Magnesium dipropan-2-olate

Endpoint summary

Description of key information

Magnesium isopropanolate rapidly hydrolyzes in aqueous environments. Toxicity is mediated by its degradation products isopropanol and Mg(OH)2 and assessed for these products.

Isopropanol

Skin: not irritating (rabbit)

Eyes: irritating (rabbit)

Mg(OH)2

Skin: not irritating based on two key in vitro studies

Eyes: not irritating (rabbit and in vitro)

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:

adverse effect observed (irritating)

Additional information

Isopropanol

Skin: 

Isopropanol did not induce dermal irritation in intact and abraded skin of rabbits or guinea pigs after a single 4-hour occlusive application. A skin irritation study on isopropanol has been performed in accordance with revised Federal Hazardous Substances Act (FHSA) procedure that had been proposed by the FDA (Nixonet al., 1975).  In this study, rabbits (strain and number of animals not reported) and Hartley guinea pigs (number of animals not reported) were exposed to isopropanol (vehicle not reported) on the intact and abraded sites (total number of sites tested was 6 for intact skin and 6 for abraded skin) under occlusive conditions. Animals were exposed to the test compound for 4 hours and observations were recorded at 4, 24, and 48 hours after removal of the patch (washing not reported).  Skin reactions were scored according to a prescribed numerical system (Edwards, 1972) and the primary irritation indice (PII) was calculated by averaging the scores for all test sites.  In addition, tissue destruction was presented as the number of sites that showed tissue destruction or a reaction grade >4.0, excluding actual abrasion, at any grading time and as a function of the total number of sites tested. 

In both rabbits and guinea pigs, the mean score for irritant response was 0 for both intact and abraded skin. The PII was 0 and the tissue destruction fraction was 0 out of 6, whether the skin was intact or abraded. Based on the results of this study, isopropanol is not a skin irritant. Isopropanol is not classified as a skin irritant according to the CLP classification criteria. 

Eye:

Eye irritation studies on isopropanol in rabbits have demonstrated that the compound is an eye irritant. In an eye irritation study conducted with rabbits (Eye Irritation: Reference chemicals data bank, 1998), undiluted isopropanol was instilled into 4 rabbit eyes (strain not reported), and ocular changes were assessed 24, 48, 72 hours as well as 7 and 10 days after treatment. Ocular changes were scored against the maximum average scoring system of Draize (1944). The modified maximum average score after 1 day was 30.5 out of a possible score of 110. Effects were fully reversed within 10 days. Therefore, isopropyl alcohol is irritating to rabbit eyes and classified accordingly.

Mg(OH)2

Skin:

Based on the two key studies, it is concluded that magnesium hydroxide is non-irritant in the in vitro skin irritation test.

In the first key study, the potential of magnesium hydroxide to induce skin irritation was tested using a human three-dimensional epidermal model. The possible skin irritation potential of magnesium hydroxide was tested using topical application for 15 minutes, followed by a 42 hour incubation period. Ten mg of magnesium hydroxide was added directly on top of the skin tissue, which was moistened with water. The mean relative tissue viabilities for magnesium hydroxide after 15 minutes of treatment were 91 %. Because the mean relative tissue viability for magnesium hydroxide was not below 50 % after the 3 minute treatment or 15 % after the 15 minute treatment, it was concluded that magnesium hydroxide is not a skin irritant under the conditions of this test.

In the second key study, the potential of magnesium hydroxide to induce skin corrision was tested using a human three-dimensional epidermal model. The possible corrosive potential of magnesium hydroxide was tested using topical application for either 3 minutes or 1 hour. Twenty five mg of magnesium hydroxide was added directly on top of the skin tissue, which was moistened with water. The mean relative tissue viabilities for magnesium hydroxide after 3 minute and 1 hour treatments were 88 % and 95 %, respectively. Because the mean relative tissue viability for magnesium hydroxide was not below 50 % after the 3 minute treatment or 15 % after the 1 hour treatment, it was concluded that magnesium hydroxide is not corrosive under the conditions of this test.

Eye:

According to the key study, since the mean in vitro irritancy score for magnesium hydroxide was below 55.1 after 240 minutes treatment, magnesium hydroxide is not classed as an irritant in the BCOP test. The study procedures were based on OECD guidelines. Magnesium hydroxide did not induce ocular irritation for both endpoints, resulting in a meanin vitroirritancy score of 5.1 after 240 minutes of treatment. Since this score is below 55.1 after 240 minutes treatment, magnesium hydroxide is not classed as an irritant in the BCOP test. An in vivo eye irritation test in rabbits did not reveal a degree of irritation that would lead to a classification as irritant to eyes.

Justification for classification or non-classification

Magnesium isopropanolate

Magnesium isopropanolate rapidly hydrolyzes in aqueous environments. Toxicity is mediated by its degradation products isopropanol and Mg(OH)2 and assessed for these products.

Both hydrolysis products are not classified for skin irritation or corrosion. Based on the available information, magnesium isopropylate thus does not have to be classified and has no obligatory labelling requirement for skin irritation/corrosion. Magnesium isopropylate is classified as Eye Irrit. 2, H319- Causes serious eye irritation, based on the harmonized classification and labelling of isopropanol.

Isopropanol

Skin irritation:

The substance does not meet the criteria for classification and labelling for this endpoint, as set out in Regulation (EC) No. 1272/2008.

Eye irritation:

According to CLP calssifcation criteria, the substance does meet the criteria for classification and labelling for this endpoint as set out in Regulation (EC) No. 1272/2008.

Isopropanol is classified as Eye Irrit. 2, H319-Causes serious eye irritation, based on a harmonized classification and labelling.

Mg(OH)2

An in vitro skin irritation study was performed on magnesium hydroxide and it was concluded that magnesium hydroxide is not irritating.

An in vitro skin corrosion study was also performed and it was concluded that magnesium hydroxide is not corrosive.

An in vitro and an in vivo eye irritation study were performed on magnesium hydroxide and it was concluded that magnesium hydroxide is not irritating.

Therefore, magnesium hydroxide is not classified as irritant or corrosive.