1-acetyl-4-(3-dodecyl-2,5-dioxo-1-pyrrolidinyl)-2,2,6,6-tetramethylpiperidine

Endpoint summary

Description of key information

Repeated dose toxicity was only observed after oral administration (Sprague Dawley rats, doses of 0, 15, 150 and 1000 mg/kg bw/d, for 28 days). No adverse effects were observed during treatment. Based on the observations made in this 28 d oral toxicity study in rats the NOAEL was considered to be 1000 mg/kg bw/d.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: 84/449/EWG, B.7; OECD 407

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (U.K:) Ltd., Kent
- Females (if applicable) nulliparous and non-pregnant: yes
- Weight at study initiation: males: 153-177 g; females: 135-157 g
- Housing: in groups of five in polypropylene gridfloor cages
- Diet (e.g. ad libitum): Rat and Mouse SQC Expanded Diet No. 1, Special Services Ltd., Essex, U.K:, ad libitum
- Water (e.g. ad libitum): Mains water, ad libitum
- Acclimation period: 7 days

DETAILS OF FOOD AND WATER QUALITY:

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%): 44-75%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

other: Arachis oil

Details on oral exposure:

Method of administration: gavage

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

Test duration: 28 days

Frequency of treatment:

Dosing regime: 7 days/week

Dose / conc.:

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

Dose / conc.:

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

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

Male: 5 animals at 0 mg/kg bw/day
Male: 5 animals at 15 mg/kg bw/day
Male: 5 animals at 150 mg/kg bw/day
Male: 5 animals at 1000 mg/kg bw/day
Female: 5 animals at 0 mg/kg bw/day
Female: 5 animals at 15 mg/kg bw/day
Female: 5 animals at 150 mg/kg bw/day
Female: 5 animals at 1000 mg/kg bw/day

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: doses chosen based on the results of a dose-range finding study

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: immediately before and one and five hours after each dosing

BODY WEIGHT: Yes
- Time schedule for examinations: o the day before the start of treatment, on days 7, 14, 21 and 28 and at necropsy

FOOD CONSUMPTION:
Food consumption was recorded for each cage group at weekly intervals

WATER CONSUMPTION: Yes
- Time schedule for examinations: recorded for each cage group at weekly intervals

HAEMATOLOGY: Yes
- Time schedule for collection of blood: day 28
- Anaesthetic used for blood collection: Not specified
- Animals fasted: No
- How many animals: all
- Parameters examined:
Haematocrit, Haemoglobin, total Leucocyte count, differential leucocyte count, platelet count, mean corpuscular haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin concentration, clotting time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day 28
- Animals fasted: No
- How many animals: all
- Parameters examined:
blood urea, total protein, albumin, albumin/globulin ratio, sodium, potassium, cloride, calcium, inorganic phosphorus, creatinine, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, glucose, total bilirubin

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, all animals

Organ weights: Adrenals, brain, gonads, heart, kidneys, liver, pituitary, spleen

HISTOPATHOLOGY: Yes, from control and high dose animals
adrenals, spleen, heart, kidneys, liver, testes, stomach and gross lesions from all animals

Samples form the following tissues/organs were removed from all animals and preserved:
adrenals, aorta, bone and bone marrow, brain, caecum, colon, duodenum, eyes, gross lesions, heart, ileum, jejunum, kidneys, liver, lymph nodes, muscle, oesophagus, ovaries, pancreas, pituitary, prostate, rectum, salivary glands, sciatic nerve, senimal vesicles, skin, spleen, stomach, trstes, thymus, thyroid/parathyroid, trachea, urinary bladder, uterus

Statistics:

One way analysis of variance incorporating F-max test for homogeneity: absolute and relative organ weights, haematological and blood chemical data
Kruskal Wallis non-parametric analysis of variance and Mann Whitney U-Test: data showing heterogenous variances

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

high dose: increased salivation either before or imediately after dosing, fur wetting and red/brown staining of the fur, mouth and/or snout

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

High dose females showed a possible slight reduction in body weight gain. Hogh dose males and animlas in the remaining dose groups showed no adverse body weight which could be attributable to treatment.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

High dose animals of either sex and intermediate dose males showed a statisitcally significant reduction in plasma bilirubin compared with controls. Intermediate dose females and low dose animals showed no treatment-related changes.

