Naphthalenesulfonic acid, dibutyl-, Me derivs., sodium salts

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / micronucleus study

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

10-Oct-2011 to 07-Apr-2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Justification for type of information:

See chapter 13 for support for read-across within the category of Alkyl Naphthalene Sulfonates (ANS).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 487 (In Vitro Mammalian Cell Micronucleus Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian cell micronucleus test

Test material

Test material information

Constituent 1

Reference substance name:

Aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulfonated, sodium salts

EC Number:

800-660-7

Cas Number:

1258274-08-6

Molecular formula:

Not applicable, UVCB substance

IUPAC Name:

Aromatic hydrocarbons, C10-13, reaction products with branched nonene, sulfonated, sodium salts

Constituent 2

Reference substance name:

Sodium alkylnaphthalene sulfonate

IUPAC Name:

Sodium alkylnaphthalene sulfonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Sodium alkylnaphthalene sulfonate
- Substance type: Amber to greenish liquid
- Physical state: Liquid
- Stability under test conditions: Stable
- Storage condition of test material: At room temperature in the dark under nitrogen

Method

Species / strain

Species / strain / cell type:

lymphocytes: human peripheral blood

Details on mammalian cell type (if applicable):

Type and identity of media:
Blood samples
Blood samples were collected by venapuncture using the Venoject multiple sample blood collecting system with a suitable size sterile vessel containing sodium heparin. Immediately after blood collection lymphocyte cultures were started.

- Culture medium
Culture medium consisted of RPMI 1640 medium, supplemented with 20% (v/v) heat-inactivated (56°C; 30 min) foetal calf serum, L-glutamine (2 mM), penicillin/streptomycin (50 U/mL and 50 µg/mL respectively) and 30 U/mL heparin.

- Lymphocyte cultures
Whole blood (0.4 mL) treated with heparin was added to 5 mL or 4.8 mL culture medium (in the absence and presence of S9-mix, respectively). Per culture 0.1 ml (9 mg/mL) phytohaemagglutinin was added.

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9-mix induced by a combination of phenobarbital and ß-naphthoflavone

Test concentrations with justification for top dose:

Dose range finding test:
Without S9-mix, 3 and 24 exposure: 53, 176, 529, 1762 and 2646 µg/mL
With S9-mix, 3 exposure: 53, 176, 529, 1762 and 2646 µg/mL
First cytogenetic test :
Without and with S9-mix, 3hr exposure; 27 hr fixation: 529, 1058 and 1323 µg/mL
Additional cytogenetic test :
Without and with S9-mix, 4.5hr exposure; 27 hr fixation: 529, 1058 and 1190 µg/mL
Second cytogenetic test:
Without S9-mix, 24 hr exposure; 24 hr fixation: 53, 476 and 582 µg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: culture medium
- Justification for choice of solvent/vehicle:
Test compound was stable in water and soluble in culture medium. Culture medium has been accepted and approved by authorities and international guidelines

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without S9 Migrated to IUCLID6: MMC-C 0.25 µg/mL for a 3 hours exposure period and 0.15 µg/mL for a 24 hours exposure period

Controls 2

Positive control substance:

other: colchicine: 0.1 µg/ml for a 3 hours exposure period and 0.05 µg/ml for a 24 hours exposure period

Remarks:

without S9

Controls 3

Positive control substance:

cyclophosphamide

Remarks:

with S9 Migrated to IUCLID6: 15 µg/mL

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 48 hr
- Exposure duration:
Short-term treatment
Without and with S9-mix: 3 hr treatment, 24 hr recovery/harvest time
Continuous treatment
Without S9-mix: 24 hr treatment/harvest time

ARREST OF CELL DIVISION: 5 µg/mL Cytochalasine B
STAIN: Giemsa

NUMBER OF REPLICATIONS: duplicates

NUMBER OF CELLS EVALUATED: 1000/culture (mono- and binucleated cells)

DETERMINATION OF CYTOTOXICITY
- The cytostasis/cytotoxicity was determined using the cytokinesis-block proliferation index (CPBI index)

Evaluation criteria:

A test substance was considered positive (clastogenic or aneugenic) in the in vitro micronucleus test if:
a) It induces a dose-related statistically significant (Chi-square test, one-sided, p < 0.05) increase in the number of mono or binucleated cells with micronuclei.
b) A statistically significant and biologically relevant increase is observed in the number of mono or binucleated cells with micronuclei in the absence of a clear dose-response relationship.

