Ammonium zinc chloride

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting 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

Data waiving:

other justification

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

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

Test material information

Constituent 1

Reference substance name:

Zinc chloride

EC Number:

231-592-0

EC Name:

Zinc chloride

Cas Number:

7646-85-7

IUPAC Name:

zinc dichloride

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 or test system 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.