17-acetoxy-1β,2β-methanopegna-4,6-diene-3,20-dione

Endpoint summary

Description of key information

Oral, subacute 4 weeks (Rat-Wistar, GLP, OECD TG 407): NOAEL = 1000 mg/kg  [Schering AG, Report No. AZ07, 1998]

 

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April to May 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

1995-07-27

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Strain: HAN: WIST (SPF)
- Source: Schering AG
- Age at study initiation: not reported
- Weight at study initiation: males 186-221 g, females 167-193 g
- Housing: singly in conventional housing conditions (Makrolon type III cages)
- Diet and water: ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-23
- Humidity (%): 46-70
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

other: 0.9 % NaCl + 0.085 Myrj 53

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The content of the test substance in the formulation was analytically verified for all doses at least at beginning and termination of the study.
Method of analysis: HPLC with UV absorption following appropriate dissolution and dilution with mobile phase appropriately.

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

once daily

Remarks:

Doses:
0, 40, 200, 1000 mg/kg in an application volume of 10 ml/kg

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes, all animals
All signs of weak health, reactions to treatment and behavioural changes were recorded.
- Time schedule: Animals were checked regularly twice daily, also on weekends.

BODY WEIGHT: Yes, all animals
- Time schedule for examinations: once weekly

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

WATER CONSUMPTION: Yes, all animals
- Time schedule for examinations: once weekly

OPHTHALMOSCOPIC EXAMINATION: Yes, all animals
- Time schedule for examinations: week 4

HAEMATOLOGY:
- Time schedule for collection of blood: Day 28
- Anaesthetic used for blood collection: No data
- Animals fasted: not specified
- Parameters checked: Hematological investigations including determination of the following parameters were performed on Day 24: erythrocyte and leucocyte count, hemoglobin, hematocrit (packed cell volume), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), reticulocyte count, platelets, and differential count [neutrophils (myelocytes, immature, band types l and II, segmented), Iymphocytes, eosinophils, basophils, monocytes].

CLINICAL CHEMISTRY: Yes, all animals
- Time schedule for collection of serum: Day 2 and Day 28
- Parameters checked: alanine aminotransferase (ALT) and alkaline phosphatase (ALP) on Day 2 (approximately 24 hours after the first treatment) and Day 28,
total cholesterol, glucose, urea nitrogen, total protein, protein electrophoresis, sodium, potassium, calcium and chloride on Day 28 only.

URINALYSIS: Yes, all animals
- Time schedule for collection of urine: Day 25
- Parameters checked: pH, specific gravity and volume as weil as protein, glucose, blood, ketones, urobilinogen, bilirubin and sediment of urine.

NEUROBEHAVIOURAL EXAMINATION: Yes
On days -6 or -5 and 22 the following neurological examinations were performed in all rats
a) brain reflexes:
pupillary light reflex, eonsensuallight reflex, palpebral reflex and corneal reflex
b) spinal reflexes:
flexor withdrawl reflex.
e) postural and attitudinal reactions:
placing reaction, righting reaction, balancing test and grasping reflex
d) sensitivity test:
sensitivity of skin (torso) and head shaking reaction

Statistics:

The Dunnett-test was used to assess the statistical significance of differences between the control and the treatment groups.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

The observed findings such as hairless areas, thinning of fur, scab formations at several locations and hematomas at the external ear were not considered to be compound-related, because they were sporadically seen in only one animal each and are known sporadic findings due to traumata.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

The animal nos.: 13F, 15F and 53F died on day 2 of the study due to the blood
sampling procedure.
Animal no. 31 F died on day 28 also accidentally after blood sampling.

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):

The findings such as vesicular inclusions at the cornea and bloodfilled vessels across the vitreous body were not considered to be compound-related because they were observed sporadically in single animals of groups 2 and 4 (40 and 1000 mg/kg) without dose-dependence.

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Decrease in MCV and hematocrit not condered to be compound-related due to lack of dose-dependency.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

The following suspected compound-related effects were observed on day 28 of the study:
- slight increase in total protein in female animals ofgroup 4 (p < 0.05);
- increase in glucose in female animals of group 4 (p < 0.01).
None of the other statistically significant differences to the control group were considered to be compound-related.

