Cyclododecane

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:

1993-12-23 to 1994-02-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according 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:

Cyclododecane

EC Number:

206-033-9

EC Name:

Cyclododecane

Cas Number:

294-62-2

Molecular formula:

C12H24

IUPAC Name:

cyclododecane

Details on test material:

Test substance: Cyclododecane of Elf Atochem, C.A.L. No. 6589/92, purity >= 99.0 %

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ORGANISMS
- Source: Charles River France (Saint-Aubin-les-Elbeuf)
- Age: approximately 6 weeks at beginning of treatment
- Weight at study initiation: females 178 g, males 199 g mean
- Number of animals:    
control and high dose group: 12 per group and sex  
50 and 150 mg/kg bw dose groups: 6 per group and sex
- Housing: two rats in wire.mesh cages
- Diet: ad libitum pelleted diet, A04 C
- Water: ad libitum, tab water
- Acclimation period:7 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 °C +/- 2 °C
- Humidity (%): 50 % */- 20%
- Air changes (per hr): 13 fold
- Photoperiod (hrs dark / hrs light): 12h/12h

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

olive oil

Details on oral exposure:

ADMINISTRATION / EXPOSURE 
- Vehicle: olive oil (Sigma)
- Total volume applied: 5 ml/kg bw/day
- Rate of preparation of substance: weekly

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Before start, the stability of the test substance suspended in olive oil was checked at 10 and 200 mg/ml,. From each preparation samples were taken
at 3 different levels (top, meddle, bottom) and gas chromatographically analyzed. On week 1 and 4 each preparation was checked for achieved
concentration of the test substance. The results of analyses revealed a good stability 9 days at 4 °C for investigated suspensions under the
conditions of preparation mentioned. Throughout the study a satisfactory concordance between obtained and nominal concentrations was found.

Duration of treatment / exposure:

29 days

Frequency of treatment:

once daily

Doses / concentrations

Remarks:

Doses / Concentrations:
50, 150, or 1000 (day 1) / 500 (following days) mg/kg bw d
Basis:

No. of animals per sex per dose:

control and high dose group: 12 per group and sex  
50 and 150 mg/kg bw dose groups: 6 per group and sex

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: 2 weeks (designated animals of control and high dose groups)
On day 2, before treatment, 1/12 females given 1000 mg/kg was found dead and 2/12 females of the same group were prematurely killed due to
poor clinical condition. Therefore, the high dose level for this group was reduced to 500 mg/kg/day from day 2 until the end of the treatment period.

Positive control:

no positive control

Examinations

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS AND FREQUENCY: 
- Clinical signs: at least twice daily (same time of day)
- Mortality: at least twice daily including weekends
- Body weight: before treatment and once a week including recovery period
- Food consumption: once a week including recovery period
- Haematology: day 27 (24 hours after preceding treatment and without  food)
- Biochemistry: day 27; for some parameters and recovery test animals  also at the end of the recovery period
- Urinalysis: day 27; for recovery test animals also at the end of the  recovery period

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC): 
- Macroscopic:   weights of adrenals, brain, heart, kidneys, liver, mesenteric and  mandibular lymph nodes, ovaries, spleen, testes, thymus, thyroids 
with  parathyroids    examination of adrenals, aorta, brain including medulla / pons,  cerebellar and cerebral cortex, caecum, colon, duodenum, 
eyes with  Harderian glands, femoral bone with articulation, heart, ileum, jejunum,  kidneys, liver, lungs with bronchi, lymph nodes (mandibular and   mesenteric), mammary glands, oesophagus, ovaries, pancreas, pituitary  gland, prostate, rectum, sciatic nerve, seminal vesicle, skeletal muscle,  
skin, spinal cord (cervical, thoracic and lumbar), spleen, sternum (with  bone marrow), stomach, salivary glands (sublingual and submaxillary),  
testes and epididymides, thymus, thyroids with parathyroids, trachea,  tongue, urinary bladder, uterus (horns and cervix), vagina
- Microscopic:    
high dose group and controls plus prematurely died animals: all  macroscopic lesions and adrenals, duodenum, heart, kidneys, liver, lungs  with 
bronchi, ovaries, spleen, stomach, testes and epididymides, thymus,  thyroids with parathyroids   
other groups: all macroscopic lesions and lungs, liver, kidneys

