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

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003-07-17 (date test substance was received) to 2003-07-21

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Only three strains are tested. However, an expert statement is added in the field "any other remarks" to justify the fact that no further testing is necessary.

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:

Only three tester strains were used and limited details on methodology were provided.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one

EC Number:

605-935-3

Cas Number:

181525-38-2

Molecular formula:

C11H12N2O3

IUPAC Name:

9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Sponsor's identification: RT002416
Description: Off white solid
Batch number: 00393669
Date received: 29 April 2003
Storage conditions: Room temperature in the dark

Method

Target gene:

histidine locus

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 102

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 100

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 98

Metabolic activation:

with and without

Metabolic activation system:

rat liver homogenate metabolising system (10% liver S9 in standard co-factors)

Test concentrations with justification for top dose:

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

Vehicle / solvent:

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

4-nitroquinoline-N-oxide

Remarks:

without metabolic activation; at 0.2 µg/plate for TA98

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

Without metabolic activation; 3 μg/plate for TA100

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without metabolic activation; at 0.5 µg/plate for TA102

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

with metabolic activation; at 5 µg/plate for TA98

Controls 5

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with metabolic activation; at 1.0 µg/plate for TA100

Controls 6

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 1,8-Dihydroxyanthraquinone

Remarks:

with metabolic activation; at 10 µg/plate for TA102

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 3 days

SELECTION AGENT: histidine


NUMBER OF REPLICATIONS: Salmonella typhimurium strains TA98, TA100 and TA102 were treated with 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).

DETERMINATION OF CYTOTOXICITY
- Method: reduction in growth of the bacterial background lawn

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

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:
- The test material caused either a visible reduction in the growth of the bacterial background lawn or a substantial decrease in revertant colony frequency in all tester strains at 5000 µg/plate. The test material was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate.
COMPARISON WITH HISTORICAL CONTROL DATA:
- The vehicle (dimethyl sulphoxide) 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.
A small increase in revertant colony frequency was observed in tester strain TA100, with and without S9-mix only. The increase observed was below two-fold increase over concurrent solvent control and the plate counts were within the in-house historical range.

Applicant's summary and conclusion

Conclusions:

Interpretation of results:
positive

The test substance was considered to be non-mutagenic under the conditions of the test. The original report stated that the substance did not show a significant increase in the frequency of revertant colonies with the strains TA98 and TA100 in the absence and in the presence of S9-mix, at concentrations up to 5000 µg/plate. However, a concentration-related increase in the number of revertant colonies was seen with strain TA100 in the absence (up to 1.9-fold at 1500 µg/plate) and in the presence of S9-mix (up to a 1.5-fold at 1500 µg/plate). Bacteriotoxic effects, visualised by a sparse or absent bacterial background lawn, were observed within strain TA100 in the absence and in the presence of S9-mix at the next concentration level of 5000 µg/plate. Based on these observations, it is concluded that the substance has mutagenic properties towards the S. typhimyrium strain TA100 in the absence and in the presence of S9-mix.