5,7-dichloro-4-(4-fluorophenoxy)quinoline;quinoxyfen (ISO)

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Reference 2

Reference Type:

other: Supplemental report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 82-1 (90-Day Oral Toxicity)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EEC Directive 87/302 EEC: Subchronic Oral Toxicity

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: MAFF Subchronic Study Guidelines

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

Cas Number:

124495-18-7

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Test substance: XR-795
Test substance ID: TSN100010
Purity: 98.7%

Test animals

Species:

mouse

Strain:

CD-1

Details on species / strain selection:

This strain of mouse was selected because of its general acceptance and suitability for toxicity testing, the availability of historical background data, and the reliability of the commercial supplier.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratory, Kingston, New York
- Age at study initiation: 8 weeks
- Weight at study initiation: Male: 25.8 to 28.2 grams; Female: 21.7 to 22.1 grams
- Housing: Animals were housed 2- 3/cage prior to randomization and allocation to test groups and 1/cage thereafter. Cages were of stainless steel construction with wire mesh floors and each contained a feed crock and pressure-activated water nipple
- Diet: Purina Certified Rodent Chow #5002, ad libitum
- Water: Tap water, ad libitum
- Acclimation period: Atleast 7 days

DETAILS OF FOOD AND WATER QUALITY: The feed was certified by the manufacturer to contain no more than specified maximum concentrations of certain heavy metals, chlorinated hydrocarbons, PCBs, aflatoxin, and organophosphates, and to have been manufactured in a plant in which the use of antibiotics and synthetic estrogens is prohibited. in which the use of antibiotics and synthetic estrogens is prohibited. Analyses of Purina Certified Rodent Chow #5002 feed revealed no contaminants which may have interfered with the results of this study.

ENVIRONMENTAL CONDITIONS
- Temperature: Approximately 72°F
- Air changes (per hr): 13
- Photoperiod (hrs dark / hrs light): 12

Administration / exposure

Route of administration:

oral: feed

Details on route of administration:

The probable routes of human exposure to test substance are via ingestion of foodstuffs that might contain low residues of the test material or from accidental ingestion or dermal contact during manufacture or use. Thus, formulation with feed was the desired method of delivery to assess the potential systemic toxicity of the test material following oral administration

Vehicle:

other: Feed

Details on oral exposure:

DIET PREPARATION
Diets and premixes were prepared weekly by serially diluting a concentrated test substance-feed mixture (premix). These dilutions were made by following computer-generated diet mixing instructions, with the concentrations of test substance in the diets based on group mean body weights and feed consumption. Initial concentrations of test material in the feed were calculated from pretest body weights and feed consumption data targeted on the desired dose levels on a mg/kg bw/day basis. Thereafter, the most recent body weight and feed consumption data were used to adjust the concentration of the test substance in the feed to maintain those targeted dose levels. Test substance concentrations in the feed were adjusted weekly to maintain the targeted exposure levels.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Data generated from the analyses indicated that appropriate concentrations of test substance were maintained such as to closely approximate the targeted dose levels

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

10 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

50 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

500 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: The high dose of 500 mg/kg bw/day was selected based upon the results of the previous 2-week study. Body weight and body weight gain reductions as well as varying degrees of hepatotoxicity were expected at this dose level. The intermediate dosages of 100 and 50 mg/kg bw/day were selected to demonstrate a pattern of dose response, while the low dosage of 10 mg/kg bw/day was expected to establish a no-observed-effect level for test substance.
- Rationale for animal assignment: Prior to the start of the study, the animals were weighed and randomly allocated to study groups using a computerized, weight-stratification and random-number based procedure.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS:
- Time schedule: All animals were observed cageside at least once daily during the workweek. These observations included evaluation of the skin, fur, mucous membranes, respiration, nervous system, and behavior patterns. Observations on weekends and holidays were limited to a check of all cages for dead animals and the availability of feed and water.

DETAILED CLINICAL OBSERVATIONS:
- Time schedule: Prior to the start of the study and weekly thereafter through the duration of the study

BODY WEIGHT:
- Time schedule for examinations: Prestudy period and weekly during the dosing period

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
- 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: Yes

OPHTHALMOSCOPIC EXAMINATION: Ophthalmological examinations were conducted on all animals during their scheduled necropsy

HAEMATOLOGY:
- Time schedule for collection of blood: At the time of necropsy, blood specimens were taken by orbital eye puncture from anesthetized animals for hematology determinations.
- Anaesthetic used for blood collection: Methoxyflurane
- Hematologic values which were measured were packed cell volume, hemoglobin concentration, red and white blood cell counts, and platelet counts using an ELT-IS Hematology Analyzer. Complete blood smear examinations were conducted which included differential leukocyte counts and an assessment of erythrocyte, leukocyte, and platelet morphology. Any morphologic abnormalities observed were reported.

