Electroanalytical Characterisation of Dopa Decarboxylase Inhibitors Carbidopa and Benserazide on Multiwalled Carbon Nanotube and Poly(Nile blue A) Modified Glassy Carbon Electrodes

Abstract

Modified glassy carbon electrodes have been made by deposition of functionalised multiwalled carbon nanotubes (MWCNTs) followed by formation of poly(Nile blue) (PNB) films by electropolymerisation, using potential cycling in 0.1 M phosphate buffer solution (PBS) at pH 6.0. The electrochemical oxidation of carbidopa (CD) and benserazide (BS) on these MWCNTs/PNBmodified electrodes was investigated using cyclic and differential pulse voltammetry in 0.1 M PBS at different values of pH between 5.0 and 8.0; both CD and BS gave one diffusion-controlled irreversible oxidation peak in cyclic voltammetry. Analytical characterisation of CD and BS was carried out in 0.1 M PBS, pH 5.0. Peak currents in differential pulse voltammetry were linear over the concentration range of 1 × 10 −5 to 1 × 10 −4 M for CD and 4 × 10 −6 to 4 × 10 −5 M for BS. The repeatability, precision, and accuracy of the method were also investigated. Higher sensitivities and lower detection limits, of 1.17 µM for CD and 0.50 µM for BS, were obtained with this new modified electrode compared with previous studies reported in the literature.

Highly Sensitive Carbon Based Sensors Using Zinc Oxide Nanoparticles Immobilized Multiwalled Carbon Nanotubes for Simultaneous Determination of Desvenlafaxine Succinate and Clonazepam

“…The diffusion coefficients of DVS and CLZ at MWCNTs/ZnO-NPs/CPE electrode were calculated from the slope of the linear plot of the catodic peak current and the square root of the potential scan rate using the Randles-Sevcik equation 22 for totally irreversible electrontransfer process. 34 Ipa = (2.69…”

“…It has large pore volume, uniform pore size and good electronic behavior which promote electrons transfer due to great electroactive surface area which promote the adsorption of molecules and reactive sites and increase electrocatalytic affect so it can be used in sensors and biosensors. [19][20][21][22][23][24] Zinc oxide nano particles (ZnO-NPs) have great importance because of their utilization in biosensors, cosmetics and also drugdelivery systems. ZnO-NPs demonstrate great electro-catalytic effect and strong adsorption ability.…”

Bioelectroanalysis of pharmaceutical compounds

“…Mixtures with cerium dioxide [263] and silica [264] have also been investigated. Finally, poly(Nile blue) has been employed with CNT to measure carbidopa and benserazide [265], the phenazine acting as redox mediator to enhance the signal and providing a more highly conducting matrix.…”

Electrochemical Sensor Based on Multi-Walled Carbon Nanotubes and N-Doped TiO2 Nanoparticles for Voltametric Simultaneous Determination of Benserazide and Levodopa

“…However, for the treatment of diseases that are associated with depletion of dopamine in the brain, such as Parkinson’s disease, high doses of L-dopa are necessary because it is rapidly decarboxylated and very little unchanged drug is available to cross the blood–brain barrier for central conversion into dopamine. To increase the amount of L-dopa that enters the brain it is usually given with a peripheral decarboxylase inhibitor such as BEZ, thus permitting a considerably higher proportion of L-dopa to enter the brain [ 1 , 2 ]. Thus, the combination of L-dopa and BEZ is effective in the treatment of Parkinson’s, and its synergistic effect reduces the required dose of L-dopa for the optimal and earlier therapeutic response [ 3 ].…”