Registration Dossier
Registration Dossier
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EC number: 239-620-3 | CAS number: 15571-48-9
Endpoint summary
Administrative data
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
Isopropanol is associated with low acute oral toxicity. The oral LD50 was reported to be 5840 mg/kg body weight in rats after administering the test article by gavage.
Mg(OH)2
Oral: LD50 > 2000 mg/kg bw for rats.
Key value for chemical safety assessment
Additional information
Isopropanol
The potential acute oral toxicity of isopropanol was assessed in rats by Smyth and Carpenter (1948). Although study documentation is lacking in methodological details, the work of this group pre-dates range finding toxicity guidelines and provided much of the basis for their development. Their results are cited by many authoritative review bodies and often found in SIDS and SIAR documents via secondary references. Therefore, the results reported by this group are deemed reliable. In their investigation, Smyth and Carpenter (1948) determined the LD50 of isopropanol in rats to be 5840 mg/kg body weight as assessed following oral gavage administration of a range of isopropanol doses to groups of 6 Sherman rats (reported as 10, 1, 0.1, etc. g/kg body weight). Ispropanol was not classified as acutely toxic by oral exposure according to CLP.
Mg(OH)2
Oral:
According to the key study, the oral LD50 value of Magnesium hydroxide in Wister rats was established to exceed 2000 mg/kg body weight. According to OECD 423 test guideline, the LD50 cut-off value was considered to exceed 5000 mg/kg body weight. Based on these results, magnesium hydroxide does not have to be classified and has no obligatory labelling requirement for acute oral toxicity according to the:- Globally Harmonised System of Classification and Labelling of Chemicals (GHS) of the United Nations (2007)-Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures.
Furthermore, magnesiumhydroxide is extensively used as a medical drug in humans as an antacid to neutralise stomach acid and assist in the treatment of indigestion and heartburn. It is also used as a laxative and as an antiperspirant deodorant and can be useful as a topical treatment for canker sores. In its form as an indigestion and heartburn treatment, it is sold over the counter in most supermarkets, chemistries and convenience stores and does not require a prescription from a physician to be purchased. It is administered orally, usually as a chewable tablet, capsule or a suspension in water known as milk of magnesia.
The ubiquitous use of magnesium hydroxide under these therapeutic conditions, with direct skin and oral exposure, further contributes to the evidence that magnesium hydroxide is a substance of low toxicological concern.
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 acute oral toxicity. Based on the available information, magnesium isopropylate thus does not have to be classified and has no obligatory labelling requirement for acute oral toxicity. Magnesium isopropylate is classified as STOT single exposure category 3, H336 -may cause drowsiness or dizziness, based on the harmonized classification and labelling of isopropanol.
Isopropanol
The oral LD50 value of isopropanol in rats exceeds 2000 mg/kg body weight. Isopropanol thus does not have to be classified and has no obligatory labelling requirement for acute oral toxicity
according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2007) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures. Isopropanol is classified as STOT single exposure category 3, H336 -may cause drowsiness or dizziness, based on a harmonized classification and labelling.
Mg(OH)2
The oral LD50 value of Mg(OH)2 in rats exceeds 2000 mg/kg body weight. Based on the available information, magnesium hydroxide thus does not have to be classified and has no obligatory labelling requirement for acute inhalation, dermal or oral toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2007) andRegulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures.
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