Isoeicosane (Hydrocarbons, C4, 1,3-butadiene-free, polymd., pentaisobutylene fraction, hydrogenated)

Genetic toxicity: in vitro

Administrative data

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:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study, the protocol and the results were described with details. Substance analytical certificate not available

Justification for type of information:

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

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

Reference

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:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study, the protocol and the results were described with details. Substance analytical certificate not available

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 source

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

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

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

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

not examined

Untreated negative controls validity:

not examined

Positive controls validity:

not examined

Additional information on results:

See tables 7.6.1/3, 7.6.1/4, 7.6.1/5 and 7.6.1/6
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no data
- Effects of osmolality: no data
- Evaporation from medium: no data
- Water solubility: no data
- Precipitation: no data
- Other confounding effects: no data

RANGE-FINDING/SCREENING STUDIES:
A preliminary toxicity assay was conducted with strains TA98 and TA100 at concentrations between 1 and 5000 µg/plate. The plates with the test article showed normal background growth up to 5000.0 µg/plate in strain TA98 and TA100.

COMPARISON WITH HISTORICAL CONTROL DATA: no

ADDITIONAL INFORMATION ON CYTOTOXICITY: no

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Table 7.6.1/3: Number of revertants per plate (mean of triplicates) in the absence of metabolic activation (First test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation		Factor +	Standard deviation	Factor +
Negative* control	12	1.2	-	8	0.6	-	16	1.0	-	77	10.0	-
Solvent control**	10	0.6	1.0	7	0.6	1.0	19	5.1	1.0	83	7.4	1.0
10	10	2.6	1.0	8	1.7	1.0	14	6.4	0.7	78	8.5	0.9
100	11	3.8	1.1	8	1.7	1.1	16	2.1	0.8	73	12.1	0.9
333.3	10	4.4	1.0	7	1.5	1.0	19	4.2	1.0	78	12.4	0.9
1000.0	11	3.6	1.1	7		1.0	17	1.2	0.9	79	4.7	0.9
5000.0	13	4.6	1.3	5	0	0.7	22	2.9	1.1	73	7.4	0.9
Positive control***	839	20.2	86.8	228	9.8	31.1	1694	244.4	87.6	1065	48.5	12.8

Negative control*: concurrent untreated control

Solvent control**: ethanol

Positive control***: see table 7.6.1/2

Table 7.6.1/4: Number of revertants per plate (mean of triplicates) in the presence of metabolic activation (First test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +
Negative control*	10	3.1	-	9	1.5	-	32	2.0	-	91	10.4	-
Solvent control**	11	2.6	1.0	7	3.0	1.0	38	6.1	1.0	85	8.5	1.0
10	12	4.7	1.1	11	4.4	1.6	26	5.3	0.7	77	5.5	0.9
100	12	2.0	1.1	8	3.5	1.2	20	4.0	0.5	72	5.0	0.8
333.3	12	3.8	1.1	8	2.0	1.1	26	0.6	0.7	73	13.6	0.9
1000.0	10	3.0	0.9	12	4.0	1.7	28	5.0	0.7	81	7.6	1.0
5000.0	12	3.2	1.1	11	1.7	1.6	36	6.7	0.9	80	5.5	0.9
Positive control***	284	11.1	25.8	252	28.0	36.0	1916	60.5	50.4	1681	150.2	19.7

Negative control*:concurrent untreated control

Solvent control** ethanol

Positive control***: see Table 7.6.1/2

Table 7.6.1/5: Number of revertants per plate (mean of triplicates) in the absence of metabolic activation (second test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +
Negative control*	6	1.2	-	5	1.0	-	15	0.6	-	80	11.0	-
Solvent control**	9	2.6	1.0	5	0.6	1.0	16	2.1	1.0	86	9.6	1.0
10	9	2.5	1.1	4	1.5	0.9	11	1.2	0.7	73	8.9	0.8
100	7	2.9	1.1	4	1.2	0.9	12	4.5	0.5	74	4.0	0.9
333.3	8	2.6	1.1	5	2.1	1.0	14	2.6	0.7	74	11.1	0.9
1000.0	7	1.0	0.9	4	0.6	0.9	14	2.6	0.7	82	4.7	1.0
5000.0	7	1.2	1.1	4	1.5	0.8	18	2.6	0.9	72	6.0	0.8
Positive control***	675	33.6	75.0	162	27.2	34.6	1068	370.0	65.4	967	150.2	11.2

Negative control*: concurrent untreated control

Solvent control**: ethanol

Positive control***: see table 7.6.1/2

Table 7.6.1/6: Number of revertants per plate (mean of triplicates) in the presence of metabolic activation (second test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +
Negative control*	7	3.5	-	5	1.0	-	27	1.2	-	82	9.6	-
Solvent control**	6	1.5	1.0	10	1.2	1.0	34	6.9	1.0	86	4.5	1.0
10	9	2.6	1.4	7	1.0	0.7	29	1.7	0.9	70	3.2	0.8
100	6	3.1	0.9	6	1.5	0.7	35	3.0	1.0	79	8.5	0.9
333.3	6	1.2	1.0	4	1.2	0.4	32	7.2	0.9	83	10.1	1.0
1000.0	7	3.5	1.2	6	2.1	0.6	31	6.0	0.9	81	9.2	0.9
5000.0	6	1.0	0.9	6	1.5	0.7	31	6.8	0.9	76	6.7	0.9
Positive control***	199	9.8	31.4	211	42.7	21.8	1250	102.1	36.8	1515	116.3	17.7

