4H-Pyrido[1,2-a]pyrimidin-4-one, 3-(2-chloroethyl)-9-hydroxy-2-methyl-, hydrochloride (1:1)

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

Study period:

2003-07-17 to 2003-07-21

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Study performed with methods similar to OECD Guideline 471 (Bacterial Reverse Mutation Assay) with the following deviations: 1) only three tester strains were used and 2) limited details on test substance (purity was lacking) and materials and methods were provided. Since the test is positive, performing an Ames test covering the 5 required strains will not provide any additional information to change the conclusion of the classification.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

1) only three tester strains were used and 2) limited details on test substance (purity was lacking) and materials and methods were provided.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3-(2-CHLOROETHYL)-9-HYDROXY-2-METHYL-4H-PYRIDO[1,2-A]PYRIMIDIN-4-ONE HYDROCHLORIDE (1:1)

EC Number:

617-648-0

Cas Number:

849727-62-4

Molecular formula:

C11H11ClN2O2.HCl

IUPAC Name:

3-(2-CHLOROETHYL)-9-HYDROXY-2-METHYL-4H-PYRIDO[1,2-A]PYRIMIDIN-4-ONE HYDROCHLORIDE (1:1)

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Description: Pale yellow powder
Batch number: 00282450
Date received: 2003-04-29
Storage condition: Room temperature in the dark

Method

Target gene:

histidine locus

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA 98, TA 100, and TA 102

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

10 % rat liver S9 in standard co-factors

Test concentrations with justification for top dose:

0, 0.5, 1.5, 5, 15, 50, 150, 500, 1500, 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: sterile distilled water
- Justification for choice of solvent/vehicle: no data

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-ethyl-N'-nitro-N-nitrosoguanidine at 3 µg/plate with TA100

Remarks:

without S9

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Mitomycin C at 0.5 µg/plate with TA102

Remarks:

without S9

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-Nitroquinoline-1-oxide at 0.2 µg/plate with TA98

Remarks:

without S9

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene at 1 µg/plate with TA100

Remarks:

with S9

Controls 5

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 1,8-Dihydroxyanthraquinone at 10 µg/plate with TA102

Remarks:

with S9

Controls 6

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Benzo(a)pyrene at 5 µg/plate with TA98

Remarks:

with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 3 days


NUMBER OF REPLICATIONS: Salmonella typhimurium strains TA98, TA100 and TA102 were treated with suspensions of the test material using the Ames plate incorporation method at nine dose levels, in triplicate, both with and without the addition of a rat liver homogenate metabolising system (10% liver S9 in standard co-factors).


NUMBER OF CELLS EVALUATED: not applicable


DETERMINATION OF CYTOTOXICITY
- Method: reduction in bacterial background lawn

Evaluation criteria:

no data

Statistics:

no data

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA 98, TA 100, and TA 102

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No test substance precipitate was observed on the plates at any of the doses tested in either the presence or absence of S9 mix.

RANGE-FINDING/SCREENING STUDIES:
- no data

COMPARISON WITH HISTORICAL CONTROL DATA:
The vehicle (sterile distilled water) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with and without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9-mix were validated.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- The test substance caused a visible reduction in the growth of the bacterial background in all of the tester strains (except TA102 with S9 mix only), initially at 1500 µg/plate. The test substance was therefore, tested up to the maximum recommended dose level of 5000 µg/plate.

Remarks on result:

other: all strains/cell types tested

Any other information on results incl. tables

Dose-related and toxicologically significant increases in the frequency of revertant colonies were recorded in bacterial strains TA100 (with and without S9) and the remaining strains in the presence of S9 only at the upper sub-toxic dose levels of the test material. The first evidence of a two-fold increase over the concurrent vehicle control was noted in TA100 at 5 and 150 μg/plate without and with S9 respectively. All of the toxicologically significant increases observed were substantially greater than the concurrent solvent control and the in-house historical maxima.

Applicant's summary and conclusion

Conclusions:

Interpretation of results:
positive with and without metabolic activation

The test substance was evaluated for mutagenic potential in the Ames test using S. typhimurium strains TA98, TA100 and TA102 in the absence and presence of metabolic activation. The test substance was considered to be mutagenic under the conditions of this test.