benzovindiflupyr (ISO); N-[9-(dichloromethylene)-1,2,3,4-tetrahydro-1,4-methanonaphthalen-5-yl]-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 February 2008 to 27 March 2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, near guideline study, available as unpublished report, minor restrictions in design and/or reporting but otherwise adequate for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

This study was conducted in a facility operating to GLP within the UK national GLP monitoring programme, however, at the request of the study sponsor, this study was not inspected nor the report audited.

Principles of method if other than guideline:

SYN545192 administered continuously by dietary admixture to 3 groups, each of 5 male and 5 female Wistar HanTM: HsdRccHanTM: WIST strain rats, for 28 days, at concentrations of 100, 400 and 1200 ppm (equivalent to a mean achieved dosage of 9, 36 and 99 mg/kg/day). A control group of 5 males and 5 females were treated with basal laboratory diet alone. Clinical signs, functional observations, body weight development and food and water consumption were monitored during the study. Haematology and blood chemistry were evaluated for all animals at the end of the study. All animals were subjected to gross necropsy examination, organ weight measurements and histopathological evaluation of selected tissues was performed.

GLP compliance:

no

Remarks:

This study was conducted in a facility operating to Good Laboratory Practice (GlP) within the national GLP monitoring programme

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N-[11-(dichloromethylidene)tricyclo[6.2.1.0²,⁷]undeca-2,4,6-trien-3-yl]-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

EC Number:

691-719-4

Cas Number:

1072957-71-1

Molecular formula:

C18H15Cl2F2N3O

IUPAC Name:

N-[11-(dichloromethylidene)tricyclo[6.2.1.0²,⁷]undeca-2,4,6-trien-3-yl]-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

Details on test material:

- Name of test material (as cited in study report): SYN545192
- Subtance type: Technical material
- Physical state: White powder
- Expiration date of the lot/batch: Not reported
- Storage condition of test material: Ambient conditions in the dark

Test animals

Species:

rat

Strain:

other: Wistar HanTM: HsdRccHanTM: WIST

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Approximately 13 weeks
- Weight at study initiation: Males 175-198 g; females 131-158 g
- Fasting period before study: None
- Housing: 5 same sex/cage in solid floor polypropylene cages with stainless steel mesh lids
- Diet: SQC Rat and Mouse Ground Diet No.1 ad libitum
- Water: Mains drinking water ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature: 21±2ºC
- Humidity: 55±15%
- Air changes: At least 15/hour
- Photoperiod: 12 hours light / 12 hours dark

IN-LIFE DATES: From: 28 February 2008 To: 27 March 2008

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: SQC Rat and Mouse Ground Diet No.1

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): Single preparation made
- Mixing appropriate amounts with (Type of food): The test material was prepared at the appropriate concentrations as a dietary admixture in SQC Rat and Mouse Ground Diet No.1
- Storage temperature of food: -20ºC (in the dark)

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

Continuous in the diet

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 400, 1200 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

5

Control animals:

yes, plain diet

Examinations

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS: Yes
- Time schedule: Once daily (overt signs of toxicity, ill-health or behavioural change)

BODY WEIGHT: Yes
- Time schedule: Twice weekly throughout the acclimatisation period, daily during week 1 of treatment and then twice weekly for the duration of the study and at terminal kill

FOOD CONSUMPTION, EFFICIENCY AND COMPOUND INTAKE (if feeding study):
- Time schedule: Twice weekly throughout the acclimatisation period, daily during week 1 of treatment and then twice weekly for the duration of the 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

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule: Daily (by visual inspection of the water bottles for any overt changes)

