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Diss Factsheets

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Pigment Yellow 120 showed no mutagenic activity in both experiments (plate incorporation assay, preincubation assay) each with and without metabolic activation.

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2021
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Cytokinesis block (if used):
Colchicine was used as the spindle inhibitor at 0.2 μg/mL
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver S9 homogenate was used as the metabolic activation system. The S9 homogenate was prepared from male Wistar rats induced with a single intraperitoneal injection of Aroclor 1254 (0.7 mL/rat ready to use solution), 5 days prior to sacrifice.
The S9 homogenate batch prepared and stored in the test facility either at -68 to -86 °C or in liquid
nitrogen until its use. Each batch of S9 homogenate is assessed for sterility, protein content (modified Lowry Assay, Sword and Thomson, 1980) and for its ability to metabolize the pro-mutagens 2-Aminoanthracene and Benzo (a) pyrene to mutagens using Salmonella typhimurium TA100 strain.

S9 homogenate was thawed immediately before use and mixed with the co-factor solution containing 4 mM NADP, 5 mM Glucose-6-phosphate, 8 mM MgCl2 and 33 mM KCl in PBS.

7.2.1 S9 Mix
The co-factor solution was prepared by dissolving the following co-factors in 18 mL PBS for the preliminary cytotoxicity test and the chromosome aberration assay.

NADP (4 mM) 57 mg
Glucose-6-phosphate (5 mM) 31 mg
Magnesium chloride (8 mM) 29 mg
Potassium chloride (33 mM) 44 mg

The S9 mix was prepared by mixing 4 mL S9 homogenate with 16 mL of the co-factor solution, for the preliminary cytotoxicity test and the chromosomal aberration assay.
Test concentrations with justification for top dose:

Test Concentrations
Following concentrations of the test item were used in the preliminary cytotoxicity test:
a) 7.81, b) 15.63, c) 31.25, d) 62.5, e) 125, f) 250, g) 500, h) 1000 and i) 2000 μg/mL (limit concentration as per OECD 473).
At the beginning and end of 3-hour exposure period, there was no precipitation of the test item, both in the presence and absence of metabolic activation at the test concentrations of 7.81, 15.63, 31.25, 62.5 and 125 µg/mL.
At the beginning and end of the 3-hour exposure, both in the presence and absence of metabolic activation, there was slight precipitation of the test item at 250 µg/mL and moderate precipitation of the test item at 500, 1000 and 2000 µg/mL.
Based on the guideline requirement, the test concentrations which exhibited moderate precipitation of the test item were not processed further and 250 µg/mL, which exhibited slight precipitation of the test item was selected as the top concentration in the preliminary cytotoxicity test.

Based on observations and preliminary cytotoxicity test results, it was decided to test up to a maximum of 250 µg/mL in the presence and absence of metabolic activation with the 3-hour exposure and in the absence of metabolic activation with the 21-hours exposure period in the chromosomal aberration assay.

Main test
Based on the observations of the preliminary cytotoxicity test, following concentrations of the test item are selected for testing in the chromosomal aberration assay

a) 15.63 b) 62.5 and c) 250 μg/mL
Vehicle / solvent:
Sterile water
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
cyclophosphamide
ethylmethanesulphonate
Details on test system and experimental conditions:
Chinese Hamster (Cricetulus griseus) ovary cell line CHO-K1, (ATCC CCL-61, Lot 63830396) with a doubling time approximately 12 -14 hours and modal chromosome number of 20 was used as the test system.
The cell line was tested for mycoplasma in the testing facility. The karyotype analysis of this cell line was periodically performed and documented.
Cells were grown in T- 25 cm2 and T-75 cm2 flasks at 37 ± 1 °C in a carbon dioxide incubator (5 ± 0.2 % CO2 in air)

The study consisted of a preliminary cytotoxicity test and a chromosome aberration assay. Chromosome aberration assay consisted of three independent experiments: Experiments 1 and 2 in the presence and absence of metabolic
activation system with 3-hour exposure, respectively, and Experiment 3 in the absence of metabolic activation system with 21-hour exposure.
The test item formed a free flowing suspension in sterile water at 200 mg/mL and a pasty suspension in DMSO at 200 mg/mL. Hence, sterile water was selected as the vehicle of choice for the chromosomal aberration test.
In a preliminary cytotoxicity test for the selection of test concentrations for the chromosomal aberration assay, the test item did not exhibit the required level of cytotoxicity (reduction in the cell growth by 55 ± 5 % of the concurrent vehicle control) up to the highest tested concentration of 250 μg/mL, both, in the presence and absence of metabolic activation (short term treatment) and in the absence of metabolic activation (long term treatment).
Based on these observations and preliminary cytotoxicity test results, it was decided to test up to a maximum of 250 μg/mL in the presence and absence of metabolic activation with the 3-hour exposure and in the absence of metabolic activation with the 21-hours exposure period in the chromosomal aberration assay.

