(Official January 1, 2007)

pH 3.6 Buffer , pH 7.0 Buffer, Mobile phase, Internal standard solution, and Chromatographic system—Prepare as directed in the Assay under Ceftizoxime Sodium.

Standard preparation— Dissolve a suitable quantity of USP Ceftizoxime RS, accurately weighed, in pH 7.0 Buffer to obtain a solution having a known concentration of about 1 mg of ceftizoxime (C13H13N5O5S2) per mL. Transfer 2.0 mL of this solution to a 100-mL volumetric flask, add 5.0 mL of Internal standard solution, dilute with pH 7.0 Buffer to volume, and mix. This Standard preparation contains about 0.02 mg of ceftizoxime per mL.

Assay preparation 1 (where it is represented as being in a single-dose container)—Constitute Ceftizoxime 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 pH 7.0 Buffer to obtain a solution containing about 1 mg of ceftizoxime per mL. Transfer 2.0 mL of this solution to a 100-mL volumetric flask, add 5.0 mL of Internal standard solution, dilute with pH 7.0 Buffer to volume, and mix.

Assay preparation 2 (where the label states the quantity of ceftizoxime in a given volume of constituted solution)—Constitute Ceftizoxime 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 pH 7.0 Buffer to obtain a solution containing about 1 mg of ceftizoxime per mL. Transfer 2.0 mL of this solution to a 100-mL volumetric flask, add 5.0 mL of Internal standard solution, dilute with pH 7.0 Buffer to volume, and mix.

Procedure— Proceed with Ceftizoxime for Injection as directed for Procedure in the Assay under Ceftizoxime Sodium. Calculate the quantity, in mg, of ceftizoxime (C13H13N5O5S2) withdrawn from the container, or in the portion of constituted solution taken by the formula: in which L is the labeled quantity, in mg of ceftizoxime (C13H13N5O5S2), in the container, or in the volume of constituted solution taken, and D is the concentration, in mg of ceftizoxime (C13H13N5O5S2) per mL, of Assay preparation 1 or Assay preparation 2, based on the labeled quantity in the container or in the portion of constituted solution taken, respectively; and the extent of dilution, C is the concentration, in mg of ceftizoxime (C13H13N5O5S2) per mL, of the Standard preparation; and RU and RS are the peak response ratios of the ceftizoxime peak to the internal standard peak obtained from the Assay preparation and the Standard preparation, respectively.