A: Place a Tablet in a mixture of acetone and 0.1 N hydrochloric acid (4:1) of sufficient volume to obtain a solution containing 2.5 mg of cefprozil per mL, shake for 5 minutes, and allow the mixture to settle. Proceed as directed for Identification test A under Cefprozil for Oral Suspension, beginning with “Use the supernatant as the Test solution.” The specified result is obtained.

B: The retention times of the cefprozil (Z)-isomer and cefprozil (E)-isomer peaks in the chromatogram of the Assay preparation correspond to those of the Standard preparations, as obtained in the Assay.

Medium: water; 900 mL.

Apparatus 1: 100 rpm.

Time: 45 minutes.

Procedure— Determine the amount of cefprozil (C18H19N3O5S) dissolved in the Dissolution Medium, as directed in the Assay, using instead of the Assay preparation a filtered portion of the Dissolution Medium, diluted if necessary, to obtain a test solution containing about 0.3 mg of cefprozil per mL. Calculate the quantity, in mg, of cefprozil (Z)-isomer and cefprozil (E)-isomer dissolved by the formula: in which D is 1 or, where the filtered Dissolution Medium was diluted to prepare the test solution, the appropriate dilution factor, and the other terms are as defined therein. Calculate the quantity, in mg, of cefprozil (C18H19N3O5S) dissolved by adding the quantity, in mg, of the cefprozil (Z)-isomer and cefprozil (E)-isomer dissolved.

Tolerances— Not less than 75% (Q) of the labeled amount of cefprozil (C18H19N3O5S) is dissolved in 45 minutes.

Mobile phase , Cefprozil (Z)-isomer standard preparation, Cefprozil (E)-isomer standard preparation, Resolution solution, and Chromatographic system—Proceed as directed in the Assay under Cefprozil.

Assay preparation— Transfer an accurately counted number of Tablets, equivalent to about 1500 mg of cefprozil, to a 250-mL volumetric flask containing about 180 mL of water. Allow the Tablets to disintegrate with the aid of swirling and sonication. Dilute with water to volume, and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, dilute with water to volume, and mix. Filter a portion of this solution through a filter having a porosity of 0.5 µm or finer, and use the filtrate as the Assay preparation. [note—Use this solution within 6 hours.]

Procedure— Proceed as directed for Procedure in the Assay under Cefprozil. Calculate the quantity, in mg, of cefprozil (Z)-isomer and cefprozil (E)-isomer in each Tablet taken by the formula: in which N is the number of Tablets taken, and the other terms are as defined therein. Calculate the quantity, in mg, of cefprozil (C18H19N3O5S) taken by adding quantities, in mg, determined for the cefprozil (Z)-isomer and for the cefprozil (E)-isomer in each Tablet.