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Day 29
- Anaesthetic used for blood collection: No data
- Animals fasted: No
- How many animals: All
- Parameters examined: Haemoglobin, mean cell haemoglobin concentration, haematocrit, platelet count, red blood cell count, total white cell count, mean cell volume, differential white cell count, mean cell haemoglobin, blood cell morphology, prothrombin time, activated partial thromboplastin time.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Day 29
- Animals fasted: No
- How many animals: All
- Parameters examined: Urea, alkaline phosphatase activity, creatinine, aspartate aminotransferase activity, glucose, alanine aminotransferase activity, albumin, gamma-glutamyl transferase activity, total protein, calcium, total cholesterol, inorganic phosphorus, triglycerides, sodium, total bilirubin,potassium,albumin/globulin ratio, chloride.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: Day 27
- Dose groups that were examined: All
- Battery of functions tested: sensory activity / grip strength / motor activity

Sacrifice and pathology:

ORGAN WEIGHTS: Yes (all animals)
- Organs weighed: Adrenal glands, ovaries, brain, spleen, epididymides, testes, heart, thymus, kidneys, uterus (with cervix), liver, macroscopic abnormalities
GROSS PATHOLOGY: Yes (all animals)
HISTOPATHOLOGY: Yes (liver and kidney from all groups, remaining tissues from controls and 1200 ppm groups only)
-Tissues examined: adrenal gland, nerve - sciatic, ovary, bone and bone marrow (sternum), parathyroid gland, brain (cerebrum, cerebellum and pons), caecum, prostate gland, colon, rectum, duodenum, epididymis, seminal vesicle, spinal cord (cervical, mid-thoracic, lumbar), heart, ileum (including peyer’s patches), spleen, jejunum, stomach, kidney, testis, liver, thymus, lung (with bronchi), thyroid gland, lymph node - cervical, trachea, lymph node - mesenteric, urinary bladder, uterus

Statistics:

Data were processed to give group mean values and standard deviations where appropriate. Haematological, blood chemical, organ weight (absolute and relative to terminal body weight), weekly body weight gain and quantitative functional performance and sensory reactivity data were assessed for dose response relationships by linear regression analysis, followed by one way analysis of variance (ANOVA) incorporating Levene’s test for homogeneity of variance. Where variances were shown to be homogenous, pairwise comparisons were conducted using Dunnett’s test. Where Levene’s test showed unequal variances the data were analysed using non-parametric methods: Kruskal-Wallis ANOVA and Mann-Whitney ‘U’ test. (The haematology variable basophils was not analysed since consistently greater than 30% of the data were recorded as the same value).

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

effects observed, treatment-related

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

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

BODY WEIGHT AND WEIGHT GAIN: Both males and females treated with 1200 ppm showed a reduction in body weight and body weight gain compared to control throughout the treatment period. There were no effects on body weight in animals treated with 100 and 400 ppm. Occasional, statistically significant differences in body weight gain were small, isolated and showed no dose response relationship and are therefore considered not to be treatment related.

FOOD CONSUMPTION, EFFICIENCY AND COMPOUND INTAKE: All animals treated with 1200 ppm showed a reduction in food intake during week 1 with the reduction extending throughout the treatment period in females at 1200 ppm. Furthermore, animals of both sexes treated with 1200 ppm showed a reduction in food efficiency throughout the treatment period compared to the controls. No effect on food intake or food efficiency was evident for animals treated with 400 or 100 ppm. Dose rates (based on nominal dietary levels of SYN545192) were calculated in terms of mg SYN545192/kg body weight. Mean values are 9, 36 and 99 mg/kg/day for 100, 400 and 12000 ppm respectively.

CLINICAL CHEMISTRY: A statistically significant (p<0.05) reduction in plasma total protein levels and albumin levels was evident in all treated females. In addition, females treated with 1200 ppm displayed a slight but statistically significant (p<0.05) increase in plasma aspartate aminotransferase activity. A slight but statistically significant (p<0.05) reduction in plasma glucose levels was observed in males at 1200 ppm.

There were a number of statistically significant changes in plasma electrolyte levels in both sexes. However, the majority of the individual values were within normal ranges and in the absence of a convincing effect on electrolyte balance or any indication of a dose-related response, the intergroup differences were considered not to be treatment related.