A test substance was considered negative (not clastogenic or aneugenic) in the in vitro micronucleus test if:
a) none of the tested concentrations induced a statistically significant (Chi-square test, one-sided, p < 0.05) increase in the number of mono and binucleated cells with micronuclei.
b) The number of mono and binucleated cells with micronuclei was within the laboratory historical control data range.
A test substance was considered positive (clastogenic or aneugenic) in the in vitro micronucleus test if:
a) It induces a dose-related statistically significant (Chi-square test, one-sided, p < 0.05) increase in the number of mono or binucleated cells with micronuclei.
b) A statistically significant and biologically relevant increase is observed in the number of mono or binucleated cells with micronuclei in the absence of a clear dose-response relationship.

A test substance was considered negative (not clastogenic or aneugenic) in the in vitro micronucleus test if:
a) none of the tested concentrations induced a statistically significant (Chi-square test, one-sided, p < 0.05) increase in the number of mono and binucleated cells with micronuclei.
b) The number of mono and binucleated cells with micronuclei was within the laboratory historical control data range.

Statistics:

The incidence of micronucleated cells (cells with one or more micronuclei) for each exposure group was compared to that of the solvent control using Chi-square statistics:

Results and discussion

Test results

Key result

Species / strain:

lymphocytes: human peripheral blood

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH:
Solvent control: 7.4
2646 µg/ml: 7.4
- Effects of osmolality: No
Solvent control: 0.294 mOsm/kg
2646 µg/ml: 0.328 mOsm/kg


- Precipitation: No precipitation was observed up to and including the top dose of 2646 µg/mL

RANGE-FINDING/SCREENING STUDIES:
- Toxicity was observed at dose levels of 1762 µg/ml and above in the absence and presence of S9, 3 hr treatment/24 hr fixation ; at the dose level of 2646 µg/ml in the absence of S9 for the continuous treatment of 24 hr.

COMPARISON WITH HISTORICAL CONTROL DATA:
- The number of cells with chromosome aberrations found in the solvent and positive control cultures was within the laboratory historical control data range.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- Appropriate toxicity was reached at the dose levels selected for scoring.

Any other information on results incl. tables

 In the first cytogenetic assay in the cultures treated with 1058, 1190 and 1323 µg/ml Sodium alkylnaphthalene sulfonate not enough mono- and binucleated cells could be scored for micronuclei in both cultures. Due to high cytotoxicity a low number of mono- and binucleated cells was present on the slides and therefore not enough cells could be examined for micronuclei. Since two repeat experiments were performed, 6 concentrations were scored for the number of micronuclei. Only three concentrations are recommended according to OECD 487. Therefore this deviation does not influence the study integrity.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Sodium alkylnaphthalene sulfonate is not clastogenic or aneugenic in human lymphocytes

Executive summary:

The number of mono- and binucleated cells with micronuclei found in the solvent control cultures was within the laboratory historical control data range. The positive control chemicals, mitomycin C and cyclophosphamide both produced a statistically significant increase in the number of binucleated cells with micronuclei. The positive control chemical colchicine produced a statistically significant increase in the number of mononucleated cells with micronuclei. In addition colchicine also showed a statistically significant increase in the number of binucleated cells with micronuclei in the first cytogenetic assay. It was therefore concluded that the test conditions were adequate and that the metabolic activation system (S9-mix) functioned properly.

Sodium alkylnaphthalene sulfonate did not induce a statistically significant or biologically relevant increase in the number of mono- and binucleated cells with micronuclei in the absence and presence of S9-mix, in either of the independently repeated experiments.