Chlorine dioxide

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian cell study: DNA damage and/or repair

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 04-30-1984 to 05-14-1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study performed similarly to OECD guideline with acceptable deviations.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 479

Deviations:

yes

Remarks:

: in vivo study, no detail on the substance

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Type of assay:

sister chromatid exchange assay

Test material

Test material information

Constituent 1

Reference substance name:

Chlorine dioxide

EC Number:

233-162-8

EC Name:

Chlorine dioxide

Cas Number:

10049-04-4

Molecular formula:

ClO2

IUPAC Name:

Chlorine Dioxide

Details on test material:

- Name of test material (as cited in study report): chlorine Dioxide
- Physical state: Yellow liquid
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: assumed to be stable during the test (sponsor responsibility)
- Storage condition of test material: no data
- Other: received on 1984/04/26

Test animals

Species:

mouse

Strain:

ICR

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley, Inc. Indianapolis, Indiana, USA.
- Age at study initiation: 9 weeks
- Weight at study initiation: 29.74 g mean weight
- Assigned to test groups randomly: yes, under following basis: according to LBI Standard Operating Procedures (SOP) # 303: "Genetics -- Animal Randomization"
- Fasting period before study: no data
- Housing: up to 5 mice per cage
- Diet (e.g. ad libitum): ad libitum (Purina Laboratory Chow)
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
no data

IN-LIFE DATES: no data

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

Vehicle: deionised water

Details on exposure:

Total volume applied: 0.15 to 0.41 ml i.p.
Dose applied: 9.04, 21.08, 28.02, 38.55 mg/kg

Approximately 1 h before dosing, all animals received subcutaneous implant of a ~50% paraffin-coated 50 mg BrdU tablet.

Duration of treatment / exposure:

one single acute dose

Frequency of treatment:

Number of applications: 1

Post exposure period:

26 h

Doses / concentrations

Remarks:

Doses / Concentrations:
0.680, 1.586, 2.113, 2.900 mg/mL
Basis:
nominal conc.
in the vehicle

No. of animals per sex per dose:

5/group

Control animals:

yes, concurrent vehicle

Positive control(s):

- Substance used as Positive Control: Cyclophosphamide
- Route of administration: by intraperitoneal injection
- Concentration: 10 mg/kg in 0.9% saline

Examinations

Tissues and cell types examined:

Tissue: Bone marrow
Number of animals: 5 per group
Number of cells: 25 per animal
Time points: 24 h after treatment
Type of cells bone marrow
Parameters: numbers of sister chromatid exchanges

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:cell cycle kinetics were evaluated from 100 metaphases cells per animal and the appropriate doses and termination times were determined.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):

DETAILS OF SLIDE PREPARATION: Slides were stained by a modification of the FPG (Fluorescence plus Giemsa) technique of Perry and Wolff (1974). The slides wre stained in Hoechst 33258.

METHOD OF ANALYSIS: the slides were exposed to black-light from a 15 W tube at 60°C for the same time required to detect SCE (15-30 minutes)

OTHER:

Evaluation criteria:

If an increase in SCE is observed, one of the following criteria must normally be met to assess the compound as positive:
- Two-fold increase: approximately a doubling in SCE frequency over the "background" (solvent and negative control) levels, at a minimum of three doses
-Dose response: a positive assessment may be made in the absence of a doubling if there is a statistically significant increase at a minimum of three doses and evidence for a positive dose response

In some cases, statistically significant increases are observed with neither a doubling or a dose response. These results are assessed according to repeatability, the magnitude of the response, and the proportion of the dose levels affected.