In the chromosomal aberration assay, CHO-K1 cells were exposed to the test item in duplicate at the concentrations of 15.63, 62.5 and 250 μg/mL in Experiments 1, 2 and 3 of the chromosomal aberration assay. Concurrent vehicle (SW) and positive controls (cyclophosphamide monohydrate in the presence of metabolic activation and ethyl methanesulfonate in the absence of metabolic activation at 21 hour exposure) were also tested in duplicate. In each case, the cells in C-metaphase were harvested at approximately 21 hours after the start of the treatment and slides were prepared for chromosomal analysis.
At the highest concentrations tested, the reduction in cell growth as RICC was 47, 43 and 53 % in experiments 1, 2 and 3, respectively, compared to the vehicle control.
A total of 300 metaphases each from the SW control, each treatment level and the positive controls were evaluated for chromosomal aberrations.
Rationale for test conditions:
Conditions according to guideline
Evaluation criteria:
Metaphases of all concentrations of the test item, the positive and vehicle control cultures were scored.

8.1 Definition for Aberrations

The chromosome and chromatid aberrations observed have been grouped into three categories - gaps, breaks (includes deletions and displacements) and exchanges.

Gap

Chromatid gap is a non-staining region of a single chromatid in which there is a minimal misalignment of the chromatid.

Chromosome gap is a non-staining region at the same locus in both chromatids of a single chromosome in which there is minimal misalignment of the chromatids.

Break

Chromatid break is discontinuity of a single chromatid in which there is clear misalignment of one of the chromatids.

Chromosome break is discontinuity at the same locus in both chromatids of a single chromosome, giving rise to an acentric fragment.

A chromatid deletion occurs when a bit of chromatid is missing as a result of a break.

A chromosome deletion occurs when bits of both chromatids are missing as a result of a break.

Chromatid displacement occurs when the fragment of the chromatid beyond the break point is not in alignment with the chromosome of origin.

Chromosome displacement occurs when the fragments of both chromatids beyond the break point are not in alignment with the chromosome of origin.

Exchange

Exchanges occur as a result of two or more chromatid lesions and the subsequent rearrangement of chromatid material.

Ring chromosomes are formed when a chromosome undergoes two breaks and the broken ends of the chromosome reunite in a ring structure either with or without a centromere.

Pulverization

In cells with pulverization, the chromosomes are reduced to masses of fragments. This represents the degree of damage inflicted on the chromosome. This aberration indicates the cytotoxic effect of the test item.

Polyploidy

Cell containing more than the diploid number (2n) of chromosomes,
Statistics:
Statistical analysis of the experimental data was carried out using validated SYSTAT Statistical package ver.12.0. Data were analyzed for proportions of aberrant metaphases in each sample excluding gaps as aberrations. Pooled data from each test concentration and the positive control were compared with the vehicle control using Fischer exact test. All analysis and comparisons were evaluated at 5 % (p < 0.05) level.
Key result
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Vehicle controls validity:
valid
Positive controls validity:
valid

TABLE 3.      Results of Preliminary Cytotoxicity Test











































































































 


Treatment


(µg/mL)



Presence of metabolic activation  (3-hour exposure)  



Absence of metabolic activation  (3-hour exposure)  



Absence of metabolic activation  (21-hour exposure)



Final – initial cell count


(1x106/flask)



Cell growth index


RICC


(%)



Cell growth


inhibition


(%)



Final – initial cell count


(1x106/flask)



Cell growth index


RICC (%)



Cell growth


inhibition


(%)



Final – initial cell count


(1x106/flask)



Cell growth index


RICC (%)



Cell growth


inhibition


(%)



Sterile water



0.78125



100



0



0.83125



100



0



0.71875



100



0



7.81



0.71875



92



8



0.79375



95



5



0.63125



88



12



15.63



0.63125



81



19



0.73125



88



12



0.55625



77



23



31.25



0.56875



73



27



0.68125



82



18



0.50625



70



30



62.5



0.51875



66



34



0.60625



73



27



0.43125



60



40



125



0.48125



62



38



0.55625



67



33



0.38125



53



47



250



0.41875



54



46



0.49375



59



41



0.31875



44



56



Base line cell count: 1.58125 X 106/flask


 


TABLE 4.      Summary Results of Chromosomal Aberration Assay - Experiment 1





























































































Treatment (µg/mL)



No. of metaphases scored



No. (%) of metaphases with aberrations@



Total No. (%) of aberrant metaphases*



Cell


Growth


Inhibition


(%)



Gaps



Breaks



Exchanges



Includi ng


Gaps



Excluding Gaps



Cs



Ct



Cs



Ct



Cs



Ct



 


Sterile water



300



 


0



 


0



 


1


(0.33)



 


0



 


0


 



