Medium— Dissolve 54.5 g of glycine and 42.6 g of sodium chloride in about 500 mL of water in a 1000-mL volumetric flask. Cautiously add, with swirling, 14.2 mL of hydrochloric acid, and allow to cool. Dilute with water to volume, and mix. Transfer 50 mL of this stock solution to a flask, and dilute with water to 900 mL to obtain a solution having a pH of 3.0 ± 0.1. [NOTE—If necessary, adjust the pH of the stock solution with 10 N sodium hydroxide so that when 50 mL is diluted with water to 900 mL the pH of the Dissolution Medium is 3.0 ± 0.1.]

Apparatus 2: 75 rpm.

Time: 30 minutes.

Procedure— Determine the amount of cefpodoxime (C15H17N5O6S2) dissolved by employing UV absorption at about 259 nm on filtered portions of the solution under test in comparison with a Standard solution having a known concentration of USP Cefpodoxime Proxetil RS prepared by dissolving an accurately weighed portion in a small volume of methanol and diluting quantitatively with Dissolution Medium.

Tolerances— Not less than 70% (Q) of the labeled amount of cefpodoxime (C15H17N5O6S2) is dissolved in 30 minutes.

(Official January 1, 2007)

Mobile phase, Diluent, and Chromatographic system— Prepare as directed in the Assay under Cefpodoxime Proxetil.

Standard preparation— Transfer about 30 mg of USP Cefpodoxime Proxetil RS, accurately weighed, to a 50-mL volumetric flask, dissolve in 5 mL of methanol, dilute with Diluent to volume, and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, dilute with Diluent to volume, and mix. Pass through a filter having a 0.45-µm or finer porosity.

Assay preparation— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 50 mg of cefpodoxime to a 100-mL volumetric flask. Dissolve in 40 mL of Diluent, sonicating for 5 minutes. Cool to room temperature, dilute with Diluent to volume, and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, dilute with Diluent to volume, mix, and pass through a filter having a 0.45-µm or finer porosity.

Procedure— Separately inject equal volumes (about 20 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 cefpodoxime (C15H17N5O6S2) in the portion of Tablets taken by the formula: in which C is the concentration, in mg per mL, of USP Cefpodoxime Proxetil RS in the Standard preparation; P is the designated potency, in µg per mg, of cefpodoxime (C15H17N5O6S2) in USP Cefpodoxime Proxetil RS; and rU and rS are the sums of the peak responses for cefpodoxime proxetil S-epimer and cefpodoxime proxetil R-epimer obtained from the Assay preparation and the Standard preparation, respectively.