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Administrative data

Description of key information

A close homologue (CAS-no. 1233873-37-4) of the registered substance, which has a branched C12 instead of a branched C9 side chain and lacks a methyl group at the oxime carbon atom, has been tested using the OECD408 protocol under GLP conditions. No treatment related adverse effects were observed up to the highest dose tested. The NOAEL of the test substance for repeated dose 90-days oral toxicity was 150 mg/kg bodyweight.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
NOAEL
150 mg/kg bw/day
Study duration:
subchronic
Species:
rat

Mode of Action Analysis / Human Relevance Framework

Additional information

A close homologue (CAS-no. 1233873 -37 -4) of the registered substance, which has a branched C12 instead of a branched C9 side chain and lacks a methyl group at the oxime carbon atom, has been tested. The repeated dose 90 day oral toxicity study was conducted in Wistar rats (strain Crl: WI) -procured from Charles River laboratories and bred at the IIBAT animal house facility in accordance with the OECD 408 guideline and GLP. A total of one hundred and sixty rats were randomly distributed into eight groups (consisting of 10 males and 10 females per group) namely G1 - Vehicle control, G2 - Low dose (15 mg/kg.b.w.), G3 - Intermediate dose (50 mg/kg b.w.), G4 - High dose (150 mg/kg b.w.), G5 Satellite vehicle

control, G6- Satellite high dose (150 mg/kg b.w.), G7 and G8- Control groups (untreated). The test substance mixed with corn oil was administered to the animal groups. Rats in satellite groups were kept for an additional 28 days without any dosing to evaluate any possible withdrawal.

Prior to the main study, a range finding study was conducted with the three sponsor suggested dose groups namely low (15 mg/kg.b.w.), intermediate (50 mg/kg b.w.), and high (150 mg/kg b.w.).

The animals were observed for 14 days for any clinical signs of toxicity, morbidity and mortality.

None of them died or exhibited overt signs of toxicity. Based on this range finding study, the doses for the main study were selected namely low (15 mg/kg.b.w.), intermediate (50 mg/kg b.w.), and high (150 mg/kg b.w.), as suggested and approved by the sponsor.

All animals were observed daily once for clinical signs of toxicity. Weekly body weight and food consumption data for all rats were recorded. Blood was collected from the orbital sinus of the rats on day 1 (pre-treatment), day 91 (on termination of treatment) and 119 (on termination of post-treatment) for hematological and biochemical investigations. Similarly, urinalysis was carried

out on day 1 and day 91 of the experimental period for all groups and on day 119 for the satellite groups.

Ophthalmoscopic examination and data of the functional observational battery including righting reflex, body temperature, salivation, respiration, mouth breathing, urination, convulsions, piloerection, diarrhea, pupil size, lacrimation, impaired gait, tremors, toe pinch, tail pinch, wire maneuver, hind leg splay, positional passivity, positive geotropism, limb rotation, auditory function, grip strength (fore and hind limb), locomotor activity (activity cage) were collected on rats at pre-treatment, at termination of dosing for all groups and after the withdrawal period (G5 and G6 only).

On day 91, all animals belonging to G1, G2, G3, G4, G7 and G8 were sacrificed. Similarly, after the withdrawal period on day 119 all animals of G5 and G6 were sacrificed. A detailed gross pathology was carried out and brain, liver, spleen, heart, adrenals, kidneys. gonads, thyroid, thymus, seminal vesicle with coagulating gland, epididymides, prostate and uterus were isolated from individual rats for weight determination. Tissues from various organs were preserved and processed for histopathological examination.

Findings

Mortality and clinical signs

No mortality and clinical signs of toxicity were observed in any of the animals of any group during treatment and the post treatment period.

Body weight

In high dose group (G4) females, a statistically significant decrease in mean body weight was observed during the l0th, 12th and 13th week of the experimental period when compared to vehicle control (G1). Although statistically significant difference in body weight was observed in the high dose group (G4), a similar effect was not observed in satellite high dose group (G6). Hence this effect

was not considered to be dose related.

On 13th week, a statistically significant decrease was noted in the mean body weight of females in the intermediate dose group (G3) when compared to the vehicle control group (G1).

