2,2,4,6,6-pentamethylheptane

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

All read across genetic toxicity tests listed below had negative results for isododecane.

Genetic Toxicity in vitro – Bacterial reverse mutation assay (OECD 471)

Genetic Toxicity in vitro - Mammalian Cell Gene Mutation Test (OECD TG 476)

Genetic Toxicity in vitro – Genetic Toxicology: In Vitro Sister Chromatid Exchange Assay in Mammalian Cells (OECD TG 479)

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1982/08/13

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: According to or similar to guideline study OECD 471.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Target gene:

Not applicable

Species / strain / cell type:

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

Species / strain / cell type:

S. typhimurium TA 1538

Metabolic activation:

with and without

Metabolic activation system:

S9 liver fractions from Aroclor exposed rats

Test concentrations with justification for top dose:

Tests (done in triplicate) with and without Metabolic Activation: DMSO (vehicle control), 0, 41.2, 123.5, 310.4, 1111.1, 3333.3, 10000 ug/plate
Negative Controls: DMSO
Positive controls: 2-nitrofluorene (2NF): 50ug/plate; 9-aminoacridine (9AA): 75ug/plate; MNNG: 5 ug/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-nitrofluorene (2NF): 50ug/plate; 9-aminoacridine (9AA): 75ug/plate; MNNG: 5 ug/plate

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

not cytotoxic up to 10000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

not cytotoxic up to 10000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

not cytotoxic up to 10000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium 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

Remarks:

not cytotoxic up to 10000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

not cytotoxic up to 10000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative

The test to assess the genotoxicity of the test material was negative. This finding does not warrant the classification of this test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Executive summary:

No treatments of any of the test strains, either in the absence or in the presence of S-9, resulted in a statistically significant increase in revertant numbers. This study was therefore considered to have provided no indication of any test material mutagenic activity. This finding does not warrant the classification of this test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Reference 2

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1998/11/11-1999/06/11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to or similar to guideline study OECD 471: GLP.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Target gene:

Not applicable

Species / strain / cell type:

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

Species / strain / cell type:

S. typhimurium TA 102

Metabolic activation:

with and without

Metabolic activation system:

S9 liver fractions from Aroclor exposed rats

Test concentrations with justification for top dose:

Tests (done in triplicate) with and without Metabolic Activation: Acetone (vehicle control), 0,128, 320, 800, 2000, 5000 ug/plate
Vehicle control: 0.1 ml/plate acetone
Positive controls: 2-nitrofluorene (2NF): 5ug/plate (TA98; -S9); Sodium azide - 2ug/plate (TA100, TA1535; -S9); 9-aminoacridine (9AA): 50ug/plate (TA1537; -S9); Glutaraldehyde (GLU): 25.0ug/plate (TA102; -S9); 2-aminoanthracene (2AA): 5ug/plate (TA98; +S9)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: acetone

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

0.1 ml/plate Acetone

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-nitrofluorene (2NF): 5ug/plate (TA98; -S9); Sodium azide - 2ug/plate (TA100, TA1535; -S9); 9-aminoacridine (9AA): 50ug/plate (TA1537; -S9); Glutaraldehyde (GLU): 25.0ug/plate (TA102; -S9); 2-aminoanthracene (2AA): 5ug/plate (TA98; +S9)

Details on test system and experimental conditions:

These platings were achieved by the following sequence of additions to 2.5 mL molten agar at 46°C:

0.1 mL bacterial culture
0.025 mL test article solution or control
0.5 mL 10% 8-9 mix or buffer solution

followed by rapid mixing and pouring on to Minimal Davis agar plates. When set, the plates were inverted and incubated at 37°C in the dark for 3 days. Following incubation, these plates were examined for evidence of toxicity to the background lawn, and where possible revertant colonies were counted.

Evaluation criteria:

The test article was considered to be mutagenic if: 1) the assay was valid, 2) Dunnett’s test gave a significant response (p<0.01), and the data set(s) showed a significant dose-correlation, and 3) the positive responses described in 2) were reproducible.

Statistics:

The m-statistic was calculated to check that the data were Poisson-distributed, and Dunnett’s test was used to compare the counts of each dose with the control. The presence or otherwise of a dose response was checked by linear regression analysis.

