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

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

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 Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3200 (Repeated Dose Dermal Toxicity -21/28 Days)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.9 (Repeated Dose (28 Days) Toxicity (Dermal))

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Requirements for Safety Evaluation of Agricultural Chemicals, JMAFF

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:

- Substance ID: TSN 100097
- Name of substance: XDE-795
- Lot number: DECO-97-152-1
- Purity: 97.4%

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Inc., Raleigh, North Carolina
- Age at study initiation: 8 weeks old
- Weight at study initiation: Males: 171.0-179.3 g; Females: 115.6-118.1 g
- Housing: One animal per cage
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 15 days

DETAILS OF FOOD AND WATER QUALITY: Analysis of the feed was performed to confirm the diet provided adequate nutrition and to quantify the levels of selected contaminants. Drinking water obtained from the municipal water source was periodically analyzed for chemical parameters and biological contaminants by the municipal water department. In addition, specific analyses for chemical contaminants were conducted at periodic intervals by an independent testing facility.

ENVIRONMENTAL CONDITIONS
- Temperature: 21.9-22.2°C
- Humidity: 48.7-60%
- Air changes: Approximately 12-15 times per hr
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

methylcellulose

Details on exposure:

TEST SITE
- Area of exposure: Back of each animal starting at the scapulae (shoulders) to the wing of the ileum (hip bone) and half way down the flank on each side
- % coverage: 10
- Type of wrap if used: Absorbent gauze pad and non-absorbent cotton and wrapped with elastic bandage
- Time intervals for shavings or clipplings: 24 hours prior to initiation of dosing

REMOVAL OF TEST SUBSTANCE
- Washing: Application site was wiped with a water-dampened towel
- Time after start of exposure: 6 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 4 mL/kg
- Constant volume or concentration used: Yes

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Concentration verification: Concentration analyses of all dose levels were conducted at the study start and during week 2 of the study. The test substance in 0.5% methylcellulose was analyzed using HPLC with ultraviolet detection and external standards.
Homogeneity: Homogeneity of the low- and high-dose suspensions was determined prior to the start of the study.
Stability: The stability of test substance in 0.5% methylcellulose was established prior to the study start by reanalyzing the low- and high-dose concentrations 12 days after the initial concentration verification.

Duration of treatment / exposure:

6 hrs per day for 4 weeks

Frequency of treatment:

5 days per week

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

10 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The high-dose level of 1000 mg/kg/day represents the limit test as specified by several governmental guidelines. The mid- and low-dose levels were expected to provide dose response data for any treatment-related effect(s) observed in the high-dose group. The low-dose was also expected to ensure definition of a no-observed-effect level (NOEL).
- Rationale for animal assignment: Animals were stratified by body weight and then randomly assigned to treatment groups using a computer program

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS
- Time schedule: Twice each day

DETAILED CLINICAL OBSERVATIONS
- Time schedule: Pre-exposure and weekly throughout the study

DERMAL IRRITATION
- Time schedule for examinations: The dermal test site was subjectively evaluated when wraps were removed on the last day of a dosing week and on the afternoon prior to necropsy

BODY WEIGHT
- Time schedule for examinations: Pre-exposure and weekly throughout the study

FOOD CONSUMPTION
- Time schedule for examinations: Pre-exposure and weekly throughout the study
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

OPHTHALMOSCOPIC EXAMINATION
- Time schedule for examinations: Prior to the study start and prior to termination
- Dose groups that were examined: All treatment groups and control group

HAEMATOLOGY
- Time schedule for collection of blood: At the scheduled necropsy
- Anaesthetic used for blood collection: Yes (carbon dioxide)
- Animals fasted: Yes

CLINICAL CHEMISTRY
- Time schedule for collection of blood: At the scheduled necropsy
- Animals fasted: Yes

URINALYSIS
- Time schedule for collection of urine: During the week prior to necropsy
- Metabolism cages used for collection of urine: Yes
- Animals fasted: No

Sacrifice and pathology:

GROSS PATHOLOGY: Fasted rodents submitted alive for necropsy were anesthetized by the inhalation of carbon dioxide (CO2) vapors, weighed, and blood samples were obtained from the orbital sinus. Their tracheas were exposed and clamped, and the animals were euthanized by decapitation. The necropsy included an examination of the external tissues and all orifices. The head was removed, the cranial cavity opened and the brain, pituitary and adjacent cervical tissues were examined. The eyes were examined in situ by application of a moistened glass slide to each cornea. The nasal cavity was flushed via the nasopharyngeal duct and the lungs were distended to an approximately normal inspiratory volume with neutral, phosphate-buffered 10% formalin using a hand-held syringe and blunt needle. The skin was reflected from the carcass, the thoracic and abdominal cavities were opened and the viscera examined. All visceral tissues were dissected from the carcass, re-examined and selected tissues were incised. The brain, liver, kidneys, heart, adrenals, testes, epididymides, uterus, ovaries, thymus and spleen were trimmed and weighed immediately. The ratios of organ weight to terminal body weight were calculated.

