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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
chronic toxicity: oral
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Justification of read-across: Both chemicals are of comparable structures with minor deviations and can be characterized as an ester of sorbitan and a fatty acid. Justification of reliability of 2: scientifically well-performed study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1978
Report Date:
1978

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Test material form:
not specified
Details on test material:
- Cream-coloured granular waxy solid at 25°C;
- acid number, 5.0-10-0: saponification value, 147-157:
- hydroxyl number, 235-260: water content, max 10%
- sulphated ash, max 0'25~o: arsenic, max 3 ppm: lead,
- max 10 ppm: copper, max 50 ppm: zinc, max 25 ppm.

Test animals

Species:
mouse
Strain:
other: TO
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: A.Tuck & Son, Ray!eigh, Essex
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 + I
- Humidity (%): 50-70

Male mice were caged singly to avoid fighting, and females were housed four to a cage.

Administration / exposure

Route of administration:
oral: feed
Vehicle:
not specified
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
80 weeks
Frequency of treatment:
feed, continuously
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 0.5, 2, 4%
Basis:
nominal in diet
No. of animals per sex per dose:
48
Control animals:
yes, plain diet

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: frequently

BODY WEIGHT: Yes
- Time schedule for examinations: Sixteen male mice from each group were weighed at the commencement of the study and subsequently at approximately monthly intervals

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At week 12 and 52, at week 80
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: at week 12 and 52: 10 male, 10 female from the control group and from the groups fed 2 or 4%; at week 80: all surviving mice
- Parameters checked : haemoglobin concentration and packed cell volume,as well as for counts of total erythrocytes and leucocytes.Differential white cell counts were performedon samples from the control and 4°/o-Span 60 groups.Slides for the demonstration of reticulocytes were prepared,but were not examined in the absence of effects on the erythrocytes.

CLINICAL CHEMISTRY: No data

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
At the end of the study all surviving animals were killed by exsanguination from the aorta under barbiturate anaesthesia after an overnight fast. At autopsy any macroscopic abnormalities were noted and the brain, heart, liver, kidneys, spleen, stomach and small intestine were weighed. Samples of these organs together with the caecum, salivary gland, thyroid, thymus, adrenal glands, lymph nodes, pancreas, pituitary, testes, seminal vesicles, prostate, ovaries, uterus, urinary bladder, lungs, trachea, oesophagus, colon, rectum, spinal cord, skeletal muscle, eye and Harderian gland and any other tissue that appeared abnormal were preserved in 10% neutral buffered formalin.


HISTOPATHOLOGY: Yes
The tissues were embedded in paraffin wax and sections were stained with haematoxylin and eosin for histopathological examination. Smears of femoral bone marrow were prepared and stained but were not examined.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
not specified
Details on results:
CLINICAL SIGNS AND MORTALITY
No effects. Deaths occurred in all groups during the course of the experiment, but there was no relationship between the number of deaths at any time and the dietary level of the dietary level of test item.

BODY WEIGHT AND WEIGHT GAIN
At week 37 the mice given diet containing 4% test item had a significantly lower weight than the controls. At week 80 after an overnight fast, the body weights of the males fed 0.5 or 4% test item were significantly lower thanthose of controls.

HAEMATOLOGY
Haemoglobin con centration and packed cell volume were similar in treated and control mice throughout the study, but at week 80 there was a slight but significantly higher total erythrocyte count in male mice fed 4% test item. In female mice fed 4% test item, there were significantly lower numbers of total leucocytes at all three examinations, whereas in the corresponding males the number of leucocytes was higher at week 2 and did not differ significantly from that of the controls at week 52 or 80. In the female animals fed 4% test item there was a signi'ficantly higher percentage of neutrophils at week 80.

ORGAN WEIGHTS
In males fed 0.5 or 4% test item there were statistically significant deviations in the mean organ weights in comparison with the controls. The organs affected were the brain, kidney and stomach (in the 0.5% group), liver (in the 4% group) and spleen (in both groups), all of which were lighter than control values. When
the organ weights were expressed relative to body weight, however, the relative brain weights in the 0.5 and 4% groups and the kidney weight in the 4% group were significantly higher than the control values. In female mice, by contrast, the mean spleen weight, however, the relative brain weights in the 0.5 groups were higher than those of the controls although the values were statistically significant only in mice fed 2% test item, Significantly higher kidney weights compared with the control values were seen in the females fed % test item. The mean stomach weight in female mice fed 2% test item was lower than the control value, as was the mean brain weight of those given 0.5% test item . When expressed relative to body weight, the stomach weights of the 0.5% and 2% groups were lower than the control values but the relative spleen weight of the mice fed 2% test item and the relative kidney weight of those fed 4% were significantly higher than those of the controls.