 


0



 


1


(0.33)



 


1


(0.33)



0



 


15.63



300



 


0


 



 


0



 


0



 


0



 


0



 


0



 


0



 


0



16



 


62.5



300



 


0


 



 


0



 


0



 


0



 


0



 


0



 


0



 


0



33



 


250



300



 


0



 


0



 


1


(0.33)



 


0



 


0



 


0



 


1


(0.33)



 


1


(0.33)



47



 


CPA 55



300



 


1


(0.33)



 


0



 


12


(4.00)



 


19


(6.33)



 


38


(12.67)



 


31


(10.33)



 


73


(24.33)



 


72+


(24.00)



35



*: Metaphase plate with one or more than one aberration considered as one metaphase plate with aberrations


@: values are the sum of two replicates and values in parenthesis represent %         


Cs: Chromosome type            Ct: Chromatid type       


CPA: Cyclophosphamide monohydrate                     +: Significantly higher than control (p <0.05) by Fischer exact test Note: There were no incidences of polyploidy and endoreduplicated cells


 


TABLE 5.      Summary Results of Chromosomal Aberration Assay - Experiment 2 
















































































Treatment (µg/mL)



No. of metaphases scored



No. (%) of metaphases with aberrations@



Total No. (%) of aberrant metaphases*



Cell Growth


Inhibition


(%)



Gaps



Breaks



Exchanges



Including Gaps



Excluding Gaps



Cs



Ct



Cs



Ct



Cs



Ct



 


Sterile water



300



 


1


(0.33)



0



0



0



0



0



 


1


(0.33)



0



0



 


15.63



300



0



0



0



0



0



0



0



0



 


10



 


62.5



300



0



 


1


(0.33)



0



0



0



0



 


1


(0.33)



0



 


25



 


250



300



0



0



0



0



0



0



0



0



 


43



   


 *: Metaphase plate with one or more than one aberration considered as one metaphase plate with aberrations


@: values are the sum of two replicates and values in parenthesis represent %         


Cs: Chromosome type            Ct: Chromatid type                              


Note: There were no incidences of polyploidy and endoreduplicated cells


 


TABLE 6.      Summary Results of Chromosomal Aberration Assay - Experiment 3


 





























































































Treatment (µg/mL)



No. of metaphases scored



No. (%) of metaphases with aberrations@



Total No. (%) of aberrant metaphases*



Cell


Growth


Inhibition


(%)



Gaps



Breaks



Exchanges



Including Gaps



Excluding Gaps



Cs



Ct



Cs



Ct



Cs



Ct



 


Sterile water



300



0



0



 


1


(0.33)



0



0



0



 


1


(0.33)



 


1


(0.33)



0



 


15.63



300



0



0



0



0



0



0



0



0



22



 


62.5



300



0



0



 


0



 


1


(0.33)



0



0



 


1


(0.33)



 


1


(0.33)



38



 


250



300



0



0



 


1


(0.33)



0



0



0



 


1


(0.33)



 


1


(0.33)



53



 


EMS 600



300



 


4


(1.33)



0



 


35


(11.67)



 


36


(12.00)



 


9


(3.00)



 


15


(5.00)



 


84


(28.00)



 


81+


(27.00)



28



*: Metaphase plate with one or more than one aberration considered as one metaphase plate with aberrations


@: values are the sum of two replicates and values in parenthesis represent %         


Cs: Chromosome type            Ct: Chromatid type       


EMS: Ethyl methanesulfonate            +: Significantly higher than control (p <0.05) by Fischer exact test


Note: There were no incidences of polyploidy and endoreduplicated cells


 


ANNEXURE 2. Historical Vehicle and Positive Control Data


                                Test System: CHO cells                                              No. of Studies: 56


 


                                Vehicle Control                                                                                  























 


Parameter



Total No. of Metaphases with Aberrations Excluding Gaps



Presence of Metabolic Activation



Absence of Metabolic Activation



Range



0 - 5



0 - 4



Mean ± SD



0 ± 1



1 ± 1



 


Positive Control 























 


Parameter



Total No. of Metaphases with Aberrations Excluding Gaps



Presence of Metabolic Activation



Absence of Metabolic Activation



Range



51 - 204



63 - 248



Mean ± SD



124 ± 37



121 ± 32



 


CHO: Chinese Hamster Ovary Cells


SD: Standard deviation

Conclusions:
The test item, C.I. Pigment Yellow 175 was not clastogenic in CHO-K1 cells at the tested concentration and under the conditions of testing employed.
Executive summary:

The clastogenic potential of the test item, C.I. Pigment Yellow 175 to induce chromosomal aberrations in mammalian cells was evaluated using cultured Chinese Hamster Ovary (CHO-K1) cells in the presence and absence of an exogenous metabolic activation system (S9 fraction prepared from Aroclor 1254 induced rat liver).


