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NORFLOXACIN TABLETS

Category Antibacterial.

      Norfloxacin Tablets contain not less than 90.0 per cent and not more than 110.0 per cent of the labelled amount of C16H18FN3O3.

Strengths available 100, 200 and 400 mg.

Dose It should be taken on an empty stomach.

      Adults----Gastro-intestinal infection: 400 mg every 12 hours for 3 to 5 days.

      Traveler’s diarrhea: 400 mg every 12 hours for 1 to 3 days.

Gonorrhea or urethritis, gonococcal: 800 mg as a single dose.

      Prostatitis: 400 mg every 12 hours for 28 days.

      Urinary tract infections, uncomplicated: 400 mg every 12 hours for 3 days.

      Urinary tract infections, complicated: 400 mg every 12 hours for 10 to 21 days.

Contra-indication; Warning; Precaution; Additional information See under Norfloxacin, p. 133.

Identification

      A. Carry out the test as described in the “Thin-layer chromatography” (Appendix 3.1), using silica gel GF254 as the coating substance and a mixture of 40 volumes of chloroform, 40 volumes of methanol, 20 volumes of toluene, 14 volumes of diethylamine, and 8 volumes of water as the mobile phase. Apply separately to the plate, 50 μl of each of the following solutions. For solution (A), shake a quantity of finely powdered tablets, equivalent to 75 mg of norfloxacin, with 50 ml of a mixture of an equal volumes of acidic methanol, prepared by mixing 1000 ml of methanol and 9 ml of hydrochloric acid, and dichloromethane. Centrifuge a portion of this suspension, and use the clear supernatant obtained as the test solution. Solution (B) is 1.5 mg per ml of Norfloxacin RS in the same solvent. After removal of the plate, allow it to dry in air for 15 minutes and examine under ultraviolet light (254 nm). The principal spot in the chromatogram obtained from solution (A) corresponds to that obtained from solution (B).

      B. 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).

      pH 4.0 buffer To 900 ml of water in a 1000-ml volumetric flask add 2.86 ml of glacial acetic acid and 1.0 ml of a 50 per cent w/v solution of sodium hydroxide, dilute with water to volume, and mix. If necessary, adjust with glacial acetic acid or the sodium hydroxide solution to a pH of 4.0.

      Dissolution medium: pH 4.0 buffer; 750 ml.

      Apparatus 2: 50 rpm. 

      Time: 30 minutes.

      Procedure Determine the amount of C16H18FN3O3 dissolved from absorbances at the maximum at about 278 nm of filtered portions of the test solution, suitably diluted with Dissolution medium, if necessary, in comparison with a standard solution having a known concentration of Norfloxacin RS in the same medium (Appendix 2.2).

      Tolerances Not less than 80 per cent (Q) of the labelled amount of C16H18FN3O3 is dissolved in 30 minutes.

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

      Mobile phase Prepare a mixture of 85 volumes of diluted phosphoric acid (1 in 1000), and 15 volumes of acetonitrile. Make adjustments if necessary.

      Standard preparation Dissolve an accurately weighed quantity of Norfloxacin RS in Mobile phase and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 200 μg per ml.

      Assay preparation Weigh and finely powder not less than 20 Norfloxacin Tablets. Transfer an accurately weighed portion of the powder containing about 100 mg of norfloxacin, to a 200-ml volumetric flask. Add 80 ml of Mobile phase, sonicate for 10 minutes, dilute with diluted phosphoric acid (1 in 1000) to volume and mix. Transfer 10.0 ml of this solution to a 25-ml volumetric flask, dilute with Mobile phase to volume, mix and filter.

      Chromatographic system The chromatographic procedure may be carried out using (a) a stainless steel column (30 cm × 3.9 mm) packed with octadecylsilane chemically bonded to porous silica or ceramic microparticles (3 to 10 μm) maintained at 40º±1º, (b) Mobile phase at a flow rate of about 2.0 ml per minute and (c) an ultraviolet photometer set at 275 nm.

      To determine the suitability of the chromatographic system, precondition the column with 0.01 M sodium dihydrogenphosphate adjusted with phosphoric acid to a pH of 4.0, flowing at a rate of 0.5 ml per minute for 8 hours. Chromatograph Standard preparation, and record the peak responses as directed under Procedure: the capacity factor is not less than 2, the symmetry factor for the norfloxacin peak is not more than 2.0 and the relative standard deviation for replicate injections is not more than 2.0 per cent.

      Procedure Separately inject equal volumes (about 10 μl) of Standard preparation and Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks.

      Calculation Calculate the content of C16H18FN3O3 in the portion of the Tablets taken, using the declared content of C16H18FN3O3 in Norfloxacin RS.

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

MONOGRAPHS • NORFLOXACIN TABLETS
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หมายเหตุ / Note : TP II 2011 PAGE 134-135