Registration Dossier

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
Study period:
1978
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
This study is classified as reliable with restrictions because, although it is not-GLP compliant, it is an acceptable and a well-documented study report, according or similar to a guideline, that meets generally accepted scientific principles, acceptable for assessment.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1978
Report Date:
1978

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
yes
Remarks:
Were used only two of the five bacterial strains recommended from the guideline.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Were used only two of the five bacterial strains recommended from the guideline.
Principles of method if other than guideline:
The test chemical in 0.1 ml dimethyl sulfoxide or H20 was placed in a tube and mixed with 0.5 ml S-9 mix (150 microliter of the S-9 fraction of rat liver pretreated with polychlorinated biphenyl, 2 micromol NADPH, 2 micromol NADH, 2.5 micromol glucose 6-phosphate, 0.25 unit glucose-6-phosphate dehydrogenase, 4 micromol MgCI2, 16.5 micromol KCI, and 50 micromol sodium phosphate buffer, pH 7.4 and 0.1 ml of culture of the bacterial tester strain (1 to 2 x 10E8 cells). Without metabolic activation 50 micromol sodium phosphate buffer, pH 7.4, in 0.5 ml were used instead of S-9 mix. The mixture was preincubated at 37° for 20 min and then mixed with 2 ml top agar (0.7% agar and 0.6% NaCI) at 45° and spread on a minimal glucose agar plate containing 0.1 micromol each L-histidine and biotin. Plates were incubated at 37° for 2 days, and then his+ revertant colonies were counted.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Prednisolone
- Other: Structure reported. Prednisolone was from Sanwa Research Institute, Tokyo, Japan.

Method

Species / strainopen allclose all
Species / strain:
S. typhimurium TA 98
Additional strain characteristics:
other: This strain carryies R-factor plasmid pKM101.
Metabolic activation:
with and without
Metabolic activation system:
S-9 mix
Species / strain:
S. typhimurium TA 100
Additional strain characteristics:
other: This strain carryies R-factor plasmid pKM101.
Metabolic activation:
with and without
Metabolic activation system:
S-9 mix
Test concentrations with justification for top dose:
Prednisolone was tested at 8.3, 17, and 33 micrograms/plate. Drug contained some vehicle, and the amount of the drug was expressed as micrograms of active principle.
Controls
Negative controls:
yes
Remarks:
Average of values in 20 experiments.
Solvent controls:
yes
Remarks:
Vehicle controls.
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
Also daunomycin hydrochloride, and adriamycin hydrochloride were reported as positive controls.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no, but tested up to limit concentrations
Remarks:
Prednisolone was not lethal at doses of up to 33 micrograms/plate.
Vehicle controls valid:
yes
Negative controls valid:
not specified
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no, but tested up to limit concentrations
Remarks:
Prednisolone was not lethal at doses of up to 33 micrograms/plate.
Vehicle controls valid:
yes
Negative controls valid:
not specified
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

               his+revertants/plate  
     TA100    TA98     
    micrograms/plate   + S-9 mix  - S-9 mix    + S-9 mix  - S-9 mix  his+revertants/nmola
 Prednisoloneb  8.3  135  125    37  34   0     
   17  145  145    39  33
   33  123  144    35  23
 Controlc    147  132    30  16  

aThe number ofhis+revertants per nmol was calculated from the data obtained under the most active conditions in

the linear dose-responsible range and a yield of 100 colonies more than the background yield.

bDrug contained some vehicle, and the amount of the drug was expressed as micrograms of active principle.

cAverage of values in 20 experiments.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Prednisolone was not mutagenic to either strain with or without S-9 mix, and it was not lethal at doses of up to 33 micrograms/plate.