(Magnesium Chloride 4.5-Hydrate, Ph. Eur. monograph 1341)
MgCl2,xH2O with x ≈ 4.5 95.21 (anhydrous substance)
DEFINITION
Content
52.5 per cent to 55.5 per cent (calculated on an as-is basis, without allowing for the results of the test for water).
CHARACTERS
Appearance
White or almost white, hygroscopic, granular powder.
Solubility
Very soluble in water, freely soluble in ethanol (96 per cent).
IDENTIFICATION
A. Water (see Tests).
B. It gives reaction (a) of chlorides (2.3.1).
C. It gives the reaction of magnesium (2.3.1).
TESTS
Solution S
Dissolve 10.0 g in carbon dioxide-free water R prepared from distilled water R and dilute to 100.0 mL with the same solvent.
Appearance of solution
Solution S is clear (2.2.1) and colourless (2.2.2, Method II).
Acidity or alkalinity
To 5 mL of solution S add 0.05 mL of phenol red solution R. Not more than 0.3 mL of 0.01 M hydrochloric acid or 0.01 M sodium hydroxide is required to change the colour of the indicator.
Bromides
Maximum 500 ppm.
Dilute 2.0 mL of solution S to 10.0 mL with water R. To 1.0 mL of the solution add 4.0 mL of water R, 2.0 mL of phenol red solution R3 and 1.0 mL of chloramine solution R2 and mix immediately. After exactly 2 min, add 0.30 mL of 0.1 M sodium thiosulfate, mix and dilute to 10.0 mL with water R. The absorbance (2.2.25) of the solution measured at 590 nm, using water R as the compensation liquid, is not greater than that of a standard prepared at the same time and in the same manner using 5.0 mL of a 3 mg/L solution of potassium bromide R.
Sulfates (2.4.13)
Maximum 100 ppm, determined on solution S.
Aluminium (2.4.17)
Maximum 1 ppm, if intended for use in the manufacture of peritoneal dialysis solutions, haemodialysis solutions, or haemofiltration solutions.
Prescribed solution: Dissolve 4 g in 100 mL of water R and add 10 mL of acetate buffer solution pH 6.0 R.
Reference solution: Mix 2 mL of aluminium standard solution (2 ppm Al) R, 10 mL of acetate buffer solution pH 6.0 R and 98 mL of water R.
Blank solution: Mix 10 mL of acetate buffer solution pH 6.0 R and 100 mL of water R.
Calcium (2.4.3)
Maximum 0.1 per cent.
Dilute 1 mL of solution S to 15 mL with distilled water R.
Iron (2.4.9)
Maximum 10 ppm, determined on solution S.
Potassium
Maximum 500 ppm, if intended for use in the manufacture of parenteral preparations.
Atomic emission spectrometry (2.2.22, Method I).
Test solution: Dissolve 1.00 g in water R and dilute to 100.0 mL with the same solvent.
Reference solutions: Prepare the reference solutions using the following solution, diluted as necessary with water R: dissolve 1.144 g of potassium chloride R, previously dried at 100-105 °C for 3 h, in water R and dilute to 1000.0 mL with the same solvent (600 μg of K per millilitre).
Wavelength 766.5 nm.
Water (2.5.12)
44.0 per cent to 48.0 per cent, determined on 50.0 mg.
ASSAY
Dissolve 0.250 g in 50 mL of water R. Carry out the complexometric titration of magnesium (2.5.11).
1 mL of 0.1 M sodium edetate is equivalent to 9.521 mg of MgCl2.
STORAGE
In an airtight container.
LABELLING
The label states:
— where applicable, that the substance is suitable for use in the manufacture of peritoneal dialysis solutions, haemodialysis solutions or haemofiltration solutions;
— where applicable, that the substance is suitable for use in the manufacture of parenteral preparations.