Since the body weight of this group (G3) on week 13 was comparable with the untreated control groups (G7 and G8) on week 13, the effect was not considered to be adverse.

Similarly, statistically significant decrease in mean body weight was noted in the satellite high dose group (G6) males from 9th to 13th week of the experimental period when compared to the satellite vehicle control (G5). Since this effect was not observed in the main dose groups, it was considered not to be treatment related.

Food consumption

Food consumption data did not show any statistically significant changes in any of the groups

Hematology

Hematology parameters namely; erythrocyte count (RBC), hemoglobin, hematocrit (PCV), MCV, MCH, MCHC, platelet count, total leukocyte count (WBC), differential count (neutrophils, eosinophils, basophils, lymphocytes and monocytes) and clotting time (CT) were determined.

Day 1 (Pre-treatment)

In males, a statistically significant decrease in the mean value of eosinophils was recorded in both the low dose (G2) and the intermediate dose (G3) groups when compared to the vehicle control (G1). A statistically significant increase in the mean basophil value was recorded in the intermediate dose (G3) group when compared to the vehicle control (G1). A statistically significant increase was recorded in MCHC of the satellite high dose group (G6) when compared to the satellite vehicle control (G5).

In females, a statistically significant decrease in WBC was recorded in both the low dose (G2) and high dose (G4) groups when compared to the vehicle control (G1). Similarly, an increase in neutrophils was recorded in the high dose group (G4) when compared to the vehicle control (G1).

Although the mean values were statistically significant for parameters mentioned above, they were within the normal range for the species.

Day 91 (Termination of treatment)

In males, a statistically significant decrease was recorded in Hb, HCT and neutrophils in the satellite high dose group (G6), and an increase in MCHC of the satellite high dose group (G6) was recorded when compared to the satellite vehicle control (G5). Since this effect was not observed in the main dose groups it was considered not to be treatment related.

In females of the high dose group (G4), a statistically significant increase was recorded in

neutrophils and a decrease in lymphocytes when compared to the vehicle control (G1).Since this effect was not observed in the satellite dose groups it was considered not to be treatment related.

Day 119 (Termination of post treatment) (G5 and G6 only)

No statistically significant changes were recorded in both males and females of the satellite high dose (G6) groups when compared to the satellite vehicle control (G5).

Clinical biochemistry

Blood samples of test animals from various groups were analysed for glucose, total cholesterol, urea, blood urea nitrogen (BUN), creatinine, total protein and albumin, calcium, triglycerides, alanine aminotransferase (AL T), aspartate aminotransferase (AST), alkaline phosphatase (ALP), sodium and potassium levels.

Day 1 (Pre-treatment)

In males, no statistically significant changes were observed in any of the parameters analysed.

In females, however, triglycerides showed a statistically significant decrease in the three test dose group namely, low (G2), intermediate (G3), and high (G4), when compared to the vehicle control (G1). Although group mean values differed statistically, they were in the normal range for the species.

Similarly, a decrease in ALT was recorded in both low (G2) and intermediate (G3) dose groups when compared to the vehicle control (G1). This effect was not considered to be biologically adverse.

In satellite high dose group (G6), a statistically significant decrease was recorded in ALP and calcium level when compared to the satellite vehicle control (G5). Although the mean values were statistically significant they are comparable with the untreated control mean values (G7 & G8).

Day 91 (Termination of treatment)

In males of the satellite high dose group (G6). a statistically significant decrease was observed in total protein and sodium values when compared to the satellite vehicle control (G5).

A recovery was observed in the mean values of sodium. Although the mean value of total protein was statistically significant it is comparable with the mean values of untreated controls (G7 & G8) and hence not considered to be treatment related.

In females, a statistically significant increase was recorded in urea and blood urea nitrogen (BUN) in three doses namely, low (G2), intermediate (G3) and high (G4) dose groups when compared to vehicle control (G1).

An increase in alkaline phosphatase (ALP) was recorded in the high dose group (G4) when compared to the vehicle control (G1). A decrease in calcium levels was recorded in the satellite high dose group (G6) when compared to the satellite vehicle control (G5). Although the mean values of above mentioned parameters were statistically significant, they were comparable with the mean values of

the untreated control groups (G7 & G8) and hence it was not considered to be treatment related.

