5 of the study.

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

not specified

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No abnormalities of the eye were reported.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

The only variations in haematological parameters reported were in males at weeks 12, 13, 15 and 22, which showed increased blood clotting times in thrombo tests in comparison with controls; however, this effect was thought to be a result of tissue fluid contamination, and therefore additional blood samples were collected by cardiac puncture at weeks 21 and 22. At week 21, the thrombo test values for rats at the two lower doses were below the upper normal limit; although the values for animals at the highest dose remained above the normal limits of variation, the values were markedly reduced from previous weeks. At week 22, a further improvement was noted in thrombotest values in blood collected by cardiac puncture in comparison with values in blood obtained from the orbital sinus.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Statistically significant variations in clinical chemistry at week 6 were limited to a reduction in serum alkaline phosphatase activity in animals at the highest dose in comparison with controls; however, the values were within the normal limits of variation. Clinical chemistry parameters examined at week 12 revealed the following statistically significant changes: increased plasma glucose and serum sodium levels, decreased serum alkaline phosphatase activity in males at the highest dose and increased total serum protein levels in both sexes. In an extension of the study, serum protein was also increased in rats of each sex at the two lower doses.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

At weeks 6 and 7, urine samples from controls and animals at the two higher doses contained leukocytes; however, none were seen at week 12. Epithelial cells were reported in urine samples taken at weeks 6 and 7, but not at week 12. Females at the highest dose had a dose-related increase in specific gravity with no change in urine volume at weeks 7 and 12, whereas males had an increase in volume output with no change in specific gravity. An increased urinary volume was observed in males at the intermediate dose at week 13. Additionally, reducing substances were found in the urine of females with increasing frequency over the test period.

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Dose-related variations in organ weights were limited to significant increases in the absolute and relative liver weights of females in all test groups in comparison with controls ,and significantly elevated relative liver weights in males at the highest dose. All other variations in organ weights were considered to be incidental or to reflect body weight differences and, as such, were not deemed to be toxicologically significant.

Gross pathological findings:

no effects observed

Description (incidence and severity):

The results of gross examinations were unremarkable

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Although histopathological examination revealed some changes in cardiac and pulmonary tissues and in the livers in all groups of animals, the changes were typical of this strain of laboratory rat and considered not to be related to treatment

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

Not specified

Dose descriptor:

NOAEL

Effect level:

300 other: mg/Kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

other: No significant effects were noted at the mentioned dose level

Dose descriptor:

LOAEL

Effect level:

100 other: mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

organ weights and organ / body weight ratios

urinalysis

Conclusions:

The no observed adverse effect level (NOAEL) for the test chemical to Sprague Dawley male rat was considered to be 300 mg/kg bw/day while to female rat it was considered to be <100 mg/kg bw/day after repeated exposure via oral route.

Executive summary:

