Registration Dossier
Registration Dossier
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EC number: 939-487-8 | CAS number: -
Endpoint summary
Administrative data
Key value for chemical safety assessment
Genetic toxicity in vitro
Description of key information
Gene mutation (Bacterial reverse mutation assay / Ames test): negative
with and without activation S. typhimurium TA 1535, TA 1537, TA 98 and
TA 100, E. coli WP2 uvr A pKM 101 and WP2 pKM101 (OECD TG 471) (Dow
Corning Corporation, 1995a).
Cytogenicity in mammalian cells: negative in Chinese hamster V79 cells
(OECD TG 473) (BSL Bioservice, 2013).
Mutagenicity in mammalian cells: negative in L5178Y mouse lymphoma cells
(OECD TG 476) (Dow Corning Corporation, 1995b).
Link to relevant study records
- Endpoint:
- in vitro gene mutation study in bacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1995-02-06 - 1995-02-16
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 471 (Bacterial Reverse Mutation Assay)
- Version / remarks:
- OECD not actually specified but mentioned in 'Statement of Compliance'.
- 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 pKM 101
- Species / strain / cell type:
- E. coli, other: WP2 pKM101
- Metabolic activation:
- with and without
- Metabolic activation system:
- Aroclor induced rat liver S9
- Test concentrations with justification for top dose:
- 100, 333, 1000, 3333 and 5000 µg/plate
- Vehicle / solvent:
- - Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: Sponsor's request and compatibility with the target cells.
NOTE: the solvent is described as acetone in the method section but in most of the tables of results it is reported to be DMSO. It is thought by the reviewer that this is a typographical error: if DMSO was used rather than acetone the study would still be valid. - Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- other: 2-aminoanthracene 1.0 µg/plate
- Remarks:
- TA98, TA100, TA1535, TA1537 with metabolic activation
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- other: 2-aminoanthracene 10 µg/plate
- Remarks:
- WP2 uvrA (pKM101) with metabolic activation
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- other: sterigmatocystin 100 µg/plate
- Remarks:
- WP2 (pKM101) with metabolic activation
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- 2-nitrofluorene
- Remarks:
- TA98 without metabolic activation 1.0 µg/plate
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- sodium azide
- Remarks:
- TA100, TA1535 without metabolic activation 1.0 µg/plate
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- 9-aminoacridine
- Remarks:
- TA1537 without metabolic activation 75 µg/plate
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- methylmethanesulfonate
- Remarks:
- WP2 uvrA (pKM101), WP2 (pKM101) without metabolic activation 1,000 µg/plate
- Details on test system and experimental conditions:
- METHOD OF APPLICATION: in agar (plate incorporation)
ACTIVATION: S9 mix contained glucose-6-phosphate and NADP as co-factors. Concentration of S9 in the mix was 10%. 0.5mlk of S9 mix were added to a total volume of 2.65ml, giving a final concentration of approximately 2% S9.
DURATION
- Preincubation period: 60 minutes +/- 2 minutes at 37ºC
- Exposure duration: 48 - 72 hours at 37ºC
SELECTION AGENT (mutation assays): histidine deficient agar
NUMBER OF REPLICATIONS: triplicate plates
DETERMINATION OF CYTOTOXICITY
- Method: other: condition of background lawn - Evaluation criteria:
- For the test to be evaluated positive, it must cause a dose-related increase in the mean revertants per plate of at least one tester strain with a minimum of two increasing concentrations of test article. TA1535 and TA1537 were judged positive if the increase in mean revertants is equal to or greater than three times the mean vehicle control value. TA98, TA100, WP2 uvrA (pKM101) and WP2 (pKM101) were judged positive in the increase in mean revertants is equal to or greater than two times the mean vehicle control value.