Statistics:

The SCE data generated in this study were analyzed by a parametric Analysis of Variance statistical test (Sokal and Rohlf, 1969). Individual animal results will be used as data points in the analysis.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Remarks:

but the doses tested are high enough (limit of toxicity at 40 mg/kg)

Vehicle controls validity:

not specified

Negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: the target dose levels of 10, 20, 40 and 60 mg/kg chosen for the preliminary study were based upon toxicity information gathered from a previous study of mouse bone marrow aberrations. 4 groups of 3 male mice per group were dosed with the test compound.
- Solubility: no data
- Clinical signs of toxicity in test animals: one animal was found dead at 40 mg/kg prior to colchicine administration.
- Evidence of cytotoxicity in tissue analyzed: the test compound caused no delay up to and including the target dose level of 40 mg/kg. there was however considerable cell cycle delay at 60 mg/kg.
- Rationale for exposure: based upon the evaluation of cell cycle kinetics data, target doses of 10, 20, 30 and 40 mg/kg were selected for the actual study.
- Harvest times: 24 h after dosing
- High dose with and without activation: no data
- Other:

RESULTS OF DEFINITIVE STUDY
- Types of structural aberrations for significant dose levels (for Cytogenetic or SCE assay): The SCE frequencies were not significantly increased in any of the dose groups relative to the negative controls and were within the range of historical controls. The positive control showed a strongly and significantly increased SCE frequency relative to control (see table 7.6.2/1). Chlorine dioxide did not induce significant increases in SCEs at any of the doses tested.
- Induction of micronuclei (for Micronucleus assay): not applicable
- Ratio of PCE/NCE (for Micronucleus assay): not applicable
- Appropriateness of dose levels and route: no data
- Statistical evaluation:
- other: All animals in the test group exhibited hyperactive behaviour immediately after dosing, but shortly thereafter resumed normal behaviour.

Any other information on results incl. tables

Table 7.6.2/1:Table summarizing SCE frequencies in animals exposedin vivoto chlorine dioxide

 

Treatment	Dose mg/kg	No. of animals	No. of cells scored/animal	Total no. of cells scored	SCE frequency^d x ± S.E.
Deionized water	13.29	4^a	25^b	92	3.89 ± 0.26
Cyclophosphamide	10.00	5	25	125	13.15 ± 0.36*
Chlorine dioxide	9.04	5	25	125	3.50 ± 0.25
Chlorine dioxide	21.08	5	25	125	4.74 ± 1.29
Chlorine dioxide	28.02	4^c	25	100	3.73 ± 0.54
Chlorine dioxide	38.55	5	25	125	5.02 ±0.80

* significantly greater than negative control, p0.01

^aOne animal had cell cycle delay, all cells in M1

^bOne animal only 17 cells were scored

^cone animal died after dosing

^dmean SCE frequency / animal constituted a data point

Applicant's summary and conclusion

Conclusions:

Chlorine dioxide is considered negative for inducing sister chromatid exchanges in male mice bone marrow under the test conditions.

Executive summary:

In an in vivo genetic toxicity study, Sister Chromatid Exchange (SCE) frequencies were determined in bone marrow cells in ICR male mice exposed to Chlorine Dioxide administered intraperitoneally as an acute dose, at dose levels of 9.04, 21.08, 28.02, 38.55 mg/kg in deionised water.

Animals were killed at 26 h post implantation, the optimum time for detection of SCE and the cells collected from the bone marrow. M2 cells were scored for the frequency of SCE per cell.

Concurrent vehicle mice were considered as a negative control. Cyclophosphamide was used as a positive control and was administered by injection at 10 mg/kg in 0.9% saline.

Genotoxicity of Chlorine Dioxide was found to be negative to bone marrow cells in ICR male mice and no toxicity effects were found.

Positive controls induced the appropriate response. 

The SCE frequencies were not significantly increased in any of the dose groups relative to the negative controls and were within the range of historical controls. The positive control showed a strongly and significantly increased SCE frequency relative to control. Chlorine dioxide did not induce significant increases in SCEs at any of the doses tested.

Under the test conditions, Chlorine dioxide is considered negative for inducing sister chromatid exchanges in male mice bone marrow.

This study is considered as acceptable as it satisfies with the requirements for Test Guideline OECD 479.