In a 22-week study, groups of 15 Sprague-Dawley (CFY) rats of each sex were given the test chemical by gavage at a dose of 0, 100, 300 or 725 mg/kg bw. The parameters examined were mortality, Clinical signs, body weight, food efficiency, Urinalysis, Haematology, Biochemistry, organ weight, Opthalmoscopy, Gross pathology and histopathology. After initial dosing, but not thereafter, several males were lethargic and had mild hypothermia, ataxia and lachrymation, and two females at the highest dose were semi-comatose. Throughout the study, mild transient salivation was noted in rats at the highest dose and to a lesser extent in those at 300 mg/kg bw per day. At the end of the second week and for the remainder of the study, rats at the highest dose and a few at the intermediate dose showed reduced grooming activity. Several rats had mild sialodacryoadenitis during weeks 8-12. One male and one female at the highest dose died at week 4; however, the deaths were probably the result of an intubation error. Another male at the highest dose was killed because of ocular haemorrhage after orbital blood sampling. One male at the intermediate dose was found dead during week 12 with signs of lung congestion. An additional 11 treated rats died during the last 3 weeks of the study, probably due to blood sampling error. Significantly reduced body-weight gain was also reported in females at the highest dose, and rats at the highest dose continued to show lower weight gain during the last 9 weeks. No significant variations were found in food consumption between test and control rats; however, during the first 3 months, males at the two higher doses had a dose-related reduction in growth rate. The reduced body-weight gain observed at the highest dose was accompanied by a reduction in feed use efficiency from week 5 of the study. The only variations in haematological parameters reported were in males at weeks 12, 13, 15 and 22, which showed increased blood clotting times in thrombo tests in comparison with controls; however, this effect was thought to be a result of tissue fluid contamination, and therefore additional blood samples were collected by cardiac puncture at weeks 21 and 22. At week 21, the thrombo test values for rats at the two lower doses were below the upper normal limit; although the values for animals at the highest dose remained above the normal limits of variation, the values were markedly reduced from previous weeks. At week 22, a further improvement was noted in thrombotest values in blood collected by cardiac puncture in comparison with values in blood obtained from the orbital sinus. Statistically significant variations in clinical chemistry at week 6 were limited to a reduction in serum alkaline phosphatase activity in animals at the highest dose in comparison with controls; however, the values were within the normal limits of variation. Clinical chemistry parameters examined at week 12 revealed the following statistically significant changes: increased plasma glucose and serum sodium levels, decreased serum alkaline phosphatase activity in males at the highest dose and increased total serum protein levels in both sexes. In an extension of the study, serum protein was also increased in rats of each sex at the two lower doses. At weeks 6 and 7, urine samples from controls and animals at the two higher doses contained leukocytes; however, none were seen at week 12. Epithelial cells were reported in urine samples taken at weeks 6 and 7, but not at week 12. Females at the highest dose had a dose-related increase in specific gravity with no change in urine volume at weeks 7 and 12, whereas males had an increase in volume output with no change in specific gravity. An increased urinary volume was observed in males at the intermediate dose at week 13. Additionally, reducing substances were found in the urine of females with increasing frequency over the test period. Dose-related variations in organ weights were limited to significant increases in the absolute and relative liver weights of females in all test groups in comparison with controls ,and significantly elevated relative liver weights in males at the highest dose. All other variations in organ weights were considered to be incidental or to reflect body weight differences and, as such, were not deemed to be toxicologically significant. The results of gross examinations were unremarkable. Although histopathological examination revealed some changes in cardiac and pulmonary tissues and in the livers in all groups of animals, the changes were typical of this strain of laboratory rat and considered not to be related to treatment. Based on the observations made, no observed adverse effect level (NOAEL) for the test chemical to Sprague Dawley male rat was considered to be 300 mg/kg bw/day while to female rat it was considered to be <100 mg/kg bw/day after repeated exposure via oral route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

300 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Data is from reliable K2 source

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: inhalation, other

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

Waiver

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: dermal, other

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Waiver

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Data available for the various test chemicals was reviewed to determine the toxic nature of the test chemical upon repeated exposure. The studies are as mentioned below:.

