Cycloheptapentylose

Carcinogenicity

Description of key information

The substance did not show any evidence of carcinogenic effects when administered orally in feed at concentrations of up to 675 mg/kg bw to rats and mice. 

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline study report

Qualifier:

according to guideline

Guideline:

OECD Guideline 451 (Carcinogenicity Studies)

Deviations:

no

Principles of method if other than guideline:

not applicable

GLP compliance:

yes

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

Two hundred and ninety-nine males and 300 female Charles River Fischer F344 rats were received from Charles River UK on 11 July 1989. The animals were about 3 weeks old on arrival. A 10% sample was weighed and ranges were 36-65 g for males and 35-64 g for females. A 12-day acclimatisation period was allowed before com-mencement of treatment. During this period, all animals were observed daily for any sign of ill-health. Prior to commencement of treatment. 10 male and 10 female rats were bled and sacrificed with gross necropsy in order to establish that a healthy batch of rats was received. Blood samples were subjected to haematological examinations. No ab-normalities were detected in haematological parameter examination at necropsy.
The animal room had its own supply of filtered air which was passed to atmosphere without recirculation; there were at least 15 air changes per hour. Periodic inspections were made of the number of air changes. Temperature and relative humidity in the ani-mal room were recorded daily and the records retained. Target values were 21°C +/- 2°C and 55% +/- 15% RH. The animals were subjected to a 12-hour light 12-hour dark cycle.

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
beta-cyclodextrin was added directly into 0.5 kg of basal diet and was mixed by hand. This' was then added to form a 1 kg mix and was mixed for 5 minutes in a Patterson-Kelley Cross Flow Y-cone mixer. This was followed by adding further quantities of diet into the mixer followed by the Serogo mixer to provide homogeneous mixes until the highest concentration to be fed to the animals was prepared. Lower concentrations were formed by step-wise dilution from the highest concentration.

DIET PREPARATION
- Rate of preparation of diet (frequency): All diets were pre-pared weekly

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

not reported in the final report

Duration of treatment / exposure:

122 weeks (males), 130 weeks (females)

Frequency of treatment:

daily (diet)

Post exposure period:

not reported

Remarks:

Doses / Concentrations:
0, 25, 75, 225 and 675 mg/kg/day
Basis:
nominal in diet

No. of animals per sex per dose:

50 animals /sex and dose

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: Oral route is the expected route of administration in humans. Dosages were selected in consultation with the Sponsor in
consideration of the intended use, human intake and known toxicity.
- Rationale for animal assignment (if not random): random

Positive control:

not applicable

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily


BODY WEIGHT: Yes
- Time schedule for examinations: weekly for first 15 weeks, then biweekly


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each cage determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes


FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations:end of study
- Dose groups that were examined: 0, 675 mg/kg/day


HAEMATOLOGY: Yes
- Time schedule for collection of blood:weeks 54, 79, 102, 121, 128
- Animals fasted: Yes


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At 12, 18, 24 months and prior to terminal kill, blood smears for differential white blood cell counts were pre-pared from all animals. Blood was collected from the tail. Blood smears for differential white blood cell counts were prepared and stained by the modified Romanowsky stain. These were examined for Groups 0 and 675 mg/kg/day only.
- Animals fasted: Yes



URINALYSIS: No data


NEUROBEHAVIOURAL EXAMINATION: No data

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
ORGAN TISSUE
Abnormalities, Adrenals Land R, Aorta, Bone (sternum incl. marrow + tibia femoral joint), Brain (medulla/pons. cerebellar + cerebral cortex), Caecum, Colon, Duodenum, Epididymides L and R, Eyes and optic nerves L and R, Harderian glands L and R, Heart, Ileum, Jejunum, Kidneys Land R, Liver (2 lobes), Lungs (incl. mainstem bron-chi), Lymph nodes (cervical. mesenteric, abnormal), Mammary glands
HISTOPATHOLOGY: Yes
After dehydration and embedding in paraffin wax, sections were cut at 4-5 micron thickness, and stained with haematoxylin and eosin. Sections of both glandular and non-glandular regions of he stomach, and both auricular and ventricular sections of the eart were prepared. The brain was sectioned at three levels. Two sections of the liver and lungs, and the eyes with optic nerves and Harderian glands, were similarly processed.

