Registration Dossier

Toxicological information

Repeated dose toxicity: oral

Currently viewing:

Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP compliant study on a structurally similar substance conducted in accordance with recognised test guidelines. For read across justification see Section 13

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1992

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)
GLP compliance:
yes
Limit test:
no

Test material

Constituent 1
Reference substance name:
Castor oil
EC Number:
232-293-8
EC Name:
Castor oil
Cas Number:
8001-79-4
IUPAC Name:
8001-79-4
Details on test material:
- Name of test material (as cited in study report): Castor oil
- Lot/batch No.: L-5G30-01
- Molecular formula (if other than submission substance): C55 H100 O9
- Molecular weight (if other than submission substance): 905.41
- Smiles notation (if other than submission substance): O=C(CCCCCCC=CCC(CCCCCC)O)OC(COC(=O)(CCCCCCCC=CCC(O)CCCCCC))C(=O)(OCCCCCCCC=CCC(O)CCCCCC)

Test animals

Species:
rat
Strain:
Fischer 344
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 weeks
- Weight at study initiation: no data
- Fasting period before study: n/a
- Housing: 5/sex/cage
- Diet (e.g. ad libitum): NIH-07 open formula diet, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 42 - 72
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light):

IN-LIFE DATES: From: April 1988 To: July 1988

Administration / exposure

Route of administration:
oral: feed
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): No data but no loner than 21 days (limit of stability)
- Mixing appropriate amounts with (Type of food): A premix of the substance and powdered diet was prepared for each dosed feed formulation. Additional portions of feed were added and the premix stirred after each addition. For the final preparation, the premix and additional feed were layered in a twin-shell blender and blended for 15 minutes
- Storage temperature of food: 5 deg C, in the dark
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Homogeneity of the dosed feed mixtures was performed with HPLC. Stability studies were performed GC/FID. The feed mixtures were found to be stable for 3 weeks when stored in the dark at 5 deg C and for 3 days when stored under animal room conditions.
Dosed feed mixtures were periodically analysed b y HPLC. All dose formulations administered were within 10% of the theoretical concentrations.
Duration of treatment / exposure:
13 weeks
Frequency of treatment:
Continuous in diet
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0, 0.62, 1.25, 2.50, 5.00 and 10.00 %
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
0, 402, 803, 1576, 3056 and 5780 mg/kg/day
Basis:
other: average of individual consumption values
No. of animals per sex per dose:
10 males / 10 females + 10 males / 10 females / group for evaluation of interim haematology and clinical chemistry parameters
Control animals:
yes, plain diet
Details on study design:
- Dose selection rationale: No data
- Rationale for animal assignment (if not random): Random
- Rationale for selecting satellite groups: Randoma
- Post-exposure recovery period in satellite groups: n/a

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes - Measured twice weekly
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Following 5 and 21 days of treatment (satellite animals) and following 13 weeks treatment
- Anaesthetic used for blood collection: Yes (identity) - carbon dioxide
- Animals fasted: No data
- How many animals: 5 males/5 females/group on Days 5 and 21, all animals at termination?
- Parameters examined: haematocrit, haemoglobin concentration, RBC count, reticulcyte count, MCV, MCHC, platelet count, white blood cell count, differential leucocyte count.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Following 5 and 21 days of treatment (satellite animals) and following 13 weeks treatment
- Anaesthetic used for blood collection: Yes (identity) - carbon dioxide
- Animals fasted: No
- How many animals: 5 males/5 females/group on Days 5 and 21, all animals at termination?
- Parameters examined: urea nitrogen, creatinine, total protein, albumin, alanine animo transferase, alkaline phosphatase, creatine kinase, sorbitol dehydrogenase, total bile acids.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

REPRODUCTIVE TOXICITY: In females, vaginal cytology was evaluated during the week preceding necropsy. For the 12 days prior to termination females were subject to vaginal lavage with saline. The aspirated cells were air-dried onto slides, stained with Toluidine Blue O and the relative abundance of leukocytes, nucleated epithelial cells, and large squamous epithelial cells were used to identify the stages of the oestrus cycle.

Sacrifice and pathology:
GROSS PATHOLOGY: Yes. The following organs were weighed - heart, right kidney, liver, lungs, testes and thymus

HISTOPATHOLOGY: Yes. Control and high-dose groups. Examination of liver from males all treatment gruops. The following were examined - adrenal glands, brain, caecum, colon, duodenum, epididymides/seminal vesicles/prostate/testes, ovaries/uterus, oesophagus, femur (including marrow), heart, ileum, jejunum, kidneys, liver, Lungs and mainstem bronchi, lymph nodes (mandibular and mesenteric), nasal cavity with turbinates, pancres, parathyroid glands, pituitary gland, preputial or clitoral glands, rectum, salivary glands, skin, spinal cord and sciatic nerve (if neurologic signs present), spleen, stomach, thymus, thyroid, trachea, urinary bladder, zymbal glands, gross abnormalities

REPRODUCTIVE TOXICITY: Sperm motility and morphology were evaluated at necropsy. The left epididymis was removed and weighed; the cauda epididymis was removed at the junction of the vas deferens and the corpus epididymis and weighed. A small cut was made in the distal cauda epididymis and the sperm that were removed from the epididymis were dispersed and the number of moving and non-moving sperm were counted in 5 fields of 30 sperm or less on each slide. After sperm sampling for motility evaluation, the cauda was placed in phosphate buffered saline and gently chopped. The solution was mixed gently and heat-fixed at 65°C. Sperm density was then determined using a haemocytometer. The left testis was frozen and stored. After thawing, testicular spermatid head count was determined by removing the tunica albuginea and homogenising the testis in phosphate buffered saline containing 10% DMSO. Homogenisation spermatid nuclei were counted using a haemocytometer.
Statistics:
Body weight and organ weight analysed by one-way ANOVA followed by Dunnett's t-test

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Slightly reduced in females at 10%
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Slightly reduced in males and females at 10%
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
Increased AP
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Liver weight increased in males at 10%
Histopathological findings: non-neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY - Exposure had no effect on survival.

