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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1988
Report Date:
1987

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)
Deviations:
not specified
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
No data

Test animals

Species:
rat
Strain:
other: Charles river CD-1, COBS (ICR derived)
Details on species / strain selection:
Charles river CD-1, COBS (ICR derived)
Sex:
male/female
Details on test animals and environmental conditions:
Charles River CD-1, COBS (ICR- derived) mice, obtained from Charles River Breeding Laboratories, Wilmington, MA were 42 days old at the start of the study. Each mouse was identified with a metal ear tag, and if the tag was lost, the animal was re-tagged and/or toe-clipped. The mice were housed individually in stainless-steel cages kept in a separate room, with a temperature and relative humidity in the range of 20-21°C and 40--60%, respectively, and a 12-hr light/dark cycle. Food was available ad lib. Control animals received the basal diet and treated animals received the appropriate dietary admixture

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Fresh diets were prepared and presented weekly. The diets were blended in a twin-shell blender, and assays were performed to determine the homogeneity and stability of the tested substance in the prepared diets prior to the start of the study
Duration of treatment / exposure:
104 weeks
Frequency of treatment:
daily with food
Doses / concentrationsopen allclose all
Dose / conc.:
0.5 other: %
Dose / conc.:
1.5 other: %
Dose / conc.:
5 other: %
No. of animals per sex per dose:
360 test nimals (60 sex/group)
Control animals:
yes
other: 240 animals
Details on study design:
The tested substance was administered in the diet to 360 mice (60/sex/group) at dietary levels of 0.5, 1.5 or 5.0%. The 240 mice in the two control groups received the basal diet for corresponding periods of time. The study protocol required exposure either for 24 months or until survival decreased to ten animals of one sex in any group, at which point all animals of that sex in the study were to be killed.
Positive control:
No data

Examinations

Observations and examinations performed and frequency:
Detailed physical examinations for signs of toxicity and palpation for masses were conducted weekly. Individual body weights and food con- sumption were determined weekly for the first 14 wk, bi-weekly for wk 16-26, and monthly thereafter. The intake of FD & C Yellow No. 5 was calculated from body weight, food consumption and dietary concen- tration and was expressed in mg/kg/day.Death, mortality and gross signs of toxicity were recorded twice daily, with at least 5 hr between ob- servations. ù
Sacrifice and pathology:
A complete histological study was conducted on all animals from the two control groups and from the high-dose (5.0%) group. Both absolute and relative organ weights were recorded for brain, gonads, kidneys, liver, spleen and thyroid. The fol- lowing tissues were examined histologically for all control and high-dose mice: adrenals (two), aorta (abdominal), bone and marrow (femur), blood smear, brain (three sections: through the frontal cortex and basal ganglia, parietal cortex and thalamus, and cerebellum and pons), oesophagus, eye (two, with optic nerve), gall bladder, heart (with coronary ves- sels), liver, lung and mainstem bronchi (lungs inflated with formalin), lymph nodes (mesenteric and medias- tinal), mammary gland (inguinal), nerve (sciatic), ovaries, pancreas, pituitary, prostate, salivary gland (mandibular), seminal vesicles (two), skeletal muscle (biceps femoris), skin, spinal cord (cervical), spleen, stomach, testes (with epididymides), thymus, thyroid with parathyroid, trachea, urinary bladder (inflated with formalin), uterus, any tissue with gross changes of an uncertain nature (with a section of an area of normal appearance from the same tissue), and any tissue or masses or suspect tumours with regional lymph nodes. If a potential effect was consistently noted in a tissue, then that tissue was examined histologically in all animals. Histology was con- ducted on any low-dose (0.5%) or mid-dose (1.0%) animal with gross lesions or masses. All excised tissues remaining after the histological examination were preserved.
Other examinations:
Ten animals of each sex from each group were randomly selected for haematology tests at months 3, 6, 12, 18 and 24 of the study. The haematological parameters evaluated were haemoglobin, hae- matocrit, erythrocyte and total and differential leuco- cyte counts, and erythrocyte morphology. Necropsies were conducted on all animals dying spontaneously, killed in a moribund condition, or killed on schedule.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Physical observations noted throughout the study included hair loss (due to friction against the cage), lacrimation, nasal discharge, staining of hair in the anogenital region and soft stools. These observations occurred randomly and in low incidence throughout all groups and were not related to compound administration. Yellow hair and skin were noted in all treatment groups
Mortality:
mortality observed, non-treatment-related
Description (incidence):
Male and female mice received the tested substance for 104 wk and the survival of the mice was found to be similar for the treated and control groups throughout the study.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
A decrease was noted in the mean body weight at study termination in male and female mice in the 5.0% group. This decrease is not considered toxicologically significant and may be due to the non-nutritive character of the tested substance. Mean body weights of male and female mice in the 5.0% treatment group, and male mice in the 1.5% treatment group were lower than the controls at a number of sampling intervals. These differences, while usually slight, were statistically significant at several intervals.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Mean food consumption was increased in male mice that consumed 5.0% of the tested substance The differences from control values were slight but statistically significant at several sampling intervals. The mean food consumptions among other treatment groups and controls were similar.
Food efficiency:
effects observed, treatment-related
Description (incidence and severity):
The tested substance does not have any nutritive properties.
Water consumption and compound intake (if drinking water study):
not specified
Haematological findings:
no effects observed
Description (incidence and severity):
There were no consistent statistically significant differences between control and treated animals for the haematological parameters evaluated.
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Description (incidence and severity):
Amber or yellow-brown coloured urine was noted at all treatment levels within 1 wk of the start of the study. The faeces of mice fed at dietary levels of 1.5 and 5.0% were purple and yellow-brown, respectively.
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
no effects observed
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
effects observed, non-treatment-related
Description (incidence and severity):
A variety of neoplasms was noted in all mice. Neither the incidence of neoplasms nor their primary locations and histological characteristics differed significantly between the control and treated animals. All of these neoplasms were of types commonly found in ageing mice (Turusov, 1979). There were no statistically significant differences for time-to-tumour analyses between the control and treated animals.
Other effects:
not specified

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
ca. 8 103 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
mortality
Dose descriptor:
NOAEL
Effect level:
ca. 9 735 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
mortality

Target system / organ toxicity

Critical effects observed:
no
System:
other: -

Applicant's summary and conclusion

Conclusions:
Not toxic for repeated dose oral exposure.
Executive summary:

There were no consistent, biologically significant compound or dose-related effects on behaviour, morbidity, mortality, haematology, or general physical observations in this study.