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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
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods

Data source

Reference
Reference Type:
publication
Title:
NTP Technical Report on the Toxicity Studies of Castor Oil in F344/N Rats and B6C3F1 Mice (Dosed Feed Studies).
Author:
Irwin, R.
Year:
1992
Bibliographic source:
National Toxicology Program (NTP TOX 12 NIH Publication No. 92 -3131). National Institutes of Health.
Report date:
1992

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
- Principle of test: Mice (10/sex/dose) received diets containing 0, 0.62%, 1.25%, 2.5%, 5.0% or 10% castor oil, continuously for 13 weeks. Ten additional rats/sex were included at each dose level for evaluation of hematological and clinical chemistry parameters. At days 5 and 21, these animals were anesthetized with carbon dioxide, and blood was collected from the orbital sinus. These animals were killed following the blood collection on day 21.Smears were prepared from peripheral blood samples obtained by cardiac puncture of dosed and control animals at the termination of the 13 week study. Slides were stained with Hoechst 33258/pyronin Y. At least 2000 PCE and 10000 NCE from each animal were scored for micronuclei.

- Short description of test conditions: Mice were housed individually. Polycarbonate cages lined with heat-treated hardwood chips and covered with polyester filter sheets were used; the cages were stored on stainless steel racks equipped with an automatic watering system. Temperature in the animal room was maintained within 68-76°F; relative humidity ranged from 42% to 72%. Incoming air was filtered to remove particulates, and a flow rate was maintained to ensure complete exchange at least 10 times per hour. A controlled light cycle of 12 hours of daylight and 12 hours of darkness was maintained. Control feed or diet formulations of castor oil were available ad libitum; feeders were changed twice per week throughout the study.

- Parameters analysed / observed: Smears were prepared from peripheral blood samples obtained by cardiac puncture of dosed and control animals at the termination of the 13 week study. Slides were stained with Hoechst 33258/pyronin Y. At least 2000 PCE and 10000 NCE from each animal were scored for micronuclei.
GLP compliance:
yes
Type of assay:
mammalian erythrocyte micronucleus test

Test material

Constituent 1
Reference substance name:
8001-79-4
Cas Number:
8001-79-4
IUPAC Name:
8001-79-4
Constituent 2
Reference substance name:
Castor oil
EC Number:
232-293-8
EC Name:
Castor oil
IUPAC Name:
232-293-8
Constituent 3
Reference substance name:
Castor oil
IUPAC Name:
Castor oil
Details on test material:
- Name of test material (as cited in study report): Castor Oil
- Synonyms: Ricinus Oil, oil of Palma Christi, tangantangan oil, phorboyl, Neoloid
- Composition of test material, percentage of components: Triglyceride of fatty acids. Fatty acid composition is approximately 87% ricinoleic,
7% oleic, 3% linoleic, 2% palmitic, 1% stearic, and trace amounts of dihydroxystearic.
- Analytical grade: USP AA grade
- Source: Cas Chemical, Inc. (Bayonne, NJ, USA)
- Stability: The stability of the study material during the toxicology studies was monitored by determination of peroxide content and by high performance liquid chromatography. No deterioration of the castor oil study material was observed over the course of the studies.
Specific details on test material used for the study:
USP AA grade castor oil was obtained in one lot (#L-5G30-01) from Cas Chemical, Inc. (Bayonne, NJ). Purity and identity analyses were conducted by Midwest Research Institute (MRI) (Kansas City, MO). MRI reports on the analyses performed in support of the castor oil studies are on file at the National Institute of Environmental Health Sciences (Research Triangle Park, NC).

Cumulative data indicated a purity consistent with the USP specifications and the reported composition for castor oil.

The stability of the study material during the toxicology studies was monitored by determination of peroxide content and by high performance liquid chromatography. No deterioration of the castor oil study material was observed over the course of the studies.