FUNCTIONAL OBSERVATIONS: Females treated at 400 ppm showed a small statistically significant (p<0.05) increase in group mean forelimb grip strength, in comparison to controls. This was confined to one out of three tests performed and in the absence of a dose-related response was considered incidental to treatment. Females from all treatment groups showed a statistically significant increase in overall mobility (p<0.05). The observed differences from control were small, not accompanied by any other related clinical symptoms and in the absence of any dose response relationship are considered to be incidental to treatment. There were no statistically significant changes in functional performance parameters measured for males.

Females treated with 1200 ppm showed a statistically significant (p<0.01) increase in landing foot splay measurements which may have been a consequence of the decrease in mean body weight of these animals. There were no statistically significant changes in sensory reactivity assessments for males.

ORGAN WEIGHTS: A statistically significant increase in absolute and relative liver (p<0.01) and heart (p<0.05) weights was observed in males at 1200 ppm. No such effect was observed for females treated with 1200 ppm or for any animals treated at 100 and 400 ppm.

HISTOPATHOLOGY: In the kidney, minimal tubular basophilia was evident in males treated with 100 (4/5) and 400 ppm (2/5). However given the absence of this change in the high dose group males, the lack of dose response at 100 and 400 ppm and the presence of a single incidence of this finding in control males, this finding is considered to be incidental to treatment. An increased incidence of minimal tubular basophilia was also observed in the treated female groups compared to controls with an apparent dose response. Given the observation of a single incidence of this finding in control males, the single incidence observed in 100 ppm females is considered unrelated to treatment.

In the liver, minimal centrilobular hepatocyte hypertrophy was observed in the 400 and 1200 ppm males. No such effect was detected in for males treated with 100 ppm or female treated animals.

All other recorded histopathological changes were typical of the spontaneously arising background findings recorded in rats of this strain and age and were considered not to be treatment related.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

2

Dose descriptor:

NOEL

Effect level:

9 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1: Intergroup comparison of body weight gain (g) - selected timepoints

	Dietary Concentration of SYN545192 (ppm)
	Males				Females
days	0	100	400	1200	0	100	400	1200
1-2	6.2	5.8	5.8	-1.6**	1.4	0.8	-0.4	-4.4**
3-4	3.6	5.6*	5.4*	5.8*	1.0	1.0	2.4	1.6
7-8	7.2	6.6	3.8*	5.0*	1.8	2.8	0.4	-0.6
19-22	14.0	9.8	12.4	10.6	5.8	5.4	4.2	1.6
1-29	127.4	114.6	116.6	93.2	43.0	42.6	36.0	20.0
* Statistically significant difference from control group mean, p<0.05 ** Statistically significant difference from control group mean, p<0.01

 

Table 2: Intergroup comparison of food consumption (g/rat/day) - selected timepoints

	Dietary Concentration of SYN545192 (ppm)
	Males				Females
days	0	100	400	12000	0	100	400	12000
1-2	19.2	19.8	18.6	11.0	14.2	13.2	10.8	4.4
4-5	21.0	22.0	19.8	19.6	16.8	15.6	14.2	10.4
8-12	22.3	22.3	21.7	21.4	14.8	14.6	14.8	13.5
19-22	23.3	21.7	21.7	22.2	16.9	15.2	15.4	12.1
26-29	22.6	22.2	22.4	21.4	15.4	14.0	15.7	11.2

 

Table 3: Intergroup comparison of food efficiency (g) - selected timepoints

	Dietary Concentration of SYN545192 (ppm)
	Males				Females
days	0	100	400	12000	0	100	400	12000
1-2	32.3	29.3	31.2	-14.6	9.9	4.5	-3.7	-100.0
4-5	33.3	31.8	29.3	33.7	23.8	25.6	19.7	5.7
8-12	21.3	21.1	20.7	18.2	10.5	13.4	14.2	15.9
19-22	20.1	15.0	19.0	15.9	11.5	11.9	9.1	4.4
26-29	15.3	8.7	14.0	11.8	6.9	7.6	3.0	3.0

 

