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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:
comparable to guideline study with acceptable restrictions
Remarks:
The data source is the competent authority and it is considered reliable. The test method is well documented and similar to OECD guideline. Although some deviations occur, the results can be considered reliable.
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report date:
1993

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
other: Guidelines for study of mutagenic activity of drugs_Ministry of Health of the USSR_January 15, 1988
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
3 strains of salmonella t.; a partial activated metabolic system is used for the identication of direct mutagens.
Principles of method if other than guideline:
Plate incorporation method.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
1,1,2-trichloro-1,2-difluoroethane
EC Number:
940-543-9
Cas Number:
354-15-4
Molecular formula:
C2HCl3F2
IUPAC Name:
1,1,2-trichloro-1,2-difluoroethane
Test material form:
other: liquid
Details on test material:
- Name of test material (as cited in study report): R122a

Method

Species / strain
Species / strain / cell type:
S. typhimurium, other: TA 97, TA 98, TA 100
Metabolic activation:
with and without
Metabolic activation system:
S9mix FMAM, S9mix PMAM
Test concentrations with justification for top dose:
0.01, 0.1, 1.0, 10, 100 mcg/plate
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
sodium azide
other: IGR 100 (191); 2-aminoanthracene

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 97
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at test concentration at 10 mcg/plate and above
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at test concentration at 10 mcg/plate and above
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at test concentration at 10 mcg/plate and above
Positive controls validity:
valid

Any other information on results incl. tables

Results of the study of mutagenic activity of R122 on the test strains

Test strain

Chemical compound

Concentration % by volume or mcg/dish

Average number of his. revertants per dish in options

FMAM

PMAM

TA 100

Control

102

94

HCFC 122a

0.01

104

100

 

0.1

90

106

 

1.0

82

101

 

10

t. e.

t. e.

 

100

t. e.

t. e.

Sodium azide

2.5

1,786

2AA

2.5

1,932

90

TA 97

Control

116

99

HCFC 122a

0.01

107

104

 

0.1

114

107

 

1.0

87

71

 

10

t. e.

t. e.

 

100

t. e.

t. e.

191

2.5

259

2AA

2.5

1,441

75

TA 98

Control

32

25

HCFC 122a

0.01

32

23

 

0.1

35

27

 

1.0

27

16

 

10

t. e.

t. e.

 

100

t. e.

t. e.

2NF

2.5

1,079

2AA

2.5

3,020

31

t. e. = toxic effect

Starting from the dose of 10 mcg/dish, the substance inhibits growth of bacteria.

Applicant's summary and conclusion

Conclusions:
Under test conditions, HCFC 122a did no have mutagenic activity when tested on standard strains TA 100, TA 98, TA 97, with and without metabolic activation up to cytotoxic doses.
Executive summary:

The objective of the reported study was the assessment both of the reprotoxicity potential and of the genotoxicity potential of HCFC 122a. To the latter scope, an in vivo micronucleus test and an Ames test were performed.

Thetest was conducted in accordance with the “Guidelines for study of mutagenic activity of drugs” approved by the Ministry of Health of theon January 15, 1988, using strains of Salmonella typhimurium TA 98, TA 100, TA 97.

The presence of mutagenic effect in the preparation was determined by induction of back mutations from histidine auxotrophy to prototrophy.

HCFC 122a was tested following the plate incorporation method at the concentrations of 0.01, 0.1, 1, 10, 100 mcg/plate. The analysis of the results was performed after 48-72 hours of incubation.

 

Concurrently, the experiment included options with FMAM (S9 Full microsomal activation mixture) and PMAM (S9 Partial microsomal activation mixture).

Options with PMAM can demonstrate action of direct mutagens, i.e. drugs that exhibit mutagenic effect due to the activity of the original structure of the substance. The action of the promutagens, i.e. compounds, the effect of which is associated with the formation of mutagenic metabolites, may be taken into account when comparing the results of analysis of test substances in options FMAM and PMAM.

In the control option, FMAM and PMAM were introduced into the upper layer of a semi-solid agar together with the bacterial suspension and the corresponding volumes of solvent. The experiment was accompanied by positive controls.

3 plates were used in each control and experimental option. The experiment was repeated twice.

The results were registered in case of mutagenic effect in all positive control options.

Analysis was performed using Dunnett’s multiple comparison method.

 

No mutations in S. typhimurium test strains were observed. Positive controls effectively induced mutations in the respective S. typhimurium test strains with and without metabolic activation. Starting from the dose of 10 mcg/dish, the preparation inhibits growth of bacteria.

In conclusion, under test conditions, HCFC 122a did no have mutagenic activity when tested on standard strains TA 100, TA 98, TA 97.