dinotefuran (ISO); 1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Remarks:

other: repeated dose

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22/01/2001 - 12/10/2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP, Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1981

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:

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

Version / remarks:

1998

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(RS)-1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine

EC Number:

605-399-0

Cas Number:

165252-70-0

Molecular formula:

C7H14N4O3

IUPAC Name:

(RS)-1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine

Test material form:

solid: particulate/powder

Remarks:

powder

Test animals

Species:

rat

Strain:

other: Crl:CD®(SD)IGS BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age at study initiation: about 8 weeks old
Weight at study initiation: 247-326 g for males. 166-218 g for females

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

0.5%

Details on exposure:

Area covered: 10 % of body surface area
Total volume applied: 2 mL/ kg dinotefuran

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analysis for the concentration of test material in the dose preparations were conducted using analytical method MP-MT47-MA, supplied by the Sponsor and validated by the laboratory.

Duration of treatment / exposure:

Duration of treatment: 28 days

Frequency of treatment:

Frequency of exposure: 7 days per week
Duration of exposure 6-7 hours per day

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (vehicle only), 40, 200 and 1000mg/kg bw/day
Basis:
nominal per unit body weight

No. of animals per sex per dose:

10 males and 10 females per group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The goal of dose selection was to achieve a gradient of toxic effects. Dose levels selected were based on preliminary results of a previous 14-day range finding dermal toxicity study with dinotefuran in rats. Dermal application on dinotefurn had no apparent effects on macroscopic or microscopic pathology findings. Based on the lack of findings, the high-dose level was considered to be the limit dose.
- Post exposure observation period: none

Positive control:

None

Examinations

Observations and examinations performed and frequency:

Clinical signs: Yes, on days 1, 8, 15, 22 and 29

Mortality: Yes, on days 1, 8, 15, 22 and 29

Body weight: Yes, pre-dose and weekly thereafter starting on the first day of treatment

Food consumption : Yes, weekly

Water consumption : No

Ophthalmoscopic examination: Yes, pre-dose and on day 26

Haematology: Yes
Number of animals: all animals
Time points: end of study
Parameters: Haematocrit, haemoglobin concentration, erythrocyte count, total and differential leukocyte count, platelet count, clotting time, prothrombin time, thromboplastin time

Clinical Chemistry: Yes
Number of animals: all animals
Time points: end of study
Parameters: sodium, potassium, glucose, total cholesterol, urea, blood urea nitrogen, total bilirubin, creatinine, total protein, albumin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transpeptidase, sorbitol dehydrogenase, methaemoglobin, lipids, hormone (specify hormones), acid/base balance, cholinesterase inhibition.

Urinalysis:No

Sacrifice and pathology:

Organ Weights: Yes
Organs: liver, kidneys, adrenals, testes, epididymides, uterus, ovaries, thymus, spleen, brain, heart

Gross and histopathology: Yes
High dose group and controls
Organs: brain, spinal cord, pituitary, thyroid, parathyroid, thymus, oesophagus, salivary glands, stomach, small and large intestines, liver, pancreas, kidneys, adrenals, spleen, heart, trachea, lungs, aorta, gonads, uterus, female mammary gland, prostate, urinary bladder, gall bladder (mouse), lymph nodes peripheral nerve, bone marrow, skin, eyes.

The decedent was also subjected to necropsy, but organ weights were not recorded.

Other examinations:

Dermal irritation reactions were scored immediately before application on days 1, 8, 15, 22, 29 and on the day of necropsy. Erythema, edema, atonia, desquamation and fissuring reactions were scored on a 4-point scale from 0 (none) to 3 (severe). The occurrence of eschar and exfoliation were also recorded.

Statistics:

Where appropriate, Levene’s test was used to test homogeneity of variance. One-way ANOVA was applied to appropriate data followed by Dunnett’s t-test if ANOVA was significant.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

Treatment-related histopathological alterations at 1000mg/kg bw/day were confined to a minimal increase in the incidence and severity of acanthosis / hyperkeratosis in the treated skin of females. The finding is considered not to be an adverse effect or toxicologically relevant because slight to moderate acanthosis / hyperkeratosis occurred in 2 control females and in the untreated skin of a female at 200mg/kg bw/day. Furthermore, all control and 1000mg/kg bw/day males also showed the skin alteration. There were no treatment-related histopathological alterations in the other tissues examined from animals treated at 1000mg/kg bw/day.

See Table 1.

There were no treatment-related effects at any dose level on any of the ECO parameters evaluated and no statistically significant (p > 0.05) effects on quantitative motor activity. One male treated at 40mg/kg bw/day and 2 females at 1000mg/kg bw/day showed slight (grade 1) skin atonia at the application site on one or two occasions during the treatment period. There were no other signs of dermal irritation at any dose level. Since the observed atonia was transient and was not accompanied by other signs of irritation, the finding is considered not to be an adverse effect.

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Based on the absence of systemic and local adverse effects at this dose level.

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1:   Incidence of selected histopathological alterations

Organ:	Incidence of lesion in:
finding	Males treated at (mg/kg bw/day):				Females treated at (mg/kg bw/day):
	0	40	200	1000	0	40	200	1000
Treated skin: - no. examined - inflammation -acanthosis/   hyperkeratosis	10 2   10	1 0   1	0 0   0	10 2   10	10 3   2	0 0   0	0 0   0	10 2   8
Untreated skin: - no. examined - inflammation - fibrosis - ulceration - acanthosis/ hyperkeratosis	10 8 0 0   0	1 0 0 0   0	0 0 0 0   0	10 4 0 0   0	10 8 0 0   1	0 0 0 0   0	1 1 1 0   1	10 7 0 1   0

 

Applicant's summary and conclusion

Conclusions:

A no-observed-adverse-effect-level (NOAEL) was established as > 1000mg/kg bw/day, based on the absence of systemic and local adverse effects at this dose level.