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This is a draft proposal for The International Pharmacopoeia (Working document QAS/14.579, June 2014).
The working document with line numbers is available for comment at www.who. int/medicines/areas/qualitv safetv/qualitv assurance/projects/en/. Please address any comments to: World Health Organization, Quality Assurance and Safety: Medicines, Dr Herbert Schmidt, 1211 Geneva 27, Switzerland; fax: +41 22 791 4730; email: [email protected].
[Note from the Secretariat. It is proposed to revise the monograph on Dexamethasone sodium phosphate in The International PharmacopoeiaJ
[Note from the editor. In accordance with WHO editorial policy the text reproduced below does not include tracked changes. Changes from the current monograph are indicated by insert and delete in the working document available at the above-mentioned web address.]
C^FNaAP
Relative molecular mass. 516.4
Chemical name. 9-Fluoro-11ß, 17,21-trihydroxy-16a-methylpregna-1,4-diene-3,20-dione 21-(dihydrogen phosphate) disodium salt; 9-fluoro-11ß,17-dihydroxy-16a-methyl-21(phosphonooxy)pregna-1,4-diene-3,20-dione disodium salt; CAS Reg. No. 2392-39-4.
Description. A white or almost white, crystalline powder.
Solubility. Freely soluble in water; slightly soluble in ethanol (-750 g/L)TS; practically insoluble in ether R and methylene chloride R.
Category. Adrenal hormone.
Storage. Dexamethasone sodium phosphate should be kept in a tightly closed container, protected from light.
Additional information. Dexamethasone sodium phosphate is very hygroscopic. Even in the absence of light it is gradually degraded on exposure to a humid atmosphere, the decomposition being faster at higher temperatures. Dexamethasone sodium phosphate may exhibit polymorphism.
Requirements
Definition. Dexamethasone sodium phosphate contains not less than 97.0% and not more than 102% of C22H28FNa208P, calculated with reference to the anhydrous and ethanol-free substance.
Identity tests
A. Carry out the test as described under 1.14.1 Thin-layer chromatography using silica gel R1 as the coating substance and a freshly prepared mixture of 3 volumes of 1-butanol R, 1 volume of acetic anhydride R and 1 volume of water as the mobile phase. Apply separately to the plate 5 pL of each of 4 solutions in methanol R containing (A) 1 mg of the test substance per ml, (B) 1 mg of dexamethasone sodium phosphate RS per ml, (C) a mixture of equal volumes of solutions (A) and (B), and (D) equal volumes of solution (A) and a solution of 1 mg of prednisolone sodium phosphate RS per ml of methanol R. After removing the plate from the chromatographic chamber allow it to dry in air until...