pH 7.0 Buffer, pH 5.0 Buffer, Mobile phase, Standard preparation, Resolution solution, and Chromatographic system— Prepare as directed in the Assay under Ceftriaxone Sodium.

Assay preparation 1— Transfer about 40 mg of Ceftriaxone for Injection, accurately weighed, to a 200-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix. Use this solution promptly after preparation.

Assay preparation 2 (where it is represented as being in a single-dose container)—Constitute Ceftriaxone 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 Mobile phase to obtain a solution containing about 180 µg of ceftriaxone per mL. Use this solution promptly after preparation.

Assay preparation 3 (where the label states the quantity of ceftriaxone in a given volume of constituted solution)—Constitute Ceftriaxone 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 Mobile phase to obtain a solution containing about 180 µg of ceftriaxone per mL. Use this solution promptly after preparation.

Procedure— Proceed as directed in the Assay under Ceftriaxone Sodium. Calculate the quantity, in µg, of ceftriaxone (C18H18N8O7S3) per mg of the Ceftriaxone for Injection taken by the formula: in which C is the concentration, in mg per mL, of USP Ceftriaxone Sodium RS in the Standard preparation; P is the designated potency, in µg, of ceftriaxone per mg of USP Ceftriaxone Sodium RS; W is the quantity, in mg, of Ceftriaxone for Injection taken to prepare Assay preparation 1; and rU and rS are the ceftriaxone peak responses obtained from Assay preparation 1 and the Standard preparation, respectively. Calculate the quantity, in mg, of ceftriaxone (C18H18N8O7S3) withdrawn from the container, or in the portion of constituted solution taken by the formula: in which L is the labeled quantity, in mg, of ceftriaxone (C18H18 N8O7S3) in the container, or in the volume of constituted solution taken; D is the concentration, in µg per mL, of ceftriaxone in Assay preparation 2 or Assay preparation 3, 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 per mL, of USP Ceftriaxone Sodium RS in the Standard preparation; P is the designated potency, in µg, of ceftriaxone per mg of USP Ceftriaxone Sodium RS; and rU and rS are the ceftriaxone peak responses obtained from the Assay preparation and the Standard preparation, respectively.