Other examinations:

none reported

Statistics:

The significance of any intergroup differences in body weight performance, food con-sumption, water intake, absolute organ weight and haematology data was assessed as follows: homogeneity of variances was tested by the Bartlett's test. Where variances were homogeneous (p>0.01) then a parametric analysis of variance (ANOVA) was ap-plied. When the F values were significant Dunnett's multiple range test was applied for differences between the controls and treated groups. Where the variances were non-homogeneous the data was analysed by the Kruskal-Wallis non-parametric ANOVA. If a
significant difference between the groups was detected then the Dunn's test was ap-plied for locating differences between the treated and control groups. Survival rate was analysed by the SAS Lifetest Procedure censoring for accidental deaths and scheduled sacrifice. Organ weights were also analysed using necropsy body weight as a covariant. Where a significant difference was found between the groups and this was at least partially accountable for by treatment (p<0.05), the multiple 't'-tests were applied for locating differences between the treated and control groups. All observations were examined by standard distribution dependent techniques as de-scribed above, except for the following data, where distribution-free techniques were used due to the lack of homogeneity amongst the variances.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

Mortality
Mortality was similar in all groups. At commencement of terminal sacrifice (Weeks 122 and 129 in males and females respectively), the survival rate (corrected for accidental deaths) in group order (beginning with control) was 24%, 26.5%, 24%, 32% and 34% in males and 30%, 36%, 30%, 34% and 28% for females.

Clinical Signs
A variety of signs was recorded in rats of all groups. The distribution of these signs be-tween the groups indicate no treatment-related effect.
During Week 14 sporadic cases of diarrhoea were recorded. As the incidences of diar-rhoea increased it was decided to investigate the phenomenon. A veterinary control rat with diarrhoea was sacrificed
and sent to the Ministry of Agriculture. Alpha haematolytic streptococci were found in faeces, but were not considered to be the cause of the diarrhoea. Food and water from the animal roam were examined but no streptococci were found. During Weeks 14-27 animals were examined daily by the Veterinary Officer and recordings take. During Weeks 22-24 the frequency of diarrhoea had declined and was reported as
normal.
The lack of dose response, the reversibility of the observed signs and the fact that no other sign was observed (i.e. shortening of life, detection of any symptom at post mor-tem, etc.) lead to the conclusion that these phenomena are not related to treatment.
In addition to the above, loose faeces were recorded sporadically during the study in all groups (including controls). This was recorded during weeks 11 termination and was not regarded as treatment-related. All other signs observed in this study are commonly ob-served in rats of this strain held in the laboratory. No difference between the groups was apparent regarding the incidence of palpable masses detected "in life".

Body Weight
No effect of treatment on body weight gain was detected throughout the entire study period. Body weight of the males of the high dosage group were significantly lower than the controls for Weeks 0, 2-4 and 7. Males of this group had commenced the study at a lower body weight following randomisation by numbers. The reduced body weight is
therefore not treatment-related. Statistically significant differences were observed spo-radically but these cases are regarded to be a result of normal biological variance.

Food Intake and Food Conversion Ratio
Sporadic cases of statistically significant values were apparent in several groups when compared to control. However, as they are scattered within the groups and not dose-related none of them are considered as related to treatment.

Waterintake
Statistical significant reduction was apparent in water consumption for the female high dosage groups compared to the controls during Weeks 8-20. Therefore measurements were carried out for all groups of males and females throughout the entire study. Al-though, in several cases statistical differences were noted, they are not considered as treatment-related.

Haematology
No consistent treatment-related effects were detected among the haematological pa-rameters examined. Sporadic statistically significant changes were present throughout the study, however these are not considered to be related to treatment with test sub-stance.