CLINICAL CHEMISTRY:
- Time schedule for collection of blood: At the time of necropsy, blood specimens were taken by orbital eye puncture from anesthetized animals for clinical chemistry determinations.
- Clinical chemistry/electrolyte determinations which were measured are alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, creatinine, total bilirubin, glucose, total protein, calcium, phosphorus, chloride, sodium, potassium, and albumin using a Spectrum Analyzer. The globulin concentrations were calculated from the total protein and albumin values.

Sacrifice and pathology:

GROSS PATHOLOGY: A complete gross necropsy was performed by a veterinary pathologist. Weights of the brain, heart, liver, kidneys, adrenal glands, and testes were recorded and the organ weight to final body weight ratios calculated for all animals. Lungs were distended to an approximately normal inspiratory volume with neutral, phosphatebuffered 10% formalin solution by tracheal instillation using a handoperated syringe.

HISTOPATHOLOGY: The tissues examined for histopathology are adrenal glands, aorta, bone, bone marrow, brain, cecum, cervix, coagulating gland, colon, duodenum, epididymides, esophagus, eyes & optic nerve, gall bladder, heart, ileum, jejunum, kidneys, lacrimal glands, larynx, liver, lungs, mammary glands, mediastinal lymph node, mediastinal tissue, nasal tissue, oral tissue, ovaries, oviducts, pancreas, parathyroid glands, peripheral nerve, pituitary gland, prostate, rectum, salivary glands, seminal vesicles, skeletal muscle, skin and subcutis, spinal cord-cervical, spinal cord-thoracic, spinal cord-lumbar, spleen, stomach, testes, thymus, thyroid gland, tongue, trachea, urinary bladder, uterus and vagina.

Statistics:

Hematology (excluding differential counts), electrolytes, clinical chemistry data, body weights, and absolute (grams) and relative (g to 100 g terminal body weight) organ weights were evaluated by Bartlett's test for equality of variances. Based on the outcome of Bartlett's test, exploratory data analysis was performed by a parametric or non-parametric analysis of variance (ANOVA), followed, if appropriate, by Dunnett's test or Wilcoxon rank-sum test with Bonferroni's correction for multiple comparisons. Statistical outliers were identified by a sequential test described by Grubbs (1969). Feed consumption data, which was used in the computation of desired test material concentrations and shown in this final report, was not analyzed for differences of statistical significance. Descriptive statistics were performed on feed efficiency and white blood cell differential data.
Differences found to be statistically significant were not necessarily accepted as toxicologically significant, i.e., final interpretation of the numerical data did consider the statistical outcomes together with other factors, such as dose-response relationships, biologic plausibility, and pathological observations.

Results and discussion

Results of examinations

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No clinical observations related to test substance administration were present for any animal. Several random instances of skin ulceration were observed during the course of the study but posed no serious health problems.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Mean body weight values for male and female mice revealed no changes that were interpreted as a result of test substance toxicity. The mean body weights in male mice administered 500 mg/kg bw/day were slightly lower than controls throughout the study. Statistically lower mean body weights were evident in male mice administered 10 mg/kg bw/day. However, due to the lack of a dose response relationship, these differences were considered to be incidental and unrelated to compound administration. The mean body weights for female mice were unaffected at all dose levels.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

effects observed, non-treatment-related

Description (incidence and severity):

There were no discernible differences in feed efficiency values for any of the male or female treatment groups, when compared to corresponding control groups. There was a high degree of variability associated with the feed efficiency data generated during this study and no dose response relationships were evident. Intervals of negative weight gain with resulting negative feed efficiency values, were excluded from analysis.

