Ethane, 1,1,2-trichloro-1,2-difluoro-

Genetic toxicity: in vitro

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: Guidelines for study of mutagenic activity of drugs_Ministry of Health of the USSR_January 15, 1988

Test guideline 2

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

Test material information

Constituent 1

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

Vehicle / solvent:

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

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 results

Test results 1

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

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

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

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 3

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

Vehicle controls validity:

valid

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.