Medium: water; 900 mL.

Apparatus 2: 50 rpm.

Time: 30 minutes.

Procedure— Determine the amount of cefaclor (C15H14ClN3O4S) dissolved from UV absorbances at the wavelength of maximum absorbances at about 264 nm of filtered portions of the solution under test, suitably diluted with water, in comparison with a Standard solution having a known concentration of USP Cefaclor RS in the same medium.

Tolerances— Not less than 80% (Q) of the labeled amount of cefaclor (C15H14ClN3O4S) is dissolved in 30 minutes.

Solvent, Blank solution, Solution A, Solution B, Mobile phase, Standard solution, System suitability solution, and Chromatographic system— Proceed as directed for Related compounds under Cefaclor.

Test solution— Remove as completely as possible the contents of not fewer than 20 Capsules, and mix. Transfer an accurately weighed portion of the combined contents, equivalent to about 50 mg of cefaclor, to a 10-mL volumetric flask. Dissolve in Solvent, using brief sonication, if necessary, to achieve dissolution. Avoid heating. Dilute with Solvent to volume, mix, and filter. Use this Test solution within 3 hours if stored at room temperature, or within 20 hours when stored under refrigeration.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the peak area responses for all the peaks. Calculate the mg of each related compound in the portion of Capsules taken by the formula: in which the terms are as defined for Related compounds under Cefaclor. Not more than 0.5% of any individual cefaclor-related compound is found; and the sum of all cefaclor-related compounds found is not more than 2.0%, not including the contribution of any peak that gives a result of less than 0.1%.

Mobile phase, Standard preparation, Resolution solution, and Chromatographic system— Proceed as directed in the Assay under Cefaclor.

Assay preparation— Remove, as completely as possible, the contents of not fewer than 20 Capsules, and weigh accurately. Mix the combined contents, and transfer an accurately weighed portion of the powder, equivalent to about 75 mg of cefaclor, to a 250-mL volumetric flask, dilute with Mobile phase to volume, and mix. Sonicate if necessary to ensure complete dissolution of the cefaclor. Filter to obtain the clear Assay preparation.

Procedure— Proceed as directed in the Assay under Cefaclor. Calculate the portion of C15H14ClN3O4S in the portion of Capsules taken by the formula: in which the terms are as defined therein.