Test animals

Species:
mouse
Strain:
B6C3F1
Details on species / strain selection:
Obtained from Simonsen Laboratories (Gilroy, CA, USA).
Sex:
male/female
Details on test animals or test system and environmental conditions:
Mice were housed individually. Polycarbonate cages lined with heat-treated hardwood chips and covered with polyester filter sheets were used; the cages were stored on stainless steel racks equipped with an automatic watering system. Temperature in the animal room was maintained within 68-76°F; relative humidity ranged from 42% to 72%. Incoming air was filtered to remove particulates, and a flow rate was maintained to ensure complete exchange at least 10 times per hour. A controlled light cycle of 12 hours of daylight and 12 hours of darkness was maintained. Control feed or diet formulations of castor oil were available ad libitum; feeders were changed twice per week throughout the study.

Administration / exposure

Route of administration:
oral: feed
Details on exposure:
Ad libitum.
Duration of treatment / exposure:
13 continuous weeks.
Frequency of treatment:
Daily
Doses / concentrationsopen allclose all
Dose / conc.:
0 other: %
Dose / conc.:
0.62 other: %
Dose / conc.:
1.25 other: %
Dose / conc.:
2.5 other: %
Dose / conc.:
5 other: %
Dose / conc.:
10 other: %
No. of animals per sex per dose:
10/sex/concentration.
Control animals:
yes, plain diet
Positive control(s):
Male mice treated for 4 weeks with urethane in the drinking water (0.2%). 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:
Complete histopathology examinations were conducted on all mice from the control and 10% dose groups.
Details of tissue and slide preparation:
Smears were prepared from peripheral blood samples obtained by cardiac puncture of dosed and control animals at the termination of the 13 week study. Slides were stained with Hoechst 33258/pyronin Y. At least 2000 PCE and 10000 NCE from each animal were scored for micronuclei.
Statistics:
Shirley's test was used to assess any significance that were different from control groups by , p <0.05.

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Frequency of Micronuclei in Peripheral Blood Erythrocytes of B6C3F1 Mice Exposed to Castor Oil in Dosed Feed for 13 Weeks

 Percent in Feed  % Normachromatic erythrocytes with micronuclei   % Polychromatic erythrocytes with micronuclei  Number of mice
 Male mice:      
 0  0.11 ± 0.02   1.20 ± 0.08  10
 0.6   0.13 ± 0.02   1.18 ± 0.10   10
 1.3   0.11 ± 0.01   1.16 ± 0.09   10
 2.5   0.13 ± 0.01  1.24 ± 0.10   10
 5.0  0.09 ± 0.02     1.40 ± 0.11   9
  10  0.09 ± 0.01

  1.21 ± 0.08

  10
 Female mice      
 0   0.10 ± 0.01  1.18 ± 0.07   10
 0.6   0.09 ± 0.01   1.21 ± 0.10   10
1.3   0.07 ± 0.01   1.11 ± 0.08   9
  2.5   0.09 ± 0.02   1.11 ± 0.08   10
 5.0   0.09 ± 0.01   1.49 ± 0.18   10
 10.0   0.06 ± 0.01   1.00 ± 0.10   10
 Urethane      
 0.2%  1.68 ± 0.25  1.710 ± 0.25  3

Applicant's summary and conclusion

Conclusions:
Castor oil was found to be negative for cytogenicity as evidenced by a lack of micronuclei in peripheral blood erythrocytes of B6C3F1 mice exposed in dosed feeding for 13 weeks.
Executive summary:

B6C3F1 mice (10/sex/dose) received diets containing 0, 0.62%, 1.25%, 2.5%, 5.0% or 10% castor oil, continuously for 13 weeks. Ten additional rats/sex were included at each dose level for evaluation of hematological and clinical chemistry parameters. At days 5 and 21, these animals were anesthetized with carbon dioxide, and blood was collected from the orbital sinus. These animals were killed following the blood collection on day 21.Smears were prepared from peripheral blood samples obtained by cardiac puncture of dosed and control animals at the termination of the 13 week study. Slides were stained with Hoechst 33258/pyronin Y. At least 2000 PCE and 10000 NCE from each animal were scored for micronuclei. Castor oil was found to be negative for cytogenicity as evidenced by a lack of micronuclei in peripheral blood erythrocytes of B6C3F1 mice exposed in dosed feeding for 13 weeks.