NON-EXTRACTIVE ULTRA-TRACE DETERMINATION OF SIMVASTATIN IN BIOLOGICAL FLUIDS BY VOLTAMMETRIC METHOD VIA COMPLEXATION WITH CADMIUM
Ali F. Alghamdi, Mohamed Hefnawy, Yasser El‐Shabrawy · 2014
The aim of the present study was to develop a rapid, non-extractive and sensitive squarewave adsorptive stripping voltammetry method for the quantitative analysis of simvastatin (SIM) in biological fluids by complex formation with Cd (II). The experimental parameters affecting the response of the SIM-Cd (II) complex were carefully investigated and optimized. This method was based on electrochemical reduction of SIM-Cd(II) complex at a hanging mercury drop electrode in Britton-Robinson buffer (pH 2.5) containing Cd(II). The cyclic voltammetry studies indicated that the reduction process was irreversible and primarily controlled by adsorption. A well-defined reduction peak was observed at -1000 mV with 30 s accumulation time and 0.0 V accumulation potential versus silver reference electrode. The developed method met ICH regulatory requirements. The AdSV peak current was proportional over the concentration range 1x10 -6 -1.5x10 -5 M, (r = 0.999), with limit of detection of 2.2x10 -10 M (n = 8). The proposed electrochemical procedure was successfully applied to the determination of SIM in human plasma and urine with mean recoveries of 85 ± 1.41% and 87 ± 1.23%, respectively. No electroactive interferences from endogenous substances were found in biological fluids.