HISTOPATHOLOGY: Representative samples of tissues were collected and preserved in neutral, phosphate-buffered 10% formalin. Transponders were removed and placed in jars with the tissues. The number of sections from all preserved tissues were processed by standard histologic procedures from control and high-dose group animals. The following tissues from the remaining groups were processed and histopathologically examined: liver, kidneys, lungs, dermal test site, and skin adjacent to the dermal test site.

Statistics:

Means and standard deviations were calculated for all continuous data. Body weights, feed consumption, organ weights, urine volume, urine specific gravity, clinical chemistry data, and appropriate hematologic data were evaluated by Bartlett's test (alpha=0.01) for equality of variances. Based on the outcome of Bartlett's test, exploratory data analysis was performed by a parametric (alpha=0.05) or nonparametric (alpha=0.05) analysis of variance (ANOVA) and if significant, followed respectively by Dunnett's test (alpha=0.05) or the Wilcoxon Rank-Sum test (alpha=0.05) with a Bonferroni correction for multiple comparisons to the control. The experiment-wise alpha level was reported for these two tests. Detailed clinical observations incidence scores were statistically analyzed by a z-test of proportions comparing each treated group to the control group (alpha=0.05). The data were analyzed separately for each time point. Descriptive statistics only (means and standard deviations) were reported for body weight gains, RBC indices, and white blood cell differential counts. Statistical outliers were identified by a sequential test (alpha=0.02) but routinely excluded only from feed consumption statistics. Outliers may have been excluded from other analyses only for documented, scientifically sound reasons.
Because numerous measurements were statistically compared in the same group of animals, the overall false positive rate (Type I errors) was greater than the nominal alpha levels. Therefore, the final interpretation of the data considered statistical analyses along with other factors, such as dose-response relationships and whether the results were consistent with other biological and pathological findings and historical control values.

Results and discussion

Results of examinations

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Weekly examinations revealed infrequent occurrences of lacrimation, and soiling (periocular, perineal, and perinasal). Since these observations did not occur in a dose-responsive manner, and are typical reactions to the semi-occlusive bandaging process, they were interpreted to not be treatment related.

Dermal irritation:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Ophthalmological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Examinations performed on all animals pre-exposure revealed a few animals with cloudy corneas, while examinations performed during Week 3 of the study revealed an increased incidence of cloudy corneas. The distribution of cloudy cornea observations occurred across all dose levels, included both sexes, and did not occur in a dose-responsive manner, and therefore was interpreted not to be treatment related. Additionally, during the Week 3 examination, pale fundus was observed in a few animals from both sexes. However, this observation did not occur in a dose-responsive manner and therefore, was also interpreted to not be treatment-related.

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

There were no treatment-related changes in absolute or relative organ weights in any dose group. Relative testes weight means for males given 100 mg/kg/day were slightly higher than the control values and statistically identified. Although the group mean relative testes weight of 1.435 g/100 was heavier than the control mean of 1.330 g/100, it was also heavier than the high-dose group mean of 1.391 g/100. Additionally, both the absolute and relative testes weights for males given 100 mg/kg/day were within test facility’s historical control range. Therefore, due to the lack of a dose-responsive manner the increase in relative testes weight for males given 100 mg/kg/day was interpreted not to be treatment-related.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were no treatment-related gross pathologic observations. All gross pathologic observations were considered unassociated with exposure to treatment.

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

There were no treatment-related microscopic changes due to exposure to the test substance in any of the tissues examined. The observations present were considered to be spontaneous alterations, unassociated with exposure to treatment.

Effect levels

Key result

Dose descriptor:

NOEL

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: There were no treatment-related effects on any of the measured parameters

Remarks on result:

other: highest dose tested

Target system / organ toxicity

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

NOEL (Rat): 1000 mg/kg bw/day (highest dose tested)

Executive summary:

The study was conducted following OECD guideline 410 and US EPA guideline 870.3200. Four groups of 10 Fischer 344 rats/sex/dose were dermally exposed at a semi-occluded test site to 0, 10, 100, or 1000 mg/kg bw/day 6hr/day, 5 days/week for 4 weeks to evaluate the potential for systemic toxicity. Daily cage-side, body weight, feed consumption, detailed clinical observation, dermal observation, ophthalmologic examination, hematology, clinical chemistry, urinalysis and organ weight data were evaluated. In addition, complete gross and histopathologic examinations were conducted.

There were no treatment-related effects on any of the measured parameters. The no-observed-effect level (NOEL) for Fischer 344 rats following dermal exposure to test substance for 4 weeks was 1000 mg/kg/day.