Repeated dose toxicity: Oral

In a 22-week study, groups of 15 Sprague-Dawley (CFY) rats of each sex were given the test chemical by gavage at a dose of 0, 100, 300 or 725 mg/kg bw. The parameters examined were mortality, Clinical signs, body weight, food efficiency, Urinalysis, Haematology, Biochemistry, organ weight, Opthalmoscopy, Gross pathology and histopathology. After initial dosing, but not thereafter, several males were lethargic and had mild hypothermia, ataxia and lachrymation, and two females at the highest dose were semi-comatose. Throughout the study, mild transient salivation was noted in rats at the highest dose and to a lesser extent in those at 300 mg/kg bw per day. At the end of the second week and for the remainder of the study, rats at the highest dose and a few at the intermediate dose showed reduced grooming activity. Several rats had mild sialodacryoadenitis during weeks 8-12. One male and one female at the highest dose died at week 4; however, the deaths were probably the result of an intubation error. Another male at the highest dose was killed because of ocular haemorrhage after orbital blood sampling. One male at the intermediate dose was found dead during week 12 with signs of lung congestion. An additional 11 treated rats died during the last 3 weeks of the study, probably due to blood sampling error. Significantly reduced body-weight gain was also reported in females at the highest dose, and rats at the highest dose continued to show lower weight gain during the last 9 weeks. No significant variations were found in food consumption between test and control rats; however, during the first 3 months, males at the two higher doses had a dose-related reduction in growth rate. The reduced body-weight gain observed at the highest dose was accompanied by a reduction in feed use efficiency from week 5 of the study. The only variations in haematological parameters reported were in males at weeks 12, 13, 15 and 22, which showed increased blood clotting times in thrombo tests in comparison with controls; however, this effect was thought to be a result of tissue fluid contamination, and therefore additional blood samples were collected by cardiac puncture at weeks 21 and 22. At week 21, the thrombo test values for rats at the two lower doses were below the upper normal limit; although the values for animals at the highest dose remained above the normal limits of variation, the values were markedly reduced from previous weeks. At week 22, a further improvement was noted in thrombotest values in blood collected by cardiac puncture in comparison with values in blood obtained from the orbital sinus. Statistically significant variations in clinical chemistry at week 6 were limited to a reduction in serum alkaline phosphatase activity in animals at the highest dose in comparison with controls; however, the values were within the normal limits of variation. Clinical chemistry parameters examined at week 12 revealed the following statistically significant changes: increased plasma glucose and serum sodium levels, decreased serum alkaline phosphatase activity in males at the highest dose and increased total serum protein levels in both sexes. In an extension of the study, serum protein was also increased in rats of each sex at the two lower doses. At weeks 6 and 7, urine samples from controls and animals at the two higher doses contained leukocytes; however, none were seen at week 12. Epithelial cells were reported in urine samples taken at weeks 6 and 7, but not at week 12. Females at the highest dose had a dose-related increase in specific gravity with no change in urine volume at weeks 7 and 12, whereas males had an increase in volume output with no change in specific gravity. An increased urinary volume was observed in males at the intermediate dose at week 13. Additionally, reducing substances were found in the urine of females with increasing frequency over the test period. Dose-related variations in organ weights were limited to significant increases in the absolute and relative liver weights of females in all test groups in comparison with controls ,and significantly elevated relative liver weights in males at the highest dose. All other variations in organ weights were considered to be incidental or to reflect body weight differences and, as such, were not deemed to be toxicologically significant. The results of gross examinations were unremarkable. Although histopathological examination revealed some changes in cardiac and pulmonary tissues and in the livers in all groups of animals, the changes were typical of this strain of laboratory rat and considered not to be related to treatment. Based on the observations made, no observed adverse effect level (NOAEL) for the test chemical to Sprague Dawley male rat was considered to be 300 mg/kg bw/day while to female rat it was considered to be <100 mg/kg bw/day after repeated exposure via oral route.

In another preliminary 28-day study, groups of one male and one female beagle dogs were given gelatin capsules containing the test chemical at a dose of 0, 600,1000 or 1500 mg/kg bw per day for 4 weeks. Occasional vomiting and loose faeces were reported in treated animals at every dose. Additionally, an incident of convulsion was reported on the first day of treatment in a dog at 600 mg/kg bw per day. Although no dose-related effects were observed on bodyweight, most dogs gained little or no weight during the first week of treatment; however, appetite was not adversely affected. At necropsy, the liver weights of most dogs were higher than the normally accepted upper limit of 4% of bodyweight; however, no macroscopic abnormalities were found. No additional study details were provided. Based on the study, low observed effect level (LOAEL) for the test chemicale to beagle dog (male/female) was determined to be 600 mg/kg bw per day after repeated exposure via oral route.

Groups of three male and three female beagle dogs were also given gelatine capsules containing test chemical at a dose of 0, 100, 300 or 1000 mg/kg bw per day for 52 weeks. One female at 1000 mg/kg bw per day died on day 271. The clinical signs consisted of loose stools in all groups, but with greater frequency in treated animals, occasional vomiting at the highest dose and convulsive episodes in one dog at the highest dose. Decreased body-weight gain was reported in females during the first 6 weeks of the study, but no differences were seen subsequently. Midway through the study (weeks 10-13 and 19-22), dogs at the highest dose drank significantly more water than controls. Food consumption was not affected by treatment. No abnormalities of the eye were reported. From week 4 and continuing until study termination, clinical chemistry revealed serum alkaline phosphatase activity approximating or in excess of the normal upper limits in animals at the highest dose. Serum alanine aminotransferase activity exceeding the normal upper limits was observed at 24 weeks in 4/6 dogs at the highest dose and 1/6 at 300 mg/kg bw per day and, at week 50, in 3/6 dogs at the highest dose, 2/6 receiving 300 mg/kg bw per day and 1/6 receiving 100 mg/kg bw per day of the test substance. The gross findings consisted of enlarged, unusually dense, discoloured livers in 4/6 dogs at the highest dose and 1/6 dogs at 300 mg/kg bw per day. The absolute and relative spleen and liver weights of dogs at the highest dose were significantly higher than those of controls. No treatment-related histopathological changes were reported. Based on the study, the low observed effect level (LOAEL) for the test chemical to beagle dog (male/female) was determined to be 100 mg/kg bw/day after repeated exposure via oral route.

