Reaction mass of cerium phosphate and lanthanum phosphate and terbium phosphate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 21-MAY-2007 to 23-NOV-2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to EU / OECD guidelines and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

cerium(3+) lanthanum(3+) terbium(3+) triphosphate

EC Number:

915-152-1

Molecular formula:

(La,Ce,Tb)PO4

IUPAC Name:

cerium(3+) lanthanum(3+) terbium(3+) triphosphate

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

Liver S9 fraction of rats induced with Aroclor 1254 (= S9)

Test concentrations with justification for top dose:

- 312.5, 625, 1250, 2500 and 5000 µg/plate, for the first experiment,
- 156.3, 312.5, 625, 1250 and 2500 µg/plate, for the second experiment.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water for injection
- Justification for choice of solvent/vehicle: the test item was not soluble in any of the vehicles usually used for in vitro tests.
- volume of vehicle/solvent in the medium: 0,1 mL per 2,60 mL medium

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: - sodium azide (TA 1535 - TA 100 without S9 mix, 1 µg/plate) - 9-aminoacridine (TA 1537 without S9 mix, 50 µg/plate) - 2- nitrofluorene (TA 98 without S9 mix, 0.5 µg/plate) - mitomycin C (TA 102 without S9 mix, 0.5 µg/plate)

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: - other: 2-Anthramine (TA 1535 - TA 1537 - TA 98 with S9 mix, 2 µg/plate ; TA 102 with S9 mix, 10 µg/plate) - benzo(a)pyrene (TA 100 with S9 mix, 5 µg/plate)

Details on test system and experimental conditions:

METHOD OF APPLICATION: All experiments were performed according to the direct plate incorporation method except for the second test with S9 mix, which was performed according to the preincubation method


DURATION
- Preincubation period: 60 minutes, 37°C
- Exposure duration: 48 to 72 hours


NUMBER OF REPLICATES: three plates/dose-level


OTHER: SCORING METHOD: automated

Evaluation criteria:

A reproducible 2-fold increase (for the TA 98, TA 100 and TA 102 strains) or 3-fold increase (for the TA 1535 and TA 1537 strains) in the number of revertants compared with the vehicle controls, in any strain at any dose-level and/or evidence of a dose-response was considered as a positive result. Reference to historical data, or other considerations of biological relevance were taken into account in the evaluation of the data obtained.

Statistics:

not concerned

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: A moderate to strong precipitate was observed in the Petri plates when scoring the revertants at dose-levels >= 312.5 µg/plate. Sometimes, the strong precipitate at 5000 µg/plate made the plates unreadable (TA 102 strain with S9 mix in the first experiment).


RANGE-FINDING/SCREENING STUDIES:
To assess the toxicity of the test item to the bacteria, six dose-levels (one plate/dose-level) were tested in the TA 98, TA 100 and TA 102 strains, with and without S9 mix. The evaluation of the toxicity was performed on the basis of the observation of the decrease in the number of revertant colonies and/or a thinning of the bacterial lawn.
A moderate to strong precipitate was observed in the Petri plates when scoring the revertants at dose-levels >= 500 µg/plate. No noteworthy toxicity was noted towards the three strains used, either with or without S9 mix.


COMPARISON WITH HISTORICAL CONTROL DATA: The control data reported in these report are in the range of the historical control data observed in the laboratory.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: First experiment (direct plate incorporation) - Mean revertant colony counts

	TA 1535			TA 1537			TA 98
Conc. (µg/plate)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	24	28	No	9	11	No	25	34	No
312.5	21	27	No (Mp)	5	9	No (Mp)	21	42	No (Mp)
625	31	20	No (Mp)	10	7	No (Mp)	29	37	No (Mp)
1250	16	20	No (Mp)	5	14	No (Mp)	38	42	No (Mp)
2500	28	19	No (Sp)	11	9	No (Sp)	31	50	No (Sp)
5000	20	17	No (Sp)	10	9	No (Sp)	21	53	No (Sp)
Positive control	668	202	No	427	111	No	172	1188	No

	TA 100			TA 102
Conc. (µg/plate)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	151	143	No	436	584	No
312.5	143	137	No (Mp)	437	416	No (Mp)
625	143	146	No (Mp)	482	516	No (Mp)
1250	166	132	No (Mp)	445	526	No (Mp)
2500	200	133	No (Sp)	492	430	No (Sp)
5000	153	169	No (Sp)	487	U	No (Sp)
Positive control	734	503	No	2059	3038	No

*solvent control with water for injection

Mp : Moderate precipitate

Sp : Strong precipitate

U : unreadable

MA : metabolic activation

Table 2: Second experiment (direct plate incorporation without S9 mix and preincubation with S9 mix) - Mean revertant colony count

	TA 1535			TA 1537			TA 98
Conc. (µg/plate)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	30	24	No	8	10	No	29	23	No
156.3	38	25	No (Mp)	7	4	No (Mp)	35	40	No (Mp)
312.5	36	27	No (Mp)	6	11	No (Mp)	25	23	No (Mp)
625	38	29	No (Mp)	7	10	No (Mp)	40	38	No (Mp)
1250	32	30	No (Sp)	4	9	No (Sp)	29	28	No (Sp)
2500	35	33	No (Sp)	5	10	No (Sp)	37	42	No (Sp)
Positive control	845	144	No	427	103	No	243	1023	No

	TA 100			TA 102
Conc. (µg/plate)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	107	106	No	347	553	No
156.3	177	131	No (Mp)	482	629	No (Mp)
312.5	127	88	No (Mp)	442	554	No (Mp)
625	192	120	No (Mp)	469	598	No (Mp)
1250	160	130	No (Sp)	503	752	No (Sp)
2500	141	118	No (Sp)	401	557	No (Sp)
Positive control	548	326	No	1965	1744	No

*solvent control with water for injections

Mp : Moderate precipitate

Sp : Strong precipitate

MA : metabolic activation

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

Under the experimental conditions, the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate did not show any mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium.

Executive summary:

The objective of this study was to evaluate the potential of the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate to induce reverse gene mutations in Salmonella typhimurium.

The study was performed according to the international guidelines OECD 471, Commission Directive No. B13/14 and in compliance with the Principles of Good Laboratory Practice Regulations.

The test item was tested in two independent experiments, with and without a metabolic activation system, the S9 mix, prepared from a liver post mitochondrial fraction (S9 fraction) of rats induced with Aroclor 1254.

Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102 were used. Each strain was exposed to at least five dose-levels of the test item (three plates/dose-level). After 48 to 72 hours of incubation at 37°C, the revertant colonies were scored.

Solvent control (water for injection) and positive controls were used.

The number of revertants for the vehicle and positive controls was as specified in the acceptance criteria. The study was therefore considered valid.

The selected treatment-levels ranged from 156.3 to 5000 µg/plate, both with and without S9 mix, whatever the strain tested.

A moderate to strong precipitate was observed in the Petri plates when scoring the revertants at dose-levels >= 312.5 µg/plate. No noteworthy toxicity was induced in any of the five tester strains.

The test item did not induce any noteworthy increase in the number of revertants which could be considered as relevant, either with or without S9 mix, in any of the five tester strains.

Under these experimental conditions, the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate did not show any mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium.