PULSE POLAROGRAPHIC (CONSTANT AND INCREASING) DETERMINATIONS OF DOXAZOSIN IN PHARMACEUTICAL TABLETS

The optimum conditions using DC polarography and the determination of doxazosin employing SIAP and SCAP polarographic techniques are describ ed in this study. All the experiments were conducted in the supporting electrolyte consisting of 20% ethanol (v/v), 0.2 M KCl and 0.2 M acet ate buffer at various PH values in order to examine the optimum condit ions, and PH 3.5 for the determination of doxazosin. Well-defined curv es were obtained in the pH range of 1.5-7.5. The system was diffusiona l and irreversible at pH 3.5. The calibration studies were performed b y using SIAP and SCAP polarography and satisfactory results were obser ved for all techniques. Since the sensitivity of SIAP and SCAP techniq ues were higher than the others, the determination of doxazosin was pe rformed in filtered and unfiltered tablet solutions containing 4 mg ac tive material. In the analysis of a tablet, the relative standard devi ations (S-rel%,) of the techniques are in the filtered solutions +/-0. 9 (SIAP), +/-0.8 (SCAP) and in the unfiltered solutions +/-0.7 (SIAP), +/-0.8 (SCAP) and no interference was observed during the analysis. T he determination methods proposed in this study appear to be accurate, rapid and practicable. Therefore, these techniques may be suitable fo r the content uniformity tests. (C) 1998 Elsevier Science B.V. All rig hts reserved.