สารบัญ

Category Antibacterial (antileprosy); dermatitis herpetiformis suppressant.

Dapsone Tablets contain not less than 92.5 per cent and not more than 107.5 per cent of the labelled amount of C₁₂H₁₂N₂O₂S.

Strengths available 25 and 100 mg.

Dose Leprosy----Adults: In combination with one or more other antileprosy agents, 50 to 100 mg once a day; or 1.4 mg per kg of body weight once a day.

Children: In combination with one or more other antileprosy agents, 1.4 mg per kg of body weight once a day.

          Dermatitis herpetiformis suppressant----Adults: Initially 50 mg daily. Doses may be increased up to 300 mg daily if symptoms are not completely controlled. The dose should then be reduced to the lowest effective maintenance dose as soon as possible.

          Children: Initially 2 mg per kg of body weight daily. Doses may be increased if symptoms are not completely controlled. The dose should then be reduced to the lowest effective maintenance dose as soon as possible.

Contra-indication; Warning; Precaution; Additional information See under Dapsone, p. 91.

Packaging and storage Dapsone Tablets shall be protected from light.

Identification

          A. Shake a portion of the powdered tablets, containing 100 mg of dapsone, with 20 ml of acetone, filter and evaporate the filtrate to dryness: the infrared absorption spectrum of the residue is concordant with the spectrum obtained from Dapsone RS (Appendix 2.1) or with the reference spectrum of Dapsone.

          B. Triturate a portion of the powdered tablets, containing 100 mg of dapsone, with 50 ml of methanol, and filter. Dilute a portion of the filtrate with methanol to make approximately a 0.0005 per cent w/v solution: the ultraviolet absorption spectrum of the resulting solution, when observed between 230 and 350 nm,exhibits two maxima at 260 nm and 295 nm (Appendix 2.2).

          C. 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.

Dissolution Carry out the test as described in the “Dissolution Test” Appendix 4.24).

Dissolution medium: diluted hydrochloric acid (2 in 100); 1000 ml.

          Apparatus 1: 100 rpm.

          Time: 60 minutes.

          Procedure Withdraw and filter a portion of the test solution. Transfer an accurately measured portion of the filtrate, estimated to contain about 200 μg of dapsone, to a 25-ml volumetric flask, add 5 ml of 1 M sodium hydroxide, dilute with water to volume, and mix. Determine the amount of C₁₂H₁₂N₂O₂S dissolved from absorbances at the maximum at about 290 nm of the solutions so obtained from the test solution in comparison with a standard solution having a known concentration of Dapsone RS in the same medium (Appendix 2.2).

          Tolerances Not less than 75 per cent (Q) of the labelled amount of C₁₂H₅N₂O₂S is dissolved in 60 minutes.

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

Mobile phase, Standard preparation, Chromatographic system, and Procedure Proceed as directed in the Assay under Dapsone, p. 92.

          Assay preparation Weigh and finely powder not less than 20 Dapsone Tablets. Transfer an accurately weighed portion of the powder, containing about 50 mg of dapsone, to a 200-ml volumetric flask. Add 150 ml of methanol and sonicate at a temperature of 35º for 15 minutes, with occasional shaking. Allow to cool to room temperature, add methanol to volume and mix. Centrifuge a portion of the mixture until clear. Pipette 5 ml of the clear supernatant liquid to a 50-ml volumetric flask, dilute with Mobile phase to volume and mix.

         Calculation Calculate the content of C₁₂H₁₂N₂O₂S in the portion of the Tablets taken, using the declared content of C₁₂H₁₂N₂O₂S in Dapsone RS. 

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