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Intermediate and high dose males showed a sight but statistically significant increase in liver weight both absolute and relative to body weight., whilst relative liver weight was also elevated in high dose females. Several individual values were abnormally high for rats of this strain and age and although there was no further evidence to support an hepatic change a treatment-rlelated liver effect cannot be entirely ruled out.

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Other effects:

not examined

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: no adverse effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no adverse effects observed

Key result

Critical effects observed:

no

Mortality Data:

There were no deaths during the study.

Clinical observations:

High dose animals of either sex showed clinically observable signs of toxicity from day 5 onwards including increased salivation either before or immediately after dosing together with associated fur wetting and red/brown staining of the external body surface. Increased salivation over a more prolonged period of time was also observed, intermittently, from day 8, whilst sporadic incidents of pilo-erection were detected during the latter half of the treatment period.

Intermediate and low dose animals showed no clinical signs which could be considered attributable to the toxicity of the test material.

Bodyweight:

High dose females showed a possible slight reduction in bodyweight gain compared with that of controls over the treatment period.

High dose males and animals in the remaining dose groups showed no adverse bodyweight effects which could be considered attributable to treatment with the test material.

Food Consumption:

No treatment-related effects were detected.

Water consumption:

No overt intergroup differences were detected.

Haematology:

No treatment-related effects were detected.

Blood chemistry:

High dose animals of either sex and intermediate dose males showed a statistically significant reduction in plasma bilirubin compared with controls.

Intermediate dose females and low dose animals showed no treatment-related blood chemical changes.

Necropsy:

No treatment-related macroscopic abnormalities were detected at necropsy.

Organ Weights:

Intermediate and high dose males showed a slight but statistically significant increase in liver weight, both absolute and relative to bodyweight, compared with controls whilst relative liver weight was also elevated in high dose females. Several of the individual values were abnormally high for rats of this strain and age. There was no further evidence to support an hepatic change. A treatment-related liver effect cannot be entirely ruled out for these animals. However, the effect on organ weight is not regarded as adverse, as they were observed in the absence of any histopathological change or relevant biochemical change of liver parameters. No treatment-related changes were apparent for either intermediate dose females or low dose animals of either sex.

Histopathology:

No treatment-related microscopic abnormalities were observed.

Conclusions:

Classified as: Not classified

Executive summary:

Oral administration of the test material to rats for a period of twenty-eight consecutive days at a maximum dose level of 1000 mg/kg/day resulted in minor treatment-related changes at 150 and 1000 mg/kg/day, especially changes of liver weight (absolute and relative) were observed. As these effects on liver weight were observed in the absence of any histopathological findings and relevant changes of clinical-biochemistry they are not regarded as adverse.The "No Observed Adverse Effect Level" (NOEL) is, therefore, considered to be 1000 mg/kg/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

reliable without restriction

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

Quality of whole database:

sufficient for evaluation

Mode of Action Analysis / Human Relevance Framework

In the absence of any evidence for species specific effects or modes of action the observed effects are regarded as relevant for humans.

Additional information

Oral administration of the test item to Sprague Dawley rats at doses of 15, 150 and 1000 mg/kg bw/ d, for 28 days resulted in no deaths, no severe test item-related findings during daily observations, no changes in body weight, food and water consumption, haematology, clinical chemistry, gross pathology and histopathology. Intermediate and high dose males showed a slight but statistically significant increase in liver weight both absolute and relative to body weight, whilst relative liver weight was also elevated in high dose females. As the effects on liver weight did ot correlate to any histopathological or clinical-biochemical changes they are not considered to be adverse. Based on the observations made in this 28 d oral toxicity study in rats the NOAEL was considered to be 1000 mg/kg bw/d.

Justification for classification or non-classification

Due to the NOAEL of 1000 mg/kg bw/day in a 28 days oral toxicity study according to OECD 407 study in rats the test substance does not have to be classified regarding systemic and target organ toxicity after repeated exposure according to the criteria laid down in the Regulation (EC) No 1272/2008.