 


The study consisted of a preliminary cytotoxicity test and a chromosome aberration assay. Chromosome aberration assay consisted of three independent experiments: Experiments 1 and 2 in the presence and absence of metabolic activation system with 3-hour exposure, respectively, and Experiment 3 in the absence of metabolic activation system with 21-hour exposure.


 


The test item formed a free flowing suspension in sterile water at 200 mg/mL and a pasty suspension in DMSO at 200 mg/mL. Hence, sterile water was selected as the vehicle of choice for the chromosomal aberration test.


 


In a preliminary cytotoxicity test for the selection of test concentrations for the chromosomal aberration assay, the test item did not exhibit the required level of cytotoxicity (reduction in the cell growth by 55± 5 % of the concurrent vehicle control)up to the highest tested concentration of 250µg/mL,both, in the presence and absence of metabolic activation (short term treatment) and in the absence of metabolic activation (long term treatment).


 


Based on these observations and preliminary cytotoxicity test results, it was decided to test up to a maximum of 250 µg/mL in thepresence and absence of metabolic activation with the 3-hour exposure and in the absence of metabolic activation with the 21-hours exposure period in the chromosomal aberration assay.


 


In the chromosomal aberration assay, CHO-K1 cells were exposed to the test item in duplicate at the concentrations of 15.63, 62.5 and 250mg/mL in Experiments 1, 2 and 3 of the chromosomal aberration assay. Concurrent vehicle (SW) and positive controls (cyclophosphamide monohydrate in the presence of metabolic activation and ethyl methanesulfonate in the absence of metabolic activation at 21 hour exposure) were also tested in duplicate. In each case, the cells in C-metaphase were harvested at approximately 21 hours after the start of the treatment and slides were prepared for chromosomal analysis.


 


At the highest concentrations tested, the reduction in cell growth as RICC was 47, 43 and 53 % in experiments 1, 2 and 3, respectively, compared to the vehicle control.


 


A total of 300 metaphases each from the SW control, each treatment level and the positive controls were evaluated for chromosomal aberrations.


 


There was no evidence of statistically significant induction of chromosomal aberrations, excluding gaps, either in the presence or in the absence of metabolic activation. In each of these experiments, under identical conditions, the respective positive control substances produced a large and statistically significant increase in aberrant metaphases.


The study indicated that the test item, C.I. Pigment Yellow 175 was not clastogenic at the concentrations tested and under the conditions of testing

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2021
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
See Read across document in chapter 13
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
Arocalor
Test concentrations with justification for top dose:
Based on these observations and preliminary cytotoxicity test results, it was decided to test up to a maximum of 250 µg/mL in the presence and absence of metabolic activation with the 3-hour exposure and in the absence of metabolic activation with the 21-hours exposure period in the chromosomal aberration assay.
Vehicle / solvent:
Sterile water
Untreated negative controls:
yes
Positive controls:
yes
Details on test system and experimental conditions:
Chinese Hamster (Cricetulus griseus) ovary cell line CHO-K1, (ATCC CCL-61, Lot 63830396) with a doubling time approximately 12 -14 hours and modal chromosome number of 20 was used as the test system.

The cell line was tested for mycoplasma in the testing facility. The karyotype analysis of this cell line was periodically performed and documented.
Cells were grown in T- 25 cm2 and T-75 cm2 flasks at 37 ± 1 °C in a carbon dioxide incubator (5 ± 0.2 % CO2 in air)
Evaluation criteria:
Metaphases of all concentrations of the test item, the positive and vehicle control cultures were scored.
Statistics:
Statistical analysis of the experimental data was carried out using validated SYSTAT Statistical package ver.12.0. Data were analyzed for proportions of aberrant metaphases in each sample excluding gaps as aberrations. Pooled data from each test concentration and the positive control were compared with the vehicle control using Fischer exact test. All analysis and comparisons were evaluated at 5 % (p < 0.05) level.
Key result
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Vehicle controls validity:
valid
Positive controls validity:
valid
Conclusions:
The test item, C.I. Pigment Yellow 175 was not clastogenic in CHO-K1 cells at the tested concentration and under the conditions of testing employed.
Executive summary:

The clastogenic potential of the test item to induce chromosomal aberrations in mammalian cells was evaluated using cultured Chinese Hamster Ovary (CHO-K1) cells in the presence and absence of an exogenous metabolic activation system (S9 fraction prepared from Aroclor 1254 induced rat liver).


The study consisted of a preliminary cytotoxicity test and a chromosome aberration assay. Chromosome aberration assay consisted of three independent experiments: Experiments 1 and 2 in the presence and absence of metabolic activation system with 3-hour exposure, respectively, and Experiment 3 in the absence of metabolic activation system with 21-hour exposure.


