Disodium octaborate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: 40 CFR Part 158 US-EPA-FIFRA, Section 156.340

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

not specified

GLP compliance:

yes

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Boric acid

EC Number:

233-139-2

EC Name:

Boric acid

Cas Number:

10043-35-3

Molecular formula:

H3BO3

IUPAC Name:

Boric acid

Details on test material:

- Name of test material: Boric acid, Granular Technical Grade; Granular Technical Grade Supplied by US Borax Inc.
- Analytical purity: > 99 %
- Stability: Stable

Method

Target gene:

Thymidine kinase, TK locus of the L5178Y mouse lymphoma cell line

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

No data

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix or other (Aroclor 1254 induced rat (Fischer 344) liver S9 fraction used at 1 %).

Test concentrations with justification for top dose:

0, 1.2, 1.7, 2.45, 3.5 and 5.0 mg/mL boric acid.

Vehicle / solvent:

No data

Controls

Controls 1

Positive controls:

yes

Positive control substance:

3-methylcholanthrene

Controls 2

Positive controls:

yes

Positive control substance:

other: Hycanthone methylsulphonate

Details on test system and experimental conditions:

METHOD OF APPLICATION: ROP plus 5 % heat treated horse serum

NUMBER OF CELLS EVALUATED: Approximately 600/dose

Evaluation criteria:

Mutations at the TK locus

Statistics:

No data

Results and discussion

Test results

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Concentration related cytoxicity (60 % reduction over controls at 5 mg/mL)

Additional information on results:

Concentration related cytotoxicity (60 % reduction over controls at 5 mg/mL).
Increase in ouabain resistance seen (not significant).

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Gene mutation assay results:

Concentration mg/mL	Number of mutant cells per 10^6cells ± SD				Comments give information on cytotoxicity or other
	Exp 1	Exp 2	Exp 1	Exp 2
	-S9	-S9	+S9	+S9
0	54 ± 10	42 ± 1	29 ± 10	36 ± 7
1.2	46 ± 28	38 ± 15	34 ± 0	36 ± 7
1.7	39 ± 17	31 ± 9	41 ± 7	49 ± 4
2.45	27 ± 3	32 ± 9	40 ± 16	36 ± 6	Minor cytotoxicity seen
3.5	31 ± 18	46 ± 1	41 ± 13	41 ± 6	Cytotoxicity seen
5	50 ± 22	41 ± 5	53 ± 2	47 ± 3	Cytotoxicity seen. Increase in + S9 in first study not reproduced.

Applicant's summary and conclusion

Conclusions:

The test substance was not mutagenic but cytotoxicity observed at 5 mg/mL (maximum dose level).