Organ Weights
No difference was noted in the absolute organ weight in any of the animals treated with beta-cyclodextrin, as compared to control rats. However, when calculated as a percent-age of body weight the relative kidney weight in males of the intenmediate group was statistically (p < 0.05) heavier than the controls. This finding is not considered to have any biological significance and is regarded as a result of the lower (p < 0.01) body weight of that group at necropsy.


Macroscopic Pathology
There was a wide range of lesions which are commonly seen in life-span studies carried out on the F344 rat. None of the observed lesions showed treatment-related increase or decrease or their incidence was comparable to that noted in control rats of the same strain and age in other experiments carried out in the test laboratory.
In addition, none of the macroscopic lesions were supported by counterpart treatment-related microscopic change. Therefore, it is concluded that beta-cyclodextrin feeding in F344 rats was devoid of any macroscopic effect.


Microscopic Pathology
A. Non-Neoplastic Lesions
None of the observed lesions is regarded as related to beta-cyclodextrin feeding. In fact, the incidences of the range of changes noted in the treated groups was comparable to that seen in the current controls or to the accumulated background data for
Fischer F344 rats of the same age.


B. Neoplastic Lesions
None of the observed neoplasms is regarded as associated with the test article feeding. In fact, the incidences 0: the various neoplasms observed in the various treated groups are compared to the current controls or to the background / data accumulated for car-cinogenicity (life span and 2-year studies) carried out at testing laboratories .
It is clear that all the noted neoplasms in the beta-cyclodextrin treated groups were within the range of acceptable background incidences for control rats of F344 rats. In particular, the uterine adenocarcinomas, although occurring at a slightly higher inci-dence in the highest dosage group, are regarded as spontaneous incidental finding and of no biological and statistical significance. In fact, the incidence of that neoplasm showed a dramatic increase (more than 100%) when the incidence of the background data accumulated for 24-month studies is compared to the current controls (range of 3.3%-8.3% in 24-month studies compared to 24% incidence in the current controls). This data indicates that the uterus of F344 rats maintained for a life-span period be-came particularly prone to develop spontaneous uterine adenocarcinoma.
Therefore, it is concluded that the slight increase of uterine t1denocarcinomas in the highest dosage group of the current study occurred by chance and has no bearing on the biological significance in regard to the beta-cyclodextrin treatment.
Other tumours, which reached statistical significance, are regarded as stated, not asso-ciated with the test article feeding. The tumours are:
Parathyroid adenoma - reached a low trend of significance in males and in the data combined by sex.
Testicular interstitial cell tumour achieved an intermediate (p<0.01) trend of statistical significance, but this tumour is unequivocally regarded as an incidental spontaneous neoplasm.
Subcutaneous fibroma -although this neoplasm achieved a low grade trend of statistical significance in males and in the combined by sex data, its incidence is well within the published background data for this strain.
The combined data by disease severity of uterine endometrial stromal polyp and sar-coma achieved a low grade of statistical significance. The incidence of these lesions in the study is within the range of 2-year background data.
Total primary tumours - only among treated males

Tumour analysis - according to their biological behaviour

There was a slight increase in the following parameters.
1. Total primary tumours - only among treated males
2. Total secondary tumours (neoplasms having metastatic dissemination) - only among females, mainly in the highest dosage group.
3. Total neoplasms whose site of origin is unknown - among treated males
The increase of total primary tumours in males is mainly due to an increase of benign tumours in treated groups. This variation, as well as the others reported, in tumour inci-dence are regarded as occurring incidentally and of no relation to beta-cyclodextrin treatment. Text Table No. 1 presents the incidences of various tumour types in the cur-rent study and compares them to the accumulated background data. It is clear that most types of tumours (except uterine adenocarcinoma - see comment on neop1astic lesions in Results section) have incidences which are included within the range of control back-ground data.
The increase in the total number of secondary tumours among the female highest dos-age group is explained by the spontaneous increased incidence occurrence of uterine adenocarcinoma; colon neurilemona; ileum leimyosarcoma and spleen fibrosarcoma. The increased incidence of total number of neoplasms whose site of origin is unknown in the mal"e treated groups is explained by the spontaneous increase of incidence of mononuclear cell leukaemia.

