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

Repeated dose toxicity: oral

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

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

EC Number:

400-600-6

EC Name:

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

Cas Number:

71868-10-5

Molecular formula:

C15 H21 N O2 S

IUPAC Name:

2-methyl-1-[4-(methylsulfanyl)phenyl]-2-(morpholin-4-yl)propan-1-one

Test animals

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

Administration / exposure

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

Doses / concentrations

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

Examinations

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.

Results and discussion

Results of examinations

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

Effect levels

1

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

2

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

Target system / organ toxicity

Critical effects observed:

no

Applicant's summary and conclusion

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.