- Statistics:
- None stated in report
- 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:
- no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
- Vehicle controls validity:
- valid
- Untreated negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Species / strain:
- E. coli WP2 uvr A pKM 101
- Metabolic activation:
- with and without
- Genotoxicity:
- negative
- Cytotoxicity / choice of top concentrations:
- no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
- Vehicle controls validity:
- valid
- Untreated negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Species / strain:
- E. coli, other: WP2 (pKM101)
- Metabolic activation:
- with and without
- Genotoxicity:
- negative
- Cytotoxicity / choice of top concentrations:
- no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
- Vehicle controls validity:
- valid
- Untreated negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Additional information on results:
- TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Precipitation was observed at 333 µg/plate and above
ADDITIONAL INFORMATION ON CYTOTOXICITY: Cytotoxicity was not evident at any concentration - Remarks on result:
- other: No mutagenic potential
- Conclusions:
- Silsesquioxanes, phenyl has been tested for mutagenicity to bacteria, in a study which was conducted according to a protocol that was similar to OECD 471, and in compliance with GLP. No evidence of a test substance related increase in the number of revertants was observed with or without activation in the experiment. Appropriate positive and solvent controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.
- Endpoint:
- in vitro cytogenicity / chromosome aberration study in mammalian cells
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2011-12-22 to 2012-09-05
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 870.5375 - In vitro Mammalian Chromosome Aberration Test
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, München, Germany
- Type of assay:
- in vitro mammalian chromosome aberration test
- Species / strain / cell type:
- Chinese hamster lung fibroblasts (V79)
- Details on mammalian cell type (if applicable):
- - Type and identity of media: MEM
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes - Metabolic activation:
- with and without
- Metabolic activation system:
- Liver S9 of Wistar phenobarbital and ß-naphthoflavone-induced rat liver S9 mix
- Test concentrations with justification for top dose:
- A pre-experiment with THF as solvent
with and without metabolic activation: 0.008, 0.016, 0.03, 0.06, 0.13, 0.25, 0.50, 1.0, 2.0 and 4.0 µl/ml
A pre-experiment using Acetone as solvent
with and without metabolic activation: 0.004, 0.008, 0.016, 0.03, 0.06, 0.13, 0.25, 0.5, 1.0 and 2.0 µl/ml
Experiment I:
without metabolic activation: 0.05, 2.0, 4.0 and 5.0 µl/ml
with metabolic activation: 0.16, 2.0, 4.0 and 5.0 µl/ml
Experiment II:
without metabolic activation: 0.16, 4.0 and 5.0 µl/ml
with metabolic activation: 0.47, 4.5 and 5.0 µl/ml - Vehicle / solvent:
- -Vehicle (s)/solvent(s) used: THF and Acetone
-Justification for choice of solvent/vehicle: A solubility test was performed up to a maximum concentration of 800 mg/ml using acetone and tetrahydrofurane (THF) as vehicle. The solvent was compatible with the survival of the cells and the S9 activity. For preparing the test concentrations the THF and acetone solutions were diluted with MEM, both formed precipitations (oily droplets). After treatment with ultrasound for around 5 minutes the test item was well suspended in both solvents. The final concentration of THF in the samples was 0.5% v/v. The final concentration of acetone in the samples was 0.25% v/v. As with THF it was possible to reach higher final concentrations of the test item and on sponsor’s request THF was used as solvent in the main experiments. - Untreated negative controls:
- yes
- Negative solvent / vehicle controls:
- yes
- Remarks:
- Tetrahydrofurane (THF)
- Positive control substance:
- ethylmethanesulphonate
- Remarks:
- without metabolic activation 400 and 900 µg/mL
- Untreated negative controls:
- yes
- Negative solvent / vehicle controls:
- yes
- Remarks:
- Tetrahydrofurane (THF)
- Positive controls:
- yes
- Positive control substance:
- cyclophosphamide
- Remarks:
- with metabolic activation 0.83 µg/mL
- Details on test system and experimental conditions:
- TREATMENT TIME:
4 hours (Experiment I with and without metabolic activation, experiment II with metabolic activation)
20 hours (Experiment II without metabolic activation)
FIXATION INTERVAL: 20 hours (Experiment I and II with and without metabolic activation)
NUMBER OF REPLICATIONS: 2 independent experiments
NUMBER OF CELLS SEEDED: 1 x 10E+04 - 5 x 10E+04 cells
NUMBER OF CULTURES: two cultures per concentration. Reviewers note, it is not clear from the study report if there were actually two cultures per concentrations, or whether, as indicated in the executive summary prepared by the test laboratory, only one culture was used, but the four slides per culture were divided into two sets for counting.