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

not cytotoxic up to 5000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

not cytotoxic up to 5000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

not cytotoxic up to 5000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium 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

Remarks:

not cytotoxic up to 5000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

not cytotoxic up to 5000ug/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative

The test to assess the genotoxicity of the test material was negative. This finding does not warrant the classification of this test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Executive summary:

No SHELLSOL TD treatments of any of the test strains, either in the absence or in the presence of S-9, resulted in a statistically significant increase in revertant numbers, when the data were analysed at the 1% level using Dunnetts test. This study was therefore considered to have provided no indication of any SHELLSOL TD mutagenic activity. The test to assess the genotoxicity of the test material was negative. This finding does not warrant the classification of this test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Reference 3

Endpoint:

in vitro DNA damage and/or repair study

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1983/01/13

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: According to or similar to guideline study OECD 479.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 479 (Genetic Toxicology: In Vitro Sister Chromatid Exchange Assay in Mammalian Cells)

Deviations:

no

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

Tests with and without Metabolic Activation: (media control), 0, 0.5, 1.7, 5.0, 17.0, 50.0 ug/plate
Negative Controls: DMSO, Cyclohexane
Positive controls: EMS - Ethylmehanesulfonate (620 ug/mL) without activation; cyclophosphamide (1.4 ug/mL) with activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: EMS - Ethylmehanesulfonate (620 ug/mL) without activation; cyclophosphamide (1.4 ug/mL) with activation

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

not cytotoxic up to 50 uL/mL (maximum dose tested)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative

The test to assess the genotoxicity of the test material was negative. This finding does not warrant the classification of this test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Executive summary:

No treatments in either the absence or in the presence of S-9 resulted in a statistically significant increase in revertant numbers. This study was therefore considered to have provided no indication of any test material mutagenic activity. This finding does not warrant the classification of this test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Reference 4

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well conducted study according to sound scientific principles.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

no

GLP compliance:

no

Type of assay:

mammalian cell gene mutation assay

Target gene:

TK+/ phenotype

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

TK+/ phenotype of L5178Y mouse lymphoma cells from subline 3.7.2C

Metabolic activation:

with and without

Metabolic activation system:

Aroclor

Test concentrations with justification for top dose:

up to was 1000 ug/mL in dimethylsulfoxide (maximum dose)

Vehicle / solvent:

dimethylsulfoxide

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

not specified

Details on test system and experimental conditions:

This assay was performed with the TK+/ phenotype of L5178Y mouse lymphoma cells from subline 3.7.2C using a minimum of eight test compound doses with and without metabolic activation by an Aroclor induced rat liver microsomal fraction. Appropriate negative, solvent, and positive controls were included with each assay. The test compound dose levels were determined by a preliminary multidose ranging study with the highest dose targeted to give approximately fifty to ninety percent inhibition of suspension cell growth depending on the solubility of the compound. C10-C13 isoalkanes achieved a homogeneous mixture at approximately 100 mg/ml in dimethylsulfoxide. The maximum dose selected for the mutagenicity test was 1000 ug/ml because it represents the limits of solubility of the test material.

Species / strain:

mouse lymphoma L5178Y cells

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:

Exposure to eight graded doses of the test material in the presence of and in the absence of metabolic activation did not increase the induction of forward mutations in L5178Y mouse lymphoma cells at the T/K locus. Therefore C10-C13 isoalkanes are not considered to be mutagenic in this test system.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative with and without metabolic activation

Exposure to eight graded doses of the test material in the presence of and in the absence of metabolic activation did not increase the induction of forward mutations in L5178Y mouse lymphoma cells at the T/K locus. Therefore C10-C13 isoalkanes are not considered to be mutagenic in this test system.

Executive summary:

Exposure to eight graded doses of the test material in the presence of and in the absence of metabolic activation did not increase the induction of forward mutations in L5178Y mouse lymphoma cells at the T/K locus. Therefore C10-C13 isoalkanes are not considered to be mutagenic in this test system.

Reference 5

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro cytogenicity study in mammalian cells or in vitro micronucleus study does not need to be conducted because adequate data from an in vivo cytogenicity test are available

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Read across genetic toxicity test listed below had negative results for isododecane.

