Triphenyl phosphite

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

AMES: negative (with and without metabolic activation), no cytotoxicity; similar to OECD TG 471, GLP, K2

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced S-9 fraction from rat liver

Test concentrations with justification for top dose:

5, 10, 50, 100 and 500 µg/plate

Vehicle / solvent:

ethanol

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: see below

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48h at 37°C

NUMBER OF REPLICATIONS:
Samples are run in duplicate

POSITIVE CONTROLS
- with metabolic activation:
TA-1535, cyclophosphamide (200 µg/plate); TA-1537, TA-1538, TA-98 and TA-100, benzofalpyrene 5 µg/plate

- without metabolic activation:
TA-1535 and TA-100, sodium azide (1 µg/plate); TA-1537, aaminoacridine (100 µg/plate); TA-1538 and TA-98, 2-nitrofuorene (50 µg/plate)

Evaluation criteria:

The assay is scored as the ratio of the number of macroscopic colonies on the test plate over the number of macroscopic colonies on the control plate. This is taken as the mutagenic index. A compound is considered to have a positive response if the mutagenic index is 2.0 and the apparent mutagenicity exhibits a dose response relationship.

Species / strain:

other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Additional information on results:

- All strains/cell types tested

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: A white precipitate formed in the aqueous agar solution at 50, 100 and 500 µg/plate

Conclusions:

The test article was not mutagenic under the conditions of this study described.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

MNT: negative in mammalian erythrocytes; mouse, according to OECD TG 474, GLP, K2

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Principles of method if other than guideline:

Method based on HRC Report Number TCO 17 & 18/ 81305

GLP compliance:

yes

Type of assay:

micronucleus assay

Species:

mouse

Strain:

other: COBS CD-I (ICR) BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River U.K. Limited, Margate, Kent
- Weight at study initiation: 18 and 21 grams
- Fasting period before study: overnight
- Housing: plastic disposable cage
- Diet: free access to Spratt's Laboratory Diet No. 1
- Water: tap water, ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22
- Air changes (per hr): 30
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: corn oil

Frequency of treatment:

The total dosoges were given as two equal administrations separated by an interval of 24 hours.

Post exposure period:

6h

Dose / conc.:

1 250 mg/kg bw/day (actual dose received)

Remarks:

total dose divided over two treatments

Dose / conc.:

2 500 mg/kg bw/day (actual dose received)

Remarks:

total dose divided over two treatments

Dose / conc.:

5 000 mg/kg bw/day (actual dose received)

Remarks:

total dose divided over two treatments

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Positive control(s):

Mitomycin C, batch number 40F-0404, was used as the positive control compound. It was prepared as a solution in sterile 0.9% saoline at a concentration of 0.4 mg/ml. It was adminitered by IP injection.

Tissues and cell types examined:

The femurs were cleared of tissue and one epiphysis removed from each bone. A direct bone marrow smear was made onto a slide containing a drop of calf serum. The slide was cleaned by inversion in methanol for 24 hours and air-dried immediately before use. One smear was mode from each femur.

Details of tissue and slide preparation:

The prepared smears were air-dried and fixed in methanol overnight. After fixation, the smears were air-dried and placed in buffered distilled water (pH 6.8) for 10 minutes prior to staining In Giemsa (dilution Factor I part Giemsa : 9 parts buffered distilled water pH 6.8) for 10 minutes. After rinsing in buffered distilled water (pH 6.8), the slides were air-dried and mounted in OPX. The stained smears were examined by light microscopy to determine the incidence of micronucleated cells per 1000 polychromatic erythrocytes per animal and the ratio of normochromatic to polychromatic erythrocytes.

Evaluation criteria:

A compound was considered to show evidence of mutagenic activity if it produced a statistically significant increase in micronucleated cells compared to the concurrent negative control values.

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: Phase I: 500, 5000, 10000, 15000, 24400 mg/kg; Phase II: 6000, 7000 and 8000 mg/kg
After administration of test substance at a total dosage of 500 mg/kg bodyweight, no toxic reactions were observed. At total dosages between 5000 and 24400 mg/ltg bodyweight, a toxic reaction consisting of tremors was observed 30 minutes after dosing. The tremors decreased over the next 1.5 hours until they were not observed two hours after each dose. From 10000 mg/kg and higher all animals died. At 6000, 7000 and 8000 mg/kg, 6/10, 6/10 and 9/10 animals died. From the above results, a top dosage of 5000 mg/kg bodyweight was chosen for the micronucleus test which, it was indicated, would cause one or two deaths.

RESULTS OF DEFINITIVE STUDY
In this experiment the negative control group gave a mean count of 0.1 micronucleated cells which was within the range for previous unrelated experiments. After administration of test substance at all dosages, the group mean micronucleated cell counts were comparable with the concurrent control value and within the laboratory standard range for negative controls obtained In previous unrelated experiments.

In this experiment the negative control group gave a mean ratio of 1.86 normochromatic to polychromatic cells. After administration of test substance at the highest total dosage of 5000 mg/kg bodyweight, the normochromatic to polychromatic cell ratios were comparable with the concurrent control values. The ratios of the two lower dosages were, therefore, not scored. The positive control group administered intraperitoneally with Mitomycin C gave a group mean ratio of 7.32 normochromatic to polychromatic cells.

At total dosages of 1250 and 2500 mg/kg bodyweight no toxic reactions or mortalities were observed. At a total dosage of 5000 mg/kg bodyweight, a toxic reaction consisting of tremors was observed 30 minutes after dosing. The tremors decreased over the next 1.5 hours until they were not observed two hours after each dose. There were 5 mortalities at this dose level. Advanced visceral autolysis prevented any post mortem examination in all animals. After administration of Mitomycin C, no toxic reactions or mortalities were observed.

Summary of results

 

	Number of micronucleated cells per 1000 polychromatic erythrocytes per animal		NCE/PCE Ratio
Test group	mean	range	mean	range
negative control	0.1	0-1	1.86	1.01-4.96
1250 mg/kg test substance	0.2	0-1	+	+
2500 mg/kg test substance	0.2	0-1	+	+
5000 mg/kg test substance	0.2	0-1	1.38	1.09-1.86
positive control (8 mg/kg)	27.7	7-67	7.52	3.24-16.37

+ Slides not scores for ratio

Conclusions:

Under the conditions of this study, no evidence of induced chromosomal damage or other damage leading to micronucleus formation was given in polychromatic erythrocytes of treated mice after oral administration of the test substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

AMES
In this GLP compliant in vitro bacterial gene mutation test that was conducted similar to the OECD TG 471 (K2) S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100 were exposed to the test substance for 48h at concentrations of 5, 10, 50, 100 and 500 µg/plate with and without metabolic activation. Under the conditions of this study the test substance did not induce cytotoxicity and was not mutagenic (MRI, 1980).

MNT

In this GLP compliant in vivo cytogenicity test that was performed according to the OECD TG 474 (K2) five COBS CD-I (ICR) BR mice/sex/dose were dosed with the test substance at 1250, 2500 or 5000 mg/kg bw/day by gavage. The total dose was divided over two treatments. Six hours after the last dosing a micronucleus assay was performed. Under the conditions of this study, no evidence of induced chromosomal damage or other damage leading to micronucleus formation in polychromatic erythrocytes was seen in mice orally treated with the test substance (Huntingdon, 1981).

 

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. No indication of genotoxicity was observed in the Ames test (OECD 471, GLP) and the in vivo MNT test (OECD 474, GLP). As a result, the substance is not considered to be classified for mutagenicity under Regulation (EC) No. 1272/2008, as amended for the fourteenth time in Regulation (EC) No. 2020/217.