NUMBER OF CELLS SCORED: 200 cells per concentration (100 cells per culture)
Except experiment I with metabolic activation : 4.0 µl/ml (500 cells), 5.0 µl/ml (300 cells)
experiment II without metabolic activation: µl/ml (400 cells)
experiment II with metabolic activation: µl/ml (400 cells)
DETERMINATION OF CYTOTOXICITY: Mitotic index, cell density
ACTIVATION: Phenobarbital (80 mg/kg bw) and β naphthoflavone (100 mg/kg bw) induced rat liver S9 was included in the S9 mix to a final protein concentration of 0.75 mg/ml. Cofactors were added to the following concentrations: 8 mM MgCl2; 33 mM KCl; 5 mM Glucose-6-phosphate; 5 mM NADP. - Evaluation criteria:
- There are several criteria for determining a positive result:
- a clear and dose-related increase in the number of cells with aberrations,
- a biologically relevant response for at least one of the dose groups, which is higher than the laboratory negative control range (0.0% - 4.0% aberrant cells (with and without metabolic activation)). - Statistics:
- According to OECD guidelines, the biological relevance of the results is the criterion for the interpretation of results, a statistical evaluation of the results is not regarded as necessary.
- Key result
- Species / strain:
- Chinese hamster lung fibroblasts (V79)
- Metabolic activation:
- with and without
- Genotoxicity:
- negative
- Cytotoxicity / choice of top concentrations:
- no cytotoxicity
- Vehicle controls validity:
- valid
- Untreated negative controls validity:
- valid
- Positive controls validity:
- valid
- Conclusions:
- Silsesquioxanes, phenyl has been tested in a reliable study which was conducted according to OECD 473 (1997) and in compliance with GLP. No evidence for a potential to cause structural or numerical damage to chromosomes was observed with or without activation when tested up to limit concentrations in Chinese hamster V79 cells in either the initial or the repeat experiment. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for cytogenicity to mammalian cells under the conditions of the test.
- Executive summary:
A solubility test was performed up to a maximum concentration of 800 mg/ml using Acetone and Tetrahydrofurane (THF) as vehicle.For preparing the test concentrations the THF solution was diluted with MEM where precipitate was formed (oily droplets). After treatment with ultrasound for around 5 minutes the test item was well suspended. The final concentration of THF in the samples was 0.5% v/v. As the test item formed precipitate upon addition to the samples, cells were incubated with a dispersed test item suspension. The vehicle was compatible with the survival of the cells and the S9 activity. However, to decide which solvent should be used and on sponsor’s request the test item was also dissolved in acetone. The acetone solution was then diluted with MEM where also precipitate was formed (oily droplets). After treatment with ultrasound for around 5 minutes the test item was well suspended. The final concentration of acetone in the samples was 0.25% v/v. The vehicle was compatible with the survival of the cells and the S9 activity.
Pre-experiments with both vehicles were performed.
As with THF it was possible to reach higher final concentrations of the test item and on sponsor’s request THF was used as solvent in the main experiments.
To investigate the potential of Silsesquioxanes, Phenyl to induce structural chromosome aberrations in Chinese hamster V79 cells, an in vitro chromosome aberration assay was carried out.
The metaphases were prepared 20 h after start of treatment with the test item. The treatment interval was 4 h with and without metabolic activation in Experiment I. In Experiment II, the treatment interval was 4 h with and 20 h without metabolic activation. For each concentration, one Quadriperm dish containing four microscopic slides was seeded. At the end of the 20 hour preparation interval, the slides were divided into sets of two. At least one slide from each set was counted. Generally at least 100 metaphases per set were scored for structural chromosomal aberrations (for exceptions, see Tables).
The following concentrations were selected for the microscopic analysis of chromosomal aberrations:
Experiment I:
without metabolic activation: 0.05, 2.0, 4.0 and 5.0 µl/ml
with metabolic activation: 0.16, 2.0, 4.0 and 5.0 µl/ml
Experiment II:
without metabolic activation: 0.16, 4.0 and 5.0 µl/ml
with metabolic activation: 0.47, 4.5 and 5.0 µl/ml
In Experiment I precipitation of the test item was noted with and without metabolic activation at concentrations of 2.0 µl/ml and higher. In Experiment II precipitation of the test item was seen without metabolic activation at concentrations of 4.0 µl/ml and higher, with metabolic activation at concentrations of 4.5 µl/ml and higher.
