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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16-May-1982 to 21-May-1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guidelines with acceptable deviations, and to GLP

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1983
Report Date:
1983
Reference Type:
secondary source
Title:
Unnamed
Year:
2008

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)
Deviations:
yes
Remarks:
No assessment of cytotoxicity; positive control dose too high to preserve anonymity of coded slides; no justification for non-standard schedule of treatment and sampling; no untreated controls (but there were vehicle controls) or historical data
GLP compliance:
yes
Type of assay:
chromosome aberration assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Cereclor S52
- Substance type: clear slightly viscous liquid
- Physical state: liquid
- Analytical purity: no data
- Impurities (identity and concentrations): no stabiliser
- Composition of test material, percentage of components: C14-17 chlorinated paraffin; total chlorine 51.8% w/w
- Isomers composition: no data
- Purity test date: date of works analysis 14-Nov-1978
- Lot/batch No.: 306
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data, shelf life >5 years
- Storage condition of test material: -20 ºC

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS- Source: Charles River Breeding Laboratories, Inc., Portage, Michigan, USA- Age at study initiation: 63 days old on receipt on 7-May-1982- Weight at study initiation: 206-217 g on receipt on 7-May-1982- Assigned to test groups randomly: yes, under following basis: For 48 animals, mean body weight calculated, individual absolute difference from mean calculated for each animal, sorted into increasing order of absolute difference, designated into required number of blocks, each successive block randomised, Bartlett’s test for homogeneity of variance performed across the groups, if heterogeneous then new randomisations generated, repeated until homogeneity across the groups was achieved.- Fasting period before study: no data- Housing: individually in suspended wire mesh cages (9.5 x 7 x 7 inches)- Diet (e.g. ad libitum): basal laboratory diet (Certified Rodent Chow® #5002 (Ralston Purina Company, St. Louis, Missouri, USA)) ad libitum- Water (e.g. ad libitum): ad libitum- Acclimation period: “conditioned” for approximately 1 weekENVIRONMENTAL CONDITIONS- Temperature (°C): 22-23 (72-73 ºF)- Humidity (%): 46-51- Air changes (per hr): no data- Photoperiod (hrs dark / hrs light): 12 h / 12 hIN-LIFE DATES: From: 16-May-1982 To: 21-May-1982

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: corn oil- Justification for choice of solvent/vehicle: no data, but well-known vehicle- Concentration of test material in vehicle: 0.050, 0.150 and 0.500 g/ml- Amount of vehicle (if gavage or dermal): 10 ml/kg bw- Type and concentration of dispersant aid (if powder): not applicable- Lot/batch no. (if required): Mazola®, no batch number stated- Purity: no data
Details on exposure:
Route = oralPREPARATION OF DOSING SOLUTIONS:Test material prepared in corn oil vehicle; concentrations adjusted to give an administration volume of 10 ml/kg bw for each dose level; fresh solutions prepared daily; contact of test substance with plastics avoided; dosing solutions stirred with a magnetic stirrer during administration.DIET PREPARATION: not applicable
Duration of treatment / exposure:
5 days
Frequency of treatment:
Daily
Post exposure period:
Bone marrow collected 24 hours after final dose
Doses / concentrations
Remarks:
Doses / Concentrations:500, 1500 and 5000 mg/kg bw/dayBasis:analytical conc.472, 1560 and 4900 mg/kg bw/day
No. of animals per sex per dose:
8
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide- Justification for choice of positive control(s): no data, but listed as an acceptable example in the OECD guideline- Route of administration: intraperitoneal injection in 0.9% aqueous sodium chloride- Doses / concentrations: 40 mg/kg bw/day administered on days 5 and 6

Examinations

Tissues and cell types examined:
bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: no data, but the OECD guideline recommends a maximum of 2000 mg/kg bw/day for limit dose studies of <14 days duration, a dose level which was achieved (and exceeded) in the studyTREATMENT AND SAMPLING TIMES (in addition to information in specific fields): colchicine (at 100 mg in 40 ml Hank’s balanced salt solution (HBSS), adjusted to pH 7.5) administered intraperitoneally at 2 ml/kg bw to all animals 6 hours prior to the scheduled sacrifice on day 6 (24 hours after final test substance dose)DETAILS OF SLIDE PREPARATION: animals killed by carbon dioxide asphyxiation, femurs dissected, bone marrow washed into centrifuge tube with HBSS using syringe and needle; cells centrifuged and resuspended, incubated in hypotonic potassium chloride solution at 37 ºC, fixed in methanol/glacial acetic acid; cleaned slides kept at -20ºC prior to slide preparation, drops of cell suspension placed on 4 slides/animal, ignited, dried; stained with Giemsa, rinsed, dried, covered; coded randomly.METHOD OF ANALYSIS: slides were read in the randomly-assigned order; metaphases were scored for chromosome aberrations using 1000x oil immersion magnification; for test and vehicle control groups 100 metaphase spreads per animal were scored where sufficient readable metaphases were available; for positive control “reading was discontinued when enough spreads with chromosomal abnormalities were found to ensure statistical significance”OTHER:- clinical signs (twice daily observations)- mortality- body weight (recorded prior to study initiation for all groups, on days 1 and 6 for test and vehicle control groups, on days 1, 4 and 6 for positive control group)- mitotic index (cytotoxicity) not reported
Evaluation criteria:
Not specified in report, but presumably statistically significant increase in frequency of aberrant metaphases and/or various types of chromosome abnormality and/or frequency of aberrations per cell
Statistics:
Method of Kastenbaum & Bowman: “mutation frequencies of each group were compared with tabulated minimum values for p < 0.05 or p < 0.01”

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RESULTS OF RANGE-FINDING STUDY: no data RESULTS OF DEFINITIVE STUDY- Types of structural aberrations for significant dose levels (for Cytogenetic or SCE assay): no statistically significant incidence of aberrant cells at any dose level- Appropriateness of dose levels and route: - OECD guideline recommends a limit dose of 2000 mg/kg bw/day, which was exceeded in the study but still yielded negative results  - OECD guideline recommends a single treatment and requires that “other dosing regimens should be scientifically justified.” The study had a 5-day dosing schedule which still yielded negative results - Statistical evaluation: no statistically significant incidence of aberrant cells at any dose level; highly significant incidence of chromosome aberrations in positive control group (p<0.01) - Other: no deaths; similar body weight gains in treated and vehicle control groups, body weight loss in positive control group; no treatment-related clinical signs

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative C14-17 chlorinated paraffin (52% chlorinated)Cereclor S52 (a C14-17 chlorinated parrafin) was not clastogenic when administered to male rats by gavage for five days at up to 5 g/kg bw/day
Executive summary:

The clastogenic potential of Cereclor S52 (a C14-17 chlorinated paraffin; 52% chlorination, unstabilised) was evaluated in a bone marrow chromosome aberration test in groups of 8 male rats administered 5 daily oral (gavage) doses of 500, 1500 or 5000 mg/kg bw in corn oil.

No toxicity was observed, as measured by mortality and body weight gain. There was no indication of whether the test substance had reached the target tissue (bone marrow) since no measure of cytotoxicity (e.g. mitotic index) was presented. The adequacy of the test system was demonstrated by a clear positive response with the positive control (cyclophosphamide).

Cereclor S52 did not induce structural chromosome aberrations under the conditions of the test.