U.S. PHARMACOPEIA

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Cefoxitin Injection
» Cefoxitin Injection is a sterile solution of Cefoxitin Sodium and one or more suitable buffer substances in Water for Injection. It contains Dextrose or Sodium Chloride as a tonicity-adjusting agent. It contains the equivalent of not less than 90.0 percent and not more than 120.0 percent of the labeled amount of cefoxitin (C16H17N3O7S2).
Packaging and storage— Preserve in Containers for Injections as described under Injections 1. Maintain in the frozen state.
Labeling— It meets the requirements for Labeling under Injections 1. The label states that it is to be thawed just prior to use, describes conditions for proper storage of the resultant solution, and directs that the solution is not to be refrozen.
Identification— The chromatogram of the Assay preparation obtained as directed in the Assay exhibits a major peak for cefoxitin, the retention time of which corresponds to that exhibited in the chromatogram of the Standard preparation obtained as directed in the Assay.
Bacterial endotoxins 85— It contains not more than 0.13 USP Endotoxin Unit per mg of cefoxitin.
Sterility 71— It meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined.
pH 791: between 4.5 and 8.0.
Particulate matter 788: meets the requirements for small-volume injections.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay—
Mobile phase , Phosphate buffer, Standard preparation, and Chromatographic system—Prepare as directed in the Assay under Cefoxitin Sodium.
Assay preparation— Allow 1 container of Injection to thaw, and mix. Dilute an accurately measured volume of Injection quantitatively with Phosphate buffer to obtain a solution containing about 0.3 mg of cefoxitin per mL. Use this solution within 5 hours.
Procedure— Proceed as directed in the Assay under Cefoxitin Sodium. Calculate the quantity, in mg, of cefoxitin (C16H17N3O7S2) in each mL of the Injection taken by the formula:
(CP / 1000)(L / D)(rU / rS),
in which L is the labeled quantity, in mg, of cefoxitin (C16 H17N3O7S2) in each mL of Injection taken; D is the concentration, in mg per mL, of the Assay preparation, based on the volume of Injection taken and the extent of dilution; and the other terms are as defined therein.
Auxiliary Information— Staff Liaison : Brian D. Gilbert, Ph.D., Scientist
Expert Committee : (MDANT05) Monograph Development-Antibiotics
USP29–NF24 Page 428
Phone Number : 1-301-816-8223