Zinc distearate

Endpoint summary

Description of key information

Skin irritation

The dermal irritation potential of target chemical was assessedin various in- vitro and in-vivo experimental studies.Based on the available key data and supporting studies,it can be concluded that the testchemical is unable to cause skin irritation and considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

 

Eye irritation

The ocular irritation potential of target chemical was assessedin various experimental studies which were conducted for test chemical and its structurally similar read across substances.Based on the available key data and supporting studies,it can be concluded thatchemical is unable to cause eye irritation and considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin Irritation:

Various studies have been summarized to determine the level of dermal irritation/corrosion caused by Zinc stearate in living organisms. The results include in vivo experimental studies performed for the target chemical on rats, rabbits as well as humans.

The test uses a single rabbit ear to indicate the Comedogenicity and irritancy of Zinc stearate.

Zinc stearate was mixed in propylene glycol at a 9 to 1 dilution for testing unless otherwise indicated (10% concentration). A colony of New Zealand albino rabbits that have genetically good ears and free from mites were used. Three rabbits, weighing two to three kilograms, were used for each assay. Animals were housed singly in suspended cages and fed Purina Rabbit Chow and water ad libitum. Animals were maintained on a 12-hour light and 12-hour dark cycle. A dose of 1 ml of the test material was applied and spread once daily to the entire inner surface of once for five days per week for two weeks. The opposite untreated ear of each animal served as an untreated control.

The irritancy produced by repeated application of the chemical on the surface epidermis in the rabbit ear is evaluated on a scale of 0 to 5. The grades are summarized as follows:

 0 = No irritation; 1 = few scales, no Erythema; 2 = diffuse scaling, no Erythema; 3 = Generalized scaling with Erythema; 4 = Scaling, Erythema and Edema; 5 = Epidermal necrosis and slough.

Zinc stearate falls under Grade 0 (no irritation observed). Hence it can be concluded that zinc stearate was not irritating to rabbit ears.

This is supported by the results of an acute dermal corrosion studies conducted according to 49 CFR 173.240(a)(l) guidelines to evaluate the dermal corrosive properties of Zinc stearate.

0.5 ml (0.5 g) of the test material was applied in a single dose under occlusion to rabbits for 4 hours, the effects were observed and scored. The Primary irritation index of zinc distearate after 4 hours of exposure was 0. Based on the Primary Irritation index, it can be considered that Zinc distearate was not corrosive to rabbit skin.

These results are supported by the study performed according to Draize method to evaluate the irritation potential of Zinc stearate.

10% zinc stearate in an eye shadow formulation was applied to the skin of 6 rabbits and the effects were observed and scored. Primary irritation index score of zinc distearate was 0. Based on the Primary Irritation index, it can be considered that Zinc distearate was not irritating to rabbit skin when applied as a formulation.

The above results are further supported by the study performed to assess the dermal toxicity and irritation potential of Zinc distearate when exposed to rats daily for 6 days. 

The animals were housed in individual boxes. Tails of the rats were kept in a vessel containing 10 % emulsion of stearate and those of control animals in a vessel containing tap water. The vessels were kept inside an electrical automatic water bath where a constant temperature was kept ( 29 deg C).The animals were housed for a whole week except for Sunday, for 4 hours a day, after which term the tails were washed with warm water and dried. There were 10 animals in each control and experimental groups.

No irritation was seen following immersion of the tails of rats in a 10% emulsion of zinc distearate (in egg yolk and water) during 4 hours a day for 6 days.

Hence, Zinc distearate can be considered to be not irritating to skin.

These results are also supported by the study performed in rabbits according to Draize method to assess the dermal irritation of Zinc stearate

500 mg of the undiluted chemical was applied under occlusion to the intact and abraded skin of 6 albino rabbits for 24 hours and observed for effects. The maximum attainable Primary Irritation Index was 8.

The Primary irritation index of zinc distearate after 24 hours of exposure was 0.

Based on the Primary Irritation index, it can be considered that Zinc distearate was not irritating to rabbit skin.

Results from the available studies for the target chemical indicate a very strong possibility of Zinc stearate being not irritating to skin.

Hence, comparing the above annotations with the criteria of CLP Regulation, Zinc stearate can be classified under the category “Not Classified”.

Eye Irritation:

Various studies have been summarized to determine the level of ocular damage caused by Zinc stearate in living organisms. The results include in vivo experimental studies performed for the target chemical on rats, rabbits as well as humans.

A study was conducted to evaluate the ocular irritation potential of the test chemical according to Draize method. 6 albino rabbits were used for the study. Undiluted test chemical was instilled into the eyes of rabbits and the eyes remained unwashed. The reactions observed were scored after 1, 2, 3 days according to Draize method. The Primary Irritation Index(PII) for the test chemical after 1,2 and 3 days of exposure was 0.0. Based on the PII, the test chemical can be considered not irritating to eyes.

This is supported by the results of another ocular irritation study performed to evaluate the ocular irritation potential of the test chemical when used in a cosmetic formulation.

The test chemical was applied as 10% in eye shadow formulation to the eyes of 6 rabbits (duration of exposure not specified) and the effects were observed. The overall irritation score of the test chemical was 0 in all animals at 24, 48, and 72 hrs.

Based on the overall irritation score, the test chemical can be considered not irritating to eyes.

The above results are further supported by a Draize study performed to evaluate the ocular irritation potential of Zinc stearate. 6 albino rabbits were used for the study. Undiluted test chemical was instilled into the eyes of rabbits and the eyes remained unwashed. The reactions observed were scored after 1,2 days according to Draize method. Scores were 2 and 0 on Days 1 and 2 respectively. Based on the PII, Zinc stearate can be considered to be not irritating to rabbit eyes.

Results from the available studies for the target chemical indicate a very strong possibility of Zinc stearate being not irritating to eyes.

Hence, comparing the above annotations with the criteria of CLP Regulation, Zinc stearate can be classified under the category “Not Classified”.

Justification for classification or non-classification

According to the available data, the test chemical is not irritating or corrosive to eyes and skin. It can be classified “Not Classified” according to CLP Regulation (EC) No. 1272/2008.