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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1991

Materials and methods

Test guideline
Qualifier:
no guideline followed
Deviations:
not applicable
Principles of method if other than guideline:
Macroscopic skin reactions, skin histological changes and epidermal keratin binding of the test material were observed after 5 d application of test material to skin using open patch test.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Zinc chloride
- Analytical purity: 98 % (minimum)
- Storage condition of test material: Test solution in deionized water was prepared 24 h before use and stored at 4 °C.

Test animals

Species:
mouse
Strain:
other: TO (outbred) strain
Details on test animals and environmental conditions:
TEST ANIMALS
- Sex: Male
- Source: Charing Cross and Westminster Medical School, London, UK
- Age at study initiation: 8-10 wk
- Diet: Complete rodent diet (CRM, Biosure, Cambridge, UK), zinc content 65 mg/kg, w/w, ad libitum
- Water: Deionized water, ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 55
- Photoperiod (h dark/h light): 12/12


Test system

Type of coverage:
open
Preparation of test site:
other: clipped
Vehicle:
water
Controls:
yes, concurrent vehicle
Amount / concentration applied:
TEST SOLUTION
- Amount(s) applied (volume): 0.5 mL
- Concentration (if solution): 1 % w/v zinc chloride solution in deionized water
- pH: 5.6

Duration of treatment / exposure:
5 d
Observation period:
Observed during and after 5 d exposure period
Number of animals:
Six animals both in test and control group
Details on study design:
Sites of 5 x 5 cm were treated with the test solution or vehicle for 5 consecutive days. Animals were gently anaesthetized with ether until the test sites had dried. Skin sites were observed during and after 5 d exposure period.

24 h after the fifth daily treatment, animals were killed and representative samples of each test and control skin sites were preserved in 10 % phosphate buffered formalin for histology. Thin sections cut along the anterior-posterior axis were stained with haematoxylin and eosin, or with morin dye, which fluoresces blue-green in the presence of zinc ions and ultraviolet light (to demonstrate zinc binding to epidermal keratin histologically).

SCORING SYSTEM: Not reported

Results and discussion

In vivo

Results
Irritation parameter:
other: not reported
Irritant / corrosive response data:
Severe irritation was observed in all animals of the test group after 5 d exposure. No reactions were observed in control group.
Other effects:
Histological changes: Profound epidermal hyperplasia with parakeratosis and ulceration was observed.

Morin fluorescence for zinc on skin: Very prominent blue-green fluorescence was observed indicating high binding of zinc to epidermal keratin.




Any other information on results incl. tables

None

Applicant's summary and conclusion

Interpretation of results:
highly irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the test conditions, 1 % w/v zinc chloride was found to be severely irritating to mouse skin.
Executive summary:

A study was conducted to evaluate the skin irritation potential of zinc chloride in TO (outbred) strain mice.

0.5 mL of 1 % w/v zinc chloride solution or vehicle was applied to clipped sites (5 cm2) of groups of six animals for 5 consecutive days. Skin sites were observed during and after 5 d exposure period. 24 h after the fifth daily treatment, animals were killed and representative samples of each test and control skin sites were analysed histologically and stained with morin dye to study epidermal keratin binding of zinc.

Severe irritation was observed in all animals of the test group after 5 d exposure. Profound epidermal hyperplasia with parakeratosis and ulceration were observed upon histological examination. No reactions were observed in control group. Very prominent morin fluorescence was observed in skin sections indicating high binding of zinc to epidermal keratin.

Under the test conditions, 1 % w/v zinc chloride was found to be severely irritating to mouse skin.