A: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

B: It meets the requirements of the tests for Manganese 191.

Phosphate buffer and Mobile phase— Proceed as directed in the Assay under Mangafodipir Trisodium.

Standard preparation— Prepare a solution of USP Mangafodipir Trisodium RS in water having a known concentration of about 2 mg per mL. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, add 5.0 mL of Phosphate buffer, dilute with water to volume, and mix. [note—Store under nitrogen to avoid excessive exposure to air and light.]

Assay preparation— Transfer an accurately measured volume of Injection, equivalent to about 100 mg of mangafodipir trisodium, to a 50-mL volumetric flask, dilute with water to volume, and mix. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, add 5.0 mL of Phosphate buffer, dilute with water to volume, and mix. [note—Store under nitrogen to avoid excessive exposure to air and light.]

Chromatographic system— Prepare as directed in the Assay under Mangafodipir Trisodium. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 1000 theoretical plates; and the tailing factor is not more than 2.3.

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 mg, of mangafodipir trisodium (C22H27MnN4Na3O14P2) in each mL of the Injection taken by the formula: in which C is the concentration, in mg per mL, of USP Mangafodipir Trisodium RS in the Standard preparation; V is the volume, in mL, of Injection taken to prepare the Assay preparation; and rU and rS are the mangafodipir peak responses obtained from the Assay preparation and the Standard preparation, respectively.