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%.
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.
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 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 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(330.31 / 308.34)(VC / N)(rU / rS)
in which 330.31 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 responses of warfarin obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Feiwen Mao, M.S.
(MDOOD05) Monograph Development-Ophthalmics Oncologics and Dermatologicals
Reference Standards Lili Wang, Technical Services Scientist
85 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
(MSA05) Microbiology and Sterility Assurance
USP32–NF27 Page 3869
Pharmacopeial Forum: Volume No. 33(3) Page 469
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.