(Official January 1, 2007)

Mobile phase, Standard preparation, and Chromatographic system— Prepare as directed in the Assay under Cefoperazone Sodium.

Assay preparation 1 (where it is represented as being in a single-dose container)—Constitute Cefoperazone 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 quantitatively dilute with Mobile phase to obtain a solution containing about 0.16 mg of cefoperazone per mL.

Assay preparation 2 (where the label states the quantity of cefoperazone in a given volume of constituted solution)—Constitute Cefoperazone for Injection in a volume of water, accurately measured, corresponding to the volume of solvent specified in the labeling. Quantitatively dilute an accurately measured volume of the constituted solution with Mobile phase to obtain a solution containing about 0.16 mg of cefoperazone per mL.

Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in µg of cefoperazone per mg, of the Cefoperazone for Injection taken by the formula: in which C is the concentration, in mg of cefoperazone (C25 H27N9O8S2) per mL, of the Standard preparation; M is the concentration, in mg per mL, of the Assay preparation based on the weight of Cefoperazone for Injection taken and the extent of dilution; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively. Calculate the quantity, in mg, of cefoperazone (C25H27N9O8S2), withdrawn from the container, or in the portion of constituted solution taken by the formula: in which L is the labeled quantity, in mg, of cefoperazone (C25 H27N9O8S2), in the container, or in the volume of constituted solution taken; and D is the concentration, in mg of cefoperazone (C25H27N9O8S2) 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; and the other terms are as defined therein.