2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one

Endpoint summary

Description of key information

The key studies provided were conducted to recognised testing guidelines and with GLP certification.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Tif: RAIf (SPF), F3-hybrid of RII 1/Tif x RII 2/Tif

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Animal Production CIBA-GEIGY LTD., Switzerland
- Age at study initiation: approx. 6 weeks
- Weight at study initiation: 187-193 g in males; 169-174 g in females
- Housing: in groups of five animals
- Diet (e.g. ad libitum): Pelleted, certified standard diet Nafag No. 890 Tox, ad libitum
- Water (e.g. ad libitum): Tap water, ad libitum.
- Acclimation period: at least one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 55± 10
- Air changes (per hr): 16-20
- Photoperiod (hrs dark / hrs light): 12 hours / 12 hours

Route of administration:

oral: gavage

Vehicle:

other: carboxymethyl-cellulose 0.5 % with 0.1 % Tween 80

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The solutions were freshly prepared every day immediately prior to the dosing of the animals and administered within 2 hours.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytically performed stability test of February 4, 1983 by the analytical Services R of CIBA-GEIGY Ltd. revealed that the test substance remains stable during 4 hours in the vehicle (analytical method KS-52/1).

Duration of treatment / exposure:

28 days

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
0, 30, 100, 300 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

5 animals

Control animals:

yes, concurrent vehicle

Positive control:

no

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations checked: mortality, symptoms

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly (midweek)

FOOD CONSUMPTION:
- Time schedule for examinations: weekly
- Food consumption ratio: calculated according to the following formula: (weekly food consumption (g) x 1000)/(midweek body weight (g))

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the treatment period. To reduce the biological variability due to circadian rhythms, blood sampling for haematology and blood chemistry was performed between the hours of 07:00 and 11:00 a.m.
- Anaesthetic used for blood collection: Ether
- Animals fasted: Yes, food was withheld for about 20 hours prior to blood removal.
- Parameters checked: Erythrocytes, Leucocytes, Haemoglobin, Haematocrit, Differential Count (Blood smear stained with a modified polychrome methylene blue (Ames, Hema-Tek Stain-Pak)), Metamyelocytes, Band Neutrophils, Segmented Neutrophils, Eosinophils, Basophils, Monocytes, Lymphocytes, Plasma Cells, Nucleated erythocytes, Nucleated RBC-Erythroblasts, Reticulocytes, Supravital staining with brilliant cresyl blue, Inclusion bodies (Heinz bodies), Supravital staining with brilliant cresyl blue, Prothrombin time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at the end of the treatment period. To reduce the biological variability due to circadian rhythms, blood sampling for haematology and blood chemistry was performed between the hours of 07:00 and 11:00 a.m.
- Animals fasted: Yes, food was withheld for about 20 hours prior to blood removal.
- Parameters checked: Urea, Total Protein, Albumin, A/G Ratio, Aspartate Aminotransferase, Alanine Aminotransferase, Total Bilirubin, Creatinine

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, organ weights (adrenals, brain, kidneys, liver, testes)

HISTOPATHOLOGY: Yes, skin, mammary area, spleen, mesenteric lymph node, axillary lymph node, sternum with bone marrow, femur with joint, skeletal muscle, trachea, lung, heart, aorta, submandibular salivary gland, liver, pancreas, oesophagus, stomach, small intestine, large intestine, kidney, urinary bladder, prostate, seminal vesicle, testis, epididymis, uterus, ovary, pituitary gland, adrenal gland, thyroid with parathyroid gland, thymus, peripheral nerve, brain, spinal cord, eye with optic nerve, orbital gland, extraorbital lacrimal gland, organs and tissues showing macroscopical changes.

- ADDITIONAL HISTOPATHOLOGICAL EXAMINATION OF THE NERVOUS SYSTEM AND EYE:
- Time schedule for examinations: at the end of the test period
- Dose groups that were examined: all animals
- Battery of functions tested: Samples of the brain, the spinal cord, the peripheral (sciatic) nerve and the eyes

Statistics:

An uni-variate statistical analysis was conducted. Each treated group was compared to the control group in respect of dispersion and displacement (Y. Lepage, Biometrika (1971) 58: pp. 213-217). In addition a trend test (H. R. Jonckheere, Biometrika (1954) 41: pp. 133-145) was applied considering all groups.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

In treated male and female animals of group 4 (300 mg/kg bw) marked signs of systemic intoxication were observed: diarrhoea, lameness of hindleg, locomotion altered, eyes, pale/opaque, ruffled fur, hairless, salivation, emaciated.