The test item formed a free flowing suspension in sterile water at 200 mg/mL and a pasty suspension in DMSO at 200 mg/mL. Hence, sterile water was selected as the vehicle of choice for the chromosomal aberration test.


In a preliminary cytotoxicity test for the selection of test concentrations for the chromosomal aberration assay, the test item did not exhibit the required level of cytotoxicity (reduction in the cell growth by 55± 5 % of the concurrent vehicle control)up to the highest tested concentration of 250µg/mL,both, in the presence and absence of metabolic activation (short term treatment) and in the absence of metabolic activation (long term treatment).


Based on these observations and preliminary cytotoxicity test results, it was decided to test up to a maximum of 250 µg/mL in thepresence and absence of metabolic activation with the 3-hour exposure and in the absence of metabolic activation with the 21-hours exposure period in the chromosomal aberration assay.


In the chromosomal aberration assay, CHO-K1 cells were exposed to the test item in duplicate at the concentrations of 15.63, 62.5 and 250mg/mL in Experiments 1, 2 and 3 of the chromosomal aberration assay. Concurrent vehicle (SW) and positive controls (cyclophosphamide monohydrate in the presence of metabolic activation and ethyl methanesulfonate in the absence of metabolic activation at 21 hour exposure) were also tested in duplicate. In each case, the cells in C-metaphase were harvested at approximately 21 hours after the start of the treatment and slides were prepared for chromosomal analysis.


At the highest concentrations tested, the reduction in cell growth as RICC was 47, 43 and 53 % in experiments 1, 2 and 3, respectively, compared to the vehicle control.


A total of 300 metaphases each from the SW control, each treatment level and the positive controls were evaluated for chromosomal aberrations.


There was no evidence of statistically significant induction of chromosomal aberrations, excluding gaps, either in the presence or in the absence of metabolic activation. In each of these experiments, under identical conditions, the respective positive control substances produced a large and statistically significant increase in aberrant metaphases.


The study indicated that the test item, was not clastogenic at the concentrations tested and under the conditions of testing

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
From 2 NOV 2004 to 27 DEC 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (OECD TG 476)
Justification for type of information:
See Read across document in chapter 13.
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
- Type and identity of media:
RPMI 1640 (Hepes buffered medium) supplemented with 15% horse serum, penicillin/streptomycin (100 U/mL respectively 100 µl/mL), 220 µg/mL sodium pyruvate and 1.25 U/mL Amphotericin
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically "cleansed" against high spontaneous background: yes
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 (induced with phenobarbital/beta-naphtoflavone)
Test concentrations with justification for top dose:
Experiment I:
without S9 mix: 11.7; 23.4; 46.9; 93.8; 187.5, and 375.0 microgram/mL
with S9 mix: 23.4; 46.9; 93.8; 187.5, and 375.0 microgram/mL
Experiment II: without S9 mix: 11.7; 23.4; 46.9; 93.8; and 187.5 microgram/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: solubility properties of the solvent and its relative non-toxicity to the cell cultures
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in suspension
DURATION
- Exposure duration: 4 h (Experiment I: with and w/o metabolic activation) and 24 h (Experiment II w/o metabolic activation)
- Expression time (cells in growth medium): 3 days total (i.e. experiment I: 4 hours treatment period plus 68 hours expression time; experiment II: 24 hours treatment period plus 48 hours expression time)
- Selection time (if incubation with a selection agent): 10 to 15 days

SELECTION AGENT (mutation assays): trifluorothymidine (TFT)

NUMBER OF REPLICATIONS: two independent experiments, using two parallel cultures each

NUMBER OF CELLS USED: Per culture 1 x 10EXP7 cells

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency; relative total growth; other: relative suspension growth
Evaluation criteria:
A test item is classified as positive if it induces either a reproducible concentration-related increase in the mutant frequency or a reproducible positive response for at least one of the test points.
A test item producing neither a reproducible concentration-related increase in the mutant frequency nor a reproducible positive response at any of the test points is considered non-mutagenic in this system.
A significant response is described as follows:
The test item is classified as mutagenic if it reproducibly induces a mutation frequency that is at least two times higher than the spontaneous mutation frequency (negative or solvent control) in the experiment.
The test item is classified as mutagenic if there is a reproducible concentration-related increase in the mutation frequency. Such an evaluation may be considered independently of the enhancement factor for induced mutants.
However, in the evaluation of the test results the historical variability of the mutation rates in negative and solvent controls and the mutation rates of all negative and solvent controls of this study are taken into consideration.
Results of test groups are rejected if the relative total growth, the relative suspension growth and/or cloning efficiency 1 (survival of the cells after treatment) is less than 10 % of the solvent control or the cloning efficiency 2 (viability) after the expression period is less than 20 %.
Whenever a test item is considered mutagenic according to the above mentioned criteria, the ratio of small versus large colonies is used to differentiate point mutations from clastogenic effects. If the increase of the mutation frequency is accompanied by a reproducible and dose dependent shift in the ratio of small versus large colonies clastogenic effects are indicated.
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
indicated by reduced relative cloning efficiency 1 in experiment I at 375 µg/mL in both cultures
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
experiment I: 1st culture at 375 µg/mL, 2nd culture at 187.5 µg/mL and above; experiment II: both cultures at 187.5 µg/mL and above
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation:
Precipitation of the test item was observed by the unaided eye at 187.5 and 375.0 microgram/mL in all experimental parts.

