Square-wave cathodic adsorptive stripping voltammetry of risperidone

Abstract

Electrochemical properties and diffusion-adsorption behavior of risperidone (RPN), an antiphyscotic drug, on hanging mercury drop electrode (HMDE) were carried out in BrittonRobinson (BR) buffer. Some electrochemical parameters such as diffusion coefficient, number of transferred electrons and proton participated to its reduction mechanism and surface coverage coefficient were calculated from the results of cyclic voltammetry, square-wave voltammetry and constant potential electrolysis. RPN was found to be reduced with single two-electron/two-proton quasi-reversible mechanism controlled mainly by adsorption with some diffusion contribution at the potential about -1.58 V (vs Ag|AgCl electrode). Experimental parameters were optimized to develop a new, accurate, rapid, selective and simple square-wave cathodic adsorptive stripping voltammetric (SWCAdSV) method for direct determination of RPN in pharmaceutical dosage forms, spiked human urine and human serum samples without time-consuming steps prior to drug assay. This method was based on the relation between the peak current and the concentration of RPN and it was recognized that peak current of reduction wave linearly changes with the concentration of RPN in the concentration range of 1.5-150 nM, when optimum preconcentration potential -0.65 V and optimum preconcentration time 60 s were applied. In this method, limit of detection (LOD) was found as 5.18 nM (2.12 ppb). The method was successfully applied to determine the RPN content of commercial pharmaceutical preparations, spiked human serum and spiked human urine. The method was found to be highly accurate and precise, having a relative standard deviation of less than 4.80% for all applications.

Cathodic Stripping Voltammetric Determination of Febuxostat in Pharmaceutical Dosage Form and Plasma Samples

“…where, E° is the standard peak potential in Volts, is the number of protons, n is the number of electrons transferred in the mechanism, R is the ideal gas constant (8.314 J K −1 mol −1 ), T is the absolute temperature (298 K), F is Faraday's constant (96485 coulomb mol −1 ), [Ox] and [Red] are the equilibrium concentrations of reduced and oxidized species, respectively. The plot of the peak potential E p versus pH showed one straight line between 8.0 and 11.0, with slope equal to 0.058, which is close to the Nernst theoretical value of 0.059 V pH [22]; the ratio of protons to electrons that participated in the mechanism was calculated as 0.986, indicating a participation of an equal number of protons and electrons in the FEB reduction [23].…”

Adsorptive stripping voltammetric methods for determination of aripiprazole

“…When the slope of this relation was evaluated in Eq. (3.4) [20] , the ratio of proton to electron participated in mechanism was calculated as 1.52: …”

Electrochemical Behavior of Trazodone at Mercury and Glassy Carbon Electrodes and Voltammetric Methods for its Determination

“…Additionally, stripping techniques extends the use of voltammetric methods ensuring lower detection limits. In literature, there are many applications of voltammetric stripping methods to determine environmentally and biologically important substances [29][30][31][32][33][34] .…”