Mortality:

mortality observed, treatment-related

Description (incidence):

One male died due to misapplication. Another male and two females of the high doe group died treatment related.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

The mean body weight of treated male and female groups 3 and 4 (100 and 300 mg/kg bw.) was significantly depressed in a dose dependent manner, up to 33 %. The mean body weight of female group 2 (30 mg/kg bw.) was only slightly and not significantly depressed.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

The mean food consumption of treated male groups 3 and 4 (100 and 300 mg/kg bw) was depressed in a dose dependent manner.
Food consumption ratio was depressed in treated male and female groups 3 and 4 (100 and 300 mg/kg bw.), which was most prominent during week 1 to 2 of treatment in groups 4 (300 mg/kg bw).

Food efficiency:

not examined

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):

Hematology investigation during week 5 showed a moderate increase in numbers of red blood cells (RBC), a marked increase in haemoglobin concentration and in haematocrit in males receiving 300 mg/kg bw. In females receiving 300 mg/kg bw a moderate increase in numbers of white blood cells (WBC) was observed. In both males and females of the 300 mg/kg bw group, a slight decrease in numbers of lymphocytes and a slight increase in numbers of segmented neutrophils was seen.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Blood chemistry investigations during week 5 revealed slightly higher alanine aminotransferase (GPT) levels in both males and
females of the 100 and 300 mg/kg bw group, up to 2-fold. Aspartate aminotransferase (GOT) levels were also slightly increased in both sexes of the 300 mg/kg bw group.

Urinalysis findings:

not specified

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

The following findings were observed during autopsy examination in treated male and female animals of group 4 (300 mg/kg bw.): Acute congestion - sometimes with hemorrhages - in various parenchymatous organs in animals which succumbed during the test period.
Minimal focal acanthosis of the epidermis and atrophy of the hair follicles as well as slight focal inflammatory infiltration in the skin was observed in those 3 female animals previously noted for loss of hair during the in-life phase in group 4 (300 mg/kg bw).

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

The following findings were observed during histopathological examination in treated male and female animals of groups 4 (300 mg/kg bw.): Slight hypertrophy of the hepatocytes in 4 of 5 male and 2 of 5 female animals.

Histopathological findings: neoplastic:

not specified

Dose descriptor:

NOEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical biochemistry

histopathology: non-neoplastic

Critical effects observed:

no

Conclusions:

the 28 day repeat dose NOEL of the test material in rats was determined to be 30 mg/kg bw/day based upon bodyweight gain and food consumption under the conditions of the test.

Reference 2

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Tif: RAIf (SPF), F3-hybrid of RII 1/Tif x RII 2/Tif

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Animal Production CIBA-GEIGY LTD., Switzerland
- Age at study initiation: approx. 6 - 7 weeks
- Weight at study initiation: 158-211 g in males; 136-189 g in females
- Housing: groups of 5 animals
- Diet (e.g. ad libitum): Pelleted, certified standard diet Nafag No. 890 Tox, ad libitum
- Water (e.g. ad libitum):Tap water, ad libitum
- Acclimation period: 11 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 55 ± 10
- Air changes (per hr): 16-20
- Photoperiod (hrs dark / hrs light): 12 hours / 12 hours

Route of administration:

oral: gavage

Vehicle:

other: Distilled water containing 0.5 % carboxymethylcellulose and 0.1 % Tween 80

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The solutions were freshly prepared every day prior to dosing and administered within 4 hours.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Prior to the initiation of the study, pretest samples of the suspension were analysed for stability during 4 hours. No significant change of concentration could be observed (Report S-8/85 of May 20, 1985). These analysis were carried out in the Central Analytical Laboratories of CIBA-GEIGY LTD., Basle/Switzerland.

