Cyclohexapentylose

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Cycloheptapentylose

EC Number:

231-493-2

EC Name:

Cycloheptapentylose

Cas Number:

7585-39-9

Molecular formula:

C42H70O35

IUPAC Name:

5,10,15,20,25,30,35-heptakis(hydroxymethyl)-2,4,7,9,12,14,17,19,22,24,27,29,32,34-tetradecaoxaoctacyclo[31.2.2.2~3,6~.2~8,11~.2~13,16~.2~18,21~.2~23,26~.2~28,31~]nonatetracontane-36,37,38,39,40,41,42,43,44,45,46,47,48,49-tetradecol (non-preferred name)

Details on test material:

COMPOUND BETA- CYCLODEXTRINE
BATCH NUMBER 0152
I.P.L. NUMBER 900903
APPEARENCE white powder

Method

Target gene:

not applicable

Species / strain

Species / strain / cell type:

lymphocytes: human

Details on mammalian cell type (if applicable):

- Type and identity of media:
- Properly maintained: yes

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

With metabolic activation 100 - 300 -1000 µg/ml
Without metabolic activation 100 - 300 - 1000 µg/ml

Vehicle / solvent:

RPMI 1640

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

yes

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

with metabolic activation

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

yes

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without metabolic activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium;

DURATION

- Exposure duration: 1 hr (with metabolic activation), 24 hr (without metzabolic activation)
- Expression time (cells in growth medium): 22 hr
- Fixation time (start of exposure up to fixation or harvest of cells): 25 hr (with metabolic activation), 48 hr (without metzabolic activation)


SPINDLE INHIBITOR (cytogenetic assays): colcemide
STAIN (for cytogenetic assays): Giemsa


NUMBER OF REPLICATIONS: 2


NUMBER OF CELLS EVALUATED: 200


DETERMINATION OF CYTOTOXICITY
- Method: mitotic index


OTHER EXAMINATIONS:
- Determination of polyploidy: yes

Evaluation criteria:

A stUdy is accepted if :
- the mean number of cells carrying aberrations (excluding cells presenting gaps only) for the two subjects is less than 5 %·,
- the number of breaks per cell and number of cells with aberrations (excluding those with gaps only) is significantly increased.
- at least 3 of the cultures treated with the test compound present a mean mitotic index for the 2 subjects greater than about 50 % that found for the reference culture.
A compound is found to demonstrate clastogenicity against cultured human Iymphocytes if it results. ina statistically significant increase in the number of breaks per cell compared with the control or in the number of cells with aberrations (excluding gaps), if this increase amounts to at least a doubling of the control value and if the genotoxicity detected shows a.dose-effeet relationship.
A compound is found to have no clastogenic effect on cultured human Iymphocytes if it does not comply with any of the 3 criteria listed above.
If neither situation occurs, the results are discussed case by case and another independent study may be envisaged after modifying the dose range taking account of the findings obtained using other test systems.

Statistics:

Two types (gaps and breaks) are analyzed using the Student's t-test, because although the standard deviations found not to demonstrate that the normal distribution is normal it can be used because of the large number of cells (200 cells)
NUMERIC ABERRATIONS.: All numeric aberrations (aneuploidy and polyploidy) are analyzed statistically using the Chi2 test.
THE NUMBER OF DAMAGED CELLS WITH AND WITHOUT GAPS : The total number is analyzed statistically using the Chi2 test. From the comments already made regarding the significance of the presence of gaps, it results that greater weight is given to change in the number of cells presenting aberrations other than gaps in
assessing the genotoxicity·of the test compound.

Results and discussion

Test results

Species / strain:

lymphocytes: human

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: not reported
- Effects of osmolality: not reported
- Evaporation from medium: not reported
- Water solubility: not reported
- Precipitation:not reported
- Other confounding effects: not reported


RANGE-FINDING/SCREENING STUDIES: yes


COMPARISON WITH HISTORICAL CONTROL DATA: Yes, compliant


ADDITIONAL INFORMATION ON CYTOTOXICITY:
With metabolic activation 10-30-100 - 300 -1000 µg/ml for 1 hr
Without metabolic activation 10-30-100 - 300 - 1000 µg/ml for 24 hr

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Substance did not induce gaps or breaks exceeding the relevant values in this Chromosome aberration test.

Executive summary:

For this endpoint the read-across approach based on grouping of substances (category approach) was used.

The read across substance .beta.-Cyclodextrin was assessed in an in vitro Chromosome Aberration assay with human lymphocytes similar to the OECD guideline 473. The substance is soluble in aqueous medium, solutions were prepared in RPMI 1640 at the maximum concentration generally used at the laboratory, ie., 10 mg/ml. This solution was added at 10 % in culture medium. The highest final concentration was 1000 µg/ml. A Preliminary test on cytotoxicity showed a low cytotoxicity of beta-cyclodextrin both with and without metabolic activation, at the highest studied dose 1000 µg/ml, demonstrated by a weak mitotic index decrease. The tests were performed with and without metabolic activation (S9 -mix) at concentrations of 100, 300 and 1000 µg/ml with 1 (with metabolic activation) and 24 hr (without metabolic activation) exposition time. Solvent, negative and positive controls worked as expected. Reference clastogens (mitomycin C without metabolic activation and cyclophosphamide with metabolic activation by the S9 mix) were tested in order to demonstrate the sensitivity of the cells and the effectiveness of the metabolic activation system. Both tests with and without metabolic showed no dose dependent positive results presents and thus the test substance did not show clastogenic activity in the in vitro human lymphocyte metaphase analysis test.