Genetic toxicity in vitro

Administrative data

Confidentiality
[Not publishable]
Justification
[Not publishable]
Use restricted to selected regulatory programmes
[Not publishable]
Endpoint
in vitro gene mutation study in mammalian cells

Type of genotoxicity: gene mutation

Type of information
experimental study
Adequacy of study
key study
Robust study summary
[Not publishable]
Used for classification
[Not publishable]
Used for SDS
[Not publishable]
Study period: start date
13-Jun-2005
End date
09-Aug-2005
Remark

13 June 2005 - 9 August 2005

Reliability
1 (reliable without restriction)
Rationale for reliability incl. deficiencies
guideline study
Data waiving
[Empty]
Justification for data waiving
[Empty]
Justification for type of information
[Empty]

Attached justification

Cross-reference

Data source

Reference
Data access
[Not publishable]
Data protection claimed
[Not publishable]

Materials and methods

Test guideline

#1 - Test guideline

Qualifier
according to guideline
Guideline
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Version / remarks

adopted 1997

Deviations
no

#2 - Test guideline

Qualifier
according to guideline
Guideline
EPA OPPTS 870.5300 - In vitro Mammalian Cell Gene Mutation Test
Version / remarks

[Empty]

Deviations
no

#3 - Test guideline

Qualifier
according to guideline
Guideline
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Version / remarks

[Empty]

Deviations
no

#4 - Test guideline

Qualifier
according to guideline
Guideline
other: ICH (1996) Guideline S2A: Genotoxicity: Guidance on Specific Aspects of Regulatory Genotoxicity Tests for Pharmaceuticals. PAB/PCD Notification No. 444.
Version / remarks

[Empty]

Deviations
no

#5 - Test guideline

Qualifier
according to guideline
Guideline
other: ICH (1998) Guideline S2B: Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals. PMSB/ELD Notification No. 554.
Version / remarks

[Empty]

Deviations
no
Principles of method if other than guideline
[Empty]
GLP compliance
yes (incl. QA statement)
Type of assay
in vitro mammalian cell micronucleus test

Test material

Test material information
Additional test material information
[Empty]
Specific details on test material used for the study

Appearance: Clear and colourless liquid

Storage conditions: Room temperature (ca. 20ºC), in the dark

Batch number: 52834

Expiry date: December 2006

Purity: >98%

Specific details on test material used for the study (confidential)
[Not publishable]

Method

Target gene

thymidine

Species / strain

#1 - Species / strain

Species / strain / cell type
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable)

CELLS USED

- Suitability of cells: heterozygous at the thymidine kinase locus, TK +/-

MEDIA USED

- Type and identity of media:

R0: RPMI 1640, buffered with 2 mg/mL sodium bicarbonate, supplemented with 2.0 mM L-glutamine and 50 µg/mL gentamicin.

R10p: R0, supplemented with 0.1% v/v Synperonic F68, 1.0 mM sodium pyruvate and HiDHS at 10% v/v.

R30p: R0, supplemented with 0.02% v/v Synperonic F68, 1.0 mM sodium pyruvate and HiDHS at 30% v/v.

- Properly maintained: yes

- Periodically checked for Mycoplasma contamination: yes

Additional strain / cell type characteristics
not specified
Cytokinesis block (if used)

[Empty]

Metabolic activation
with and without
Metabolic activation system

S9

Test concentrations

[Empty]

High dose level used
[Empty]
Justification for deviation from the high dose level
[Not publishable]
Vehicle / solvent

- Vehicle(s)/solvent(s) used: water

- Justification for choice of solvent/vehicle: the test item was found to be soluble

Controls

#1 - Controls

Untreated negative controls
no
Negative solvent / vehicle controls
yes
True negative controls
no
Positive controls
yes
Positive control substance
  • methylmethanesulfonate
Remarks

In the absence of S9 mix; solvent: DMSO

#2 - Controls

Untreated negative controls
no
Negative solvent / vehicle controls
yes
True negative controls
no
Positive controls
yes
Positive control substance
  • 3-methylcholanthrene
Remarks

In the presence of S9 mix; solvent: DMSO

Details on test system and experimental conditions

Exposure period (with metabolic activation): 3 hours

Exposure period (without metabolic activation): 24 hours

Expression time:

2 days

Selection time:

10-14 days

DETERMINATION OF CYTOTOXICITY

- Method: cloning efficiency

Rationale for test conditions

Data are presented for concentrations tested up to the maximum exposure of 1041 µg/mL (10mM) for freely soluble compounds, in accordance with current guidelines.