Duration of treatment / exposure:

92 days

Frequency of treatment:

1 dose per day, 5 times per week

Remarks:

Doses / Concentrations:
0, 10, 25, 75 and 220 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

10 animals

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: according to results of range finder and 28d study

Positive control:

no

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations checked: Mortality,

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: any reaction to treatment, examination was carried out daily, and observations were recorded at least weekly

BODY WEIGHT: Yes, of all animals
- Time schedule for examinations: weekly (midweek) weighing sessions. The first weighing occurred during the acclimatisation period.

FOOD CONSUMPTION: - was recorded weekly (cagewise).
- FEED CONVERSION: Group mean feed consumption ratio was calculated according to the following formula: (weekly food consumption (g) x 1000) / (midweek body weight (g)

WATER CONSUMPTION: Yes
- Time schedule for examinations: weekly

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations and dose groups: in all surviving animals of the control and treatment group 220 mg/kg bw on day - 1, 29, 57-58 and 85 of the study. Additionally animals of the dose group 75 mg/kg bw were examined at day 29 and animals of the dose groups 10, 25, 75 on day 57-58 and 85 mg/kg bw of the study.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the treatment period, between 07:00 and 09:00 a.m
- Anaesthetic used for blood collection: Yes, Ether
- Animals fasted: Yes, food was withheld for about 20 hours prior to blood removal
- Parameters checked: Erythrocyte Count, Hemoglobin, Hematocrit, Mean corpuscular volume, Mean corpuscular hemoglobin, Mean corpuscular hemoglobin concentration, Leucocyte Count, Differential Leucocyte Count, Thrombocyte Count, Prothrombin Time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at the end of the treatment period, between 07:00 and 09:00 a.m
- Animals fasted: Yes, food was withheld for about 20 hours prior to blood removal
- Parameters checked: Glucose, Urea, Creatinine, Total bilirubin, Total protein, Albumin, Globulins, A/G Ratio, Cholesterol, Aspartate aminotransferase, Alanine aminotransferase, Alkaline phosphatase, Gamma-glutamyltranspeptidase, Sodium, Potassium, Calcium, Phosphate inorganic,

URINALYSIS: Yes
- Time schedule for collection of urine: at the end of the treatment period, overnight
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes, food was withheld during the time of urine collection
- Parameters checked: Urine Volume, Urine specific gravity, pH-value, Protein, Glucose, Ketones, Bilirubin, Blood, Urobilinogen

NEUROBEHAVIOURAL EXAMINATION: Yes, Additionally a neurological examination was carried out
- Time schedule for examinations: at the end of the study.
- Dose groups that were examined: groups of 3 males and 3 females treated with the top dose (220 mg/kg bw), with the 2 highest doses causing no neurological changes (75 and 25 mg/kg bw) and with the controls.
- Battery of functions tested: patellar, the flexor and the pain reflex, corneal reflex, pupillary constriction, light reflex, Gait, activity and stance (exploratory activity and motor coordination), Cliff avoidance, Geotaxis, Visual placing, Vibrissal placing, Hopping response of the hind legs, Loss of support, Sommersault, Grip strength, Spinal and bulbar reflexes, Pupillary size and presence of light response

OTHER:
HEARING TEST:
- Time schedule for examinations: before (day-1), during (day 29) and towards the end (day 85) of the application period.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, weighing of the brain, heart, liver, kidneys, adrenals, gonads and spleen
HISTOPATHOLOGY: Yes, skin, mammary area, spleen, mesenteric lymph node, axillary lymph node, sternum with bone marrow, femur with joint, skeletal muscle, trachea, lung, heart, aorta, submandibular salivary gland, liver, pancreas, oesophagus, stomach, small intestine, large intestine, kidney, urinary bladder, prostate, seminal vesicle, testis, epididymis, uterus, ovary, pituitary gland, adrenal gland, thyroid with parathyroid gland, thymus, peripheral nerve (sciatic nerve with distal branches), brain, spinal cord, eye with optic nerve, orbital gland, extraorbital lacrimal gland, organs and tissues showing macroscopical changes

Statistics:

