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Warfarin Sodium for Injection
» Warfarin Sodium for Injection is a sterile, freeze-dried mixture of Warfarin Sodium and suitable added substances. It contains not less than 95.0 percent and not more than 105.0 percent of the labeled amount of warfarin sodium (C19H15NaO4). It may contain a suitable buffer.
Packaging and storage— Preserve in light-resistant Containers for Sterile Solids as described under Injections 1.
Completeness of solution 641 A 1.0-g portion dissolves in 10 mL of carbon dioxide-free water to yield a clear solution.
Constituted solution— At the time of use, it meets the requirements for Constituted Solutions under Injections 1.
Bacterial endotoxins 85 It contains not more than 24.0 USP Endotoxin Units per mg of warfarin sodium.
Water, Method I 921: not more than 4.5%.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Other requirements— It responds to Identification tests A and B, and meets the requirements for pH and Heavy metals under Warfarin Sodium. It meets also the requirements for Sterility Tests 71, Uniformity of Dosage Units 905, and Labeling under Injections 1.
pH 7.4 Buffer , Mobile phase, and Chromatographic system—Prepare as directed in the Assay under Warfarin Sodium.
Internal standard solution— Dissolve propylparaben in a solvent consisting of a mixture of acetonitrile and glacial acetic acid (988:12) to obtain a solution having a concentration of about 1.0 mg per mL.
Standard preparation— Transfer about 94 mg of USP Warfarin RS, accurately weighed, to a 100-mL volumetric flask, and dissolve in 39.1 mL of 0.1 N sodium hydroxide. Add 25.0 mL of 0.2 M monobasic potassium phosphate, dilute with water to volume, and mix. Pipet 5 mL of this solution and 5 mL of Internal standard solution into a 50-mL volumetric flask, dilute with pH 7.4 Buffer to volume, and mix.
Assay preparation— Dissolve the contents of not fewer than 10 containers of Warfarin Sodium for Injection in a sufficient volume, accurately measured, of pH 7.4 buffer to obtain a solution containing about 1 mg of warfarin sodium per mL. Pipet 5 mL of the resulting solution and 5 mL of Internal standard solution into a 50-mL volumetric flask, dilute with pH 7.4 buffer to volume, and mix.
Procedure— Proceed as directed for Procedure in the Assay under Warfarin Sodium. Calculate the average quantity, in mg, of warfarin sodium (C19H15NaO4) in each container of Warfarin Sodium for Injection taken by the formula:
10(330.32 / 308.34)(VC / N)(RU / RS),
in which 330.32 and 308.34 are the molecular weights of warfarin sodium and warfarin, respectively; V is the volume, in mL, of the solution prepared from the contents of the 10 or more containers; C is the concentration, in mg per mL, of USP Warfarin RS in the Standard preparation; N is the number of containers taken; and RU and RS are the peak response ratios of warfarin to propylparaben obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Staff Liaison : Feiwen Mao, M.S., Senior Scientific Associate
Expert Committee : (MDOOD05) Monograph Development-Ophthalmics Oncologics and Dermatologicals
USP29–NF24 Page 2262
Phone Number : 1-301-816-8320