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Category Antibacterial (first-generation cephalosporin).

Cefadroxil Capsules contain the equivalent of not less than 90.0 per cent and not more than 120.0 per cent of the labelled amount of C₁₆H₁₇N₃O₅S.

Strength available 500 mg (anhydrous).

Dose Adults: 1 to 2 g daily as a single dose or in two divided doses.
          Children: 30 mg per kg of body weight as a single dose or in two divided doses.

Contra-indication; Warning; Precaution See under Cephalexin, p. 58.

Additional information See under Cefadroxil, p. 37.

Packaging and storage Cefadroxil Capsules shall be kept in tightly closed containers.

Labelling The label on the container states (1) the quantity equivalent to the amount of anhydrous cefadroxil; (2) whether it is in the monohydrate or hemihydrate form.

Identification
          A. The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
          B. Carry out the test as described in the “Thin-layer Chromatography” (Appendix 3.1), using silica gel H as the coating substance and a mixture of 3 volumes of a 6.7 per cent w/v solution of ninhydrin in acetone,80 volumes of 0.1 M disodium hydrogenphosphate and 120 volumes of 0.1 M citric acid as the mobile phase. Impregnate the plate by development with a 5 per cent v/v solution of n-tetradecane in hexane. Allow the solvent to evaporate and carry out the chromatography in the same direction as the impregnation. Apply separately to the plate, 20 μl of each of the following solutions. For solution (A) stir a quantity of the contents of the capsules containing the equivalent of 200 mg of anhydrous cefadroxil with 100 ml of water, filter and use the filtrate. Solution (B) contains 0.2 per cent w/v of Cefadroxil RS in water. After removal of the plate, allow it to dry in air, spray with a 0.2 per cent w/ v solution of ninhydrin in absolute ethanol, heat the plate at 110º for 10 minutes and allow it to cool. The principal spot in the chromatogram obtained from solution (A) is similar in position and size to that in the chromatogram obtained from solution (B).

Dissolution Carrry out the test as described in the “Dissolution Test” (Appendix 4.24).
          Dissolution medium: water; 900 ml.
          Apparatus 1: 100 rpm.
          Time: 30 minutes.
          Procedure Determine the amount of C₁₆H₁₇N₃O₅S dissolved from absorbances at the maximum at about 263 nm of filtered portion of the test solution, suitably diluted with Dissolution medium, if necessary, in comparison with a standard solution having a known concentration of Cefadroxil RS in the same medium (Appendix 2.2).

Tolerances Not less than 80 per cent (Q) of the labelled amount of C₁₆H₁₇N₃O₅S is dissolved in 30 minutes.

Water Not more than 7.0 per cent w/w (Karl Fischer Method, Appendix 4.12). Use 500 mg.

Assay Carry out the determination as described in the “High-pressure Liquid Chromatography” (Appendix 3.5).

          Mobile phase, Resolution solution, Chromatographic system and Procedure Proceed as directed in the Assay described under Cefadroxil, p 37.
          Standard preparation Dissolve an accurately weighed quantity of Cefadroxil RS, in Buffer phosphate solution and dilute quantitatively to obtain a solution having a known concentration of about 1 mg per ml.
          Assay preparation Remove as completely as possible, the contents of not less than 20 Cefadroxil Capsules and weigh accurately. Mix the combined contents, and transfer an accurately weighed quantity, containing about 200 mg of cefadroxil, to a 200-ml volumetric flask. Add 150 ml of Buffer phosphate solution, and shake for 5 minutes. Dilute with the same solvent to volume and filter.
          Calculation Calculate the content of C₁₆H₁₇N₃O₅S in the portion of the Capsules taken, using the declared content of C₁₆H₁₇N₃O₅S in Cefadroxil RS.

Other requirements Comply with the requirements described under “Capsules” (Appendix 1.16).