Zinc dipropionate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-01-01 to 2018-01-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

2015-07-28

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Version / remarks:

30 May 2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal Irritation)

Version / remarks:

August 1998

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2015-06-05

Test material

Test material information

1

Reference substance name:

Zinc dipropionate

EC Number:

209-167-6

EC Name:

Zinc dipropionate

Cas Number:

557-28-8

Molecular formula:

C3H6O2.1/2Zn

IUPAC Name:

zinc dipropionate

Test material form:

solid: pellets

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: dry; < 30 °C

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, 97633 Sulzfeld, Germany
- Age at study initiation: approx 26 and 27 weeks old
- Weight at study initiation: >2 kg
- Housing: individually housed in ABS-plastic or Noryl rabbit cages, floor 4200 cm2
- Diet (ad libitum): autoclaved hay and Altromin 2123 maintenance diet for rabbits, rich in crude fibre
- Water (ad libitum): tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 18 ± 3 °C
- Relative humidity: 55 ± 10 %
- Air changes: at least 10 x / hour
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g of the test item
Because of testing a solid, the test chemical was moistened with the smallest amount of water, sufficient to ensure good skin contact.

Duration of treatment / exposure:

initial animal: 4 hours
confirmatory animal: 4 hours

Observation period:

Initial animal: 72 hours after the patch removal
Confirmatory animal: 14 days

Number of animals:

2 male rabbits

Details on study design:

TEST SITE
- Area of exposure/Type of wrap if used: approx. 24 hours before the test, the fur was removed from the dorsal area of the trunk by using an electric clipper. The test item was applied to a small area (approx. 6 cm²) of skin on one side of the dorsal area and covered with a gauze patch, which was held in place with a non-irritating tape. The untreated other side served as control. The test item was applied to the patch first and then applied to the skin. The patch was fixed with a semi-occlusive dressing. The limits of the application site were marked with an ink marker.

INITIAL AND CONFIRMATORY TESTING
The results of the initial test indicate that the test item is neither corrosive nor irritant to the skin using the procedure described. In order to confirm the negative response, one additional animal was treated in the same manner. According to OECD 404, section 17, treatment of a third animal can be omitted when animal no. 1 and 2 exhibit the same response. Also, considering the classification directives the results of animal no. 1 and 2 were sufficient for classification of the test item. Moreover, as the test item showed no signs of irritation in two animals, it is considered that adding a third animal would not change the outcome of the study.

REMOVAL OF TEST SUBSTANCE
- Washing: At the end of the exposure period, for animal no.1 the residual test item was removed with aqua ad injectionem, without altering the existing response or the integrity of the epidermis For animal no.2 the test item had not to be removed

OBSERVATION TIME POINTS
- initial animal: immediatley and 1 hour, 24, 48 and 72 hours after patch removal
- confirmatory animal: 1 hour, 24, 48 and 72 hours after patch removal and thereafter once per day (14 observation days in total)

SCORING SYSTEM: according to the Draize scale
In addition, all local effects such as hyperplasia, scaling, discolouration, fissures and scabs were also recorded.

FURTHER OBSERVATIONS
- body weights: prior to the administration and at the end of the observation period
- any systemic effects were also recorded.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 2

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 3

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 4

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

Neither erythema nor oedema was observed in two male rabbits (strain NZW) after a contact time of 4 hours during the complete observation period of 72 hours for animal no.1 and 14 days for animal no. 2.
No severe changes were observed at the skin sites. The circular redness at application site of animal no. 2 from 24h after removal of the patch until day 14 was not diagnosed as erythema or oedema, therefore it is not mentioned as dermal irritation according to Annex I of Regulation (EC) 1272/2008. It is assumed that this finding is an irrelevant and not test item related biological response.

Other effects:

- body weight: there were no significant body weight changes during the observation period
- clinical signs: no mortality was observed.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item is not irritating to the skin.
According to Annex I of Regulation (EC) 1272/2008, the test item Zinc dipropionate is not irritating to skin, hence no classification and labelling is required.