HISTOPATHOLOGY: NON-NEOPLASTIC
The histopathological findings were similar in all groups of mice, apart from an increased incidence of nephrosis in the kidneys of both male and female mice fed 4% test item. A single mouse (male, 2% group) showed calcification of the stomach. Chronic inflammation of the skin was apparent in one male control, two males given 0.5%, one male given 2% and four males given 4% test item.

HISTOPATHOLOGY: NEOPLASTIC
Most of the turnouts found in the study occurred either with comparable frequency in the test and control groups or more frequently in the controls.
One carcinoma of the liver occurred in the 4% group of female mice without any similar tumours in control or lower-dose groups, but similar liver tumours were identified in male mice, one in the control group and one each in the 0.5 and 4% treatment groups. Generalized lymphosarcomas occurred in all four groups of female mice, the numbers affected being one, five, three and two in the 0, 0.5, 2 and 4% groups respectively, Two otherisolated malignant tumours were found; one was a pancreatic islet-cell adenocarcinoma (male, 2%) and the other a subcutaneous fibrosarcoma (female, 2%). The non-malignant neoplasms found in treated mice without comparable findings in controls or in the highest dose group, were a luteoma and a papillary cystadenoma of the ovary (0.5 and 2% groups respectively), a uterine leiomyofibroma (2%), two well-differentiated renal adenomas (males, 2%), a pancreatic islet-cell adenoma (male, 0.5%) and a well-differentiated squamous papilloma of the skin (male, 2%).The only benign turnout found at the highest dietary level without a comparable control finding was the
solid pulmonary adenoma found in a female.

Effect levels

open allclose all
Dose descriptor:
NOEL
Effect level:
ca. 2 600 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: enlargement of the kidneys and a higher incidence of nephrosis compared with controls
Dose descriptor:
NOEL
Effect level:
20 000 mg/kg diet
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: enlargement of the kidneys and a higher incidence of nephrosis compared with controls

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

The analogue approach using sorbitan stearate as source chemical is justified:

Both chemicals are of comparable structures with minor deviations and can be characterized as an ester of sorbitan and a fatty acid. Compared to the source chemical, the target chemical has a shorter alkyl chains that affect its physicochemical properties. But based on the kinetic / metabolic investigations on both chemicals, the length of the alkyl chain is not considered to have significant impact on the metabolic pathway or toxicological mode of action. Oral gavage studies in rats administered C14 labeled sorbitan stearate in oil solutions have demonstrated that about 90% of the substance was absorbed and hydrolyzed to stearic acid and sorbitan. The metabolic fate of sorbitan caprylate was investigated using a lipase assay. The hydrolysis mediated by porcine pancreas lipase was quantitatively determined. The target chemical sorbitan caprylate is proved to be hydrolyzed and caprylic acid was formed . These findings suggest that metabolism of the sorbitan occur initially via enzymatic hydrolysis, leading to sorbitan and the corresponding natural acids.

Based on the above mentioned information, it is reasonable to consider that these two substances are comparable in their metabolic fate and thereby toxicological profiles. Hence, the source chemical is considered as “suitable with interpretation” analog.

According to the available toxicity studies, the findings are also comparable for target and source chemicals:

·        The findings in acute toxicity studies are comparable. Both chemicals are of no acute toxicity.

·        The findings in subacute dose toxicity studies are comparable. No treatment effects were observed in 28-day repeated toxicity studies in Wistar rats. The same NOEL of 1000 mg/kg bw/d was derived for both chemicals.

·        The findings in genetic toxicity are comparable. Both chemicals did not induce gene mutations in Ames tests, but induced structural chromosomal aberrations in cell lines of Chinese Hamster.

·        The findings in reproduction / developmental toxicity studies are comparable.

Applicant's summary and conclusion

Conclusions:
The repeated dose toxicity of sorbitan monostearate was investigated in mice for 80 weeks. The no effect level in mice was 2% of the diet, providing an intake of approximately 2600mg/kg/day.
Executive summary:

The repeated dose toxicity of sorbitan caprylate was assessed based on the analogue approach using sorbitan monostearate as a read-across supporting substance.

Sorbitan monostearate was given to groups of 48 male and 48 female mice at dose levels of 0 (control), 0.5, 2.0 or 4.0% of the diet for 80 weeks. There was no evidence of carcinogenic activity at any of these dose levels. The treatment had no adverse effects on the death rate or rate of body-weight gain. Both male and female mice receiving 4% test item showed enlargement of the kidneys and a higher incidence of nephrosis compared with controls. Other organ-weight changes appeared unlikely to be directly related to treatment, as did a significant depression in the total leucocyte count in the blood of female but not of male mice given 4% test item.

The no-untoward-effect level in this study was considered to be 2.0% of the diet, or approximately 2600 mg/kg body weight/day.