COMPARISON WITH HISTORICAL CONTROL DATA:
The mutation frequency did not exceed the historical range of negative and solvent controls at any concentration with and without metabolic activation. The threshold of two times the number of mutant colonies/10EXP6 cells was reached at 46.9 microgram/mL in the second culture of experiment I (with S9 mix). Since this effect was not observed at higher concentrations or in the parallel culture, this isolated effect was judged as biologically irrelevant.
The mutation frequency of the positive control in the first culture of experiment I fell just short of the historical range of positive controls with 233 versus 292 colonies per 10EXP6 cells. Since the threshold of twice the mutation frequency of the solvent control was clearly exceeded and the mean value of both positive controls is well within the historical range, this effect was considered as irrelevant fluctuation.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
In experiment I without metabolic activation relevant toxicity (relative cloning efficiency 1 and / or relative total growth of less than 50 % survival) was detected at 187.5 µg/mL and above in the second culture. In culture I a clear toxic effect occurred at the highest concentration of 375 µg/mL.
In experiment I with metabolic activation a toxic effect indicated by a reduced relative cloning efficiency 1 was observed at 375 µg/mL in both cultures.
In the second experiment (24 h treatment without metabolic activation) relevant toxic effects occurred at 187.5 µg/mL and above in both cultures.
Remarks on result:
other: all strains/cell types tested
Conclusions:
Interpretation of results (migrated information):
negative

The test substance did not increase the mutant frequency at the TK+/- locus in L5178Y cells and is therefore considered to be non-mutagenic under the conditions of the test.
Executive summary:

Mouse Lymphoma cells (L5178Y TK+/-) were treated with the test substance at five or six concentrations in the range of 11.7 to 375 microgram/mL. Precipitation of the test substance was detectable at dose level 187.5 and 375 microgram/mL. The solvent control gave mutant frequencies within the normal range. The positive controls gave marked increases in the mutant frequency, both in the presence or absence of metabolic activation, indicating the satisfactory performance of the test system. The test substance demonstrated no statistically significant or dose related increases in mutant frequency at any dose level, either with or without metabolic activation, thus indicating that the test item is not mutagenic under the conditions tested.

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2 NOV 2004 to 27 DEC 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (OECD TG 476)
Qualifier:
according to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
- Type and identity of media:
RPMI 1640 (Hepes buffered medium) supplemented with 15% horse serum, penicillin/streptomycin (100 U/mL respectively 100 µl/mL), 220 µg/mL sodium pyruvate and 1.25 U/mL Amphotericin
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically "cleansed" against high spontaneous background: yes
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 (induced with phenobarbital/beta-naphtoflavone)
Test concentrations with justification for top dose:
Experiment I:
without S9 mix: 11.7; 23.4; 46.9; 93.8; 187.5, and 375.0 microgram/mL
with S9 mix: 23.4; 46.9; 93.8; 187.5, and 375.0 microgram/mL
Experiment II: without S9 mix: 11.7; 23.4; 46.9; 93.8; and 187.5 microgram/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: solubility properties of the solvent and its relative non-toxicity to the cell cultures
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in suspension
DURATION
- Exposure duration: 4 h (Experiment I: with and w/o metabolic activation) and 24 h (Experiment II w/o metabolic activation)
- Expression time (cells in growth medium): 3 days total (i.e. experiment I: 4 hours treatment period plus 68 hours expression time; experiment II: 24 hours treatment period plus 48 hours expression time)
- Selection time (if incubation with a selection agent): 10 to 15 days

SELECTION AGENT (mutation assays): trifluorothymidine (TFT)

NUMBER OF REPLICATIONS: two independent experiments, using two parallel cultures each

