Abstract
The aim of the present study was to develop a rapid, non-extractive and sensitive square-wave 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.