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

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003-11-17 (date test substance was received) to 2004-10-05

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

GLP compliance:

no

Type of assay:

micronucleus 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 : RT 002416
Description : Off-white solid
Batch number : 00414101
Date received : 2003-11-17
Storage conditions : Room temperature, in the dark

Test animals

Species:

mouse

Strain:

not specified

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS: no data

ENVIRONMENTAL CONDITIONS: no data

IN-LIFE DATES: no data

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: arachis oil
- Justification for choice of solvent: not indicated

Duration of treatment / exposure:

single intraperitonal administration

Frequency of treatment:

once

Post exposure period:

Animals were killed 24 or 48 hours after administration, the bone marrow was extracted, and smear preparations made and stained.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

50 mg/kg bw/day (nominal)

Remarks:

24-hour sampling time

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Remarks:

24-hour sampling time

Doses / concentrations 3

Dose / conc.:

200 mg/kg bw/day (nominal)

Remarks:

24-hour and 48-hour sampling time

No. of animals per sex per dose:

- 7 mice/dose level of test substance.
- 7 mice administered vehicle only (administered IP)
- 5 mice administered positive control (cyclophosphamide administered orally)

Control animals:

yes, concurrent vehicle

Positive control(s):

- cyclophosphamide
- Justification for choice of positive control(s): no data
- Route of administration: orally
- Doses / concentrations: 50 mg/kg

Examinations

Tissues and cell types examined:

2000 bone marrow cells were scored to measure polychromatic (PCE) and normochromatic (NCE) erythrocytes

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:
- A range-finding test was performed to find suitable dose levels of the test substance, route of administration and to investigate to see if there was a marked difference in toxic response between the sexes. There was no marked difference in toxicity of the test substance between the sexes; therefore the main test was performed using only male mice.
- In the range-finding test no evidence of toxicity was observed in animals dosed with test substance via the oral route and, therefore systemic absorption could not be confirmed using this dose route. In the range finding test animals dosed with the test substance via the intraperitoneal route premature deaths occurred at and above 400 mg/kg, no clinical signs were observed.

TREATMENT AND SAMPLING TIMES (in addition to information in specific fields):
- The micronucleus test was conducted using the intraperitoneal route in groups of seven mice (males) at the maximum tolerated dose (MTD) 200 mg/kg and with 100 and 50 mg/kg as the two lower dose levels. Animals were killed 24 or 48 hours later, the bone marrow was extracted, and smear preparations made and stained.
- Further groups of mice were given a single intraperitoneal dose of arachis oil (7 mice) or dosed orally with cyclophosphamide (5 mice), to serve as vehicle and positive controls respectively. Vehicle control animals were killed 24 or 48 hours later, and positive control animals were killed after 24 hours.

Evaluation criteria:

No data

Statistics:

No data

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: not indicated
- Solubility: no data
- Clinical signs of toxicity in test animals: deaths occurred at and above 400 mg/kg, no clinical signs were observed
- Evidence of cytotoxicity in tissue analyzed: no data
- Rationale for exposure: In the range-finding test no evidence of toxicity was observed in animals dosed with test material via the oral route and, therefore systemic absorption could not be confirmed using this dose route.
In the range finding test animals dosed with the test material via the intraperitoneal route premature deaths occurred at and above 400 mg/kg, no clinical signs were observed.
- Harvest times: no data
- High dose with and without activation: not applicable

RESULTS OF DEFINITIVE STUDY
- Types of structural aberrations for significant dose levels (for Cytogenetic or SCE assay): no data
- Induction of micronuclei: There were no statistically significant increases in the frequency of micronucleated PCEs in any of the test material dose groups when compared to their concurrent vehicle control groups. The positive control substance induced a marked increase in the incidence of micronucleated polychromatic erythrocytes hence confirming the sensitivity of the system to the known mutagenic activity of cyclophosphamide under the conditions of the test.
- Ratio of PCE/NCE: There was a statistically significant decrease in the PCE/NCE ratio in the 48-hour 200 mg/kg test material group when compared to the concurrent vehicle control group. This was taken to indicate that systemic absorption had occurred and exposure to the bone marrow achieved.
- Appropriateness of dose levels and route: not indicated

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative
The test substance was found not to produce a significant increase in the frequency of micronuclei in polychromatic erythrocytes in male mice under the conditions of the test and was therefore considered to be non-genotoxic under the conditions of the test.