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Acute Toxicity: dermal

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Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 02 November 1995 to 30 January 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study conducted according to OECD Guideline 402 with some deviation: stability of the test article in the vehicle (acetone) is unknown
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
yes
Remarks:
Stability of the test article in the vehicle (acetone) is unknown
Qualifier:
according to guideline
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Deviations:
yes
Remarks:
Stability of the test article in the vehicle (acetone) is unknown
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. QA statement)
Remarks:
16-06-1994
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
422-940-4
EC Name:
-
Cas Number:
155633-54-8
Molecular formula:
C24H39N3O3Si3
IUPAC Name:
2-(2H-1,2,3-benzotriazol-2-yl)-4-methyl-6-[2-methyl-3-(2,2,4,6,6-pentamethyl-3,5-dioxa-2,4,6-trisilaheptan-4-yl)propyl]phenol
Test material form:
other: solid
Details on test material:
- Name of test material (as cited in study report): G4375
- Physical state: whitish solid
- Analytical purity: 98% minimum
- Impurities (identity and concentrations): Methanol (<100 ppm) and Isopropanol (<100 ppm)
- Purity test date: certificate of analysis 20/10/1995
- Lot/batch No.: DEF/C 95003/B
- Expiration date of the lot/batch: No data
- Stability under test conditions: Stable under storage condition (date of reanalysis sep-1996); Unknown in acetone, therefore it is excluded from the statement of compliance.
- Storage condition of test material: In the original container at room temperature away from direct sunlight.

Test animals

Species:
rat
Strain:
other: HanIbm: WIST (SPF)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: BRL, Biological Research Laboratories, Ltd. Wölferstrasse 4, 4414 Füllinsdorf / Switzerland
- Age at study initiation: 7 weeks old for males; 9 weeks old for females
- Weight at study initiation: 266.5-298.0 g for males; 228.2-247.3 g for females
- Housing:
During acclimatization: Groups of five rats in Makrolon type-4 cages with autoclaved standard softwood bedding ("Lignoce1", Scill AG, CH-4132 Muttenz).
During treatment and observation: individually in Makrolon type-3 cages with autoclaved standard softwood bedding.
- Diet (e.g. ad libitum): Pelleted standard Kliba 343, Batch no. 66/95 rat maintenance diet ("Kliba", Klingentalmuehle AG, CH-4303 Kaiseraugst) available ad libitum.
- Water (e.g. ad libitum): Community tap water from Füllinsdorf, available ad libitum.
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-23°C
- Humidity (%): 37-70 %
- Air changes (per hr): 10 to 15
- Photoperiod (hrs dark / hrs light): 12h dark/ 12h light

IN-LIFE DATES: From 02 November 1995 to 23 November 1995

Administration / exposure

Type of coverage:
semiocclusive
Vehicle:
acetone
Details on dermal exposure:
TEST SITE
- Area of exposure: Clipped backs of the animals
- % coverage: approximately10% of the total body surface.
- Type of wrap if used: semi-occlusive dressing wrapped around the abdomen and fixed with an elastic adhesive bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Dressing was removed and the skin was washed with lukewarm tap water and dried with disposable paper towels.
- Time after start of exposure: 24h

TEST ITEM
- Constant volume or concentration used: no data
- For solids, paste formed: yes

VEHICLE
- Amount(s) applied (volume or weight with unit): 4.0 ml/kg bw
- Concentration (if solution): the test article was placed into a glass beaker on a tared Mettler PM 480 balance, and the vehicle (acetone) was added. A weight by volume dilution was prepared using a homogenizer (Ultra-Turrax, Janke & Kunkel, D-79219 Staufen). Homogeneity of the test article in the vehicle was maintained during treatment using a magnetic stirrer (Janke&Kunkel, D-79219 Staufen). The preparation was made shortly before dosing.
- Purity: no data
Duration of exposure:
24 h
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
5
Control animals:
other: reference control
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Mortality and viability were observed four times during test day 1 and daily during days 2-15, as well as clinical signs (changes in appearance and behavior with special emphasis on the application area, except for the time when the semi-occlusive dressing was in place).
Body weights were measured on test day1 (pre-administration), 8 and 15.
- Necropsy of survivors performed: yes; at the end of the observation period all animal were anesthetized by intraperitoneal injection of NARCOREN (Rhone Merieux GmBH, D-88471 Laupheim) at a dose of at least 2.0 ml/kg bw (equivalent to at least 320 mg sodium pentobarbitone/kg bw) and sacrificed by exsanguination. The animals were examined macroscopically.
Statistics:
None

Results and discussion

Preliminary study:
Not applicable
Effect levels
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No deaths occurred during the study period
Clinical signs:
other: No clinical signs of systemic toxicity were observed during the observation period.
Gross pathology:
No findings were observed at necropsy
Other findings:
Skin reactions: no local effects of the test article on the skin at the application site were observed during the observation period

Any other information on results incl. tables

None

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Remarks:
Criteria used for interpretation of results: EU
Conclusions:
Under the test conditions, the dermal LD50 of the test item, Silatrizole (encoded "G4375"), was higher than 2000 mg/kg in rats and no mortality occurred at this concentration. Therefore Silatrizole should not be classified for acute dermal toxicity according to the Regulation (EC) N° 1272-2008 (CLP) and the Directive 67/548/EEC.
Executive summary:

Silatrizole (encoded "G4375") was tested for acute dermal toxicity in (HanIbm: WIST (SPF)) male and female rats in a GLP-compliant limit dose assay according to OECD guideline 402. Groups of rats (5/sex) were administered a single dermal dose of undiluted test material at 2000 mg/kg bw on clipped skin (approximately 10 % of the total body surface area) using a semi-occlusive patch held in place for 24 h. Residual test item was removed at the end of the 24 h exposure period using lukewarm tap water and the application site was dried with disposable paper towels. Examinations for mortality, clinical signs, body weight gain and dermal reactions were performed during a 14-day observation period. All surviving animals were necropsied at the end of the observation period.

No deaths occurred during the observation period. No clinical signs of systemic toxicity were observed during the observation period. The body weight gain of the animals was within the normal range for rats of this strain and age, when compared to the body weights from reference control. A slight loss of body weight in one female animal during the first observation week was considered to be a consequence of the semi-occlusive dressing. Commonly female animals prove to be more sensitive in relation to the effects on body weight caused by semi-occlusive dressing than males. At necropsy, no findings were observed.

Dermal LD50 in rats (male and female) > 2000 mg/kg bw

No local effects of the test article on the skin at the application site were observed during the observation period.

Under the test conditions, Silatrizole should not be classified for acute dermal toxicity according to the Regulation (EC) N° 1272-2008 (CLP).

This study is considered as acceptable and satisfies the requirement for acute dermal toxicity endpoint.