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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 26 October to 12 December 1988
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report date:
1989

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
not specified
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
N-(n-octyl)-2-pyrrolidinone
EC Number:
403-700-8
EC Name:
N-(n-octyl)-2-pyrrolidinone
Cas Number:
2687-94-7
Molecular formula:
C12 H23 N O
IUPAC Name:
N-(n-octyl)-2-pyrrolidinone
Details on test material:
Batch No.: 20.9.88/2
Purity: not specified

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River U.K. Limited, Margate, Kent, England
- Age at study initiation: approximately 35 days old
- Weight at study initiation: between 22 and 24 grams
- Assigned to test groups randomly: yes
- Fasting period before study: overnight
- Housing: kept in a plastic disposable cage
- Diet (e.g. ad libitum): pelleted Labsure LAD 1 rodent breeding diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: approximately 4 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C
- Humidity (%):
- Air changes (per hr): 30 changes of air per hour.
- Photoperiod (hrs dark / hrs light): The room was illuminated by artificial light for 12 hours per day.

IN-LIFE DATES: From: 26 October 1988 To: 12 December 1988

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Corn oil
Duration of treatment / exposure:
Immediately

Frequency of treatment:
Single dose
Post exposure period:
24, 48 or 72 hours


Doses / concentrations
Remarks:
Doses / Concentrations:
1720 mg/kg
Basis:
actual ingested
No. of animals per sex per dose:
Preliminary toxicity test:
2 males and 2 females per dose for Phase I.
5 males and 5 females per dose for Phase II.

Micronucleus test:
15 males and 15 females for vehicle control.
20 males and 20 females for the test substance.
5 males and 5 females for positive control.

Control animals:
yes
Positive control(s):
Mitomycin C
- Justification for choice of positive control(s):
- Route of administration: Oral by intragastric gavage.
- Doses / concentrations: 12 mg/kg

Examinations

Details of tissue and slide preparation:
The femurs were cleared of tissue and one epiphysis removed from each bone. A direct bone marrow smear was made onto a slide containing a drop of calf serum. One smear was made from each femur. The prepared smears were fixed in methanol. The smears were air-dried and stained for 10 minutes in 10% Giemsa. Following rinsing in distilled water and differentiation in buffered distilled water, the smears were air-dried and mounted with coverslips using DPX.
Evaluation criteria:
None stated

Statistics:
For a comparison of an individual treated group with a concurrent control group, Wilcoxon's sum of ranks test is used.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Signs and mortalities:
One male and three female animals died after treatment with the test substance in the main study. On post mortem examination, none of the animals showed signs of having been misdosed. None of the animals in the positive control or vehicle control groups showed any clinical signs for the duration of the test.

Micronucleated polychromatic erythrocyte counts (mnp):
The test substance did not cause any statistically significant increases in the number of micronucleated polychromatic erythrocytes at any of the three skill times (P>0.05 using Wilcoxon's sum of ranks test). Mitomycin C caused large, highly significant increases (P<0.001) in the frequence of micronucleated polychromatic erythrocytes.

Micronucleated normochromatic erythrocytes (mnn):
The test substance did not cause any substantial increases in the incidence of micronucleated normochromatic erythrocytes at any of the three kill times.

Ratio of polychromatic to normochromatic erythrocytes (p/n):
Both the test substance and mitomycin C failed to cause any significant decreases in the ratio of polychromatic to normochromatic erythrocytes (P>0.05 using Wilcoxon's sum of ranks test).

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
From the results obtained it is concluded that the test substance shows no evidence of mutagenic potential or bone marrow cell toxicity when administered orally in this in vivo test procedure.
Executive summary:

In a GLP compliant Mammalian Erythrocyte Micronucleus test according to OECD guideline 474, mice were once orally dosed with 1720 mg/kg bw test substance in corn oil and bone marrow cells were examined 24, 48 and 72 h later (1989). In contrast to the positive control, no increase of micronucleated PCE was observed, but one male and 3 female animals died after test substance administration. No substantial increase of NCEs and no significant decrease of the PCE/NCE ration was observed after administration of the test substance or the positive control.

Therefore, the test substance showed no evidence of mutagenic potential or bone marrow cell toxicity under the conditions of this test.