Tumour analysis - multiplicity of tumours
The different analysed parameters (i.e. the total number of animals having one, two or more different types of tumours) were comparable among treated and control groups.

Relevance of carcinogenic effects / potential:

The carcinogenic effects seen in the study are within the historical control data for this strain at the laboratory.

Dose descriptor:

NOEL

Effect level:

>= 675 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: overall effects

Remarks on result:

other: Effect type: carcinogenicity (migrated information)

Dose descriptor:

NOEL

Effect level:

>= 675 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: overall effects

Remarks on result:

other: Effect type: toxicity (migrated information)

Conclusions:

The substance is not carcinogenic to rats under the conditions used in this study.

Executive summary:

beta-cyclodextrin (86.6 and 87.0 % pure) was examined in an oncogenicity study in F344 rats according to OECD Guideline 451 found to have no effect on survival,or potential to cause carcinogenic effects in this species. 50 animals of each sex were administered with 0, 25, 75, 225 and 675 mg/kg/day for 122 weeks (males) and 130 weeks (females) respectively. In addition, neither toxic clinical signs nor effects on body weight, food and water consumption were detected throughout the study period. The highest dosage tested in this study was 675 mg/kg per day.Regarding the observed increased incidence of several tumors in the study, none of the tumors exceed the background data. Uterine adenocarcinomas, although occurring at a slightly higher incidence in the highest dosage group, but not statistically significant, are regarded as a spontaneous, incidental finding, and of no biological significance. In fact, the incidence of this neoplasm showed a dramatic increase when the incidence of the testing facility background data accumulated for 24 month studies, was compared to the concurrent controls (range of 3.3-8.3% in 24 month studies, compared to 24% incidence in the current control). Therefore it can be concluded that the slight increase of uterine adenocarcinoma in the current study in the highest dosage group occurred by chance and has no bearing on the treatment with beta-cyclodextrin. Regarding the parathyroid adenoma and subcutaneous fibroma, the incidence in all groups was comparable with the background data. In relation to the significant trend for the Leydig cell tumour, this effect was not considered related to treatment but due to the naturally high incidence of this tumor in this strain, and due to the fact that the incidence of the tumor did not exceed the literature data on this tumor in Fischer 344 rats, which is generally considered to be about 100%. In conclusion, chronic feeding of beta-cyclodextrin to Fischer 344 rats mice did not cause any treatment related carcinogenic effects.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