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

None of the findings observed in urine, such as protein, blood, ketones, urobilinogen and bilirubin as well as urinary sediment findings were considered to be compound-related,
because of the lack of a dose dependence or they were also seen in control animals or occurred only sporadically.

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

None of the findings which were observed at the histopathological examination was regarded
as being compound-related because they ocurred at comparable incidence in contra I and
treatment goups or they occurred only sporadically or they were known spontaneaus findings in the used strain of rats.

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Coagulation:
The only suspected compound-related effect was a statistically significant slight decrease (p < 0.05) in fibrinogen observed in female animals of group 4 on day 29.

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:

behaviour (functional findings)

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

gross pathology

haematology

histopathology: non-neoplastic

mortality

neuropathology

ophthalmological examination

organ weights and organ / body weight ratios

serum/plasma biochemistry

urinalysis

water consumption and compound intake

Critical effects observed:

not specified

The repeated intragastric administration of ZK 5690 at doses of 40, 200 and 1000 mg/kg to male and female rats over aperiod of 4 weeks was tolerated without general or organ toxicity.
The increase in glucose in females of graup 4 is only suspected as being compound-related although a clear difference to the control animals was noted. However, the glucose values of the treated animals remained well within the reference range whereas the respective values of the control group were in the lower range of the reference values. Therefore, this finding is
regarded as being of minor biological significance.
The slight decrease in fibrinogen in females of group 4 was suspected to be treatment-related but was regarded as being of minor toxicological relevance. The value remained within the historical reference value range, i.e. within the normal biological variability and the difference of the value between the high-dose group and the control group was too slight to be of biological significance. The increase in organ weight of the liver in female animals of dose group 4, which correlates with the slight increase in total protein in the same group, is regarded to be related to an adaptation to the high metabolic loading of the liver.

Conclusions:

The daily intragastric administration of ZK 5690 at dose levels of 40, 200 and 1000 mg/kg to male and female rats over a treatment period of 4 weeks was tolerated without relevant toxic effects. At the high dose, signs of an adaptation to the high metabolite loading of the liver occurred in female rats, but no indications of general or organ toxicity were found in either gender.

Executive summary:

Three groups of 10 M/10 F rats (Han: WIST) each received daily intragastric administrations of 40, 200 and 1000 mg ZK 5690/kg, respectively, at a volume of 10 ml/kg over aperiod of ca. 4 weeks (28-31 applications). Another group of 10 M/10 F received the vehicle at the same volume and served as control.

The effects of ZK 5690 were evaluated using clinical, biochemical and hematological parameters as well as bane marrow examination, urinalysis, organ weight analysis and pathological macroscopic and microscopic examination.
For statistical evaluation, the Dunnett-test was used.
No compound-related effect was observed after the low and mid doses of 40 and 200 mg ZK 5690/kg.

The following suspected compound-related effects were observed after the high dose of 1000 mg/kg in females:
- slight increase (p < 0.05) in total protein in females;
- increase (p < 0.01) in glucose in females;
- slight decrease (p < 0.05) in fibrinogen in females;
- increase in absolute (p< 0.05) and relative (p < 0.01) organ weight of the liver in female animals.

Of the above-mentioned findings the slight increase in total protein accompanied by an increase of liver weight in females of group 4 is regarded as indication of metabolic activation of the liver. The slight decrease in fibrinogen as well as the increase in glucose were regarded as minor changes because the values remained within the reference range. Therefore, it was not regarded as being of biological significance.

Therefore, the NOAEL can be regarded to be 1000 mg/kg/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Experimental exposure time per week (hours/week):

7

Species:

rat

Quality of whole database:

Klimisch score 2

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The daily intragastric administration of ZK 5690 at dose levels of 40, 200 and 1000 mg/kg to male and female rats over a treatment period of 4 weeks was tolerated without relevant toxic effects. At the high dose, signs of an adaptation to the high metabolite loading of the liver occurred in female rats, but no indications of general or organ toxicity were found in either gender.

Therefore, the NOAEL in male and female rats was established to be 1000 mg/kg body weight/day.

Justification for classification or non-classification

Based on the study results a classification according to Directive 67/548/EEC and Regulation (EC) No. 1272/2008 (CLP) is not required.