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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
14 - 21 September 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Deviations:
no
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
5-Amino-1-(tetrahydro-pyran-4-yl)-1H-pyrazole-4-carbonitrile
EC Number:
821-117-0
Cas Number:
1082745-49-0
Molecular formula:
C9H12N4O
IUPAC Name:
5-Amino-1-(tetrahydro-pyran-4-yl)-1H-pyrazole-4-carbonitrile
Test material form:
solid: particulate/powder

Test animals

Species:
rat
Strain:
other: Crl:WI(Han)
Sex:
female
Details on test animals or test system and environmental conditions:
TST ANIMALS
- Animals chosen for this study were selected from a supply of healthy nulliparous and nonpregnant
female Crl:WI(Han) rats obtained from Charles River (UK) Ltd.
- bodyweights were in the range 173 to 196 g and they were approximately eight to twelve weeks of age prior to dosing
(Day 1)

CONDITIONS:
- Animals were housed inside a barriered rodent facility (Building F21, Room 044/045)
- The animals were allowed free access to a standard rodent diet (Rat and Mouse No. 1
Maintenance Diet), except for overnight prior to and approximately four hours after dosing
-The temperature and relative humidity controls were set to maintain the range of 19 to 23C and 40 to 70%
respectively
-Artificial lighting was controlled to give a cycle of 12 hours continuous light and 12 hours continuous dark per
24 hours.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Hydroxyethylcellulose (Natrosol 250) 0.5%.
Details on oral exposure:
The appropriate dose volume of the test substance was administered to each rat by oral
gavage using a plastic syringe and plastic catheter
Doses:
300 mg/kg and 2000 mG/kg bodyweight
No. of animals per sex per dose:
300 mg/kg: 6 female; 2000 mg/kg: 3 female
Control animals:
no
Details on study design:
- Cages of rats were checked at least twice daily for any mortalities
-Animals were observed soon after dosing and at frequent intervals for the remainder of
Day 1. On subsequent days, surviving animals were observed once in the morning and again
at the end of the experimental day (with the exception of Day 15 - morning only). The nature
and severity, where appropriate, of the clinical signs and the time were recorded at each
observation
- The weight of each rat was recorded on Days 1 (prior to dosing), 2, 8 and 15 or at death.
Individual weekly bodyweight changes and group mean bodyweights were calculated.

Results and discussion

Effect levels
Key result
Sex:
female
Dose descriptor:
LD50
Effect level:
> 300 - < 2 000 mg/kg bw
Based on:
test mat.
Mortality:
All females dosed at 2000 mg/kg died, one on Day 1, and two females on Day 2. Clinical
signs seen from approximately 30 minutes after dosing comprised unsteady gait, underactive
behaviour, reduced body tone, fast breathing, flat posture, lachrymation, irregular breathing
and unresponsive behaviour in all three females, cold to touch, rales/noisy breathing and
shallow breathing in two females with gasping and piloerection seen in one female. A loss in
bodyweight was noted for two decedents. Macroscopic examination of the decedents
revealed congestion of the subcutaneous tissue and lungs, pallor of the liver, spleen and
kidneys, atrophy of the heart and caecum, red or yellow fluid contents of the stomach along
the alimentary tract and solid black contents of the caecum.
Clinical signs:
other: There were no clinical signs of reaction to treatment in surviving females throughout the study.
Gross pathology:
Macroscopic examination of the surviving animals revealed atrophy of the stomach in one
female (X6) dosed at 300 mg/kg. No other abnormalities were noted in any surviving animal
at the macroscopic examination at study termination on Day 15.

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Conclusions:
The acute median lethal oral dose (LD50) to rats of BI 409306 Pyrazol was demonstrated to be between 300 and 2000 mg/kg bodyweight.
Executive summary:

SUMMARY

The study was performed to assess the acute oral toxicity of BI 409306 Pyrazol (a

pharmaceutical intermediate), to the rat.

Two groups of three fasted female rats received a single oral gavage dose of the test

substance, formulated in Hydroxyethylcellulose (Natrosol 250) 0.5%, at a dose level of

300 mg/kg bodyweight. As results at this dose level indicated the acute (median) lethal oral

dose of the test substance to be greater than 300 mg/kg bodyweight, in compliance with the

study guidelines a further group of three fasted females was similarly dosed at 2000 mg/kg

bodyweight to complete the study.

RESULTS

All females dosed at 2000 mg/kg died, one on Day 1, and two females on Day 2. Clinical

signs seen from approximately 30 minutes after dosing comprised unsteady gait, underactive

behaviour, reduced body tone, fast breathing, flat posture, lachrymation, irregular breathing

and unresponsive behaviour in all three females, cold to touch, rales/noisy breathing and

shallow breathing in two females with gasping and piloerection seen in one female. A loss in

bodyweight was noted for two decedents. Macroscopic examination of the decedents

revealed congestion of the subcutaneous tissue and lungs, pallor of the liver, spleen and

kidneys, atrophy of the heart and caecum, red or yellow fluid contents of the stomach along

the alimentary tract and solid black contents of the caecum.

There were no clinical signs of reaction to treatment in surviving females throughout the

study.

A loss in bodyweight was noted for one surviving female (X5) on Day 8. A notably low

bodyweight gain was noted for one surviving female (X2) dosed at 300 mg/kg on Day 15.

All other surviving animals were considered to have achieved satisfactory bodyweight gains

throughout the study.

Macroscopic examination of the surviving animals revealed atrophy of the stomach in one

female (X6) dosed at 300 mg/kg. No other abnormalities were noted in any surviving animal

at the macroscopic examination at study termination on Day 15.

CONCLUSION

The acute median lethal oral dose (LD50) to rats of BI 409306 Pyrazol was demonstrated to

be between 300 and 2000 mg/kg bodyweight.

BI 409306 Pyrazol is included in Category 4 >300-2000, according to the Globally

Harmonised System (GHS), (UNITED NATIONS, 2005).