Voltammetric behavior of lercanidipine and its differential pulse polarographic determination in tablets

Abstract

Lercanidipine is a new third generation 1,4-dihydropyridine calcium antagonist derivative used in hypertension treatments. From the structural point of view lercanidipine contains a nitroaromatic moiety which can be electrochemically reduced. Lercanidipine in ethanol/0.04 M Britton Robinson buffer solution (20/80) presents a well-defined cathodic response, studied by both differential pulse and Tast polarography. This response was due to the irreversible, diffusion controlled, four-electron and four-proton reduction of the nitro aromatic moiety producing the corresponding hydroxylamine derivative. The DPP peak was adequately well-resolved, reproducible and linear dependent with the lercanidipine concentration. For quantification the calibration plot method for lercanidipine concentrations ranging between 3 x 10(-5) M and 9 x 10(-5) M at pH 4.0 was selected. A recovery of 98.3 +/- 0.9, with a variation coefficient of 0.94, reveal adequate precision and accuracy for the developed method. The proposed DPP method was successfully applied to the individual tablet assay in order to verify the uniformity content of lercanidipine in commercial tablets. For comparative purposes a HPLC with UV detection determination also was developed.