Electrochemical Behavior of Carvedilol and Its Adsorptive Stripping Determination in Dosage Forms and Biological Fluids

Abstract

Carvedilol is used in the management of hypertension and angina pectoris and as an adjunct to standard therapy in symptomatic heart failure. The electrochemical oxidation of carvedilol was investigated using cyclic, linear sweep voltammetry at a glassy carbon electrode. In cyclic voltammetry, in all values of pH, the compound shows two irreversible oxidation peaks. These two peaks are related to the different electroactive part of the molecule. First and second peak currents were found as diffusion and adsorption controlled, respectively. Using second oxidation step, two voltammetric methods were described for the determination of carvedilol by differential pulse adsorptive stripping voltammetry (AdSDPV) and square-wave adsorptive stripping voltammetry (AdSSWV) at a glassy carbon electrode. Accumulation of carvedilol was found to be optimized in 0.2 M H 2 SO 4 solution following 275 second accumulation time at open circuit condition. Under optimized conditions, the current showed a linear dependence with concentration in the range between 2 Â 10 À7 M and 2 Â 10 À5 M in supporting electrolyte and in the range between 2 Â 10 À7 M and 1 Â 10 À5 M in spiked human serum samples for both methods. These methods were successfully applied for the analysis of carvedilol pharmaceutical dosage forms and spiked human serum samples. The repeatability and reproducibility of the methods for all media were determined. Precision and accuracy were also found. No electroactive interferences from the tablet excipients and endogenous substances from biological material were found.

Development and Application of Electrochemical Sensor Based on Molecularly Imprinted Polymer and Carbon Nanotubes for the Determination of Carvedilol

“…This result is attributed to the synergic effect of MWCNT, which assists in the transfer of electrons, and the MIP, making the working electrode more selective for CAR. Moreover, the presence of two redox pairs can be observed, which was reported by other authors such as Dogan and Ozkan [34] and Rofouei et al [35]. On the other hand, it is well known that the electrooxidation of CAR is irreversible, thus the presence of MIP and MWCNT may improve the reversibility of the CAR redox process.…”

“…From these results, it is possible to infer that interaction of CAR with binding sites of MIP may take place by both hydrogen bonding and electrostatic attraction. Moreover, as reported in literature [34,35], alkaline pH values between 8.0 and 11.0 promote greater deprotonation in species and, consequently, higher current variation (∆I). The influence of Nafion ® 5% (m/v) on the performance of the sensor was also evaluated.…”

“…Based on this, the process was characterized as being controlled by adsorption, since the value obtained for the slope, 0.7924, tends to the theoretical value of 1, which expresses an ideal reaction controlled by adsorption, as has been documented by literature [34,38]. …”

The Analytical Applications of Square Wave Voltammetry on Pharmaceutical Analysis

“…The electrochemical oxidation of carvedilol was investigated using cyclic, linear sweep voltammetry at a glassy carbon electrode by Dogan and Ozkan [179]. In cyclic voltammetry, in all values of pH, the compound shows two irreversible oxidation peaks.…”

Application of Bromocresol Green and Bromothymol Blue for the Extractive Spectrophotometric Determination of Anti-hypertensive Drugs

“…β-blockers affect the heart and blood circulation (Flanagan, 1998). Analytical methods such as HPLC (Belal et al, 2013;Machida et al, 2003;Zarghi et al, 2007), differential pulse voltammetry (Dogan and Ozkan, 2005) and spectrofuorimetry (Önal, 2011;Cardoso et al, 2007) have been used for the determination of CRV. Fig.…”