» Cephradine Tablets contain not less than 90.0 percent and not more than 120.0 percent of the labeled amount of cephradine, calculated as the sum of cephradine (C16H19N3O4S) and cephalexin (C16H17N3O4S).
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Identification Mix a quantity of finely powdered Tablets with water to obtain a concentration of about 3 mg of cephradine per mL, and filter (Test solution). Proceed as directed in the Identification test under Cephradine Capsules, beginning with Place a suitable thin-layer chromatographic plate: the RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Medium: 0.12 N hydrochloric acid; 900 mL.
Apparatus 2: 75 rpm.
Time: 60 minutes.
Procedure Determine the amount of C16H19N3O4S dissolved from UV absorbances at the wavelength of maximum absorbance at about 255 nm of filtered portions of the solution under test, suitably diluted with Dissolution Medium, in comparison with a Standard solution having a known concentration of USP Cephradine RS in the same medium.
Tolerances Not less than 85% (Q) of the labeled amount of C16H19N3O4S is dissolved in 60 minutes.
Uniformity of dosage units 905: meet the requirements.
Water, Method I 921: not more than 6.0%.
Mobile phase, Standard preparation, Resolution solution, and Chromatographic system Proceed as directed in the Assay under Cephradine.
Assay preparation Place not less than 5 Tablets in a high-speed glass blender jar containing an accurately measured volume of water, sufficient to yield a concentration of not less than 5 mg of cephradine per mL, and blend for 4 ± 1 minutes. Dilute an accurately measured volume of this stock solution quantitatively and stepwise with Mobile phase to obtain an Assay preparation containing about 0.5 mg of cephradine per mL.
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 cephradine (sum of cephradine and cephalexin) in each Tablet taken by the formula:
(CP)(L / 1000D)(rU / rS)in which C is the concentration, in mg per mL, of USP Cephradine RS in the Standard preparation; P is the designated potency, in µg per mg, of USP Cephradine RS; L is the labeled quantity, in mg of cephradine, in each Tablet; D is the concentration, in mg of cephradine per mL, of the Assay preparation, based on the labeled quantity per Tablet, the number of Tablets taken, and the extent of dilution; and rU and rS are the sums of the cephradine and cephalexin peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 2596