NUMBER OF CELLS USED: Per culture 1 x 10EXP7 cells

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency; relative total growth; other: relative suspension growth
Evaluation criteria:
A test item is classified as positive if it induces either a reproducible concentration-related increase in the mutant frequency or a reproducible positive response for at least one of the test points.
A test item producing neither a reproducible concentration-related increase in the mutant frequency nor a reproducible positive response at any of the test points is considered non-mutagenic in this system.
A significant response is described as follows:
The test item is classified as mutagenic if it reproducibly induces a mutation frequency that is at least two times higher than the spontaneous mutation frequency (negative or solvent control) in the experiment.
The test item is classified as mutagenic if there is a reproducible concentration-related increase in the mutation frequency. Such an evaluation may be considered independently of the enhancement factor for induced mutants.
However, in the evaluation of the test results the historical variability of the mutation rates in negative and solvent controls and the mutation rates of all negative and solvent controls of this study are taken into consideration.
Results of test groups are rejected if the relative total growth, the relative suspension growth and/or cloning efficiency 1 (survival of the cells after treatment) is less than 10 % of the solvent control or the cloning efficiency 2 (viability) after the expression period is less than 20 %.
Whenever a test item is considered mutagenic according to the above mentioned criteria, the ratio of small versus large colonies is used to differentiate point mutations from clastogenic effects. If the increase of the mutation frequency is accompanied by a reproducible and dose dependent shift in the ratio of small versus large colonies clastogenic effects are indicated.
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
indicated by reduced relative cloning efficiency 1 in experiment I at 375 µg/mL in both cultures
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
experiment I: 1st culture at 375 µg/mL, 2nd culture at 187.5 µg/mL and above; experiment II: both cultures at 187.5 µg/mL and above
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation:
Precipitation of the test item was observed by the unaided eye at 187.5 and 375.0 microgram/mL in all experimental parts.

COMPARISON WITH HISTORICAL CONTROL DATA:
The mutation frequency did not exceed the historical range of negative and solvent controls at any concentration with and without metabolic activation. The threshold of two times the number of mutant colonies/10EXP6 cells was reached at 46.9 microgram/mL in the second culture of experiment I (with S9 mix). Since this effect was not observed at higher concentrations or in the parallel culture, this isolated effect was judged as biologically irrelevant.
The mutation frequency of the positive control in the first culture of experiment I fell just short of the historical range of positive controls with 233 versus 292 colonies per 10EXP6 cells. Since the threshold of twice the mutation frequency of the solvent control was clearly exceeded and the mean value of both positive controls is well within the historical range, this effect was considered as irrelevant fluctuation.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
In experiment I without metabolic activation relevant toxicity (relative cloning efficiency 1 and / or relative total growth of less than 50 % survival) was detected at 187.5 µg/mL and above in the second culture. In culture I a clear toxic effect occurred at the highest concentration of 375 µg/mL.
In experiment I with metabolic activation a toxic effect indicated by a reduced relative cloning efficiency 1 was observed at 375 µg/mL in both cultures.
In the second experiment (24 h treatment without metabolic activation) relevant toxic effects occurred at 187.5 µg/mL and above in both cultures.
Remarks on result:
other: all strains/cell types tested
Conclusions:
Interpretation of results (migrated information):
negative

The test substance did not increase the mutant frequency at the TK+/- locus in L5178Y cells and is therefore considered to be non-mutagenic under the conditions of the test.
Executive summary:

Mouse Lymphoma cells (L5178Y TK+/-) were treated with the test substance at five or six concentrations in the range of 11.7 to 375 microgram/mL. Precipitation of the test substance was detectable at dose level 187.5 and 375 microgram/mL. The solvent control gave mutant frequencies within the normal range. The positive controls gave marked increases in the mutant frequency, both in the presence or absence of metabolic activation, indicating the satisfactory performance of the test system. The test substance demonstrated no statistically significant or dose related increases in mutant frequency at any dose level, either with or without metabolic activation, thus indicating that the test item is not mutagenic under the conditions tested.

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 2 MAY 2006 to 12 MAY 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (OECD TG 471)
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 (induced with phenobarbital/beta-naphtoflavone; experiment I); hamster liver S9 (non-induced; experiment II)
Test concentrations with justification for top dose:
Experiment I: 3; 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate.
Experiment II: 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: solubility properties of the solvent and its relative non-toxicity to the bacteria
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: sodium azide (TA 1535 and TA 100), 4-Nitro-o-phenylene-diamine (TA 1537 and TA 98), methyl methane sulfonate (WP2 uvrA)
Remarks:
without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (for all strains)
Remarks:
with metabolic activation (rat liver S9)
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (TA 1535, TA 100, TA 1537, WP2 uvrA), congo red (TA 98)
Remarks:
with metabolic activation (hamster liver S9)
Details on test system and experimental conditions:
METHOD OF APPLICATION:
Experiment I: plate incorporation assay without and with induced rat liver S9 mix (induction with phenobarbital/beta-naphthoflavone)
Experiment II: preincubation assay without and with non-induced hamster liver S9 mix

DURATION
- Preincubation period: Experiment II: 30° C for 30 minutes
- Exposure duration: at least 48 hours at 37° C

