Voltammetric determination of nilvadipine in dosage forms and spiked human urine

The voltammetric behaviour of nilvadipine was studied adopting direct-current, differential-pulse and alternating current polarography. Nilvadipine-being nitroderivative-exhibited well-defined cathodic waves over the whole pH range in Britton-Robinson buffers. At pH 5, the diffusion-current constant, (ld) was 4.78. The current-concentration plots are rectilinear over the range 1.5-20 and 0.2-10 mug/ml using the direct current and differential pulse-polarographic techniques with minimum detectability of 0.05 mug/ml (1.3 x 10(-7) M) using the latter technique. The proposed method was applied to commercial capsules containing the drug. The percentage recoveries were in agreement with those obtained by a reference method. Furthermore, the method was applied to spiked human urine, the percentage recovery was 95.54 +/- 2.137. (C) 2001 Elsevier Science B.V. All rights reserved.