Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study according to guideline. Although only summary available it has been peer internationally reviewed within OECD and assigned reliability 1.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2003

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Tosyl chloride
EC Number:
202-684-8
EC Name:
Tosyl chloride
Cas Number:
98-59-9
Molecular formula:
C7H7ClO2S
IUPAC Name:
4-methylbenzene-1-sulfonyl chloride
Details on test material:
4-Methylbenzenesulfonyl chloride, purity = 99.7 %,
Sigma-Aldrich Corporation, LOT No. – 422308/1

Test animals

Species:
mouse
Strain:
ICR
Sex:
male
Details on test animals or test system and environmental conditions:
- Age at study initiation: 8 weeks

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
Corn oil
Duration of treatment / exposure:
Duration of test: 3 days
Frequency of treatment:
Frequency of treatment: single treatment per day
Post exposure period:
Sampling times and number of samples: 24 hours after the administration
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 20, 40, 80 mg/kgbw
Basis:
nominal conc.
No. of animals per sex per dose:
6
Control animals:
yes
Positive control(s):
Negative control (Corn oil), administered once a day for 3 days
Positive control (2 mg/kg of Mitomycin C), administered once on the day 3 of administration.

Examinations

Tissues and cell types examined:
bone marrow, erythrocytes
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION:
preliminary test had conducted with 100, 200, 500, 1,000, and 2,000 mg/kg b.w. to determine appropriate starting dose level

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
24 hours after the administration

DETAILS OF SLIDE PREPARATION:
Bone marrow, a specimen was fixed with methanol for 10 minutes. Giemsa solution (5 %) and 0.004 % citric acid were used for dyeing and washing, respectively.

METHOD OF ANALYSIS:
Ratio of polychromatic erythrocytes.
Criteria for evaluating results: at least 2,000 polychromatic erythrocytes per animals were scored for the incidence of micronuclei.
Statistics:
Chi-squire test

Results and discussion

Test results
Genotoxicity:
negative
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No deaths were observed in relation to the treatments.
In the 80 mg/kg treatment group, some clinical symptoms such as piloerection and soft stool were observed on day 3 and 4.
On day 4, body weights were decreased significantly in both 40 and 80 mg/kg treatment groups compared to the control group.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Tosyl chloride induced no increase in micronucleus in bone marrow up to dosing of 80 mg/kgbw for 3 days ip in mice.
Executive summary:

The objective of this study was to evaluate Tosyl chloride, for in vivo clastogenic activity and/or disruption of the mitotic apparatus by quantifying micronuclei in polychromatic erythrocyte (PCE) cells in ICR mouse bone marrow. The assay design was based on OECD Guideline 474 and performed in compliance to GLP.

The test substance was dissolved in corn oil and dosed at 0, 40, 80 mg/kg bw via i.p. route to groups of 6 male mice for three consecutive days. The dose levels were based on a preliminary MTD study.

A positive control group received 2 mg/kg of Mitomycin C by i.p. injection once.

After 24 hours following the last treatment animals were euthanized for extraction of the bone marrow.

At least 2000 PCEs per animal were analyzed for the frequency of micronuclei. Cytotoxicity was assessed by scoring the number of PCEs and normochromatic erythrocytes (NCEs).

No deaths were observed in relation to the treatments. In the 80 mg/kg treatment group, some clinical symptoms such as piloerection and soft stool were observed on day 3 and 4. On day 4, body weights were decreased significantly in both 40 and 80 mg/kg treatment groups compared to the control group.

No statistically significant increase in micronucleus frequencies occurred in polychromatic erythrocytes (PCEs) in mice treated with up to 80 mg/kg of Tosyl chloride. In both the positive control and at the highest dose of 80 mg/kg bw a decrease was observed in the PCE:normochromatic erythrocytes (NCE) ratio. When observed, a significant decrease in the PCE:NCE ratio is direct evidence of test article exposure to the bone marrow resulting in cytotoxicity.

In conclusion,Tosyl chloridewas evaluated as negative in the mouse bone marrow micronucleus assay under the conditions of this assay.