Genetic Toxicity in vivo – Rodent Dominant Lethal Test (OECD TG 478)

Link to relevant study records

Reference

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented study report equivalent or similar to OECD guideline 478.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 478 (Genetic Toxicology: Rodent Dominant Lethal Test)

GLP compliance:

no

Type of assay:

rodent dominant lethal assay

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: Males (7-8 weeks); females pre-treatment mating period (8-9 weeks); females post treatment mating period (7-8 weeks)
- Weight at study initiation:
- Assigned to test groups randomly: [no/yes, under following basis: ]
- Fasting period before study:
- Housing: males were house individiually during the treatment period and hosed with two females per week during the 2 week pretreatment mating period and the 6 week post-treatment mating period. Females were housed individually during the pre-mating and post-mating periods and housed with males in a 2:1 ratio during mating.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum):ad libitum

Route of administration:

inhalation: vapour

Details on exposure:

TYPE OF INHALATION EXPOSURE: whole body


GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
MRD-77-44 was transferred from a reservoir using a metering pump into a heated flask and flash evaporated. A stream of clean air was also passed through the flask and the vapor laden air transferred to a port in the chamber air inlet where it was diluted with normal chamber intake air to give the desired concentration.
- Exposure apparatus: inhalation chamber
- Rate of air: 125 liters/minute



- Air flow rate: 125 liters/minute
- Air change rate: 8 minutes
- Method of particle size determination:
- Treatment of exhaust air:


TEST ATMOSPHERE
- Brief description of analytical method used: Wilks Scientific Copr, Miran IA Ambient Air Analyzer (long path infrared)
- Samples taken from breathing zone: no

Duration of treatment / exposure:

Six hours /day

Frequency of treatment:

five days
Triethylenemelamine was administered by intraperitoneal injection (normal saline) as a single dose.

Post exposure period:

Following exposure, the males were mated with unexposed females (two female rats were mated with each male rat per week) for 6 consecutive weeks. The females were sacrificed 12 days after the last day of cohabitation

Remarks:

Doses / Concentrations:
900 ppm
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
300 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

Negative control: 10 males; 120 females during six week post-treatment mating period (two females/male/week)
Positive control: 10 males; 120 females during six week post-treatment mating period (two females/male/week)
300ppm MRD-77-43: 10 males; 120 females during six week post-treatment mating period (two females/male/week)
900ppm MRD-77-43: 10 males; 120 females during six week post-treatment mating period (two females/male/week)

Control animals:

yes

Positive control(s):

triethylenemelamine

- Route of administration: Intraperitoneal injection
- Doses / concentrations: 0.5mg/kg/bw

Tissues and cell types examined:

Males: seminal vesicle, epididymides, prostate, and any abnormal lesion or tissue masses, testes.
Females: reproductive tissues examined (uterine horns preserved, implantation sites, resorption sites)

Statistics:

Comparisons were made during the treatment and post-treatment periods between negative control, positive control and test substance-treated groups by the chi-square method where applicable. Absolute data were compared using the F-test and Students t-test. When variances differed significantly, Students T-test was appropriately modified using Cochran’s approximation.

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Conclusions:

Interpretation of results: negative
When administered by vapor inhalation, MRD-77-43 is not mutagenic by the dominant lethal test. This finding does not warrant classification of (the test material as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Executive summary:

In a dominant lethal assay,  MRD-77-43 was administered by vapor inhalation for six hours/day for five consecutive days to male rats at dose levels of 300 and 900 ppm to test for mutagenic potential.  Included in the study was a negative (chamber exposed) control group and a positive control group.  The latter received 0.5mg/kg of triethylenemelamine administered intraperitoneally on a single day, two hours prior to mating.  Each group contained 10 proven fertile rats.  Following exposure, the males were mated with unexposed females (two female rats were mated with each male rat per week) for 6 consecutive weeks.  The females were sacrificed 12 days after the last day of cohabitation.  Exposure of males to MRD-77-43 produced no adverse effects on mortality or body weight gain during the post-treatment mating period. Overall, no treatment related effects were observed on the number of pregnant females, number of implantations per litter, number of live fetuses, number of dead implantations, and the number of resoprtions.  Exposures to male rats had no effect on their ability to mate and impregnate females, and to produce live fetuses.  Based on these data, MRD-77-43 when administered by vapor inhalation to male rats is not considered mutagenic by the dominant lethal test.  This finding does not warrant the classification of MRD-77-43 as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP) or under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.  

