Registration Dossier

Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
Identity: CP-163,625-BV
Intended use: Intermediate in the synthesis of a pharmaceutical
candidate
Appearance: Powder
Storage conditions: Room temperature in the dark
Batch number: CRD/02/4/151/1
Re-test date: December 2003
Purity: 98.8%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
The animals chosen for this study were selected from a stock supply of healthy male and female CD rats
of Cri: CD BR origin, obtained from Charles River UK Ltd, Margate, Kent, England.
They were in the weight range of 235.1 to 307.2 g and approximately eight to twelve weeks of age prior
to dosing (Day 1). All the rats were acclimatised to the experimental environment for a period of
six days prior to the start of the study.
The rats were allocated without conscious bias to cages within the treatment group. They were housed
individually in metal cages (RS Biotech Sub-Dividable Rodent Cages - polished stainless steel) until
Day 3 when they were returned to group housing. The cages were fitted with grid floors to ensure
rapid removal of waste material to undertrays. The cages were suspended in mobile stainless steel
racks in Building F21 Room 28.
A standard laboratory rodent diet (Special Diet Services RM1(E) SQC expanded pellet) and drinking
water were provided ad libitum. The batch(es) of diet used for the study was analysed by the supplier
for certain nutrients, possible contaminants and micro-organisms. Results of routine physical and
chemical examination of drinking water, as conducted by the supplier, are made available to Huntingdon
Life Sciences Ltd at regular intervals throughout the year.
Animal room environmental controls were set to maintain temperature within the range 22 ± 3°C and
relative humidity 40 - 70%. Any minor deviations from these ranges would not have had an adverse
effect on the animals and would not affect the integrity or validity of the study. These environmental
parameters were recorded daily and the permanent record archived with other depai tmental raw data.
Lighting was controlled by means of a time switch to provide 12 hours of artificial light (0600 - 1800
hours GMT) in each 24-hour period.
Each animal was identified by tail marking. Each cage was identified by a coloured label displaying the
dose level, study schedule number, animal mark and the initials of the Study Director and Home Office
licensee.

Administration / exposure

Type of coverage:
other: porous gauze held in place with a non irritating dressing, and further covered by a waterproof dressing
Vehicle:
methylcellulose
Details on dermal exposure:
CP-163,625-BV was formulated at a maximum practical concentration of 50% w/v in 1% w/v aqueous
methylcellulose and administered at a dose volume of 4 ml/kg bodyweight.
The test substance formulation was prepared on the day of dosing.
The absorption of the test substance was not determined.
Characterisation of the homogeneity, stability and purity of the test substance was not undertaken in this
study and remained the responsibility of the Sponsor.

A group of ten rats (five males and five females) was treated at 2000 mg/kg bodyweight.
One day prior to treatment, hair was removed from the dorso-lumbar region of each rat with electric
clippers taking care to avoid damaging the skin, exposing an area equivalent to approximately 10% of
the total body surface area.
The test substance was applied by spreading it evenly over the prepared skin. The treatment area
(approximately 50 mm x 50 mm) was covered with porous gauze held in place with a non irritating
dressing, and further covered by a waterproof dressing encircled firmly around the trunk of the animal.
Treatment in this manner was performed on Day 1 (day of dosing) of the study only.
At the end of the 24 hour exposure period, the dressings were carefully removed and the treated area of
skin on each animal was washed with warm water (30 - 40°C) to remove any residual test substance.
The treated area was blotted dry with absorbent paper.
Duration of exposure:
24 hours
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
5/sex/dose
Control animals:
not required
Details on study design:
OBSERVATIONS
Mortality
Cages of rats were checked at least twice daily for mortalities.
Clinical signs
Animals were observed soon after dosing and at frequent intervals for the remainder of Day 1. On
subsequent days, 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 of the clinical signs and
time were recorded at each observation.
All animals were observed for 14 days after dosing.

Dermal responses
Local dermal irritation at the treatment site was assessed daily using the following numerical
scoring system:

Erythema and eschar formation:
No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beet redness) to eschar formation (injuries in depth) 4

Oedema formation:
No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 mm) 3
Severe oedema (raised more than 1 mm and extending beyond the
area of exposure) 4

Bodyweight
The bodyweight of each rat was recorded on Days 1 (prior to dosing), 8 and 15. Individual weekly
bodyweight changes and group mean bodyweights were calculated.

TERMINAL STUDIES
Termination
All animals were killed on Day 15 by carbon dioxide asphyxiation.

Macroscopic pathology
All animals were subjected to a macroscopic examination which consisted of opening the thoracic and
abdominal cavities. The macroscopic appearance of all tissues was recorded.
Statistics:
N/A

Results and discussion

Preliminary study:
No Preliminary study
Effect levels
Key result
Sex:
male/female
Dose descriptor:
discriminating dose
Effect level:
ca. 2 000 mg/kg bw
Based on:
test mat.
Mortality:
There were no deaths following a single dermal application of
CP-163,625-BV to a group of ten rats (five males and five females) at a dose level of 2000 mg/kg
bodyweight.
Clinical signs:
There were no systemic response to treatment following a single dermal application of
CP-163,625-BV to a group of ten rats (five males and five females) at a dose level of 2000 mg/kg
bodyweight.
Body weight:
Low bodyweight gains were recorded for two females (Nos. B6 and B7) on Day 8 and all females
(Nos. B6, B7, B8, B9 and B10) on Day 15. All males were considered to have achieved satisfactory
bodyweight gains throughout the study.
Gross pathology:
No abnormalities were recorded at the macroscopic examination at study termination on Day 15.
Other findings:
DERMAL REACTIONS
No dermal reactions were observed in any animal throughout the duration of the study.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute lethal dermal dose to rats of CP-163,625-BV was demonstrated to be greater than 2000 mg/kg bodyweight.
Executive summary:

A study was performed to assess the acute dermal toxicity of CP-163,625-BV to the rat. The method followed was based on that described in: EEC Methods for the determination of toxicity, Annex to Directive 92/69/EEC (Official Journal No. L383A, 29.12.92), Part B, Method B.3. Acute toxicity (dermal). OECD Guideline for Testing of Chemicals No. 402 "Acute Dermal Toxicity". Adopted: 24 February 1987. A group of ten rats (five males and five females) received a single topical application of the test substance, formulated at a maximum practical concentration in 1% w/v aqueous methylcellulose, at a dosage of 2000 mg/kg bodyweight (EEC and OECD limit dosage). All animals were killed and examined macroscopically on Day 15, the end of the observation period. There were no deaths, no systemic response and no dermal reactions in any animal throughout the study. Low bodyvveight gains were recorded for two females on Day 8 and all females on Day 15. All males were considered to have achieved satisfactory bodyweight gains throughout the study. No abnormalities were recorded at the macroscopic examination at study termination on Day 15. The acute lethal dermal dose to rats of CP-163,625-BV was demonstrated to be greater than 2000 mg/kg bodyweight. CP-163,625-BV will not require labelling with the risk phrase R21, "Harmful in contact with skin", in accordance with Commission Directive 2001/59/EC. CP-163,625-BV will not require labelling with the risk phrase R38, "Irritating to skin", in accordance with Commission Directive 2001/59/EC.