1H-Imidazole-5-methanol, 2-butyl-4-chloro-1-[[2'-(2H-tetrazol-5-yl)[1,1'-biphenyl]-4-yl]methyl]-

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Although the study was conducted according to GLP and well documented methods, " Practical guide 10: How to avoid unnecessary testing on animals", Section 3.3.2 states it is important that the reliability indicator (Klimisch score) reflects the assumptions of similarity. Thus, a score of 1 (reliable without restrictions) should normally not be used for results derived from read-across.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Ames-88, Edition 5

Principles of method if other than guideline:

Substance was testest for mutagenic activity in Salmonella typhimurium strains TA1535, TA97, TA98, and TA100, with and without activiation.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Losartan potassium

IUPAC Name:

Losartan potassium

Constituent 2

Reference substance name:

1H-Imidazole-5-methanol, 2-butyl-4chloro-1-1[2'(1H-tetrazol-5-yl)[1,1'-biphenyl]-4-ylmethyl]-potassium salt

IUPAC Name:

1H-Imidazole-5-methanol, 2-butyl-4chloro-1-1[2'(1H-tetrazol-5-yl)[1,1'-biphenyl]-4-ylmethyl]-potassium salt

Details on test material:

- Name of test material (as cited in study report):1H-imidazole-5-methanol, 2-butyl-4-chloro-1-[2'-(1H-tetrazol-5-y1)[1,1'-biphenyl]-4-ylmethyl]-, potassium salt

- Substance type:
- Physical state:

- Analytical purity: 99.5%

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 97

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 100

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

0, 67, 135, 673, 1000, 5000 micrograms/plate

Controls

Untreated negative controls:

yes

Remarks:

distilled-deionized water

Negative solvent / vehicle controls:

no

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

2-nitrofluorene

sodium azide

other: 2-aminoanthracene

Details on test system and experimental conditions:

PLATE INCORPORATION ASSAY

The assay was perfomre din the presence and the absence of a rat liver homogenate activation system (S-9 mix) similar to the method described by Ames et al (Mutation Res.113:173-215, 1983). All tester strains were obtained from Dr. B. Ames, Berkeley, CA. Positive indicators and negative controls were included in all assays. Treatments without activation (nonactivated) were conducted by adding 0.1 mL of the solvent or a solution of DuP 753 and 0.1 mL of an overnight culture containing approximately 10^8 bacteria to 2mL of top agar (0.6% agar, 0.6% NaCl, 0.05 mM L-histidine, 0.05 mM biotin). These components were mixed and poured on the surface of a plate containing 25mL of Davis minimal agar. Treatments with activation were conducted by adding 0.5 mL of S-9 mix to the bacteria/test sample/top agar as described above and pouring the mixture onto a minimal agar plate. The S-9 mix contained per mL: 0.3 mL of S-9 diluted to 5.6 mg/mL with phosphate buffered saline (PBS), and 0.7 mL of a cofactor solution containing 8 micromoles MgCl2, 33 micormoles KCl, 5 micromoles glucose-6-phosphate, 4micromoles NADP and 100 micromoles sodium phosphate (pH 7.4). The S-9 (Sitek Research Laboratories, Rockville, MD Lot 871215) was the 9000xg supernatant of liver homogenate (1g wet liver : 3.0mL PBS). The livers were obtained from 8 to 9 week old male Crl:CD BR (Charles River, Kingston, NY) rats injected intraperitoneally with Aroclor 1254 (500 mg/kg) 5 days before sacrifice. The revertant colonies were counted after the individually labelled plates were incubated at 37 deg C for 48 hours.

Evaluation criteria:

Classification Guidelines:

Positive:
A. The average number of induced revertants at one more of the test sample concentrations studied is at least two times greater than the average number of revertants in the solvent control.

And

B. There is a dose response relationship

Negative:
A. Average number of induced revertants at each concentration is similar to the average number of revertants in the solvent control.
OR
B. There is no dose-response relationship.

Equivocal:
Neither of the criteria for a positive or negative is satisfied.

Statistics:

Doses with and without activation were ranked and results from a strain were analysed individually by multiple linear regression. Comparison were made between each dose/concentration and the solvent control (0 rank), using the mean square error estimate. All comparisons were at the 95% level of confidence (alpha=0.05).

Results and discussion

Test results

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Additional information on results:

DuP 753 was tested for cytotoxicity in Salmonella typhimurium strain TA98 with and without activation. DuP 753 exhibited no toxicity to strain TA 98 without or with activaition at dose levels of 5000 ug/plate. Based on these results, 5000 ug/plate with and without activation were chosen as the highest doses for mutagenicity assays.

DuP 753 was tested for mutagenicity activity in Salmonella typhimurium strains TA1535, TA97, TA98 and TA100 with and without activation. No mutagenic activity was detected in any strain either with or without activation at dose levels up to 5000 ug/plate. Under the conditions of this assay, DuP 753 is negative.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Concentration μg/plate	Colonies/plate w/o activation	Colonies/plate w/activation
0	1743, 1644	1791, 1800
67	1779, 1729	1795, 1827
135	1723, 1773	1842, 1854
673	1695, 1759	1785, 1855
1000	1782, 1903	1781, 1784
5000	1688, 1818	1704, 1679

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Under the conditions of this assay, DUP 753 (losartan potassium) is negative. Therefore, by read-across, losartan free acid is negative for mutagenicity.

Executive summary:

DUP 753 was testest for mutagenic activity in Salmonella typhimurium strains TA1535, TA97, TA98, and TA100, with and without activiation. Results of the mutagenicity trials are shown in Tables II thorugh IX. No mutagenic activity was detected in any strain either with or without activation at dose levels up to 5000 micrograms / plae. Under the conditions of this assay, DUP 753 is negative.