Other examinations:

no other examinations

Statistics:

STATISTICAL METHODS: sequence as follows:
- normality of distribution (Kolmogorov-Smirnov's test)
- homogeneity of variances: Fisher's test (2 groups) or
Bartlett's test (> 2 groups)
- no significant heterogeneity: Dunnett's test
- heterogeneous variances: Mann Whitney's test (2 groups) or Dunn's test  (> 2 groups)
- no normal distribution: repeat analysis after logarithmic  transformation (except for organ weights)
- still no normal distribution: Dunn's test (original values)

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not examined

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

not specified

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

no effects observed

Behaviour (functional findings):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

TOXIC RESPONSE/EFFECTS BY DOSE LEVEL: 
- Mortality and time to death: On day 2, 1/12 females was found dead and  2/12 females were prematurely killed due to poor clinical conditions. No  
other mortalities occurred during the treatment or recovery periods.
- Clinical signs: Signs of poor clinical condition and locomotory  difficulties were noted in females given 1000 mg/kg/day on day 1. After  the 
decrease of the high dose level to 500 mg/kg/day, these clinical  signs disappeared. Ptyalism was observed at all dose levels during the  treatment 
period.
- Body weight gain: No relevant effects on body weight were noted in  treated animals during the treatment and recovery periods.
- Food consumption: A slight increase in food consumption was noted  in the females of the high dose group during the last week of 
treatment.  Evidence of reversibility was found.
- Clinical chemistry: Slight to moderate decrease in glucose level was  noted in males and females of the high dose group. Evidence of  reversibility
 was found.
- Haematology: No relevant findings were noted in treated animals.
- Urinalysis: No findings of toxicological significance were found at the  end of the treatment or recovery period.
- Organ weights: An increase in kidney weight was noted in males at all  dose levels, and an increase in liver weight was noted in females of the  
high dose group. Evidence of reversibility was found.
- Gross pathology: Irrecular colour of the kidneys was noted in males of  the high and medium dose groups. Evidence of reversibility was found.
- Histopathology: In line with the increase in liver weight,  hepatocellular hypertrophy was noted in females of the high dose group.  In line with the 
increase in weights and the irregular colour, excessive  acidophilic globules were found in the cortical tubular epithelium of the  kidneys of the
treated males at all dose levels. Evidence of  reversibility was found for these microscopic findings.

Effect levels

Dose descriptor:

NOAEL

Effect level:

150 mg/kg bw/day (nominal)

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

no further remarks

Applicant's summary and conclusion

Conclusions:

For all findings, evidence of reversibility was found after two weeks without treatment. Therefore, in the experimental conditions of the study, the
No Observable Adverse Effect Level is reported as 150 mg/kg bw/day.

Executive summary:

In this 28-day repeated dose oral toxicity study three groups of male and female rats were dosed with 50, 150, and 500 mg (except first day 1000mg/kg) Cyclododecane/kg bw daily for 4 weeks by oral gavage. A concurrrent control group received olive oil only. The test material was diluted in olive oil at a temperature of about 61 °C and prepared weekly. First 6 animals of the control and the high dose group remained untreated after the 4 weeks applicationn period for a 2 week recovery period. The daily administration of cyclododecane induced mortalities and poor clinical conditions in females after one treatment at 1000 mg/kg/day, ptyalism at all dose levels and a slight increase in food consumption in females given 1000/500 mg/kg/day. A decrease in glucose level was noted at 1000/500 mg/kg/day and granular casts were found in the urine of males at all dose levels. In addition, an increase in liver weight, correlated to hepatocellular hypertrophy was noted in femals given 1000/500 mg/kg/day. An increase in kidney weights correlated to irregular colour and presence of acidophilic globules (due to the presence of alpha 2 µ globulin) in the cortical tubular epithelium was found in males at all dose levels, and were considered to be of no toxicological significance, in regard to the specificity of this urinary protein in the male rat. For all these findings, evidence of reversibility was found after two weeks without treatment. Therefore, under this experimental conditions, the No Observe Adverse Effect level is 150 mg/kg/day.