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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1982-09-20 to 1982-11-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restrictions because it was GLP compliant and was conducted in close accordance with OECD 476 guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1983
Report Date:
1983

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
This substance is very similar with regard to health endpoints to the substance being registered.

- Name of test material (as cited in study report): Gulftene C12-16
- Substance type: C12-16 alpha olefins
- Physical state: Colourless liquid

Method

Target gene:
Hypoxanthine guanine phosphoribosyl transferase (HGPRT)
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
No details provided
Test concentrations with justification for top dose:
Range finding study: 4, 8, 16, 32, 64, 128, 256, 512, 1024, and 2048 ug/mL
Mutagenicity test: 4, 16, 128, 512, 1024, and 2048 ug/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: F68 Pluronic Polyol
- Justification for choice of solvent/vehicle: Not provided
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 2 days
- Exposure duration: 5 hours

NUMBER OF REPLICATIONS: six, three with S9 and three without

NUMBER OF CELLS EVALUATED: 1 million





Evaluation criteria:
Range finding study:
Mean and standard deviations of the colony counts from cultures derived from each treatment flask were computed using standard statistical methods. Ratios were set up as follows: Relative survival-Mean colony count in vehicle treated cultures/colony count in untreated cultures and mean colony count in substance-treated cultures/colony count in vehicle treated cultures; Cloning efficiency: mean colony count in each group/number of cell seeded per plate.

Mutagenicity Aspect:
Mean and standard deviations of the colony counts from cultures derived from each treatment flask were computed using standard statistical methods. For mutagenicity cultures, a ratio of total colony counts in mutagenicity plates/total colony counts in the respective viability plates. Once the ratio was determined, the group mean of the ratios was calculated.

A test was considered positive if there was significant increase in mutant colonies at any dose level and a dose-related response. It was considered negative if neither of these criteria were met. If only one criterion was met, the results were considered equivocal.

Statistics:
Students "t" test

Results and discussion

Test resultsopen allclose all
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
2048 mcg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
≥64 mcg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
In the range finding study, cytotoxicity was observed at 2048 ug/mL in the absence of metabolic activation and ≥64 ug/mL in the presence of metabolic activation; however, the cytotoxicity was clearly not dose-dependent

Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

In the range finding study, cytotoxicity was observed at 2048 ug/mL in the absence of metabolic activation and ≥64 ug/mL in the presence of metabolic activation; however, the cytotoxicity was clearly not dose-dependent. In the main mutagenicity study, there was no increase in the frequency of mutant colonies at any test concentration with or without metabolic activation (±S9). The vehicle control was well within the <90% toxicity level, while the two positive control groups (ethyl methane sulfonate & benzo(a)pyrene) exhibited a positive response indicating that the assay was functional.

Applicant's summary and conclusion

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

The study authors concluded that there was no increase in the frequency of mutant colonies in cells treated with Gulftene C12-16 when compared to the controls.
Executive summary:

Justification for Read Across

Several criteria justify the use of the read across approach to fill data gaps for isomerised olefins; alpha, internal, linear and branched – multiple carbon number substances using linear alpha olefin substances.Studies indicate that changing the carbon number, the location of the double bond, or adding branching does not measurably alter effects on mammalian health endpoints. There is a consistent toxicity potency pattern for linear alpha olefins supported by a low toxicity concern for acute oral, dermal and inhalation exposure. These materials are slightly irritating to skin and mildly irritating to non-irritating to eyes of rabbits. Screening studies indicate that they are not genotoxic. Study results for the aforementioned endpoints indicate a low hazard potential for human health. Since the addition of branching does not measurably alter the results of studies on mammalian health endpoints, there should not be any toxicological differences between substances in multiple carbon number isomerised olefins and linear alpha olefins.  Therefore, read across between these categories can be justified.

In an in vitro mammalian gene mutation assay, Chinese hamster ovary cells (CHO-K1) were treated with Gulftene 12-16 to study its potential to induce point mutations in the HGPRT gene in the CHO-K1 cell line in the absence and presence of metabolic activation (±S9). The test conditions were appropriate for this study type and appeared to closely follow OECD 476 guidelines. Concentrations of 4, 8, 16, 32, 64, 128, 512, 1024, and 2048 ug/mL Gulftene 12-16 (vehicle-F68 Pluronic®Polyol) were used for the range finding. Cytotoxicity was observed at 2048 ug/mL in the absence of metabolic activation and ≥64 ug/mL in the presence of metabolic activation; however, the cytotoxicity was clearly not dose-dependent. Mutagenicity was evaluated at 4, 16, 128, 512, 1024, and 2048 ug/mL Gulftene 12-16 (±S9); however, results were only provided for concentrations ≥128 ug/mL.  In the absence of S9, there were an insufficient number of cells to sub-culture 1 million cells per dish at the 1024 and 2048 ug/mL test concentrations and cell counts for these concentrations were also reduced with metabolic activation (+S9). In addition, the cloning efficiency was depressed at 1024 and 2048 ug/mL, indicating that the immediate toxic effect also delayed growth of surviving cells.  There was no increase in the frequency of mutant colonies at any test concentration with or without metabolic activation (±S9). The vehicle control was well within the <90% toxicity level, while the two positive control groups (ethyl methane sulfonate & benzo(a)pyrene) exhibited a positive response indicating that the assay was functional. Based on these results, the study authors concluded that there was no increase in the frequency of mutant colonies in cells treated with Gulftene C12-16 when compared to the controls.

This study received a Klimisch rating of "reliable without restrictions" because it was GLP compliant and was conducted in close accordance with OECD 476 guidelines.