The voltammetric behavior of nizatidine and its determination in biological fluids.

The voltammetric behavior of nizatidine (a newly introduced antiulcer drug) was studied using direct current (DCt), alternating current and differential pulse polarography (DPP). Well-defined cathodic waves were obtained over the whole pH range in Britton-Robinson buffers, in addition to 0.1 and 1 M HCl media. The main reduction wave was characterized as being irreversible and diffusion-controlled, although adsorption phenomena played a limited role in the electrode process. The current-concentration relationship was found to be rectilinear over the range 1x10(-5)-6x10(-4) and 2x10-6) -2x10(-4) M using DCt and DPP modes respectively, with a minimum detectability (S/N = 2) of 2x10(-7) M using the latter technique. The number of electrons involved in the reduction process was established, and the mechanism of electrode reaction was verified. The proposed method was successfully applied to determination of nizatidine in spiked human plasma and urine and the percentage recoveries were 96.12+/-0.40 and 97.12+/-0.17, respectively.

AC-polarographic quantitation of tolmetin sodium.

Fundamental harmonic alternating current polarography has been described for the determination of tolmetin sodium and its capsules, (Tolectin-200 mg). The AC procedure was applied by superimposing 10 mV, rms, AC voltage on a DC ramp in the range -1200 to -1450 mV at a frequency of 50 Hz in acetate buffer of pH 5.0 containing 0.001% gelatin as a maxima suppressor. A three electrode assembly consisting of dropping mercury electrode (dme) and two Ag/AgCl/KCl (sat.) electrodes was employed. Mercury flow rate was 3 mg sec(-1) under a corrected head pressure of 80 cm. The electrode reaction was investigated by Kalousek K1 and K2 techniques which indicated the non-reversibility of the electrode process on the AC time scale. The percent result obtained by standard addition procedure was 101.4 +/- 2.0 for tolmetin sodium capsules.