Cyclohexane-1,4-dicarboxylic acid

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Cyclohexane-1,4-dicarboxylic acid

EC Number:

214-068-6

EC Name:

Cyclohexane-1,4-dicarboxylic acid

Cas Number:

1076-97-7

Molecular formula:

C8H12O4

IUPAC Name:

cyclohexane-1,4-dicarboxylic acid

Details on test material:

batch no. 75002

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

ANIMALS: Five male and five female rats (CD®(SD)BR) from Charles RiverLaboratories, Wilmington, MA, were randomly assigned to each test group and a control group. Animals were isolated for five days prior to testing. At the start of the study, rats were approximately 6 (males) and 7 (females) weeks old and weighed (mean: SO) 177 ± 3 g (males) and 143: 3 g (females). Rats were chosen for this study because they are a common representative
species for toxicity studies.
HOUSING: Rats were housed in groups of five segregated by sex. The study was conducted in the vivarium area of Building 320. The study room was maintained at 72 "F and 62-63% relative humidity. A photoperiod of 12 hours from 6 a.m. to 6 p.m. was maintained. No other study was housed in the same room as this study. Cages and racks were washed once a week. Absorbent paper under the cages was changed daily.
fEED ANP WATER: Agway Prolab Animal diet (RMH 3200), certified ground chow was fed ad libitum. Feed containers were cleaned weekly. Feed containers
were refilled at least once a week. Water was supplied ad libitum through an automatic watering system. The source of the water was the Monroe County
Water Authority. No known contaminants in feed or water were expected which would interfere with the outcome of this study.
IDENTIFICATION: All rats were identified by a uniquely numbered metal ear tag.
RANDOMIZATION: All culling and randomization was done by computer-generated lists using the Automated Animal Toxicology System.
BODY AND FEED WEIGHT DETERMINATIONS: Body weights were collected on Days O, 4, 7, 14, 18, 22, and 29. Feed consumption was determined on Days 4, 7, 10, 14, 18, 22, 25, and 29.
CLINICAL OBSERVATIONS: Each rat was removed from its cage on the mornings of body weight measurement and examined by a trained technician. Every workday afternoon and on mornings on which body weights were not collected, cageside observations were conducted. Cageside observations included, but were not limited to, examination of the hair, skin, eyes, motor activity, feces, and urine.

Administration / exposure

Route of administration:

oral: feed

Vehicle:

corn oil

Details on oral exposure:

Rats were given 0.0, 0.1, 0.3, or 1.0% of the test material, with 1.0% corn oil, in ground rodent chow, for 29 doses over 30 days. The test diets were fed seven days per week.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The purity of the test article was 99.0% when analyzed by gas chromatography with flame ionization detection. Stability of the test article in animal diets was determined by serial analysis using gas chromatography with flame ionization detection on Days 0, 3, 7, 14, 20, 27, and 36 after diet preparation. The target levels of the diets analyzed in the stability study were 0.0, 0.1, and 1.0% test article. Extraction of the test article from the diet and the carrier (corn oil) was variable resulting in fluctuations in the concentrations of test article measured in the diets. None of the fluctuations indicated that there was any significant loss of test article from the diets during storage. The concentration (mean % SD) of the test article in the 0.1% diet was 0.091 % 0.010% and in the 1.0% diets was 0.92 % 0.12%. Both levels of diet were considered stable for at least a 36-day period. The composition of the test diets fed to the rats were targeted for 0.0, 0.1, 0.3, and 1.0% test article plus 1.0% corn oil in feed. Efficacy of the diet preparation method was determined by measuring the concentrations in diet samples taken from three levels of the mixing container (top, middle, and
bottom). Analytically determined concentrations (mean% SD) of test article in the diets were 0.10 % 0.003, 0.28 % 0.02, and 1.0 % 0.1% indicating that the test article was mixed homogeneously throughout the diets. The 1.0% test diet was reanalyzed 1 week after preparation to confirm the concentration. The concentration (mean % SD) was 0.99 % 0.1%. All analysis were performed by the Chemical Quality Services Division, KP.

Duration of treatment / exposure:

Rats were given 0.0, 0.1, 0.3, or 1.0% of the test material, with 1.0% corn oil, in ground rodent chow, for 29 doses over 30 days. The test diets were fed seven days per week.

Frequency of treatment:

Rats were given 0.0, 0.1, 0.3, or 1.0% of the test material, with 1.0% corn oil, in ground rodent chow, for 29 doses over 30 days. The test diets were fed seven days per week.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1.0 %
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
0.3 %
Basis:
nominal in diet

Doses / concentrations 3

Remarks:

Doses / Concentrations:
0.1 %
Basis:
nominal in diet

Doses / concentrations 4

Remarks:

Doses / Concentrations:
0.0 %
Basis:
nominal in diet

No. of animals per sex per dose:

5

Control animals:

yes, sham-exposed

Details on study design:

IDENTIFICATION: All rats were identified by a uniquely numbered metal ear tag.
RANDOMIZATION: All culling and randomization was done by computer-generated lists using the Automated Animal Toxicology System.

Examinations

Observations and examinations performed and frequency:

BODY AND FEED WEIGHT DETERMINATIONS: Body weights were collected on Days O, 4, 7, 14, 18, 22, and 29. Feed consumption was determined on Days 4, 7, 10, 14, 18, 22, 25, and 29.

