The polarographic determination of tenoxicam in the pharmaceutical preparations

Abstract

In this study, the polarographic behaviour and the optimum polarographic conditions for the determination of TNX using DC (direct current), DP (differential pulse), SCAP (superimposed constant amplitude pulse) and SIAP (superimposed increasing amplitude pulse) polarographic techniques are described based on the reduction of enol group of the molecule on the dropping mercury electrode. The experiments were conducted in the aqueous supporting electrolyte solution containing 0.2 M KCl and 0.2 M buffer solution. Single waves were obtained at various pH values. The limiting currents were decreased and E-1/2 values were linearly shifted to more negative potentials with an increase in the pH. The system was irreversible at both the acidic and the basic media and it was adsorptional in the acidic medium and diffusional at pH 10.8. The variation in the limiting current was found to be 0.86 mu A/degrees C. Good relations were obtained for DC, DP, SCAP and SIAP polarographic techniques at pH 10.8. The determination of TNX in pharmaceutical preparations, namely Tilcotil(R) tablets, containing 20 mg of TNX were tested employing DC, DP, SCAP, SIAP polarographic techniques. The results were compared to those of HPLC and the standard deviations (SD) were found to be in the range of 0.14 and 0.22 for the techniques employed for;filtered and unfiltered solutions. The polarographic techniques used for the determination of TNX seem to be accurate, rapid and practical. Therefore, the suggested method may be promising in the routine analysis.