In yet another 28-day study, groups of six Crj:CD(SD) rats of each sex were given the test chemical by gavage daily at a dose of 0 (vehicle control), 8, 40, 200 or 1000 mg/kg bw. Two additional groups were given the vehicle or 1000 mg/kg bw per day for 28 days, followed by a 14-day recovery period. Observations were made for the mortality, clinical signs, food consumption, urinalysis, Body-weight gain, haematology, clinical chemistry, organ weights, Histopathology and Gross pathology. No unscheduled deaths were reported and no changes in food consumption or urinary parameters were observed. Clinical signs (e.g. salivation, decreased spontaneous locomotion, tremor, staggering gait) indicative of general toxicity were reported in rats at the highest dose. Milder effects were reported at 200 mg/kg bw per day (e.g. salivation) in both sexes and at 40 mg/kg bw per day (e.g. salivation) in males. Body-weight gain was significantly reduced in males at the highest dose. Changes in haematological and clinical chemistry parameters were noted in rats given the highest dose and consisted of increased prothrombin time and reticulocyte count (both sexes), increased white blood cell count and activated partial thromboplastin time (males), increased y-guanosine triphosphatase, total cholesterol, triglyceride and calcium values (both sexes), increased total protein (females) and decreased alkaline phosphatase activity and chloride (females). Increased liver weights were reported in males and females at 1000 mg/kg bw per day and in females at 200 mg/kg bw per day. In males at the highest dose, kidney and testis weights were also increased. At necropsy, the gross findings included a dosedependent response consisting of spotty patterns on kidney surfaces and enlarged livers in males at 200 and 1000 mg/kg bw per day, enlarged livers and blackish changes in the spleen in females at 1000 mg/kg bw per day, and enlarged kidneys in males at 1000 mg/kg bw per day. Histopathological examination revealed dosedependent swelling of hepatocytes and increased haemosiderin-Iaden cells in the spleens of treated animals of each sex at 200 and 1000 mg/kg bw per day, congestion of the spleen in animals of each sex at 1000 mg/kg bw per day, and increased numbers of eosinophilic bodies in the kidneys of males at ≥ 40 mg/kg bw per day. Males at the highest dose continued to show reduced body-weight gain until day 15 of recovery, after which the body-weight gains began to normalize. In both sexes at the highest dose, increased liver weight, swelling of hepatocytes, increased haemosiderin-Iaden cells in the spleen, increased eosinophilic bodies in the kidneys, increased total protein levels and decreased chloride concentrations continued to be observed during the recovery period; however, the severity and frequency of the renal and hepatic changes were less marked than directly after treatment. Based on the observations made, no observed effect level (NOEL) for the test chemical to Crj:CD(SD) rat (male/female) was determined to be 8 mg/kg bw per day after repeated exposure via oral route.

 

Repeated dose toxicity: Inhalation

N-ethyl-2-(isopropyl)-5-methylcyclohexanecarboxamide (CAS no 39711-79-0) has very low vapor pressure of 0.0072 Pa (5.4004433e-5 mm Hg), so the potential for the generation of inhalable vapours is very low, also the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be highly unlikely and therefore this end point for repeated dose toxicity by inhalation route of exposure was considered for waiver.

Repeated dose toxicity: Dermal

The acute dermal toxicity value for 3 N-ethyl-2-(isopropyl)-5-methylcyclohexanecarboxamide (CAS no 39711-79-0) (as provided in section 7.2.3) is >2000 mg/kg body weight. Considering this, the end point for repeated dermal toxicity is considered as waiver

Based on the data available, the test chemical does not exhibit toxic nature upon repeated exposure by oral route of exposure. Hence it is not likely to classify as a toxicant upon repeated exposure by oral, dermal and inhalation route of exposure as per the criteria mentioned in CLP regulation.