CLINICAL OBSERVATIONS: Each rat was removed from its cage on the mornings of body weight measurement and examined by a trained technician. Every workday afternoon and on mornings on which body weights were not collected, cageside observations were conducted. Cageside observations included, but were not limited to, examination of the hair, skin, eyes, motor activity, feces, and urine.

HEMATOLOGY AND CLINICAL CHEMISTRY EXAMINATIONS: At the time of necropsy, blood was collected from the posterior vena cava while the rats were under CO2 anesthesia. All assays were conducted by the Animal Clinical Analysis Group, HAEL. Hematology tests included: hemoglobin concentration,hematocrit, red blood cell count, white blood cell count, differential white blood cell count, platelet count, red blood cell indices, and examination of the blood smears for cellular morphology. Clinical chemistry tests included: aspartate aminotransferase, alanine aminotransferase, sorbitol dehydrogenase, alkaline phosphatase, creatinine, urea nitrogen, and glucose.

Sacrifice and pathology:

NECROPSY: Rats were fasted overnight, anesthetized with C02, and exsanguinated by severing the posterior vena cava after collecting blood for
analysis. Necropsies were conducted according to pathology SOP No. TP 180. The liver, kidneys, adrenal glands, testes, spleen, and thymus were weighed.Paired organs were weighed together. Organ/body weight ratios were calculated. The following organs were fixed in 10% buffered formalin:
trachea, lungs, heart, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, pancreas, liver, salivary glands, kidneys, urinary bladder, pituitary gland, adrenal glands, thyroid glands, parathyroid glands, thymus, spleen, mesenteric lymph nodes, bone marrow (femoral), brain, testes, epididymides, male accessory sex glands, ovaries, vagina, uterus, Fallopian tubes, and gross lesions. All tissues were examined microscopically from the control and high-dose groups and gross lesions were examined from other groups.

Statistics:

Mean values were calculated for body weight, feed consumption, organ weights, hematology, and clinical chemistries. All mean data, except feed consumption, were evaluated using the following computer-generated statistical tests: Bartlett's test (p < 0.01), one-way analysis of variance (ANOVA) (p < 0.05), and Duncan's multiple range test (p < 0.05) to indicate statistical significance. Feed consumption was not analyzed statistically because the animals were group housed.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not examined

Details on results:

MORTALITY: No mortality was observed during this study.

DOSE RECEIVED: The animals consumed feed containing 0.0, 0.1, 0.3, or 1.0% of the test material. The dose received was calculated from feed consumption and body weight data. The mean doses of the test article received by the males were 0, 81, 246, or 871 mg/kg/day; females received 0, 86, 259, or 894 mg/kg/day.

CLINICAL SIGNS: No clinical abnormalities were observed in the males at any dose level during the study. A single 0.1% female had malocclusion of the incisor teeth on Day 22 and porphyrin tears sporadically for the remainder of the study. Three 0.3% females had minimal to minor alopecia between Day 22 and the end of the study. No other clinical abnormalities were observed in the females. None of the clinical signs observed during the study were related to exposure to the test material.

BODY WEIGHT AND FEED CONSUMPTION: Body weight gain and feed consumption were comparable among treated and control animals for both sexes. A weighing error on Day 4 resulted in the loss of feed consumption data for the control males.

HEMATOLOGY AND CLINICAL CHEMISTRY: Hematology and clinical chemistry determinations for the treated animals of both sexes were comparable to the controls.

ORGAN WEIGHTS: Absolute and relative kidney, liver, thymus, spleen, adrenal gland, and testes weights were comparable among treated and control animals for both sexes.

PATHOLOGY: No compound-related lesions were identified at gross necropsy or on histological examination of tissues.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

>= 871 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

2

Dose descriptor:

NOEL

Effect level:

>= 894 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The test compound did not produce mortality or adverse clinical signs at any dose level. No changes in body weight gain, feed consumption, hematology, serum clinical chemistries, or organ weights were observed. No morphological changes in organs and tissues were noted for either sex at any dose level. A site of toxic action was not identified. The no-observed-effect-level was 871 mg/kg/day for the males and 894 mg/kg/day for the females.

Executive summary:

The subacute effects of 1,4 -cyclohexanedicarboxylic acid (CHDA) were evaluated in rats that were given diet containing the material for four weeks. Diets were prepared to contain 1.0% corn oil and either 0.0, 0.1, 0.3, or 1.0% of CHDA, and the test diets were fed seven days per week to male and female rats (n=5/sex/group) that were group-housed. At the end of a 4-week feeding period, rats were anesthetized with CO₂ inhalation and exsanguinated. Blood was collected for hematology and clinical chemistry assessments and organs were collected, weighed, and processed for histopathological evaluations. Mean values were calculated for body weight, feed consumption, organ weights, hematology, and clinical chemistries. All mean data were evaluated using Bartlett's test (p < 0.01), a one-way ANOVA (p< 0.05), or duncan's multiple range test (p<0.05), to indicate statistical significance. Data indicate that treatment with CHDA did not produce mortality or adverse clinical signs at any dose level, and no changes in body weight gain, feed consumption, hematology, serum clinical chemistries, or organ weights were observed. The no-observed-effect-level (NOEL) for male and female rats was determined to be 871 and 894 mg/kg/day, respectively.