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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: No guideline study. No GLP study. Testing was performed at non physiological pH.

Data source

Reference
Reference Type:
publication
Title:
Effects of pH in the in vitro chromosomal aberration test
Author:
Morita et al.
Year:
1989
Bibliographic source:
Mutat Res, 225, 55-60

Materials and methods

Principles of method if other than guideline:
The clastogenic activity of NaOH was studied in an in vitro chromosomal aberration test using Chinese hamster ovary (CHO) K1 cells.
GLP compliance:
no
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
no data

Method

Species / strain
Species / strain / cell type:
other: Chinese hamster ovary cells (CHO-K1 cells)
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Test concentrations with justification for top dose:
4-16 mM

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
non-physiological pH might give false-positive responses
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
not specified
Positive controls validity:
not specified
Remarks on result:
other: other: Chinese hamster ovary cells (CHO-K1 cells)
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

No clastogenic activity was found at NaOH concentrations of 0, 4, 8 and 16 mM NaOH, which corresponded with initial pH
values of 7.4, 9.1, 9.7 and 10.6 respectively. Incubation of
CHO-K1 cells with NaOH in the presence of rat liver S9
increased the clastogenic activity of S9, or induced new
clastogens by breakdown of the S9. Therefore, testing at
non-physiological pH might give false-positive responses,
which means that the effect of sodium hydroxide is of a
methodical kind and not valid to assess the genotoxicity
under realistic conditions.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

No clastogenic activity was found at NaOH concentrations of 0, 4, 8 and 16 mM NaOH, which corresponded with initial pH values of 7.4, 9.1, 9.7 and 10.6 respectively. Incubation of CHO-K1 cells with NaOH in the presence of rat liver S9 increased the clastogenic activity of S9, or induced new clastogens by breakdown of the S9. Therefore, testing at non-physiological pH might give false-positive responses, which means that the effect of sodium hydroxide is of a methodical kind and not valid to assess the genotoxicity under realistic conditions.