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

There is no data available for isododecane. However, data is available for structural analogues Hydrocarbons, C10-C12, isoalkanes, <2% aromatics; Hydrocarbons, C10-C13, isoalkanes, and isohexadecane. This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

In Vitro

In vitro gene mutation study in bacteria

Hydrocarbons, C10-C12, isoalkanes, <2% aromatics

In a key Guideline OECD 471 bacterial reverse mutation test (Shell, 1999), no test material (Hydrocarbons, C10-C12, isoalkanes, <2% aromatics) treatments of any of the test strains, either in the absence or in the presence of S-9, resulted in a statistically significant increase in revertant numbers, when the data were analysed at the 1% level using Dunnetts test. This study was therefore considered to have provided no indication of any mutagenic activity. The test to assess the genotoxicity of the test material was negative.

In another key Guideline OECD 471 study (Chevron Phillips, 1982), no treatments of any of the test strains, either in the absence or in the presence of S-9, resulted in a statistically significant increase in revertant numbers. This study was therefore considered to have provided no indication of test material (Hydrocarbons, C10-C12, isoalkanes, <2% aromatics) mutagenic activity.

Isohexadecane

In a supporting reverse gene mutation assay in bacteria (EC Erdolchemie, 1990), strains TA98, TA100, TA1535 and TA1537 of S. typhimurium were exposed to isohexadecane at concentrations of 10.0, 100.0, 333.3, 1000.0 and 5000.0 µg/plate in the presence and absence of mammalian metabolic activation. No cytotoxicity was observed with all the dose tested. Up to the highest investigated dose, no significant and reproducible dose-dependent increase in revertant colony numbers was obtained in any of the Salmonella typhimurium strains used (+/- S9). The positive controls induced the appropriate responses in the corresponding strains. Under the test conditions, isohexadecane did not induce in vitro mutagenic activity in the bacterial test system in the presence and the absence of S9 activation system.

In Vitro Chromosome Aberration in Mammalian Cells

Hydrocarbons, C10-C12, isoalkanes, <2% aromatics

In a key in vitro Sister Chromatid Exchange Assay in Mammalian Cells (Chevron Phillips, 1983), no treatments in either the absence or in the presence of S-9 resulted in a statistically significant increase in revertant numbers. This study was therefore considered to have provided no indication of test material (Hydrocarbons, C10-C12, isoalkanes, <2% aromatics) mutagenic activity.

In vitro Gene Mutation study in Mammalian Cells

C10-C13 isoalkanes

In a key mammalian cell gene mutation assay (Chevron Phillips, 1982), exposure to eight graded doses of the test material (C10-C13 isoalkanes) in the presence of and in the absence of metabolic activation did not increase the induction of forward mutations in L5178Y mouse lymphoma cells at the T/K locus. Therefore C10-C13 isoalkanes are not considered to be mutagenic in this test system.

In Vivo

Hydrocarbons, C10-C12, isoalkanes, <2% aromatics

In a key in vivo dominant lethal assay (ExxonMobil Corp., 1978), the test material (Hydrocarbons, C10-C12, isoalkanes, <2% aromatics) was administered by vapor inhalation for six hours/day for five consecutive days to male rats at dose levels of 300 and 900 ppm to test for mutagenic potential.  Included in the study was a negative (chamber exposed) control group and a positive control group.  The latter received 0.5mg/kg of triethylenemelamine administered intraperitoneally on a single day, two hours prior to mating.  Each group contained 10 proven fertile rats.  Following exposure, the males were mated with unexposed females (two female rats were mated with each male rat per week) for 6 consecutive weeks.  The females were sacrificed 12 days after the last day of cohabitation.  Exposure of males to the test material produced no adverse effects on mortality or body weight gain during the post-treatment mating period. Overall, no treatment related effects were observed on the number of pregnant females, number of implantations per litter, number of live fetuses, number of dead implantations, and the number of resoprtions. Exposures to male rats had no effect on their ability to mate and impregnate females, and to produce live fetuses.  Based on these data, the test material when administered by vapor inhalation to male rats is not considered mutagenic by the dominant lethal test. 

Justification for classification or non-classification

The negative results observed in in vitro and in vivo genotoxicity assays do not warrant the classification of isododecane as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).