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Toxicological information

Genetic toxicity: in vivo

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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:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
Study period:
From Apr. to Jul., 1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study meets generally accepted scientific principles, acceptable for assessment
Justification for data waiving:
other:
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes
Remarks:
FDA Good Laboratory Practices Regulations (21 CFR 58)
Type of assay:
micronucleus assay

Test material

Constituent 1
Reference substance name:
Glycerides, C16 and C18-unsatd. and C18-unsatd. hydroxy
IUPAC Name:
Glycerides, C16 and C18-unsatd. and C18-unsatd. hydroxy
Details on test material:
- Name of test material (as cited in study report): Castor oil (CAS N° 8001-79-4, EC N° 232-293-8); under the SDA nomenclature, the name of this substance is ‘Glycerides, C16 and C18-unsatd. and C18-unsatd. hydroxy'
- Physical state: Liquid
- Analytical purity: Purity and identity analyses were conducted by Midwest Research Institute (MRI) (Kansas City, MO)
- Analytical method used: Karl Fischer water analysis, thin layer and high performance liquid chromatography, and a battery of U.S. Pharmacopeia (USP) standard analyses for castor oil
- Composition of test material, percentage of components:
- Lot/batch No.: #L-5G30-01
- Other: Source: Cas Chemical, Inc.

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Simonsen Laboratories, Gilroy, CA
- Age at study initiation: 6 wk
- Fasting period before study: No
- Housing: Individually caged in polycarbonate cages lined with heat-treated hardwood chips and covered with polyester filter sheets. The cages were stored on stainless steel racks equipped with an automatic watering system
- Diet: NIH 07; available ad libitum
- Water: Ad libitum
- Acclimation period: 15 d
- Other: Feed hoppers in the animal cages were changed twice weekly


ENVIRONMENTAL CONDITIONS
- Temperature: 68-76 °F
- Humidity: 42-72%
- Air changes: 10 room air changes/h
- Photoperiod: 12 h dark/12 h light



- Age when killed: 19 wk

Administration / exposure

Route of administration:
oral: feed
Vehicle:
Plain diet


- Vehicle(s)/solvent(s) used: None
Details on exposure:
DIET PREPARATION
- Method of mixing: Formulated diets were prepared by blending the appropriate amount of castor oil with a small quantity of feed to prepare a premix. The premix then was layered between the required amounts of feed in a twin-shell blender and blended for 15 minutes to achieve a uniform mix.
- Mixing appropriate amounts with (Type of food): 10% (100 mg/g) determined by gravimetric analysis, and blends at 0.5% (5 mg/g) determined by HPLC analysis.
- Storage temperature of food: Stored for no longer than 3 weeks at 5 °C
- Stability under test conditions: 0.5% dose level is stable for at least 21 days when stored in the dark at 5 °C and for 3 days when stored open to air and light in a rodent cage.
Duration of treatment / exposure:
13 wk or 90 d
Frequency of treatment:
Daily
Post exposure period:
At termination of 13 wk study
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 0.6, 1.3, 2.5, 5.0 and 10.0% in feed
Basis:
actual ingested
No. of animals per sex per dose:
10 mice per sex per dose

Control animals:
yes, plain diet
Positive control(s):
- Positive control: Urethane
- Dose: 0.2%
- Brief description: Male mice treated for 4 weeks with urethane in the drinking water (0.2%) were used as positive control. These animals were not part of the 13-week study, but were added as a measure of quality control for the assay.

Examinations

Tissues and cell types examined:
Peripheral blood samples were examined for frequency of polychromatic and normochromatic micronucleated erythrocytes (PCE and NCE)
Details of tissue and slide preparation:
- Method of sampling: Cardiac puncture
- Stain used: Hoechst 33258/pyronin Y (MacGregor et al., 1983)
- Number of cells scored for micronuclei: 2,000 PCE and 10,000 NCE from each animal
Evaluation criteria:
Not reported
Statistics:
Not reported

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
Not reported

Any other information on results incl. tables

No significant elevation in the frequency of micronucleated erythrocytes was observed in either male or female mice administered castor oil in dosed feed.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Under the test conditions, castor oil can be considered to be non-mutagenic in the micronucleus test in B6C3F1 mice.
Executive summary:

A study was performed to investigate the potential of castor oil to induce micronuclei in polychromatic erythrocytes (PCE) in the peripheral blood of the mouse.

Groups of 10 mice/sex were exposed to 0, 0.6, 1.3, 2.5, 5.0 and 10.0% concentrations of castor oil mixed in diet for 13 weeks. At termination, smears were prepared from peripheral blood samples obtained by cardiac puncture of dosed and control animals. Slides were stained with Hoechst 33258/pyronin Y. About 2,000 PCE and 10,000 NCE from each animal were scored for frequency of micronuclei.

No significant elevation in the frequency of micronucleated erythrocytes was observed in either male or female mice administered castor oil in dosed feed.

Therefore, under the test conditions, castor oil is considered to be non-mutagenic in the micronucleus test in B6C3F1 mice.