Nitrilotrimethylenetris(phosphonic acid)

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

12/96 final draft

Deviations:

no

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

[nitrilotris(methylene)]trisphosphonic acid, sodium salt

EC Number:

243-900-0

EC Name:

[nitrilotris(methylene)]trisphosphonic acid, sodium salt

Cas Number:

20592-85-2

Molecular formula:

General formula C3H12NO9P3.xNa where x=3-5 ATMP-3Na C3H9NNa3O9P3 ATMP-4Na C3H8NNa4O9P3 ATMP-5Na C3H7NNa5O9P3

IUPAC Name:

Sodium salt of [nitrilotris(methylene)]trisphosphonic acid (3-5Na:1)

Test animals

Species:

mouse

Strain:

other: Crl: CD-1 (ICR) BR

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Labs Raleigh NC
- Age at study initiation: approx 8 weeks
- Weight at study initiation: 30.6 - 33.9 grams (males); 23.6-28.4 grams (females)
- Assigned to test groups randomly: Yes
- Fasting period before study: No
- Housing: 5 animals per polycarbonate cage
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-26 °C
- Humidity (%): 30-70 %
- Air changes (per hr): at least 10 per hour
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: water
- Amount of vehicle: 10 mL/kg

Duration of treatment / exposure:

2 days

Frequency of treatment:

At 24 and 48 hours

Doses / concentrations

Dose / conc.:

2 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

Range finding experiments: 3 male and 3 female per dose; 6 males per dose in the main experiment.

Control animals:

yes, concurrent vehicle

Positive control(s):

- cyclophosphamide;
- Justification for choice of positive control(s): None given
- Route of administration: Oral gavage
- Doses / concentrations: 80 mg/kg

Examinations

Tissues and cell types examined:

Bone marrow erythrocytes

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:
Based on two range-finding studies.

TREATMENT AND SAMPLING TIMES: 500 mg/kg bw, 1000 mg/kg bw and positive control harvested at 24 hours; 2000 mg/kg bw and vehicle control harvested at 24 and 48 hours.

DETAILS OF SLIDE PREPARATION: Giesma stain

METHOD OF ANALYSIS: Scored for micronuclei and PCE NCE ratio

Evaluation criteria:

Criteria for positive: Statistically significant increase in micronucleated PCEs or at least one dose level and a statistically significant dose-related response.

Statistics:

ANOVA followed by Dunnett's t-test when ANOVA positive

Results and discussion

Test results

Key result

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Remarks:

up to limit concentration

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Any other information on results incl. tables

No clinical toxicity and no cytotoxicity to the bone marrow was observed in any treated animals. No increase in the frequency of micronucleated erythrocytes occurred in any test substance dose.

Table 1: Mean Results of in vivo micronucleus test in mouse bone marrow

-	Solvent Control (water)		Positive Control (Cyclophosphamide)	Low dose 500 mg/kg	Mid dose 1000 mg/kg	High dose 2000 mg/kg
Sampling time (h)	24	48	24	24	48	24	48
Number of cells analysed	2000	2000	2000	2000	2000	2000	2000
Micronucleated cells per animal %	0.07	0.07	2.73	0.04	0.09	0.02	0.06
Ratio PCE/NCE	0.52	0.47	0.50	0.59	0.44	0.41	0.60

Applicant's summary and conclusion

Conclusions:

In a reliable in vivo micronucleus study (reliability 1), conducted according to OECD Test Guideline 474 and in compliance with GLP, ATMP-xNa has been tested for clastogenicity. No increase in the frequency of micronucleated erythrocytes was observed. Vehicle and positive controls were included and gave expected results. It is concluded that ATMP-xNa is negative for the induction of micronuclei under the conditions of this test.