Reaction mass of 3-[3-(9-butyl-1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxanyl)propoxy]-2-hydroxypropyl 2methylprop-2-enoate and 1-[3-(9-butyl-1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxanyl)propoxy]-3-hydroxypropan-2-yl 2-methylprop-2-enoate

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:

April 6-27, 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of relevant results. Conducted to method equivalent to OECD and to Japanese GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Principles of method if other than guideline:

To set the dose levels in this study, a dose-setting study was conducted to examine the number of reverse mutant colonies, antimicrobial activity and precipitation. In the dose-setting study, six dose levels were set up with 5000 μg/plate as the highest level and common ratio of 4.

The test article neither showed antimicrobial activity to any of the microbial strains regardless of the presence or absence of a metabolic activator at all dose levels nor increased the number of reverse mutant colonies twice or more than that in the negative vehicle. The test article precipitated at concentrations of 1250 μg/plate or higher regardless of the presence or absence of a metabolic activator but this had no effect on the counting of reverse mutant colonies.
Based on the above results, it was decided to use 5 dose levels with 5000 μg/plate as the highest dose level and common ratio of 2 for all microbial strains regardless of the presence or absence of a metabolic activator.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(2R)-1-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-2-yl 2-methylprop-2-enoate; (2R)-2-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-1-yl 2-methylprop-2-enoate; (2S)-1-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-2-yl 2-methylprop-2-enoate; (2S)-2-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-1-yl 2-methylprop-2-enoate

EC Number:

700-043-1

Molecular formula:

C24H56O8Si5

IUPAC Name:

(2R)-1-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-2-yl 2-methylprop-2-enoate; (2R)-2-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-1-yl 2-methylprop-2-enoate; (2S)-1-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-2-yl 2-methylprop-2-enoate; (2S)-2-hydroxy-8,8,10,10,12,12,14,14,16,16-decamethyl-4,9,11,13,15-pentaoxa-8,10,12,14,16-pentasilaicosan-1-yl 2-methylprop-2-enoate

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): L1
-Lot numbeer: 060620
- Appearance: liquid

Method

Target gene:

Genes involved in histidine synthesis
Genes involved in tryptophan synthesis

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

5, 20, 78, 313, 625, 1250, 2500 and 5000 μg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: The vehicle for the test article was decided based on the result of the dissolution test, which was conducted in distilled water, DMSO, and acetone. The concentration of the dissolution test was set at 50 mg/mL in distilled water and DMSO and 100 mg/mL in acetone. The test article was added to each of the vehicles to give 50 or 100 mg/mL and solubility and reactions with the vehicle such as heat and fume generation were observed macroscopically. As a result, the test article dissolved in acetone. It also gave a uniformly dispersed suspension in DMSO by ultrasonication. Dispersion by ultrasonication was also attempted in distilled water but a uniform dispersion was not observed. The reactivity of the test article with vehicles such as heat and fume generation was examined. No reaction was observed with any of the vehicles. Based on the above results, acetone, which gave a solution of the test article without reacting and in which the test article was stable as a solution, was selected as the vehicle. The acetone used in the preparation was dehydrated by molecular sieving.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

benzo(a)pyrene

other: 2-(-2-furyl)-3-(5-nitro-2-furyl)acrylamide, sodium azide, 2-aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes
- Expression time (cells in growth medium): 48 hours

NUMBER OF REPLICATIONS: 2

DETERMINATION OF CYTOTOXICITY
Revertant colonies and checking background lawn.

Evaluation criteria:

Dose-dependent increase in the reverse mutant colonies of any of the microbial strains regardless of the presence or absence of metabolic activation and a twice or more increase in comparison to the negative (vechicle) control.

Statistics:

Standard deviation.

Results and discussion

Test results

Test results 1

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

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

Additional information on results:

RANGE-FINDING/SCREENING STUDIES:
Six dose levels in total were prepared with the highest dose level of 5000 μg/plate, which was diluted by a common ratio of 4.

COMPARISON WITH HISTORICAL CONTROL DATA:
The reverse mutant colony counts in the negative (vehicle) control and the positive controls were within the normal ranges based on the respective background data. 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, sodium azide, 9—aminoacridine, 2-aminoanthracene and benzo[α]pyrene, used as positive controls, increased the reverse mutant colonies twice or more in comparison to the negative (vehicle) control. These results demonstrate appropriate conduct of the study. Neither environmental factor that might have affected the study reliability adversely nor deviation from the protocol was observed.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
The test article did not show a dose-dependent increase in the reverse mutant colonies of any of the microbial strains regardless of the presence or absence of metabolic activation and a twice or more increase in comparison to the negative (vehicle) control. The result was reproduced in the dose-setting study and the main study. In the sterility test performed in Nutrient broth No. 2 used in the pre-culture, in the test article solution at the highest concentration used in the study, S9 Mix and 0.1 M phosphate buffer, no microbial contamination was confirmed.

The test article did not show antimicrobial activity to any of the microbial strains regardless of the presence or absence of a metabolic activator. It was precipitated at doses of 625 μg/plate or higher in the absence of a metabolic activator and 1250 μg/plate or higher in the presence of a metabolic activator.

Remarks on result:

other: not mutagenic under the conditions of this study.

Any other information on results incl. tables

Please refer to the attached background material for the results of the dose-setting study (Table 1) and the result of the main study (Table 2).

Applicant's summary and conclusion

Conclusions:

The test article did not show a dose-dependent increase in the reverse mutant colonies of any of the microbial strains regardless of the presence or absence of metabolic activation and a twice or more increase in comparison to the negative (vehicle) control. The result was reproduced in the dose-setting study and the main study. It was concluded that the test article was not mutagenic under the conditions of this study.

Executive summary:

In a reverse gene mutation assay in bacteria strains TA 1535, TA 1537, TA 98 and TA 100 of S. typhimurium and strain WP2 uvr A of E. coli  were exposed to the test substance in acetone, at concentrations of 5, 20, 78, 313, 625, 1250, 2500 and 5000 µg/plate in the presence and absence of mammalian metabolic activation pre-incubation. 

 

The test substance was tested up to cytotoxic the limit concentration (5000 µg/plate). The test article precipitated at doses of 625 µg/plate or higher in the absence of a metabolic activator and 1250 µg/plate or higher in the presence of a metabolic activator.

No growth inhibition was detected.

The number of reverse mutant colonies was within the range of the historical data both in the negative and positive controls. Absence of contamination in the study system was also confirmed validating proper conduct of the study.

Based on the results, it was concluded that the test article was not mutagenic under the conditions of the study.