BODY WEIGHT AND WEIGHT GAIN - Group mean body weights of treated rats were not significantly different from controls. In treated females, mean body weights were slightly lower than that of controls but the differences were not dose-related.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study) - No significant differences in food consumption were observed, although food consumption of male and female rats receiving diets containing 10% castor oil was slightly lower than that of controls.

HAEMATOLOGY – In males treated with 10% substance in the diet a slight decrease in MCHC was observed at Day 21 and there was a statistically significant decrease in MCV. A decreased MCH was noted in animals treated at concentrations of 5% and 10% and an increase in platelets was apparent in animals treated at concentrations of 1.25%, 5% and 10%. The only change noted in females was a statistically significant decrease in reticulocyte count at Day 5 in those animals treated with dietary concentrations of 0.62% or 10%. None of the changes were considered biologically significant

CLINICAL CHEMISTRY – An increase in the activity of serum alkaline phosphatase was observed in male and female rats at Days 5 and 21 and at study termination that was both treatment- and dose-related. Total bile acids were increased among males receiving higher dietary concentrations at Days 5 and 21 but this was no longer apparent at study termination. Other minor changes included increases in albumin observed at study termination in males receiving 5% diets and at Day 5 in females receiving 10% diets, and an increase in urea nitrogen at study termination in males that received 0.62% diets and a decrease at Day 5 in females that received 10% in the diet.

ORGAN WEIGHTS - Absolute and relative (to body weight) liver weights were increased in male rats treated with 10% concentration in the diet. Relative heart weight was increased in males receiving 0.62%, 2.5% and 10% diets. Absolute heart weights were not increased and the differences in body weight ratios were small and not considered treatment related.

HISTOPATHOLOGY: NON-NEOPLASTIC - Histopathologic examination did not reveal any treatment-related lesions in any organ or tissue. There were no morphologic changes associated with the slight differences observed in organ weights.

OTHER FINDINGS - Reproductive parameters: In males, a slight decrease in epididymal weight (6-7%) was observed in the middle- and high-dose groups, but this was not dose-related. There were no effects on any other male rat reproductive endpoint and no effects were seen on any female rat reproductive endpoint.

Effect levels

Dose descriptor:
NOAEL
Effect level:
5 780 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: clinical signs; mortality; body weight; food consumption; haematology; clinical chemistry; organ weights; histopathology

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
A 13 -week subchronic toxicity study has been undertaken on castor oil. Dietary levels of 0.00, 0.62, 1.25, 2.50, 5.00 and 10.00% (equivalent to 0, 404, 809, 1583, 3067 and 5835 mg/kg/day in males and 0, 401, 797, 1569, 3045 and 5725 mg/kg/day in females). Exposure was associated with only minimal indications of toxicity with absolute and relative liver weights increased in male rats receiving diets that contained the higher concentrations. These increases were not accompanied by corresponding histopathologic lesions or alterations in clinical chemical endpoints that would indicate hepatotoxicity. Since castor oil is composed of triacylglycerols, the increased liver weights could be a reflection of elevated metabolic activity associated with increased lipid absorption, rather than a toxic response. This conclusion is consistent with the observed increases of total bile acids in serum of male rats and of alkaline phosphatase activity in the serum of both sexes of rats. Bile acids and alkaline phosphatase (intestinal form) are both involved with intestinal absorption and metabolism of lipids, and the serum concentrations are normally increased in association with ingestion of a lipid-rich diet. Although there was some variation in epididymal weights, their small magnitude and the absence of changes in other endpoints suggested that there was little or no evidence of any reproductive toxicity associated with exposure.
Executive summary:

A 13 -week subchronic toxicity study has been undertaken on castor oil. Dietary levels of 0.00, 0.62, 1.25, 2.50, 5.00 and 10.00% (equivalent to 0, 404, 809, 1583, 3067 and 5835 mg/kg/day in males and 0, 401, 797, 1569, 3045 and 5725 mg/kg/day in females).Exposure was associated with only minimal indications of toxicity with absolute and relative liver weights increased in male rats receiving diets that contained the higher concentrations. These increases were not accompanied by corresponding histopathologic lesions or alterations in clinical chemical endpoints that would indicate hepatotoxicity. Since castor oil is composed of triacylglycerols, the increased liver weights could be a reflection of elevated metabolic activity associated with increased lipid absorption, rather than a toxic response. This conclusion is consistent with the observed increases of total bile acids in serum of male rats and of alkaline phosphatase activity in the serum of both sexes of rats. Bile acids and alkaline phosphatase (intestinal form) are both involved with intestinal absorption and metabolism of lipids, and the serum concentrations are normally increased in association with ingestion of a lipid-rich diet. Although there was some variation in epididymal weights, their small magnitude and the absence of changes in other endpoints suggested that there was little or no evidence of any reproductive toxicity associated with exposure.