亚硒酸钠英国药典2009.pdfVIP

Browse: British Pharmacopoeia 2009 British Pharmacopoeia Volume I II Monographs: Medicinal and Pharmaceutical Substances Sodium Selenite Pentahydrate Sodium Selenite Pentahydrate General Notices (Ph Eur monograph 1677) Na SeO ,5H O263.026970-82-1 2 3 2 Action and use Used in treatment of selenium deficiency. Ph Eur DEFINITION Content 98.5 per cent to 101.5 per cent. CHARACTERS Appearance White or almost white, crystalline powder, hygroscopic. Solubility Freely soluble in water, practically insoluble in ethanol (96 per cent). IDENTIFICATION A. Dissolve 50 mg in 5 ml of a mixture of equal volumes of dilute hydrochloric acid R and water R and heat to boiling. Add 0.05 g of ascorbic acid R; a red precipitate is formed which may become black. B. Dissolve 50 mg in a mixture of 1 ml of dilute hydrochloric acid R and 5 ml of water R. Add 1 ml of barium chloride solution R1; the solution remains clear. C. It gives reaction (a) of sodium (2.3.1). D. It complies with the limits of the assay. TESTS Solution S Dissolve 5.0 g in carbon dioxide-free water R and dilute to 50.0 ml with the same solvent. Appearance of solution Solution S is clear (2.2.1) and colourless (2.2.2, Method II). pH (2.2.3) ©Crown Copyright 2006 1 pH (2.2.3) 9.8 to 10.8 for solution S. Chlorides (2.4.4) Maximum 50 ppm. To 10 ml of solution S add 2 ml of nitric acid R and dilute to 15 ml with water R. Sulphates and selenates (2.4.13) Maximum 300 ppm (determined as sulphates). Dissolve 0.5 g in 10 ml of distilled water R. Add 0.5 ml of hydrochloric acid R1 and dilute to 15 ml with distilled water R. Iron Maximum 50 ppm. To 2 ml of solution S add 2 ml of a 200 g/l solution of sulphosalicylic acid R, 5 ml of concentrated ammonia R and dilute to 10 ml with water R. The solution is not more intensely coloured