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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
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:
1995-01-05 to 1995-03-03
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it is GLP compliant and follows OECD 471 guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial reverse 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): Alkane 4
- Molecular formula (if other than submission substance): C30-36.H62-74
- Molecular weight: 506
- Analytical purity: 100%
- Substance type: Poly alpha olefin (1-dodecene trimer, hydrogenated)
- Physical state: Liquid
- Analytical purity: Not reported
- Lot/batch No.: C1527-04-4
- Stability under test conditions: Not reported
- Storage condition of test material: Room temperature
- Other: Clear colourless liquid; boiling point: 400 to 540°C; vapour pressure: 6.0 x 10-3 mm/hg at 25°C; partition co-efficient: >8.0

Method

Species / strain
Species / strain / cell type:
other: S. typhimurium strains TA98, TA100, TA1535, TA 1537 and E.coli strain WP2uvrA
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver cells
Test concentrations with justification for top dose:
Preliminary cytotoxicity assay - 0, 0.27, 0.5, 1.5, 5, 15, 50, 150, 500, 1500, or 5000 µg/plate (±S9)
Mutation assay - 0, 15, 50, 150, 500, 1500, or 5000 µg/plate (±S9) [Experiment 1 and Experiment 2]
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Pluronic in ethanol (25% w/w)
- Justification for choice of solvent/vehicle: Not reported
Controls
Untreated negative controls:
yes
Remarks:
Untreated plates
Negative solvent / vehicle controls:
yes
Remarks:
pluronic in ethanol (25% w/w)
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG); 9-Aminoacridine (9AA); 4-Nitroquinoline-1-oxide (4NQO); 2-Aminoanthracene (2AA)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: Not reported
- Exposure duration: 48 hours
- Expression time (cells in growth medium): 48 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 48 hours

NUMBER OF REPLICATIONS: 3


NUMBER OF CELLS EVALUATED: Number of revertant bacterial colonies counted


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
For a substance to be considered positive in this test system, it should have induced a dose-related and statistically significant increase in mutation rate (of at least twice the spontaneous reversion rate) in one or more strains of bacteria in the presence and/or absence of the S9 microsomal enzymes in both experiments at sub-toxic dose levels. To be considered negative the number of induced revertants compared to spontaneous revertants should be less than two fold at each dose level employed, the intervals o f which should be between 2 and 5 fold and extend to the limits imposed by toxicity or solubility or up to the maximum recommended dose of 5000 µg/plate.
Statistics:
Statistical analysis was conducted using the methods recommended by the UKEMS and Dunnetts method of linear regression was used to evaluate the result.

Results and discussion

Test results
Species / strain:
other: S. typhimurium strains TA98, TA100, TA1535, TA 1537 and E.coli strain WP2uvrA
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: No toxicity was observed at any dose tested in all of the tester strains that were evaluated in the preliminary cytotoxicity assay.

COMPARISON WITH HISTORICAL CONTROL DATA: Not reported

ADDITIONAL INFORMATION ON CYTOTOXICITY: No cytotoxicity was observed at any dose tested in the mutation assay.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Alkane 4 was not mutagenic either in the presence or absence of S9 at the highest tested dose of 5000 µg/plate.
Executive summary:

Justification for Read Across

Several criteria justify the use of the read across approach to fill data gaps for the poly alpha olefin 1-decene trimer and tetramer hydrogenated (CAS number 68649-12-7) using alkane 4 (1-dodecene, trimer, hydrogenated) as an analog. Both of these compounds are poly alpha olefins, i.e., highly branched isoparaffinic chemicals produced by oligomerization of 1-octene, 1-decene, and/or 1-dodecene. They have similarities in chemical structure and physiochemical properties. The literature also indicates that alkanes with 30 or more carbon atoms are unlikely absorbed when administered orally. In turn, studies indicate that they have similar health effect endpoints. Both of these poly alpha olefins have low order acute toxicity and repeated dose toxicity. Additionally gene mutations assays in bacterial cells, as well as in vitro chromosomal aberrations in mammalian cells assays demonstrate no evidence of genotoxicity regardless of metabolic activation. In vivo chromosomal aberrations assays in rats and mice also show no mutagenic potential regardless of metabolic activation. There do not appear to be any toxicological differences between 1-decene trimer and tetramer hydrogenated and alkane 4. Therefore, read across between 1-decene trimer and tetramer hydrogenated and alkane 4 can be justified.

In a reverse gene mutation assay in bacteria, strains TA98, TA100, TA1535, and TA1537 of S. typhimurium and strain WP2uvrA of E. coli were exposed to Alkane 4 in Pluronic in ethanol (25% w/w) at concentrations of 0, 0.27, 0.5, 1.5, 5, 15, 50, 150, 500, 1500, or 5000 µg/plate (Preliminary cytotoxicity assay) and at concentration of 0, 15, 50, 150, 500, 1500, or 5000 µg/plate (Mutation assay) in the presence and absence of mammalian metabolic activation using the plate-incorporation method.

 

No toxicity was observed at any of the doses in all of the tested strains in the absence or presence of S9 in the preliminary range-finding assay and in the main mutation test, a precipitate was observed in the two highest doses (1500 and 5000 µg/plate) tested. This however, did not interfere with the scoring. The positive controls provided an appropriate response. Alkane 4 was not mutagenic either in the presence or absence of S9 at the highest tested dose of 5000 µg/plate. There was no evidence (or a concentration related positive response) of induced mutant colonies over background.

 

This study received a Klimisch score 1 and is classified as reliable without restriction because it is GLP compliant and follows OECD 471 guidelines.