Calcium di(octanoate)

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosomal Aberration Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals

Deviations:

no

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

1

Reference substance name:

Docosanoic acid

EC Number:

204-010-8

EC Name:

Docosanoic acid

Cas Number:

112-85-6

Molecular formula:

C22H44O2

IUPAC Name:

docosanoic acid

Method

Target gene:

Not applicable

Species / strain

Species / strain / cell type:

Chinese hamster lung (CHL/IU)

Details on mammalian cell type (if applicable):

MEDIA USED
- Type and composition of media: Eagle-MEM liquid medium
-Properly maintained: yes

Additional strain / cell type characteristics:

other: Not specified

Metabolic activation:

with and without

Metabolic activation system:

- source of S9 : S9 from rat liver
- method of preparation of S9 mix: S9 from rat liver, induced with phenobarbital and 5,6-benzoflavone

Test concentrations with justification for top dose:

-S9 mix (short-term exposure): 0, 875, 1750, 3500 µg/mL
+S9 mix (short-term exposure): 0, 875, 1750, 3500 µg/mL
-S9 mix (24 h continuous exposure): 0, 350, 700, 1400, 2800 µg/mL
-S9 mix (48-hour continuous exposure): 0, 288, 575, 1150, 2300 µg/mL

Vehicle / solvent:

1.0% carboxymethylcellulose sodium

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

cyclophosphamide

mitomycin C

Details on test system and experimental conditions:

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable):
- Test substance added in medium; preincubation;

TREATMENT AND HARVEST SCHEDULE:
- Preincubation period: 3 days
- Exposure duration/duration of treatment: 6 (short-term exposure), 24, 48 h

FOR CHROMOSOME ABERRATION AND MICRONUCLEUS:
- Methods of slide preparation and staining technique used including the stain used (for cytogenetic assays): Giemsa
- Number of cells spread and analysed per concentration (number of replicate cultures and total number of cells scored): 200

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method: relative total growth (RTG)

Evaluation criteria:

The frequency of polyploid cells or cells with abnormal structure of each test group were determined according to the criteria of Ishidate.

Results and discussion

Test results

Key result

Species / strain:

Chinese hamster lung (CHL/IU)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Water solubility: insoluble in water, soluble in alcohol, ether, chloroform and acetone
- Precipitation and time of the determination: observed on the slide of continuous exposure high dose group

RANGE-FINDING/SCREENING STUDIES: see 'Any other information on material and method incl. tables'

HISTORICAL CONTROL DATA: this test was valid, since the frequency of chromosomal aberration in positive control was within background data.

Any other information on results incl. tables

Table 1: Results of growth inhibition test

Test item	Concentration in µg/mL	Survival in %
Exposure period 24 h, without S9 mix
1% CMC▪Na		100
Test substance	272	97.7
	454	95.2
	756	96.5
	1260	83.1
	2100	62.1
	3500	37.8
Exposure period 48 h, without S9 mix
1% CMC▪Na		100
Test substance	272	101.1
	454	104.6
	756	98.9
	1260	89.7
	2100	75.9
	3500	1.3
Exposure period 6 h, without S9 mix
1% CMC▪Na		100
Test substance	272	109.6
	454	93.7
	756	102.5
	1260	110.7
	2100	89.8
	3500	95.1
Exposure period 6 h, with S9 mix
1% CMC▪Na		100
Test substance	272	84.3
	454	85.9
	756	85.3
	1260	86.5
	2100	68.3
	3500	76.3

Table 2: Results of chromosome aberration test

Test item	Concentration	Aberrant cells in %			Polyploid cells in %
	in µg/mL	with gaps	without gaps
Exposure period 24 h, without S9 mix
1% CMC▪Na		0.5	0.5	0.0
MMC	0.05	56.0	52.5	0.5
Test substance	350	1.0	1.0	0.5
	700	1.0	0.5	0.5
	1400	0.5	0.0	0.0
	2800	Toxic
Exposure period 48 h, without S9 mix
1% CMC▪Na		0.0	0.0	0.5
MMC	0.025	58.5	54.5	0.0
Test substance	288	1.0	1.0	0.0
	575	0.5	0.0	0.5
	1150	2.0	1.5	0.0
	2300	Toxic
Exposure period 6 h, without S9 mix
1% CMC▪Na		1.5	0.5	0.5
CP	12.5	0.5	0.0	0.5
Test substance	875	0.5	0.5	0.0
	1750	3.0	2.5	0.0
	3500	1.0	0.5	0.5
Exposure period 6 h, with S9 mix
1% CMC▪Na		1.5	1.0	0.0
CP	12.5	63.5	61.5	0.0
Test substance	875	2.5	1.5	1.0
	1750	2.0	2.0	0.0
	3500	2.0	2.0	0.0

CMC▪Na: carboxymethylcellulose sodium (solvent)

MMC: Mitomycin C; CP: Cyclophosphamide (positive controls)

Applicant's summary and conclusion

Conclusions:

The test substance did not induce structural chromosomal aberrations in the absence or presence of an exogenous metabolic activation system.

Executive summary:

Mammalian cells (CHL) were exposed to docosonic acid in vitro in both the absence and presence of a metabolica activation system (S9). The exposure groups included a range of dose levels that caused dose-related cytotoxic effects that were sufficient to validate the assay methodology. There was no evidnce of clastogenicity in CHL after exposure to docosonic acid and the substance was concluded to be not genotoxic in this assay.