7487-88-9

Magnesium sulfate (MgS04) is a colorless crystal with a bitter, saline taste. It is soluble in glycerol and used in fireproofing, textile processes, ceramics, cosmetics, and fertilizers.

Magnesium Sulfate is found widely in nature as either a double salt or as a hydrate, colorless crystals,very soluble in water, soluble in glycerol, sparingly soluble in alcohol.

In their hydrated form, these salts have a pH of 6.0 (5.5 to 6.5) in solution. These magnesium sulfates are white crystalline solids. Their densities are: 2.66 g/cm3 (anhydrous); 2.445 g/cm3 (monohydrate); 1.68 g/cm3 (heptahydrate). Solubilities in water are: anhydrous＝ 26.9 g/100 ml (0°C); monohydrate＝ 25.5 g/100 ml (20°C); heptahydrate＝71 g/100 ml (20°C). Magnesium sulfate is found in nature in many salt deposits and mineral waters, occurring as hydrates or double salts. The heptahydrate or Epsom salt was discovered in 1695, found inthemineralwater at Epsom. Kieserite and epsomite are the two most important minerals. Other than these and the above hydrates, magnesium sulfate is also found in several other minerals, including langbeinite, leonite,vanthoffite,bloedite,kainite,polyhalite,

Magnesium sulfate is utilized in the potassium chemicals industry for the manufacture of potassium sulfate (from potassium chloride), sodium sulfate and potash magnesia (potassium magnesium sulfate). Magnesium sulfate, particularly as kieserite, is used as a fertilizer (ca. 80% of total consumption). It is also used in the textile industry, in the manufacture of building and refractory materials, in the pulp industry and in the production of animal feedstuffs and motor oil additives.

ChEBI: A magnesium salt having sulfate as the counterion.

Magnesium sulfate prevents convulsions in preeclampsia and directly uncouples excitation–contraction in myometrial cells through inhibition of cellular action potentials. Furthermore, magnesium sulfate decreases calcium uptake by competing for its binding sites, activating adenylyl cyclase (thereby reducing intracellular calcium), and stimulating calcium-dependent adenosine triphosphatase (ATPase), which promotes calcium uptake by the sarcoplasmic reticulum. Magnesium is filtered by the glomerulus, so patients with low glomerular filtration will have low magnesium clearance. Although the compound does have some cardiac side effects, magnesium sulfate may be preferred over β- adrenergic agents in patients with heart disease, diabetes, hypertension, or hyperthyroidism.

Magnesium sulfate is widely distributed in nature, e.g. in salt deposits as kieserite, as Epsom salt MgSO4 . 7H20, in the form of double salts such as kainite 4KCl . 4MgSO4 . 11H20 and langbeinite K2SO4 . 2MgSO4, and in brines. Large quantities of kieserite, Epsom salt and anhydrous magnesium sulfate are produced in the processing of potassium salts. Magnesium sulfate is also produced by reacting magnesium carbonate or seawatermagnesium hydroxide with sulfuric acid.

Magnesium sulfate may be effective in terminating refractory ventricular tachyarrhythmias, particularly polymorphic ventricular tachycardia. Digitalis-induced arrhythmias are more likely in the presence of magnesium deficiency. Magnesium sulfate can be administered orally, intramuscularly, or, preferably, intravenously,when a rapid response is intended.The loss of deep tendon reflexes is a sign of overdose.

Magnesium sulphate is a white compound existing both in anhydrous (rhombic) and hydrated crystalline forms. The monohydrate MgSO₄·H₂O (monoclinic) occurs in nature as kieserite. It is a greyish-white crystalline powder which contains about 16 % magnesium and is used as a fertilizer. It is regarded as a concentrated form of epsom salt, having less water of crystallization. The commonest hydrate is heptahydrate MgSO₄·7H₂O(also called rhombic or epsom salt) which occurs naturally as the mineral epsomite. It is a white powder with a bitter, saline taste. The salt in the monocliic form loses its structural water at 150°C, while the rhombic form loses water at 200°C.
Magnesium sulphate is used in sizing and freproofng cotton and silk, in tanning leather, in the manufacture of fertilizers, in explosives and matches, in medicines as a laxative, and as a veterinary medicine for the treatment of inflammations and infected wounds.

Magnesium sulfate has anti-convulsant, anti-inflammatory and vasodilatory properties. Magnesium sulfate relaxes smooth muscles. In acute asthma patients, use both intravenous and nebulization of magnesium sulfate as additive treatment improves pulmonary function. Magnesium sulfate reduces preterm labor in high risk pregnant women.

There is much debate as to the efficacy of magnesium sulfate. For effective inhibition of uterine activity, enough must be given to maintain a blood plasma level of at least 5.5 mEq/L. Even at this level, tocolysis may be hard to achieve.

The side effects of magnesium sulfate administration are dose dependent. As magnesium levels increase, skeletal muscle weakness increases and CNS depression and vascular dilation occur. Magnesium sulfate infusion commonly results in a slight decrease in blood pressure during epidural anesthesia.
Cardiac muscle is not affected to a clinically evident degree when magnesium is administered at therapeutic levels, although magnesium can have profound myocardial effects during a gross overdose.
Magnesium antagonizes the vasoconstrictive effect of α-agonists, so ephedrine and phenylephrine are likely to less effectively increase maternal blood pressure when administered concomitantly with magnesium.
Magnesium is eliminated unchanged by the kidneys. In a patient who is receiving a maintenance infusion of magnesium and who has decreasing urine output, blood levels of magnesium quickly increase, as do related side effects.
Other side effects of magnesium sulfate include the following: (1) Cutaneous vasodilation with flushing (2) Headache and dizziness (3) Nausea (4) Skeletal muscle weakness (5) Depression of deep tendon reflexes (6) Respiratory depression (7) ECG changes

Crystallise it from warm H2O (1g/mL) by cooling. Dry the heptahydrate (Epsom salt) at ~250o until it loses 25% of its weight. Its solubility in H2O is 36% at 20o, 55% at 60o and 74% at 100o; above 110o the solubility decreases with rise of temperature. Store it in a sealed container.

Magnesium sulfate is not for use in patients with heart block or extensive myocardial damage. Use it with caution in patients with impaired renal function, in digitalized patients, and with concomitant use of other central nervous system depressants or neuromuscular blocking agents. Intravenous administration is contraindicated during the 2 hours preceding delivery. Oral administration is contraindicated in patients with abdominal pain, nausea, vomiting, fecal impaction, or intestinal irritation, obstruction, or perforation.