NUMBER OF REPLICATIONS: 3 plates per strain and dose level, including the control
Evaluation criteria:
A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, WP2 uvrA) or thrice (strains TA 1535, TA 1537) the colony count of the corresponding solvent colony is observed.
A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration.
An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment. A dose dependent increase in the number of revertant colonies below the thresshold is regarded as an indication of mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative annd solvent controls such an increase is not considered biologically relevant.
Statistics:
Arithmetic means and standard deviation of the counted colonies were calculated.
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
in strain TA1537, TA98, TA100 (exp. I, without S9, starting from 2500 µg/plate); strain TA1537, TA98 (exp. II, without S9, starting from 1000 µg/plate);TA 100 exp. II, without S9, starting from 333 µg/plate); TA1537, TA98 (exp. II, with S9, 5000 µg/plate)
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
noted in exp. II, without S9 mix, at 5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: The test item precipitated in the overlay agar from 333 pg/plate up to 5000 µg/plate in experiment I. In experiment II, precipitation was observed from 100 µg/plate up to 5000 µg/plate. The undissolved particles had no influence on the data recording.

COMPARISON WITH HISTORICAL CONTROL DATA:
In experiment I, the data in the negative control with metabolic activation of strain WP2uvrA were slightly above our historical control range. Since this deviation is rather small, this effect is considered to be based upon biologically irrelevant fluctuations in the number of colonies.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Cytotoxicity was observed in
- strain TA1537, TA98, TA100 (exp. I, without S9, starting from 2500 µg/plate);
- strain TA1537, TA98 (exp. II, without S9, starting from 1000 µg/plate);
- strain TA 100 exp. II, (without S9, starting from 333 µg/plate);
- strain TA1537, TA98 (exp. II, with S9, 5000 µg/plate) and
- E.coli strain WP2 uvrA (exp. II, without S9 mix, at 5000 µg/plate)
Remarks on result:
other: all strains/cell types tested
Conclusions:
Interpretation of results (migrated information):
negative

The test item showed no mutagenic activity in both experiments (plate incorporation assay, preincubation assay) each with and without metabolic activation.
Executive summary:

Mutagenic activity of the test item was investigated in Salmonella typhimurium strains TA 1535, TA 1537, TA98 and TA100 as well as Escherichia coli strain WP2 uvrA with (induced rat liver S9 mix) and without metabolic activation at concentrations of 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate using the plate incorporation assay. Due to the test items characteristic as an azo-dye the test was also conducted using the Prival modification, i.e. testing the above mentioned bacterial strains in the preincubation assay without and with uninduced hamster liver S9 mix for metabolic activation. This test was performed using the concentrations 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate.

The test item did not reveal any mutagenic activity under the conditions tested. The appropriate reference mutagenes showed distinct positive mutagenic effects.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Mutagenic activity of the test item was investigated in Salmonella typhimurium strains TA 1535, TA 1537, TA98 and TA100 as well as Escherichia coli strain WP2 uvrA with (induced rat liver S9 mix) and without metabolic activation at concentrations of 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate using the plate incorporation assay. Due to the test items characteristic as an azo-dye the test was also conducted using the Prival modification, i.e. testing the above mentioned bacterial strains in the preincubation assay without and with uninduced hamster liver S9 mix for metabolic activation. This test was performed using the concentrations 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate.


The test item did not reveal any mutagenic activity under the conditions tested. The appropriate reference mutagenes showed distinct positive mutagenic effects.


Mouse Lymphoma cells (L5178Y TK+/-) were treated with the test substance at five or six concentrations in the range of 11.7 to 375 microgram/mL. Precipitation of the test substance was detectable at dose level 187.5 and 375 microgram/mL. The solvent control gave mutant frequencies within the normal range. The positive controls gave marked increases in the mutant frequency, both in the presence or absence of metabolic activation, indicating the satisfactory performance of the test system. The test substance demonstrated no statistically significant or dose related increases in mutant frequency at any dose level, either with or without metabolic activation, thus indicating that the test item is not mutagenic under the conditions tested.


 


In the chromosomal aberration assay, CHO-K1 cells were exposed to the test item in duplicate at the concentrations of 15.63, 62.5 and 250mg/mL in Experiments 1, 2 and 3 of the chromosomal aberration assay. Concurrent vehicle (SW) and positive controls (cyclophosphamide monohydrate in the presence of metabolic activation and ethyl methanesulfonate in the absence of metabolic activation at 21 hour exposure) were also tested in duplicate. In each case, the cells in C-metaphase were harvested at approximately 21 hours after the start of the treatment and slides were prepared for chromosomal analysis.


At the highest concentrations tested, the reduction in cell growth as RICC was 47, 43 and 53 % in experiments 1, 2 and 3, respectively, compared to the vehicle control. 


There was no evidence of statistically significant induction of chromosomal aberrations, excluding gaps, either in the presence or in the absence of metabolic activation. In each of these experiments, under identical conditions, the respective positive control substances produced a large and statistically significant increase in aberrant metaphases.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Justification for classification or non-classification

No classification - No adverse effects observed.