2-octyldodecan-1-ol

Genetic toxicity: in vitro

Some information in this page has been claimed confidential.

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 22 to August 28, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well-documented guideline study according to GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Constituent 2

Reference substance name:

2-hexyldecan-1-ol

EC Number:

219-370-1

EC Name:

2-hexyldecan-1-ol

Cas Number:

2425-77-6

Molecular formula:

C16H34O

IUPAC Name:

2-hexyldecan-1-ol

Details on test material:

- Name of test material: 2-hexyl-1-decanol
- Substance type: pure active substance
- Physical state: liquid
- Analytical purity: 98.6 %
- Lot/batch No.: 03507
- Expiration date of the lot/batch: 2012-04-01
- Storage condition of test material: room temperature, protected from moisture and light

Method

Species / strain

Species / strain / cell type:

lymphocytes: human

Metabolic activation:

with and without

Metabolic activation system:

S9 mix prepared from S9 fraction obtained from male rats, dosed with phenobarbital and 5,6-benzoflavone

Test concentrations with justification for top dose:

First test:
-S9 mix: 16, 22 and 24 µg/ml
+S9 mix: 25, 65 and 80 µg/ml
Second test:
-S9 mix: 9, 15 and 17 µg/ml
+S9 mix: 120, 130 and 150 µg/ml

Vehicle / solvent:

- Vehicle/solvent used: DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: -S9 mix: mitomycin C; +S9 mix: Cyclophosphamide

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration:
1. Experiment: -S9/+S9: 3 hours
2. Experiment: -S9: 21 hours; +S9: 3 hours
Harvesting and fixation: Two hours before the cells were harvested, mitotic activity was arrested by addition of Colcemid. After 2 hours incubation , each cells suspension was centrifuged. The cell pellets were treated with hypotoic solution , incubated for 10 minutes, centrifuged and fixed by addition of cold fixative.

SPINDLE INHIBITOR (cytogenetic assays): Colcemid (0.1 µg/ml)
STAIN (for cytogenetic assays): Giemsa

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: 100 per culture

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index

OTHER EXAMINATIONS:
- Determination of polyploidy: yes
- Other: mitotic index

Evaluation criteria:

The assay is considered accepltable if the solvent and positive control values lie within the current histrorical control range.

The test substace is considerd to cause a positive response if the following conditions are met:

- Statistically significant increases (P<0.01) in the frequency of methaphases with aberrant chromosomes (excluding gaps) are observed at one or more test concentration.
- The increases exceed the solvent control range of this laboratory, taken at the 99% confidence limit.
- The increases are reproducible between replicate cultures.
- The increases are not associated with large changes in pH, osmolality of the treatment medium or extreme toxicity.
Evidence of a concentration-related response is considered to support the conclusion.

A negative response is claimed if no statistically significant increases in the numer of aberrant cells above concurrent control frequencies are observed, at any concentration.

Statistics:

The number aberrant metaphase cells in each test substance group was compared with the solvent control valueusing the one-tailed Fisher exact test.
A Colchran-Armitage test for trend was applied to the control and all test sbstance groups. If this is significant at the !% level, the test is reiterated excluding the highest concentration - this process continues until the trend test is no longer significant.

D20s (the minimum concentration (mg/ml) at which aberrations were found in 20% of metaphases) were estimated using logistic regression on a log(concentration) scale, allowing the number of control aberrations to be non-zero. The following model was used

p = C + [1-C/(1+ exp(-intercept-slopeln(conc)))]


P is the proportion of cells with aberrations, conc is the concentration of the test substance. C is a parameter estimating the control proportion of aberrations.

Results and discussion

Test results

Key result

Species / strain:

lymphocytes: human

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no changes in pH of more than 1.0 unit at doses up to 2424.5 µg/ml
- Effects of osmolality: no fluctuations in osmolality of more than 50 mOsm/kg at doses up to 2424.5 µg/ml
- Precipitation: -S9: At treatment a visible oily film was present at final concentrations of 872.82 µl/ml and above. After 3 hours treatment an oily layer was still present at final concentrations of 188.53 µg/ml and above. +S9: At treatment a visible oily film was present at final concentrations of 872.82 µl/ml and above. After 3 hours treatment an oily layer was still present at final concentrations of 314.22 µg/l and above.

Any other information on results incl. tables

Test 1
Exposure period	S9 mix (v/v)	Nominal concentration of test substance (µg/ml	Cells with aberrations excluding gaps			Cells with aberrations including gaps			Relative mitotic index (%)	Polyploid mean incidence (%)
			Individual values	(%)	Mean (%)	Individual values	(%)	Mean (%)
3	-	0 (DMSO)	0.0	1.0	0.5	0.0	1.0	0.5	100	0.0
		16	0.0	0.0	0.0	0.0	1.0	0.5	95	0.5
		22	0.0	0.0	0.0	2.0	0.0	1.0	60	1.0
		24	2.0	2.0	2.0	2.0	3.0	2.5	47	0.5
		0.2 (Mitomycin)	14.7	14.7	14.7***	17.6	16.2	16.9***	-	0.5
3	+	0 (DMSO)	0.0	0.0	0.0	2.0	1.0	1.5	100	0.5
	(2%)	25	0.0	0.0	0.0	2.0	0.0	1.0	92	1.5
		65	0.0	0.0	0.0	0.0	1.0	0.5	67	3.0
		80	1.0	2.0	1.5	1.0	2.0	1.5	48	4.0
		5 (Cyclophosphamide)	19.2	23.3	21.1***	19.2	23.3	21.1***	-	0.0
One tailed Fisher's exact test
*** p<0.001
Otherwise p>=0.01
Test 2
Exposure period	S9 mix (v/v)	Nominal concentration of test substance (µg/ml	Cells with aberrations excluding gaps			Cells with aberrations including gaps			Relative mitotic index (%)	Polyploid mean incidence (%)
			Individual values	(%)	Mean (%)	Individual values	(%)	Mean (%)
21	-	0 (DMSO)	2.0	1.0	1.5	3.0	1.0	2.0	100	1.5
		9	1.0	1.0	1.0	2.0	1.0	1.5	90	0.5
		15	0.0	3.0	1.5	1.0	3.0	2.0	73	0.0
		17	3.0	2.0	2.5	4.0	4.0	4.0	50	0.0
		0.1 (Mitomycin)	25.0	45.5	32.3***	30.0	45.5	35.5***	-	0.0
3	+	0 (DMSO)	1.0	0.0	0.5	1.0	1.0	1.0	100	0.0
	(5%)	120	2.0	1.0	1.5	3.0	1.0	2.0	105	2.0
		130	1.0	0.0	0.5	2.0	0.0	1.0	82	0.0
		150	1.0	1.0	1.0	2.0	1.	1.5	48	2.0
		5 (Cyclophosphamide)	17.2	17.2	17.2***	19.0	19	19.0***	-	0.0
One tailed Fisher's exact test
*** p<0.001
Otherwise p>=0.01

Applicant's summary and conclusion

Conclusions:

2-Hexyldecan-1-ol has shown no evidence of causing an increase in the frequency of structural chromosome aberrations in this in vitro cytogenetic test system, under the experimental conditions described.

Executive summary:

2-Hexyldecan-1-ol has shown no evidence of causing an increase in the frequency of structural chromosome aberrations in this in vitro cytogenetic test system, under the experimental conditions described.