Table 4: Intergroup comparison of selected clinical chemistry parameters

	Dietary Concentration of SYN545192 (ppm)
	Males				Females
Parameter	0	100	400	12000	0	100	400	12000
Total protein	5.674	6.044	5.922	5.842	6.678	6.132**	6.286**	6.202**
Albumin	3.556	3.684	3.614	3.612	4.340	4.048*	4.082*	3.996**
AST	60.00	59.60	58.40	67.60	53.80	56.60	67.80	81.00*
Glucose	163.8	159.4	168.0	138.6*	198.0	162.4	155.0	153.4
* Statistically significant difference from control group mean, p<0.05 ** Statistically significant difference from control group mean, p<0.01

 

Table 5: Intergroup comparison of selected organ weights

		Dietary Concentration of SYN545192 (ppm)
		Males				Females
Organ		0	100	400	12000	0	100	400	12000
Liver	absolute (g)	11.0220	10.6768	10.9509	11.3377**	6.10612	5.99588	6.19758	6.15786
	relative (%)	3.474	3.532	3.607	4.047**	3.310	3.187	3.502	3.782
Heart	absolute (g)	0.89236	0.92384	0.90958	0.91720*	0.60294	0.60874	0.62228	0.53946
	relative (%)	0.282	0.306	0.299	0.328*	0.326	0.325	0.353	0.331
* Statistically significant difference from control group mean, p<0.05 ** Statistically significant difference from control group mean, p<0.01

 

Table 6: Intergroup comparison of selected histopathological findings

	Dietary Concentration of SYN545192 (ppm)
	Males				Females
Organ	0	100	400	12000	0	100	400	12000
Number examined	5	5	5	5	5	5	5	5
Kidney
tubular basophilia (minimal)	1	4	2	0	0	1	2	3
Liver
centrilobular hepatocyte hypertrophy (minimal)	0	0	2	5	0	0	0	0

 

Applicant's summary and conclusion

Conclusions:

Oral (dietary) administration of SYN545192 to rats for a period of twenty-eight days resulted in a toxicologically significant reduction in body weight and body weight gain at 1200 ppm.

Minimal tubular basophilia was observed in the kidneys of females at 400 and 1200 ppm. Minimal centrilobular hypertrophy was observed in males at 400 and 1200 ppm.

A clear No Observed Effect Level (NOEL) was established at 100 ppm, equivalent to 9 mg/kg/day in both males and females.

Executive summary:

SYN545192 was administered continuously dietary admixture for 28 consecutive days to three groups of five male and five female young adult Wistar Han: HsdRccHan: WIST rats at dietary concentrations of 100, 400 and 1200 ppm (equivalent to a mean achieved dosage of 9, 36 and 99 mg/kg/day). A control group of five males and five females were treated with basal laboratory diet alone.  

Clinical signs, functional observations, body weight development and food and water consumption were monitored during the study. Haematology and blood chemistry were evaluated for all animals at the end of the study. All animals were subjected to gross necropsy examination, organ weight measurements and histopathological evaluation of selected tissues was performed.  

There were no unscheduled deaths during the study and no adverse clinical signs were observed. There were no treatment-related changes in the behavioural or sensory reactivity assessments and no changes in the functional performance parameters. There was a reduction in body weight gain and food consumption in those animals dosed at 1200 ppm. There were no treatment-related changes in the haematology or clinical chemistry parameters. Increases in liver and heart weights were evident in males treated at 1200 ppm. Microscopic examination of the tissues identified minimal tubular basophilia in the kidneys of females at 400 and 1200 ppm. The remaining histopathological changes were confined to the liver with centrilobular hepatocyte hypertrophy observed in males treated at 400 and 1200 ppm.

Oral (dietary) administration of SYN545192 to rats for a period of twenty-eight days resulted in a toxicologically significant reduction in body weight and body weight gain at 1200 ppm. Minimal tubular basophilia was observed in the kidneys of females at 400 and 1200 ppm. Minimal centrilobular hypertrophy was observed in males at 400 and 1200 ppm. A clear No Observed Effect Level (NOEL) was established at 100 ppm, equivalent to 9 mg/kg/day in both males and females.