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Toxicological information

Acute Toxicity: dermal

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Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
Apr. 21, 1986 to May 5, 1986
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to a method comparable to OECD guideline 402 and conducted according to GLP. It is a read across study, hence maximum reliability rating of 2 assigned according to ECHA guidance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report date:
1986

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Reference substance name:
A mixture of: hexyldioctylphosphineoxide; dihexyloctylphosphineoxide; trioctylphosphineoxide
IUPAC Name:
A mixture of: hexyldioctylphosphineoxide; dihexyloctylphosphineoxide; trioctylphosphineoxide
Constituent 2
Reference substance name:
A mixture of: hexyldioctylphosphineoxide; dihexyloctylphosphineoxide; trioctylphosphineoxide
EC Number:
403-470-9
EC Name:
A mixture of: hexyldioctylphosphineoxide; dihexyloctylphosphineoxide; trioctylphosphineoxide
IUPAC Name:
403-470-9
Test material form:
other: Liquid
Details on test material:
- Name of the test substance (as cited in the report): CYANEX® 923 Extractant
- Lot number: 860-12,13, CT-229-85
- Physical state: clear liquid

Test animals

Species:
rabbit
Strain:
New Zealand White
Sex:
male/female
Details on test animals or test system and environmental conditions:
- Source: an FDRL-and USDA approved supplier.
- Age at Initiation: young adult.
- Identification: ear tag, color coded cage tag.
- Housing: individually housed in wire-mesh bottom cages
- Feed: NIH 09 Rabbit Ration, ad libitum, supplied fresh daily
- Water: tap water, ad libitum. Monitored for contaminants at periodic intervals according to FDRL Standard Operating Procedures.
- Photoperiod: 12 h light/dark cycle
- Weight before the beginning of the test: 2-3 kg

Administration / exposure

Type of coverage:
occlusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
The back of each rabbit was clipped with an electric clipper on the day prior to dosing. The test substance was topically applied to the non-abraded dorsal skin at a dose level of 2,000 mg/kg bw. The test sites were wrapped with an occlusive binder consisting of a layer of plastic wrap and stockinette sleeve held in place with tape. The binders were removed 24 h post-dose administration and the exposure sites gently wiped with gauze to remove as much non-absorbed test substance as possible.
Duration of exposure:
24 h
Doses:
2,000 mg/kg bw
No. of animals per sex per dose:
5/sex
Details on study design:
- Duration of observation period following administration: 14 d
- Frequency of observations and weighing: mortality and toxicity signs were recorded three times on the day of dosing and twice daily thereafter. Individual body weight data were recorded on Day 1, (prior to dose-administration) 8 and 15.
- Necropsy of survivors performed: yes

Results and discussion

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 whole study.
Clinical signs:
All animals exhibited well-defined erythema and edema at study Day 2. Eschar formation was noted in all animals by study Day 4. Diarrhea, soft stools and nasal discharge were sporadically noted from study Day 2. These findings are common among laboratory stock animals. One male exhibited anorexia and respiratory irregularity on study Day 4 and 5.
Body weight:
Weight loss was noted at Day 8 in four males and five females. This effect was transient as weight gain was noted in all animals at study termination.
Gross pathology:
No internal lesions or abnormalities were noted in any animal at study termination. The test site of all animals exhibited prominent subcutaneous vascularization.

Applicant's summary and conclusion

Interpretation of results:
not classified
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The acute dermal LD50 of the test substance was found to be >2,000 mg/kg bw in New Zealand White rabbits (Busch BA, 1986).
Executive summary:

A study was conducted in rabbits to evaluate the acute dermal toxicity of the read across substance ‘A mixture of: hexyldioctylphosphineoxide; dihexyloctylphosphineoxide; trioctylphosphineoxide’ in a method equivalent to the OECD Guideline 402, in compliance with GLP. The back of each rabbit was clipped with an electric clipper on the day prior to dosing. The test substance was topically applied to the non-abraded dorsal skin at a dose level of 2,000 mg/kg bw. The test sites were wrapped with an occlusive binder consisting of a layer of plastic wrap and stockinette sleeve held in place with tape. The binders were removed 24 h post-dose administration and the exposure sites gently wiped with gauze to remove as much non-absorbed test substance as possible. The observation period after the dermal administration lasted for 14 d. Mortality and toxicity signs were recorded three times on the day of dosing and twice daily thereafter. Individual body weight data were recorded on Days 1 (prior to dose-administration), 8 and 15. All animals killed at the termination of the study were subjected to gross necropsy. Under the study conditions, the acute dermal LD50 of the test substance was found to be >2,000 mg/kg bw in New Zealand White rabbits (Busch BA, 1986).