In Experiments I and II with and without metabolic activation no cytotoxic effects of the test item were noted at the evaluated concentrations.
In both experiments, no biologically relevant increase of the aberration rates was noted after treatment with the test item with and without metabolic activation. The aberration rates of all dose groups treated with the test item were within the historical control data of the solvent control. However, there were 3.5% exchanges found on one slide at a concentration of 4 µl/ml in the first experiment with metabolic activation. Exchanges are not always detected with Giemsa staining (depending on their size), therefore the induction of exchanges should be evaluated additionally for example by using Fluorescence in situ hybridisation (FISH) analysis. However, these analyses were not performed, because that method is not established at BSL at this time.
In the Experiments I and II with and without metabolic activation no biologically relevant increase in the frequencies of polyploid cells was found after treatment with the test item as compared to the solvent controls.
EMS (400 and 900 µg/ml) and CPA (0.83 µg/ml) were used as positive controls and induced distinct and biologically relevant increases in cells with structural chromosomal aberrations, thus proving the efficiency of the test system to indicate potential clastogenic effects.
The positive controls induced the appropriate response.
There was no evidence of chromosome aberration induced over background.
This study is classified as acceptable. This study satisfies the requirement for Test Guideline OPPTS 870.5375; OECD 473 for in vitro cytogenetic mutagenicity data.
- Endpoint:
- in vitro gene mutation study in mammalian cells
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1995-02-17 - 1995-03-25
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
- Version / remarks:
- 1984
- GLP compliance:
- yes
- Type of assay:
- mammalian cell gene mutation assay
- Target gene:
- Thymidine kinase locus of L5178Y
- Species / strain / cell type:
- mouse lymphoma L5178Y cells
- Details on mammalian cell type (if applicable):
- - Type and identity of media: Fischer's Medium for Leukemic Cells of Mice
- Properly maintained: yes/no
- Periodically checked for Mycoplasma contamination: yes
- Periodically "cleansed" against high spontaneous background: yes - Metabolic activation:
- with and without
- Metabolic activation system:
- Aroclor 1254 induced rat liver S9
- Test concentrations with justification for top dose:
- 3000, 3500, 4000, 4500 and 5000 µg/ml
- Vehicle / solvent:
- - Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: Chosen by the sponsor. The test substance was soluble in acetone at a maximum concentration of approx 500 mg/ml - Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- ethylmethanesulphonate
- Remarks:
- without metabolic activation 0.25 and 0.50 µg/ml
- Untreated negative controls:
- no
- Negative solvent / vehicle controls:
- yes
- True negative controls:
- no
- Positive controls:
- yes
- Positive control substance:
- 7,12-dimethylbenzanthracene
- Remarks:
- with metabolic activation 2.5 and 5.0 µg/ml
- Details on test system and experimental conditions:
- METHOD OF APPLICATION: in medium
DURATION
- Exposure duration: 4 hours with and without metabolic activation
- Expression time (cells in growth medium): 24 - 48 hours after treatment
- Selection time (if incubation with a selection agent): 10 - 12 days
SELECTION AGENT (mutation assays): Trifluorothymidine
NUMBER OF REPLICATIONS: 2 flasks per culture, 3 replicate dishes
NUMBER OF CELLS EVALUATED:
DETERMINATION OF CYTOTOXICITY
- Method: other: % viability
ACTIVATION: S9 mix contained 250 μl S9, and NADP as co-factor in 750 μl medium. Final concentration of S9 is not clearly presented in the study report. - Evaluation criteria:
- The mutant frequency of the positive controls must be at least twice that of the appropriate solvent controls. The spontaneous mutant frequency of the solvent controls must be between 20 and 100 TFT-resistant mutants per 10x6 surviving cells. The cloning efficiency of the solvent controls must be greater than 50%.