Evaluation criteria

The test agent was regarded as negative if: The Induced mutation frequency (test concentration MF minus mean control MF) for any test concentration was less than the Global Evaluation Factor (126 x 10-6). If the IMF of any test concentration exceeded the GEF, a linear trend test was applied: If the linear trend test was negative, the result was regarded as negative. If the linear trend test was positive, this indicated a positive, biologically relevant response.

Statistics

[Empty]

Model and software

Model name and version

[Empty]

Software name and version

[Empty]

Remarks
[Not publishable]

Any other information on materials and methods incl. tables

[Not publishable]

Results and discussion

Test results

#1 - Test results

Key result
Species / strain
mouse lymphoma L5178Y cells
Metabolic activation
without
Genotoxicity
negative
Cytotoxicity / choice of top concentrations
not specified
Vehicle controls validity
valid
Untreated negative controls validity
not applicable
True negative controls validity
[Empty]
Positive controls validity
valid

#2 - Test results

Key result
Species / strain
mouse lymphoma L5178Y cells
Metabolic activation
with
Genotoxicity
negative
Cytotoxicity / choice of top concentrations
not specified
Vehicle controls validity
valid
Untreated negative controls validity
not applicable
True negative controls validity
[Empty]
Positive controls validity
valid

#3 - Test results

Key result
Species / strain
mouse lymphoma L5178Y cells
Metabolic activation
without
Genotoxicity
negative
Cytotoxicity / choice of top concentrations
not specified
Vehicle controls validity
valid
Untreated negative controls validity
not applicable
True negative controls validity
[Empty]
Positive controls validity
valid
Additional information on results

Preliminary toxicity test (Relative suspension growth):

Concentrations from 2 to 1041 µg/mL:

3 hours exposure :

- without S9 mix:127% to 44%

- with S9 mix: 98% to 89%

24 hours exposure :

- without S9 mix: 93% to 78%

Overall remarks on result
other: after 3 hour treatment

Additional information about applicability domain and reliability of (Q)SAR predictions

Fit with the applicability domain
[Empty]
Justification for the fit with the applicability domain

[Empty]

Fit with the space defined by the training set of the model
[Empty]
Mechanistic and metabolic considerations

[Empty]

Similar substances with experimental data

Performance of the model for similar substances

[Empty]

Conclusions on applicability domain and reliability
[Empty]
Uncertainty
[Empty]

Any other information on results incl. tables

[Empty]

Overall remarks, attachments

Overall remarks
[Not publishable]

Attachments

Applicant's summary and conclusion

Conclusions

MBD did not demonstrate mutagenic potential up to limit concentrations (1041 µg/mL; 10mM) in this in vitro mammalian cell gene mutation assay (OECD 476, GLP), under the experimental conditions described.

Executive summary

In a mammalian cell gene mutation assay (the thymidine kinase (tk) locus (TK+/-), OECD 476, GLP) L5178Y mouse lymphoma (3.7.2c) cells cultured in vitro were exposed to 3-Methyl-1,3-butandiol (MBD, purity >98%) dissolved in sterile water at concentrations of 32.53, 65.06, 130.13, 260.25, 520.5, 1041 µg/mL in the presence and absence of mammalian metabolic activation (S9 mix). The cells were exposed for either 3 hours or 24 hours in the absence of exogenous metabolic activation (S9 mix) or 3 hours in the presence of S9 mix.

3-Methyl-1,3-butandiol was tested up to the maximum recommended concentration specified in OECD TG 476 (10 mM). There were no increases in induced mutation frequency that exceeded the Global Evaluation Factor (GEF) or the mutant frequency of the concurrent solvent control at any of the concentrations tested within acceptable levels of cytotoxicity. The positive controls induced an acceptable increase in mutation frequency. The results for the solvent controls were within acceptable ranges of historical control data.

This study is classified as acceptable. This study satisfies the requirement for Test Guideline OECD 476 for in vitro mutagenicity (mammalian forward gene mutation) data.