Negative control*: concurrent untreated control

Solvent control**: ethanol

Positive control***: see table 7.6.1/2

Conclusions:

Interpretation of results:
negative TA1535; TA1537; TA98 and TA 100

Under the conditions of the assay, Isohexadecan did not demonstrate in vitro mutagenic activity in the Salmonella test system with and without S9 mix activation system.

Executive summary:

This data is being read across from the source study that tested Isohexadecane based on analogue read across.

In a reverse gene mutation assay in bacteria (Poth, 1990) and in compliance with Good Laboratory Practice, strains TA98, TA100, TA1535 and TA1537 of S. typhimurium were exposed to Isohexadecan 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, Isohexadecan did not induce in vitro mutagenic activity in the bacterial test system in the presence and the absence of S9 activation system.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

only 4 bacterial strains were used instead of 5

Principles of method if other than guideline:

Guideline study

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2,2,4,4,6,8,8-heptamethylnonane

EC Number:

224-506-8

EC Name:

2,2,4,4,6,8,8-heptamethylnonane

Cas Number:

4390-04-9

Molecular formula:

C16H34

IUPAC Name:

2,2,4,4,6,8,8-heptamethylnonane

Details on test material:

- Name of test material (as cited in study report): BP Solvent IH/Isohexadecan
- Substance type: petroleum product, UVCB
- Analytical purity : 100% commercial product

Method

Target gene:

Reversion Histidine auxotrophy

Species / strain

Species / strain / cell type:

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

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not applicable

Remarks:

The strain cultures were stored as stock cultures in ampoules with nutrient broth + 5% DMSO in liquid nitrogen.

Metabolic activation:

with and without

Metabolic activation system:

The S9 liver microsomal fraction was obtained from the liver of 8-12 weeks old male wistar rats; strain WU (Savo-Ivanovas, med. Versuchstier Zuchten GmbH) which received a single i.p. injection of 500 mg/kg b.w. Aroclor 1254 in olive oil 5 days previously

Test concentrations with justification for top dose:

10.0; 100.0; 333.3; 1000 and 5000 µg/plate (With and without S9 mix)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: the solvent was chosen to its solubility properties and its relative non-toxicity for the bacteria.

Controls

Untreated negative controls:

yes

Remarks:

concurrent untreated control

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: See below Table 7.6.1/2

Remarks:

6 plate for negative control (untreated strains), 6 plate for solvent, 3 plates for positive controls.

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)
After range-finding test, two independent experiments were conducted in the main test by agar plate incorporation with and without S9 mix. The different controls (negative, solvent and positive controls) were tested in the same conditions.

DURATION
- Preincubation period: the bacterial culture was incubated in a shaking water bath for 6 hours at 37°C.
- Exposure duration: 3 days at 37°C in the dark

SELECTION AGENT (mutation assays):histidine

NUMBER OF REPLICATION: three scoring (3 measurements/plate), the mean number and standard deviation of revertants are calculated for all groups. the means for all treatment groups are compared with those obtained for the solvent control groups.

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency; relative total growth
Other: the colonies were counted using the BIOTRAN III counter. If precipitation of the test article precluded automatic counting the revertant colonies were counted by hand.

Evaluation criteria:

- A positive response was indicated by a reproducible, dose-related increase, whether it be two-fold over background or not.
- Mutation Factors (MF) (induced/spontaneous revertants) were calculated for all strains at the dose level tested.

Statistics:

A compound is deemed to provide evidence of mutagenic potential if:
- a statistically significant dose-related increase in the number of revertant colonies is obtained in two separate experiments, and
- the increase in the number of revertant colonies is at least twice the concurrent solvent control value.

Results and discussion

Test results

Test results 1

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

not examined

Untreated negative controls validity:

not examined

Positive controls validity:

not examined

Additional information on results:

See tables 7.6.1/3, 7.6.1/4, 7.6.1/5 and 7.6.1/6
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no data
- Effects of osmolality: no data
- Evaporation from medium: no data
- Water solubility: no data
- Precipitation: no data
- Other confounding effects: no data

RANGE-FINDING/SCREENING STUDIES:
A preliminary toxicity assay was conducted with strains TA98 and TA100 at concentrations between 1 and 5000 µg/plate. The plates with the test article showed normal background growth up to 5000.0 µg/plate in strain TA98 and TA100.

