Packaging and storage—
Preserve in tight containers.
Labeling—
The Tablets prepared using the hemihydrate form of Cefadroxil are so labeled.
Identification—
Mix a quantity of powdered Tablets, equivalent to about 250 mg of cefadroxil, with water to obtain a concentration of about 2 mg of cefadroxil per mL, and filter: the filtrate so obtained responds to Identification test B under Cefadroxil.
Dissolution 
711
—
Medium:
water; 900 mL.
Apparatus 2:
50 rpm.
Time:
30 minutes.
Procedure—
Determine the amount of C
16H
17N
3O
5S dissolved from UV absorbances at the wavelength of maximum absorbance at about 263 nm of filtered portions of the solution under test, suitably diluted with water if necessary, in comparison with a Standard solution having a known concentration of
USP Cefadroxil RS in the same medium.
Tolerances—
Not less than 75% (Q) of the labeled amount of C16H17N3O5S is dissolved in 30 minutes.
Assay—
pH 5.0 Buffer, Mobile phase, Standard preparation, and Chromatographic system—
Prepare as directed in the
Assay under
Cefadroxil.
Assay preparation—
Weigh and finely powder not fewer than 10 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 200 mg of cefadroxil, to a 200-mL volumetric flask, dilute with pH 5.0 Buffer to volume, and stir by mechanical means for 5 minutes. Use this solution on the day prepared.
Procedure—
Proceed as directed for
Procedure in the
Assay under
Cefadroxil. Calculate the quantity, in mg, of C
16H
17N
3O
5S in the portion of Tablets taken by the formula:
0.2CE(rU / rS),
in which the terms are as defined therein.