- Statistics:
- None in report
- Key result
- Species / strain:
- mouse lymphoma L5178Y cells
- Metabolic activation:
- with and without
- Genotoxicity:
- negative
- Cytotoxicity / choice of top concentrations:
- no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
- Vehicle controls validity:
- valid
- Untreated negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Additional information on results:
- TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Some globules of the test article stuck to the side of the culture tubes or floated in the treatment medium. The discrepancy in precipitation profile could be result of being inadvertently not documented during preliminary toxicity assay. - Remarks on result:
- other: No mutagenic potential
- Conclusions:
- Silsesquioxanes, phenyl was tested in a L5178Y/TK+/- mouse lymphoma mutagenesis assay, in a study which was conducted according to OECD 476 and in compliance with GLP. No evidence of a test substance related increase in mutant frequency was detected at any concentration in the presence or absence of metabolic activation. Appropriate solvent and positive controls were concluded and gave expected results. It is concluded that the test substance is negative for the induction of mutation in L5178Y cells under the conditions of the test.
Referenceopen allclose all
Summary of results – Experiment B1 revertants per plate (mean of 3 plates)
Dose µg/plate |
+/- metabolic activation |
Average revertants per plate |
|||||
TA98 |
TA100 |
TA1535 |
TA1537 |
WP2 uvrA (pKM101) |
WP2 (pKM101) |
||
Solvent control |
- |
21 |
143 |
11 |
7 |
210 |
44 |
100 |
- |
19 |
158 |
11 |
6 |
212 |
52 |
333 |
- |
24 |
141 |
11 |
7 |
199 |
50 |
1000 |
- |
20 |
136 |
15 |
6 |
232 |
48 |
3333 |
- |
20 |
142 |
14 |
4 |
163 |
53 |
5000 |
- |
22 |
153 |
14 |
6 |
169 |
46 |
Positive control |
- |
804 |
675 |
467 |
156 |
1963 |
205 |
Solvent control |
+ |
28 |
157 |
15 |
9 |
276 |
58 |
100 |
+ |
27 |
159 |
15 |
9 |
294 |
61 |
333 |
+ |
29 |
188 |
10 |
8 |
242 |
50 |
1000 |
+ |
30 |
182 |
12 |
8 |
254 |
52 |
3333 |
+ |
30 |
157 |
14 |
7 |
287 |
55 |
5000 |
+ |
28 |
180 |
12 |
7 |
270 |
58 |
Positive control |
+ |
1363 |
1241 |
94 |
179 |
1395 |
2018 |
NOTE: the solvent is described as acetone in the method section but in most of the tables of results it is reported to be DMSO. It is thought by the reviewer that this is a typographical error, however if DMSO was used rather than acetone the study would still be valid.
| Results of chromosome analysis | |||||||||||||||
| without metabolic activation | |||||||||||||||
| Cytotoxicity | Chromatid aberrations | Isochromatid aberrations | rel. Mitotic index (%) | rel. Cell density (%) | Poly-ploidy | mean % aberrant cells | |||||||||
| Scored cells | gaps | breaks | inter-changes | other | gaps | breaks | inter-changes | other | incl. Gaps | excl. Gaps | |||||
| Experiment I without metabolic activation | |||||||||||||||
| negative control | 200 | - | 2 | 3 | 0 | 0 | 0 | 0 | 1 | 0 | 102 | 99 | 1 | 3.0 | 2.0 |
| solvent control | 200 | - | 2 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 100 | 100 | 0 | 2.0 | 0.5 |
| 0.016 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 98 | n.d. | n.d. | n.d. | n.d. |
| 0.05 µL/mL | 200 | no | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 94 | 99 | 1 | 1.5 | 0.5 |
| 0.16 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 101 | n.d. | n.d. | n.d. | n.d. |
| 0.5 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 108 | n.d. | n.d. | n.d. | n.d. |
| 1.0 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 110 | n.d. | n.d. | n.d. | n.d. |
| 2.0 µL/mL | 200 | no | 2 | 2 | 1 | 1 | 0 | 0 | 0 | 0 | 105 | 101 | 1 | 3.0 | 2.0 |
| 4.0 µL/mL | 200 | no | 3 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 102 | 104 | 0 | 2.0 | 1.0 |
| 5.0 µL/mL | 200 | no | 3 | 2 | 0 | 0 | 0 | 0 | 1 | 0 | 112 | 100 | 1 | 2.5 | 1.5 |