675 mg/kg bw/day

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The carcinogenic potential of beta-cyclodextrin (86.6 and 87.0 % pure) was investigated in a life-time feeding study according to OECD Guidelines 451. Four groups of CD-1 mice were fed diet containing beta-cyclodextrin continuously to provide dosages of 25, 15, 225 and 675 mg/kg/day for a maximum of 106 weeks in females and 93 weeks in males. A control group fed basal diet, was treated concurrently. Treatment at all doses was well tolerated with no clinical signs of reaction to treatment. There were no palpable masses attributed to treatment. Survival rate was similar in all groups. Body weight, food intake and water consumption were similar in all groups throughout the entire study period. Slight changes sporadically observed in the haematology parameters examined are not considered as treatment-related but the result of normal biological variances. At terminal sacrifice no difference was apparent in any of the organs weighed at necropsy.Findings related to treatment with beta-cyclodextrin were noted in the large intestine; a reduction of abdominal fat pads in decedent mice, mainly of the highest dosage group was also observed. The main changes in the highest dosage group observed in the large intestine included: abnormal contents, distended lumen and oedematous mucosa. All other macroscopic changes were considered unrelated to treatment with beta-cyclodextrin.None of the observed neoplastic lesions was associated with the life-span treatment with beta-cyclodextrin. The only treatment-related changes associated with this compound were of the non-neoplastic type and were observed particularly in decedent mice mainly of the highest dosage group (7 male and 6 female mice of the highest dosage group, one male mouse of the high intermediate and two male mice of the low intermediate dosage group). Such changes were limited to various segments of the large intestine, mostly the caecum, and atrophy of abdominal fat pads. The latter achieved statistical significance (p<0.05) with an increase of dose in males and in data combined by sex. The lesions observed in the large intestine included: evidence of active desquamation of surface epithelium and mucosa covered by mucous secretion containing exfoliated cells. Changes noted solely in the caecum were: acute catarrhal inflammation, mucosal flattening and atrophy of intestinal glands. The last two lesions achieved significant values for males and females (p < 0.01, p < 0.01) respectively. Colonic mucosa covered by mucous secretion achieved a highly significant value (p < 0.01) in females and in data combined by sex. No non-neoplastic treatment-related lesion was observed in terminally killed mice, except for one male mouse of the highest dosage group showing caecal lesions. Under the conditions of this study beta-cyclodextrin is assessed as showing no evidence of carcinogenicity in the mouse.

beta-cyclodextrin (86.6 and 87.0 % pure) was examined in an oncogenicity study in F344 rats according to OECD Guideline 451 found to have no effect on survival,or potential to cause carcinogenic effects in this species. 50 animals of each sex were administered with 0, 25, 75, 225 and 675 mg/kg/day for 122 weeks (males) and 130 weeks (females) respectively. In addition, neither toxic clinical signs nor effects on body weight, food and water consumption were detected throughout the study period. The highest dosage tested in this study was 675 mg/kg per day. Regarding the observed increased incidence of several tumors in the study, none of the tumors exceed the background data. Uterine adenocarcinomas, although occurring at a slightly higher incidence in the highest dosage group, but not statistically significant, are regarded as a spontaneous, incidental finding, and of no biological significance. In fact, the incidence of this neoplasm showed a dramatic increase when the incidence of the testing facility background data accumulated for 24 month studies, was compared to the concurrent controls (range of 3.3-8.3% in 24 month studies, compared to 24% incidence in the current control). Therefore it can be concluded that the slight increase of uterine adenocarcinoma in the current study in the highest dosage group occurred by chance and has no bearing on the treatment with beta-cyclodextrin. Regarding the parathyroid adenoma and subcutaneous fibroma, the incidence in all groups was comparable with the background data. In relation to the significant trend for the Leydig cell tumour, this effect was not considered related to treatment but due to the naturally high incidence of this tumor in this strain, and due to the fact that the incidence of the tumor did not exceed the literature data on this tumor in Fischer 344 rats, which is generally considered to be about 100%. In conclusion, chronic feeding of beta-cyclodextrin to Fischer 344 rats mice did not cause any treatment related carcinogenic effects.

Another examination of the carcinogenicity of .beta.-cyclodextrin was carried out in Fischer 344 (F344) rats.Groups of 50 males and 50 females were given the compound in their diet at concentrations of 0 (control), 2.5 or 5% for 104 wk. Surviving rats were then given a basal diet for a further 5 wk and killed at 109 wk. The dose levels were selected from the results of a 13-wk subchronic toxicity study. Dose dependent inhibitory effects of .beta.-cyclodextrin on growth were observed in both sexes of the treated groups. The survival rates, mean survival times and range, however, demonstrated no significant differences between the control and treated groups.A variety of tumours developed in all groups, including the control group, but all the neoplastic lesions were histologically similar to those known to occur spontaneously in this strain of rat. and no statistically significant increase in the incidence of any tumour was found for either sex of the treated groups. Thus it is concluded that under the present experimental conditions the high dose, about 340-400 times higher than the current daily human intake from ingestion as a food additive and from pharmaceutical usedoes not have any carcinogenic potential in F344 rats.