pH3.6buffer ,pH7.0buffer,Mobile phase,Internal standard solution,and Chromatographic system—Prepare as directed in the Assayunder Ceftizoxime Sodium.

Standard preparation— Dissolve a suitable quantity of USP Ceftizoxime RS,accurately weighed,in pH7.0bufferto obtain a solution having a known concentration of about 1mg of ceftizoxime (C13H13N5O5S2)per mL.Transfer 2.0mLof this solution to a 100-mLvolumetric flask,add 5.0mLof Internal standard solution,dilute with pH7.0bufferto volume,and mix.This Standard preparationcontains about 0.02mg 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 pH7.0bufferto obtain a solution containing about 1mg of ceftizoxime per mL.Transfer 2.0mLof this solution to a 100-mLvolumetric flask,add 5.0mLof Internal standard solution,dilute with pH7.0bufferto 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 pH7.0bufferto obtain a solution containing about 1mg of ceftizoxime per mL.Transfer 2.0mLof this solution to a 100-mLvolumetric flask,add 5.0mLof Internal standard solution,dilute with pH7.0bufferto volume,and mix.

Procedure— Proceed with Ceftizoxime for Injection as directed for Procedurein the Assayunder Ceftizoxime Sodium.Calculate the quantity,in mg,of ceftizoxime (C13H13N5O5S2)withdrawn from the container,or in the portion of constituted solution taken by the formula: in which Lis the labeled quantity,in mg of ceftizoxime (C13H13N5O5S2),in the container,or in the volume of constituted solution taken,and Dis the concentration,in mg of ceftizoxime (C13H13N5O5S2)per mL,of Assay preparation 1or 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,Cis the concentration,in mg of ceftizoxime (C13H13N5O5S2)per mL,of the Standard preparation,and RUand RSare the peak response ratios of the ceftizoxime peak to the internal standard peak obtained from the Assay preparationand the Standard preparation,respectively.