Cefoxitin for Injection
» Cefoxitin for Injection contains Cefoxitin Sodium equivalent to 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 Sterile Solids as described under Injections 1.
USP Reference standards 11
USP Cefoxitin RS Click to View Structure
USP Endotoxin RS
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 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.
Particulate matter 788: meets the requirements for small-volume injections.
Other requirements— It responds to the Identification tests and meets the requirements for pH and Water under Cefoxitin Sodium. It meets also the requirements for Uniformity of Dosage Units 905 and for Labeling under Injections 1.
Assay—
Mobile phase , Phosphate buffer, Standard preparation, and Chromatographic system—Prepare as directed in the Assay under Cefoxitin Sodium.
Assay preparation 1 (where it is represented as being in a single-dose container)—Constitute Cefoxitin for Injection in a volume of water, accurately measured, corresponding to the volume of solvent specified in the labeling. Withdraw all of the withdrawable contents, using a suitable hypodermic needle and syringe, and dilute quantitatively with water to obtain a solution having a concentration of about 0.3 mg of cefoxitin per mL. Use this solution within 5 hours.
Assay preparation 2 (where the label states the quantity of cefoxitin in a given volume of constituted solution)—Constitute Cefoxitin for Injection in a volume of water, accurately measured, corresponding to the volume of solvent specified in the labeling. Dilute an accurately measured volume of the constituted solution quantitatively with water 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 the portion of constituted solution taken by the formula:
0.001(CP)(L / D)(rU / rS)
in which L is the labeled quantity, in mg, in the portion of constituted solution taken; D is the concentration, in mg per mL, of Assay preparation 1 or Assay preparation 2, based on the volume of constituted solution taken and the extent of dilution; and the other terms are as defined therein.
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USP35–NF30 Page 2565