Day 119 (Termination of post treatment) (G5 and G6 only)

In males, a statistically significant decrease in urea, BUN, triglycerides, ALP, total protein, calcium was recorded in the satellite high dose group (G6) when compared to the satellite vehicle control group (G5). Although group mean values differed statistically for parameters mentioned above, they were in the normal range for the species and were not dose related. Hence, these changes were

considered to be not test substance related and have no toxicological importance.

In females, no statistically significant changes were recorded in any of the parameters analysed.

Functional observational battery

Day 0 (Pre-treatment)

In males, a statistically significant increase in the activity levels of LAH and LAV was observed in the satellite high dose group (G6) when compared to the satellite vehicle control group (G5). A statistically significant increase in the auditory response for amplitude I (90 db) was recorded in both intermediate (G3) and high dose (G4) groups when compared to the vehicle control group (G1).

Similarly, a statistically significant increase was observed for the auditory response at amplitude III (120 db) in the high dose satellite groups (G6) when compared to the satellite vehicle control group (G5).

In females, a statistically significant increase in foot splay, LAH and LAV was recorded in the satellite high dose group (G6) when compared to the satellite vehicle control group (G5). A statistically significant increase in body temperature was recorded in the intermediate dose (G3) group when compared to the vehicle control (G1).

Day 90 (Termination of treatment)

A statistically significant increase was recorded in the activity level (LAV) of the high dose group males (G4), and similarly in the intermediate and low dose group females (G2 and G3) when compared to the vehicle control (G1). A statistically significant decrease in auditory response was recorded in the satellite high dose group males (G6) for amplitude I (90 db) and amplitude II (105 db) when compared to the satellite vehicle control (G5).

Although group mean values differed statistically for parameters mentioned above, the values were comparable with the untreated control animals (G7 & G8). Hence, these changes noted were considered not to be test substance related and biologically not adverse.

Day 118 (Termination of post treatment) (G5 and G6 only)

There were no statistically significant changes observed in any of the FOB parameters.

Ophthalmologic examination

No test substance related changes in the eye were noted in any of the treated groups (G2, G3, G4 and G6).

Urinalysis

Day 1

In males, there were no statistically significant changes in the urinalysis parameters in any of the groups.

In females of the intermediate group (G3), a statistically significant increase was observed in specific gravity value when compared to the vehicle control group (G1). Since this effect was not observed in any of the treatment groups, it was not considered to be biologically adverse.

Day 91 & 119

There were no statistically significant changes observed in any of the urinalysis parameters.

Organ weights

In males, there were no statistically significant changes in both relative and absolute organ weights in any of the groups.

In females, a statistically significant increase was recorded in the relative organ weights of brain and adrenals in the high dose group (G4) when compared to the vehicle control (G1). A statistically significant increase in the absolute organ weights of adrenals and a statistically significant decrease in the absolute organ weights of spleen were recorded in the high dose group (G4) when compared to

the vehicle control (G1). Since these effects were not observed in satellite groups and not correlated with microscopic findings, it was considered not to be treatment related.

Gross pathology

No test substance related gross pathological changes were recorded. All gross lesions noted were incidental or they are routinely observed in Wistar rats of this age and are unrelated to the administration of the test substance.

Histopathology

A statistically significant pancreatic agonal hemorrhage was observed in high dose group (G4) females perhaps due to mechanical stress factor not related to the dose.

Lesions observed were either related to infectious, to spontaneous and/or to physiological effects that were incidental and of the type routinely observed in Wistar rats of this age.

Conclusion

On the basis of the results obtained in the present study. the No Observed Adverse Effect Level (NOAEL) of the test substance for repeated dose 90 day oral toxicity exceeded 150 mg/kg b.w. for Wistar rats under the experimental conditions employed.

Justification for classification or non-classification

As the NOAEL of 150 mg/kg bodyweight/day is higher than the guidance value of 100 mg/kg bodyweight/day as specified in Regulation (EC) No. 1272/2008, the registered substance has not to be labelled with regard to specific target organ toxicity — repeated exposure.