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This is a draft proposal for The International Pharmacopoeia (Working document QAS/14.580, 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. To prevent oxidative decomposition of dexamethasone phosphate in aqueous solution sodium metabisulfite is used as an antioxidant. Dijkstra and Dekker1 reported the addition of bisulfite at the C-1 of the corticosteroid. Comments are in particular sought regarding an appropriate limit for this adduct (impurity I) (see also test for related substances).]
Description. A clear, colourless solution
Category. Adrenal hormone.
Storage. Dexamethasone phosphate injection should be kept in a tightly closed container, protected from light. It should not be allowed to freeze.
Labelling. The designation on the container should state the amount of active ingredient as the equivalent quantity of Dexamethasone phosphate in a suitable dose volume.
Additional information. Strength in the current WHO Model list of essential medicines for dexamethasone: 4 mg/mL (as disodium phosphate salt) in 1 ml ampoule. Strength in the current WHO Model list of essential medicines for children: 4 mg/mL (as disodium phosphate salt) in 1 ml ampoule.
4 mg of dexamethasone phosphate is approximately equivalent to 4.37 mg of dexamethasone sodium phosphate.
Requirements
Complies with the monograph for Parenteral Preparations.
Definition. Dexamethasone sodium phosphate injection is a sterile solution of Dexamethasone sodium phosphate in water for injections. It contains not less than 90.0% and not more than 110.0% of the amount of Dexamethasone phosphate C^H^FOgP stated on the label.
Identity tests
A. Carry out the test as described under 1.14.1 Thin-laver chromatography using silica gel R2 as the coating substance and a mixture of 60 volumes of 1-butanol R, 20 volumes of acetic acid (-300 g/L) TS and 20 volumes of water R. Apply separately to the plate 5 pL of the following 3 solutions in methanol R. For solution (A) dilute a volume of the injection to obtain a solution containing 1.0 mg of dexamethasone phosphate per ml. For solution (B) use dexamethasone sodium phosphate RS...