Belal F, Abdine H, Zoman N
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
J Pharm Biomed Anal. 2001 Nov;26(4):585-92. doi: 10.1016/s0731-7085(01)00485-x.
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, (Id) was 4.78. The current-concentration plots are rectilinear over the range 1.5-20 and 0.2-10 microg/ml using the direct current and differential pulse-polarographic techniques with minimum detectability of 0.05 microg/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.