An uni-variate statistical analysis was conducted. Due to the routine manner of the analysis system, parameter free methods were applied. Each treated group was compared to the control group in respect of dispersion and displacement (Y. Lepage, Biometrika (1971) 58: pp. 213-217). In addition a trend test (H. R. Jonckheere, Biometrika (1954) 41: pp. 133-145) was applied considering all groups.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Paresis of hind legs was observed in males and females of the high dose group beginning on day 7 of treatment. Locomotor impairment improved at week 4 of treatment to the extent that the animals were again able to walk, however, with unsteady gait until week 10 of treatment.
Diarrhoea was only observed in one female of group 5, but loss of hair beginning in one female at the second week was found in all surviving animals at the end of the study.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Three animals died from accidental causes.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

The mean body weight gain of treated male and female group 5 (220 mg/kg bw.) was slightly decreased.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

The mean feed consumption ratio of treated male and female groups 5 was slightly elevated

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

effects observed, treatment-related

Description (incidence and severity):

A trend to slightly elevated water consumption was observed in treated females group 5

Ophthalmological findings:

effects observed, treatment-related

Description (incidence and severity):

One male in dose group 220 mg/kg bw first exudate on both eyes, then opacity of the right eye and subsequently both eyes were observed.
An increasing number of high dose females showed dim or opaque eyes.
Except absence of the pupillary light reflex beginning on day 29 of the study in one male of dose group 220 mg/kg bw, which also showed opacity of both eyes, no alterations of lid, eye surrounding or eye ball were observed in treated males.
Nine of ten females of the highest dose group (220 mg/kg bw) showed uni- or bilateral absence of pupillary light reflex on day 29 of the study. On day 57-58 and 85 of the study nine of ten females of the highest dose group (220 mg/kg bw) showed opacity of both eyes and absence of pupillary reflex to a light beam.
In contrast to the above findings, pupillary light reflex was found in the three females of each group during neurological examination at termination of the study, which however was performed more than 24 hours after the last application and by a different examiner, at a different location and with a different light source.
Additionally, paleness of eye fundus was observed in two males of dose groups 25 and 75 mg/kg at time of neurological examination.
In all three female rats of the highest dose group (220 mg/kg bw) bilateral severe lens opacities and loss of visual placing was observed. In one of these rats hopping was slower and the pupils were narrower.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

In the females of group 4 and 5 the percentage of segmented neutrophils was minimally higher and the percentage of lymphocytes slightly lower

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

minimally higher activity of alkaline phosphatase in the male group 5 and a slightly increased activity of alanine aminotransferase in the female group 5, minor increase in the plasma cholesterol level was noted in the females of the high dose group

Urinalysis findings:

no effects observed

Behaviour (functional findings):

effects observed, treatment-related

Description (incidence and severity):

Paresis of hind legs was observed in males and females of the high dose group beginning on day 7 of treatment. Locomotor impairment improved at week 4 of treatment to the extent that the animals were again able to walk, however, with unsteady gait until week 10 of treatment.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

In females of the highest dose group absolute and relative mean liver weight was significantly increased. Further the kidney to body (+ 18 %) and brain weight ratio (+ 13 %) was significantly increased in female of dose group 220 mg/kg bw.

Gross pathological findings:

no effects observed

Description (incidence and severity):

alopecia

Neuropathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

At the end of the treatment period aneurological examination was performed on 3 animals of 4 dose groups (0, 25,75 and 220 mg/kg bw). One among three male rats of the highest dose group (220 mg/kg bw) showed a bilateral severe lens opacity. This male also showed spontaneous shaky head movements, visual placing was absent and hopping was slow and performed with large steps. The pupils were slightly narrower than in controls while pupillary constriction to light was normal. The other two male rats of this group showed no neurologic abnormalities.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Increased occurrence (8/10) of hemosiderosis in the spleen of high dose females. Segmental demyelination of the peripheral nerve fibers in males (9/10) and females (9/10) of the high dose group, which was associated with increased cellularity of the peripheral nerve. Cataract of the eye lens in males (1/10) and females (6/10) of the 220 mg/kg bw group.

