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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No OECD guideline defined.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: EEC Directive 92/69, L 383 A, Annex V, B 12 dated December 29, 1992
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Diphenyl cresylphosphate (BG-Chemie No. 195); 99.9% (GC) total of Phenyl cresylphosphate; on the day of the experiment.

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
The test article was formulated in corn oil. The vehicle was chosen to its reletive non-toxicity for the animals.
Duration of treatment / exposure:
single administration
Frequency of treatment:
All animals received a single standard volume of 10 ml/kg body weight intraperitoneally.
Post exposure period:
Sampling of the bone marrow from animals treated with the highest dose was done 16,24, 48 hours after treatment. Bone marrow samples from animals treated with the low and medium dose were taken only at preparation interval 24 hours.
Doses / concentrations
Remarks:
Doses / Concentrations:
100, 300, 1000 mg/kg
Basis:
other: intraperitoneally
No. of animals per sex per dose:
5
Control animals:
yes
Positive control(s):
CPA; Cyclophosphamide

Examinations

Tissues and cell types examined:
The bone marrow cells were collected for micronuclei analysis; 1000 polychromatic erythrocytes per animal were scored for micronuclei

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Summary of results:

 test group dose (mg/kg bw)  sampling time (h)  PCEs with micronuclei (%)  range  PCE/NCE 
 test article  1000 16  0.17  0 -5  1000/ 801 
 vehicle  0  24  0.11  0 -5  1000/ 721
 test article  100  24  0.09  0 -4  1000/ 746
 test article  300  24  0.14  0 -3  1000/ 905
 test article  1000  24  0.22  1 -5  1000/1033
 cyclophosphamide  30  24  1.70  6 -31  1000/ 829
 test article  1000  48  0.08  0 -2  1000/ 824

The animals treated with 1000 mg/kg bw Diphenyl cresylphosphate expressed toxic reactions. Reduction of spontaneous activity, eyelid closure, and convulsion (females only within the first hour after administration of the test article) followed by apathy were observed. One out of 18 femeles treated with 1000 mg/kg bw Diphenyl cresylphosphate died.

Applicant's summary and conclusion

Conclusions:
The in-vivo micronuleus test in male and female mice was negative. In comparison to the corresponding negative controls there was no significant enhancement in the frequency of the micronuclei at any preparation interval after application of the test article and with any dose level used.
Executive summary:

A micronucleus assay was performed to investigate the potential of Diphenyl cresyl phosphate to induce micronuclei in polychromatic erythrocytes (PCE) in the bone marrow of the mouse. The test article was formulated in corn oil. This vehicle was used as negative control. The volume administered intraperitoneally was 10 ml/kg bw. 16h, 24h, and 48h after a single application of the bone marrow cells were collected for micronuclei analysis. The occurrence of micronuclei in ten animals (5males, 5 females) per test group was evaluated. 1000 polychromatic erythrocytes (PCE) per animal were scored for micronuclei. To describe a cytotoxic effect due to the treatment with the test article the ratio between polychromatic and normochromatic erythrocytes (NCE) was determined in the same sample and reported as the number of NCE per 1000 PCE.

The following dose levels of the test article were investigated:

16 h preparation interval: 1000 mg/kg bw;

24 h preparation interval: 100, 300, and 1000 mg/kg bw.;

48 h preparation interval: 1000 mg/kg bw.

In a pre-experiment the highest dose administered was estimated to be the maximum tolerated dose. The animals expressed toxic reactions. Reduction of spontaneous activity, eyelid closure, and convulsions (females only within the first hour after administration of the test article) followed by apathy were observed. In the micronucleus assay the same toxic symptoms occurred and 1 out of 18 females treated with 1000 mg/kg bw Diphenyl cresylphosphate died. After treatment with the highest test article dose at preparation interval 24 hours the number of NCEs was slightly increased as compared to the corresponding negative control thus indicating that Diphenyl cresylphosphate had a cytotoxic effect. In comparison to the corresponding negative controls there was no significant enhancement in the frequency of the micronuclei at any preparation interval after application of the test article and with any dose level used. 30 mg/kg bw cyclophosphamide administered intraperitoneally was used as positive control which induced a distinct increase of the micronucleus frequency. In conclusion it can be stated that during the study described and under the experimental conditions reported, the test article did not induce micronuclei as determined by the micronucleus test with bone marrow cells of the mouse. Therefore, Diphenyl cresylphosphate is considered to be nonmutagenic in this micronucleus assay.