| EMS 900 µg/mL | 200 | - | 4 | 10 | 6 | 0 | 0 | 0 | 1 | 0 | 96 | 95 | 0 | 9.0 | 8.0 |
| Experiment II without metabolic activation | |||||||||||||||
| negative control | 200 | - | 4 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 86 | 102 | 1 | 4.5 | 2.5 |
| solvent control | 200 | - | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 100 | 100 | 0 | 1.0 | 1.0 |
| 0.016 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 96 | n.d. | n.d. | n.d. | n.d. |
| 0.05 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 101 | n.d. | n.d. | n.d. | n.d. |
| 0.16 µL/mL | 400 | no | 1 | 2 | 3 | 1 | 1 | 0 | 1 | 0 | 104 | 102 | 2 | 2.3 | 1.8 |
| 0.5 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 91 | n.d. | n.d. | n.d. | n.d. |
| 1.0 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 93 | n.d. | n.d. | n.d. | n.d. |
| 2.0 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 95 | n.d. | n.d. | n.d. | n.d. |
| 4.0 µL/mL | 200 | no | 1 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 107 | 115 | 1 | 1.5 | 1.5 |
| 5.0 µL/mL | 200 | no | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 102 | 107 | 1 | 0.5 | 0.0 |
| EMS 400 µg/mL | 200 | - | 4 | 13 | 3 | 2 | 0 | 1 | 1 | 0 | 83 | 103 | 0 | 10.0 | 9.0 |
| Results of chromosome analysis | |||||||||||||||
| with metabolic activation | |||||||||||||||
| Cytotoxicity | Chromatid aberrations | Isochromatid aberrations | rel. Mitotic index (%) | rel. Cell density (%) | Poly-ploidy | mean % aberrant cells | |||||||||
| Scored cells | gaps | breaks | inter-changes | other | gaps | breaks | inter-changes | other | incl. Gaps | excl. Gaps | |||||
| Experiment I with metabolic activation | |||||||||||||||
| negative control | 200 | - | 3 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 95 | 104 | 0 | 2.5 | 0.5 |
| solvent control | 200 | - | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 100 | 100 | 2 | 0.5 | 0.5 |
| 0.016 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 104 | n.d. | n.d. | n.d. | n.d. |
| 0.05 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 105 | n.d. | n.d. | n.d. | n.d. |
| 0.16 µL/mL | 200 | no | 4 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 110 | 95 | 0 | 3.0 | 1.0 |
| 0.5 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 109 | n.d. | n.d. | n.d. | n.d. |
| 1.0 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 116 | n.d. | n.d. | n.d. | n.d. |
| 2.0 µL/mL | 200 | no | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100 | 99 | 1 | 2.5 | 0.0 |
| 4.0 µL/mL | 500 | no | 9 | 4 | 5 | 0 | 0 | 0 | 4 | 0 | 97 | 99 | 4 | 3.8 | 2.6 |
| 5.0 µL/mL | 300 | no | 9 | 6 | 0 | 1 | 0 | 0 | 0 | 1 | 118 | 105 | 1 | 5.3 | 2.7 |
| CPA 0.83 µg/mL | 200 | - | 6 | 13 | 6 | 1 | 0 | 0 | 1 | 0 | 91 | 92 | 0 | 12.0 | 9.5 |
| Experiment II with metabolic activation | |||||||||||||||
| negative control | 200 | - | 6 | 3 | 0 | 0 | 1 | 0 | 0 | 0 | 105 | 98 | 2 | 5.0 | 1.5 |
| solvent control | 200 | - | 3 | 5 | 1 | 1 | 1 | 0 | 0 | 0 | 100 | 100 | 2 | 4.5 | 3.0 |
| 0.047 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 97 | n.d. | n.d. | n.d. | n.d. |
| 0.15 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 88 | n.d. | n.d. | n.d. | n.d. |
| 0.47 µL/mL | 400 | no | 10 | 5 | 2 | 2 | 0 | 0 | 1 | 0 | 104 | 87 | 3 | 5.5 | 2.5 |
| 1.5 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 91 | n.d. | n.d. | n.d. | n.d. |
| 2.5 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 100 | n.d. | n.d. | n.d. | n.d. |
| 3.5 µL/mL | - | no | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 104 | n.d. | n.d. | n.d. | n.d. |
| 4.5 µL/mL | 200 | no | 4 | 3 | 0 | 1 | 0 | 0 | 0 | 0 | 92 | 81 | 0 | 4.0 | 2.0 |
| 5.0 µL/mL | 200 | no | 6 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 106 | 88 | 0 | 3.5 | 1.0 |
| CPA 0.83 µg/mL | 200 | - | 8 | 20 | 6 | 0 | 0 | 1 | 0 | 0 | 77 | 77 | 1 | 14.0 | 10.5 |
n.d. not determined