Histopathological findings: neoplastic:

not examined

Dose descriptor:

NOEL

Effect level:

10 mg/kg bw (total dose)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

ophthalmological examination

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

behaviour (functional findings)

histopathology: non-neoplastic

Critical effects observed:

no

Conclusions:

The 90 day repeat dose NOEL of the test material in rats was determined to be 10 mg/kg bw/day based upon opthamascopic effects under the conditions of the test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

75 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

1

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

A 28 day repeated dose study with albino rats was performed compliant to the OECD guideline 407 following GLP requirements. The test substance was administered daily by gavage for 28 days at dosages of 0, 30, 100, and 300 mg/kg bodyweight to a total of 40 albino rats, 5 males and 5 females per dose group.

Three animals of the high dose group died treatment related. In animals of dose group 300 mg/kg bw marked signs of systemic intoxication were observed, such as diarrhoea, lameness of hind legs with altered locomotion, pale or opaque eyes, ruffled fur, loss of hair, salivation and emaciation. The mean body weight and food consumption of treated males and females of the dose groups 100 and 300 mg/kg bw were significantly depressed in a dose dependent manner.

Haematological investigation during week 5 showed a moderate increase in numbers of red blood cells (RBC), a marked increase in haemoglobin concentration and in haematocrit in males receiving 300 mg/kg bw. In females receiving 300 mg/kg bw, a moderate increase in numbers of white blood cells (WBC) was observed.

Acute congestion - sometimes with haemorrhages - in various parenchymatous organs was noted in animals of dose group 300 mg/kg bw which succumbed during the test period. Minimal focal acanthosis of the epidermis and atrophy of the hair follicles as well as slight focal inflammatory infiltration in the skin was observed in those 3 female animals previously noted for loss of hair during the in-life phase in dose group 300 mg/kg bw. Slight hypertrophy of the hepatocytes was seen in 4 of 5 male and 2 of 5 female animals of dose group 300 mg/kg bw.

The “no observed adverse effect level” for the test substance after sub-acute administrationis 100 mg/kg bw/day.

 

The systemic toxic potential of the test substance was then assessed in a 90 day repeated dose toxicity study in rats by oral administration according to OECD guideline 408 and following GLP requirements. A total of 100 RAI (SPF) rats (10 males and 10 females per dose group) were used. The test article was administered by gavage for 3 months at doses of 0, 10, 25, 75 and 220 mg/kg bodyweight.

Paresis of hindlimbs was observed in males and females of dose group 220 mg/kg bw beginning at day 7 of treatment. Locomotor impairment improved at week 4 of treatment to the extent that the animals were again able to walk. Alopecia was found in all high dose females at the end of the study. Diarrhea was only observed in one female of this group. Further ruffled fur and loss of hair was observed at week 3 and 8 respectively in one male only.

In one high dose male exudate and opacity on both eyes was observed. An increasing number of females in dose group 220 mg/kg bw showed dim or opaque eyes. 9/10 females of dose group 220 mg/kg bw showed bilateral absence of pupillary light reflex and later on opacity of both eyes. In contrast to the above findings, pupillary light reflex was found in the three animals of each group subjected to neurological examination at termination of the study, which however was performed under different circumstances.

Neurological abnormalities, including loss of visual placing, miosis, slowed pupillary constriction, were found in dose group 220 mg/kg bw. The mild to moderate impairment of hopping observed in 2/6 and spontaneous head shaking in 1/6 rats indicated an additional derangement of motor coordination unrelated with visual impairment.

In females of dose group 220 mg/kg bw absolute and relative mean liver weight was significantly increased. Further the kidney to body and brain weight ratio was significantly increased in female of the high dose group. Microscopical examination of animals treated at the highest dose level revealed segmental demyelination of the peripheral nerve fibers and cataract of the eye lens. Further, increased occurrence of hemosiderosis was observed in the spleen of treated females of the highest dose group. At the highest dose level (220 mg/kg bw.) peripheral neuropathy was observed as well as oculotoxicity (formation of cataract).

The “no observed adverse effect level” for the test substance after sub-chronic administrationis 75 mg/kg bw/day.

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for repeated dose toxicity under Regulation (EC) No. 1272/2008.