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

In both male and female mice, after 13 weeks of dietary exposure to test substance, no statistically significant differences were observed for any hematology or leukocyte parameters measured at any dose level. Slightly lower erythrocyte (RBC), hemoglobin (HGB), and hematocrit (PVC) values were seen in both male and female treatment groups and slightly higher white blood cell counts (WBC) were seen in male treatment groups. However, all of these differences were judged to be within normal limits for CD-1 mice of this age and of no biological significance. All other parameters were judged unchanged and normal.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

Several parameters demonstrated statistical significance even though no toxicological significance was indicated. Parameters shown to be statistically different from control in male mice were lower albumin (ALB), 10, 50, and 100 mg/kg bw/day groups; lower total protein (TPRO), 50 mg/kg bw/day group; and lower calcium (CA), 50 mg/kg bw/day group. None of these differences reflect any definite response to test susbtance administration as affected values were random with no dose response relationships evident.
In female animals, the only parameter which was statistically different from controls was lower albumin (ALB) in the 100 and 500 mg/kg bw/day groups, however these differences were minor. Examination of individual animal data showed albumin concentrations for animals in the 100 and 500 mg/kgbw/day dose levels identical with those reported for control animals. Therefore, the lower albumin mean values reported for these dose groups were interpreted as incidental and random, rather than treatment related.

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

In male mice, organ weight values shown to be statistically different from controls were lower absolute heart weight in 10 mg/kg bw/day group, lower absolute kidney weights in 10 and 50 mg/kg bw/day groups, lower relative kidney weight in 50 mg/kg bw/day group, lower absolute liver weights in 10 and 50 mg/kg bw/day groups and higher relative liver weight in 500 mg/kg bw/day group. All of these differences except for the higher relative liver weight in the 500 mg/kg bw/day dose group, were judged to be reflections of lower terminal body weights in these groups, rather than toxic effects. The statistically higher relative liver weight in the male 500 mg/kg bw/day dose group coupled with a lower terminal body weight compared to controls, was judged to be a definite toxic effect of test substance administration in these animals. This conclusion is further supported by hepatic alterations seen histologically in this dose group.
In female mice, the only organ weight data demonstrating statistical significance are absolute and relative liver weights in the 500 mg/kg bw/day dose group. Although the terminal body weight for this group was slightly higher than controls, the differences between the absolute and relative mean liver weight values of the high dose females and controls is substantial and, as in male mice, was judged to represent a toxic response to test material ingestion. Histologic alterations seen in the livers of high dose female mice further supported this conclusion.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No gross lesions attributable to dietary administration of test susbtance were observed at any dose level. The splenomegaly seen in several mice was associated with dermal inflammatory lesions in these animals. These dermal lesions were considered to be secondary to localized skin reactions caused by ear tags in some of these animals.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Treatment-associated tissue alterations were confined to the liver of mice administered 500 mg/kg bw/day. These consisted of slight or moderate hypertrophy of centrilobular and midzonal hepatocytes. Additionally, 3 of 10 males and 4 of 10 females demonstrated minimal individual cell necrosis of hepatocytes. Dermal inflammatory lesions noted grossly were characterized by chronic inflammatory changes and ulcerative necrosis of the affected tissues. In one high dose level female mouse this was also accompanied by reactive lymphoid hyperplasia of the cervical lymph node. Splenomegaly was characterized by extramedullary hematopoiesis secondary to the dermal inflammatory changes.

Effect levels

Key result

Dose descriptor:

NOEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

organ weights and organ / body weight ratios

Target system / organ toxicity

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

500 mg/kg bw/day (nominal)

System:

hepatobiliary

Organ:

liver

Treatment related:

yes

Applicant's summary and conclusion

Conclusions:

NOEL (Mice) (Male/Female): 100 mg/kg bw/day

Executive summary:

The test was conducted according to guideline OECD 408 to evaluate 13-week dietary toxicity of test substance in mice. Ten male and ten female CD-1 mice were administered test substance, in their feed at concentrations of 0 (control), 10, 50, 100, or 500 mg/kg bw/day for 13 weeks. Parameters measured included: clinical observations, feed consumption, feed efficiency, body weight, hematology, clinical chemistries and electrolytes, organ weights, and gross and histopathologic evaluation of tissues.

The only toxic effects following administration of test substance for 13 weeks at the prescribed dosages were seen in male and female mice in the 500 mg/kg bw/day dose group. These effects were limited to the liver and consisted of organ weight changes and histologic alterations. Both absolute and relative liver weights in male and female 500 mg/kg bw/day mice were greater than controls. Histologic alterations observed in animals administered 500 mg/kg bw/day consisted of slight to moderate hypertrophy of centrilobular and midzonal hepatocytes and minimal individual cell necrosis. All other parameters measured: feed consumption, feed efficiency, body weight, hematology, clinical chemistries and electrolytes revealed no changes suggestive of test substance toxicity.

Animals in the other dose groups, 10, 50 and 100 mg/kg bw/day, were judged to have been unaffected by 13 weeks of test substance administration. Based on the data generated in this study, the no-observed-effect-level (NOEL) was 100 mg/kg bw/day in male and female CD-1 mice.