COMPARISON WITH HISTORICAL CONTROL DATA: no

ADDITIONAL INFORMATION ON CYTOTOXICITY: no

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 7.6.1/3: Number of revertants per plate (mean of triplicates) in the absence of metabolic activation (First test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation		Factor +	Standard deviation	Factor +
Negative* control	12	1.2	-	8	0.6	-	16	1.0	-	77	10.0	-
Solvent control**	10	0.6	1.0	7	0.6	1.0	19	5.1	1.0	83	7.4	1.0
10	10	2.6	1.0	8	1.7	1.0	14	6.4	0.7	78	8.5	0.9
100	11	3.8	1.1	8	1.7	1.1	16	2.1	0.8	73	12.1	0.9
333.3	10	4.4	1.0	7	1.5	1.0	19	4.2	1.0	78	12.4	0.9
1000.0	11	3.6	1.1	7		1.0	17	1.2	0.9	79	4.7	0.9
5000.0	13	4.6	1.3	5	0	0.7	22	2.9	1.1	73	7.4	0.9
Positive control***	839	20.2	86.8	228	9.8	31.1	1694	244.4	87.6	1065	48.5	12.8

Negative control*: concurrent untreated control

Solvent control**: ethanol

Positive control***: see table 7.6.1/2

Table 7.6.1/4: Number of revertants per plate (mean of triplicates) in the presence of metabolic activation (First test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +
Negative control*	10	3.1	-	9	1.5	-	32	2.0	-	91	10.4	-
Solvent control**	11	2.6	1.0	7	3.0	1.0	38	6.1	1.0	85	8.5	1.0
10	12	4.7	1.1	11	4.4	1.6	26	5.3	0.7	77	5.5	0.9
100	12	2.0	1.1	8	3.5	1.2	20	4.0	0.5	72	5.0	0.8
333.3	12	3.8	1.1	8	2.0	1.1	26	0.6	0.7	73	13.6	0.9
1000.0	10	3.0	0.9	12	4.0	1.7	28	5.0	0.7	81	7.6	1.0
5000.0	12	3.2	1.1	11	1.7	1.6	36	6.7	0.9	80	5.5	0.9
Positive control***	284	11.1	25.8	252	28.0	36.0	1916	60.5	50.4	1681	150.2	19.7

Negative control*:concurrent untreated control

Solvent control** ethanol

Positive control***: see Table 7.6.1/2

Table 7.6.1/5: Number of revertants per plate (mean of triplicates) in the absence of metabolic activation (second test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +
Negative control*	6	1.2	-	5	1.0	-	15	0.6	-	80	11.0	-
Solvent control**	9	2.6	1.0	5	0.6	1.0	16	2.1	1.0	86	9.6	1.0
10	9	2.5	1.1	4	1.5	0.9	11	1.2	0.7	73	8.9	0.8
100	7	2.9	1.1	4	1.2	0.9	12	4.5	0.5	74	4.0	0.9
333.3	8	2.6	1.1	5	2.1	1.0	14	2.6	0.7	74	11.1	0.9
1000.0	7	1.0	0.9	4	0.6	0.9	14	2.6	0.7	82	4.7	1.0
5000.0	7	1.2	1.1	4	1.5	0.8	18	2.6	0.9	72	6.0	0.8
Positive control***	675	33.6	75.0	162	27.2	34.6	1068	370.0	65.4	967	150.2	11.2

Negative control*: concurrent untreated control

Solvent control**: ethanol

Positive control***: see table 7.6.1/2

Table 7.6.1/6: Number of revertants per plate (mean of triplicates) in the presence of metabolic activation (second test)

Test substance concentration (µg/plate)	TA 1535			TA 1537			TA 98			TA 100
	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +	Mean	Standard deviation	Factor +
Negative control*	7	3.5	-	5	1.0	-	27	1.2	-	82	9.6	-
Solvent control**	6	1.5	1.0	10	1.2	1.0	34	6.9	1.0	86	4.5	1.0
10	9	2.6	1.4	7	1.0	0.7	29	1.7	0.9	70	3.2	0.8
100	6	3.1	0.9	6	1.5	0.7	35	3.0	1.0	79	8.5	0.9
333.3	6	1.2	1.0	4	1.2	0.4	32	7.2	0.9	83	10.1	1.0
1000.0	7	3.5	1.2	6	2.1	0.6	31	6.0	0.9	81	9.2	0.9
5000.0	6	1.0	0.9	6	1.5	0.7	31	6.8	0.9	76	6.7	0.9
Positive control***	199	9.8	31.4	211	42.7	21.8	1250	102.1	36.8	1515	116.3	17.7

Negative control*: concurrent untreated control

Solvent control**: ethanol

Positive control***: see table 7.6.1/2

Applicant's summary and conclusion

Conclusions:

Interpretation of results:
negative TA1535; TA1537; TA98 and TA 100

Under the conditions of the assay, Isohexadecan did not demonstrate in vitro mutagenic activity in the Salmonella test system with and without S9 mix activation system.

Executive summary:

In a reverse gene mutation assay in bacteria (Poth, 1990) and in compliance with Good Laboratory Practice, strains TA98, TA100, TA1535 and TA1537 of S. typhimurium were exposed to Isohexadecan 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, Isohexadecan did not induce in vitro mutagenic activity in the bacterial test system in the presence and the absence of S9 activation system.