Cloning data in the absence and presence of metabolic activation
Dose level µg/ml |
+/- metabolic activation |
Mutant Frequency |
% Total Growth |
Solvent control 1 |
- |
38 |
- |
Solvent control 2 |
- |
33 |
- |
3000 A |
- |
25 |
100 |
3000 B |
- |
49 |
74 |
3500 A |
- |
26 |
92 |
3500 B |
- |
43 |
96 |
4000 A |
- |
28 |
105 |
4000 B |
- |
27 |
92 |
4500 A |
- |
27 |
91 |
4500 B |
- |
28 |
92 |
5000 A |
- |
25 |
98 |
5000 B |
- |
33 |
110 |
DMSO 1 |
- |
27 |
- |
DMSO 2 |
- |
29 |
- |
Positive control 1 |
- |
400 |
66 |
Positive control 2 |
- |
817 |
26 |
Solvent control 1 |
+ |
25 |
- |
Solvent control 2 |
+ |
32 |
- |
3000 A |
+ |
38 |
93 |
3000 B |
+ |
33 |
89 |
3500 A |
+ |
34 |
101 |
3500 B |
+ |
46 |
100 |
4000 A |
+ |
33 |
110 |
4000 B |
+ |
30 |
113 |
4500 A |
+ |
29 |
107 |
4500 B |
+ |
39 |
116 |
5000 A |
+ |
41 |
94 |
5000 B |
+ |
26 |
110 |
DMSO 1 |
+ |
24 |
- |
DMSO 2 |
+ |
26 |
- |
Positive control 1 |
+ |
203 |
25 |
Positive control 2 |
+ |
++ |
++ |
++ = too toxic to clone
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (negative)
Genetic toxicity in vivo
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
The selected in vitro studies are the only available cytogenicity and
bacterial and mammalian mutagenicity studies for the substance. The
bacterial study was conducted according to a protocol that is equivalent
to an appropriate OECD guideline; the studies in mammalian cells were
conducted according to appropriate OECD guidelines. All studies were
conducted in compliance with GLP.
Information is available for phenyl silsesquioxanes from reliable in vitro studies on mutagenicity to bacterial and mammalian cells, and cytogenicity to mammalian cells. The results of all the studies were in agreement: no evidence for mutagenicity was obtained. It is therefore considered that in vivo testing is not required.
Phenyl silsesquioxanes has been tested for mutagenicity to bacteria, in a study which was conducted according to a protocol that was similar to OECD Test Guideline 471, and in compliance with GLP (Dow Corning Corporation, 1995a). No evidence of a test substance related increase in the number of revertants was observed with or without activation in the experiment, which tested Salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100, and E. coli WP2 uvr A pKM 101 and WP2 pKM101up to limit concentrations. Appropriate positive and solvent controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.
Information on the potential of phenyl silsesquioxanes to cause structural or numerical damage to chromosomes is available from a reliable study which was conducted according to OECD Test Guideline 473 (1997) and in compliance with GLP (BSL Bioservice, 2013). No evidence for a potential to cause structural or numerical damage to chromosomes was observed with or without activation when tested up to limit concentrations in Chinese hamster V79 cells. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for cytogenicity to mammalian cells under the conditions of the test.
Phenyl silsesquioxanes was tested in a L5178Y/TK+/- mouse lymphoma
mutagenesis assay, in a study which was conducted according to OECD Test
Guideline 476 and in compliance with GLP (Dow Corning Corporation,
1995b). No evidence of a test substance related increase in mutant
frequency was detected at any concentration in the presence or absence
of metabolic activation. Appropriate solvent and positive controls were
concluded and gave expected results. It is concluded that the test
substance is negative for the induction of mutation in L5178Y cells
under the conditions of the test.
Justification for classification or non-classification
Based on the available in vitro data, phenyl silsesquioxanes does not require classification for mutagenicity according to Regulation (EC) No 1272/2008.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
