Cyanocobalamin

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test method equivalent or similar to OECD Guideline 471 (Bacterial Reverse Mutation Assay).

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1991

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Cyanocobalamin

EC Number:

200-680-0

EC Name:

Cyanocobalamin

Cas Number:

68-19-9

Molecular formula:

C63H88CoN14O14P

IUPAC Name:

cyanocobalamin

Details on test material:

- Name of test material (as cited in study report): Vitamin B12

Method

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Species / strain 3

Species / strain / cell type:

E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

10% Aroclor 1254-induced liver S9 from male Sprague-Dawley.

Test concentrations with justification for top dose:

0.033, 0.10, 0.33, 1.0, 3.3 and 10 mg/plate.

Vehicle / solvent:

Solvent: Potassium or sodium phosphate buffer.

Controls

Controls 1

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

Without metabolic activation, for S.typhimurium strains TA98 and TA1538.

Positive control substance:

2-nitrofluorene

Remarks:

(5.0 or 10 µg/plate)

Controls 2

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

Without metabolic activation, for S.typhimurium strains TA100 and TA1535.

Positive control substance:

sodium azide

Remarks:

(0.50 or 1.0 µg)

Controls 3

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

Without metabolic activation, for S.typhimurium strain TA1537.

Positive control substance:

9-aminoacridine

Remarks:

(50 or 100 µg)

Controls 4

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

Without metabolic activation, for E.coli WP2.

Positive control substance:

furylfuramide

other: N-methyl-N'-nitro-N-nitrosoguanidine

Remarks:

(0.1 µg (furylfuramide) or 10 µg (N-methyl-N'-nitro-N-nitrosoguanidine))

Controls 5

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

With metabolic activation, for all bacterial strains.

Positive control substance:

other: 2-Anthramine

Remarks:

(at 1.0 or 2.5 µg/plate for S.typhimurium strains TA98, TA100 and TA1538, at 2.5 µg/plate for strains TA1535 and TA1537, and at 10 µg/plate for E.coli stain WP2).

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation). The test substance was dissolved in 0.067 M potassium or sodium phosphate buffer, pH 7.0.

Results and discussion

Test results

Test results 1

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative (with and without metabolic activation)

The test substance was determined to be not mutagenic with or without metabolic activation in any of the tested strains.

Executive summary:

An in-vitro reverse mutation assay (Ames test) was performed with the test substance following a method equivalent or similar to OECD Guideline 471. Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 and TA1538, and E.coli strain WP2 were exposed to concentrations of 0.033, 0.10, 0.33, 1.0, 3.3 and 10 mg/plate of the test substance, in the presence and in the absence of the S9 mix, using the plate incorporation method. Concurrent positive and negative controls were run with the test.

The test item did not significantly increase the number of revertant colonies both in the absence or presence of a metabolic activation. The test substance was determined to be non-mutagenic under test conditions.