Development of a Diamond Nanoparticles-based Nanosensor for Detection and Determination of Antiviral Drug Favipiravir

This study developed a nanosensor for the detection and determination of favipiravir, a presumed drug that has potential therapeutic efficacy in treating COVID-19 patients, from tablets and serum samples. This nanosensor was obtained by adding the optimum amount of diamond nanoparticles into carbon paste. For the determination of favipiravir adsorptive stripping differential pulse (AdSDPV) and adsorptive stripping square wave voltammetry (AdSSWV) were used. Limit of detection values were found as 4.83×10⁻⁹ M and 2.44×10⁻⁷ M for bulk and 5.18×10⁻⁸ M and 4.38×10⁻⁸ M for serum samples using AdSDPV and AdSSWV, respectively. Recovery studies made of the tablet and serum produced satisfactory results.     

Electrochemical Biosensor Design with Multi-walled Carbon Nanotube to Display DNA-Schiff Base Interaction

This paper demonstrates a Schiff base i. e. 5-(diethylamino)-2-((2,6-diethylphenylimino)methyl)phenol (5-DDMP) that was sensed by DNA biosensor. dsDNA was immobilized onto GCE modified with functionalized multi-walled carbon nanotubes to prepare a biosensor. The efficiency of dsDNA biosensor was determined and binding of 5-DDMP with dsDNA was searched by UV-vis spectrophotometry and differential pulse voltammetry. Molecular docking simulations between 5-DDMP and dsDNA were explored and as a result, a hydrogen bond and a π-π contact were observed between 5-DDMP and deoxyguanosine base (dG22) of the strand B, deoxyadenosine base (dA5) of the strand A, respectively. These studies could be useful for new anticancer drug design and development.     

Sensitive voltammetric assay of etoposide using modified glassy carbon electrode with a dispersion of multi-walled carbon nanotube

A sensitive electroanalytical method for the determination of anticancer drug etoposide (ETP) using adsorptive stripping differential pulse voltammetry (AdSDPV) at a multi-walled carbon nanotube-modified glassy carbon electrode (MWCNT-modified GCE) is presented. The surface morphology of modified electrode was characterized by scanning electron microscopy. The effects of accumulation time and potential, pH, scan rate, and amount of MWCNT suspension were investigated. The calibration curve was linear in the concentration range of 2.0?×?10^?8–2.0?×?10^?6 M with the detection limit of 5.4?×?10^?9 M. The reproducibility of the peak current was found at 1.55 % (n?=?5) RSD value in pH 6.0 Britton–Robinson buffer for the MWCNT-modified GCE. The method was then successfully utilized for the determination of ETP in pharmaceutical dosage form, and a recovery of 99.55 % was obtained. The possible oxidation mechanism of ETP was also discussed. The proposed electroanalytical method using MWCNT-modified GCE is the most sensitive method for the determination of ETP with lowest limit of detection in the previously published electrochemical methods.     

Electroanalytical Investigation and Simultaneous Determination of Etodolac and Thiocolchicoside at a Non-modified Glassy Carbon Electrode in Anionic Surfactant Media

In this study, a differential pulse voltammetry method was designed for the simultaneous determination of etodolac and thiocolchicoside in a tablet dosage form. This method is a sensitive, costless and reproducible one initially designed for the simultaneous determination of etodolac and thiocolchicoside using bare/unmodified glassy carbon electrode in the presence of sodium dodecyl sulfate. At optimized conditions, the method showed linear responses with etodolac and thiocolchicoside concentration in the range of 1 μM to 80 μM. The limits of detection and quantification were calculated as 0.11 μM and 0.38 μM for etodolac and 0.20 μM and 0.67 μM for thiocolchicoside, respectively.     

Comparative study for voltammetric investigation and trace determination of pramipexole at bare and carbon nanotube-modified glassy carbon electrodes

A sensitive, simple, and reproducible method was developed in this study for the determination of pramipexole, and in doing that, a glassy carbon electrode modified with –COOH-functionalized multi-walled carbon nanotube was utilized. The modified electrode was compared with a bare glassy carbon electrode in order to prove the sensitivity of the developed sensor. Cyclic, differential pulse, and adsorptive stripping differential pulse voltammetric techniques were used to investigate the oxidation behavior and stripping techniques were used for the determination of pramipexole. Based on optimum experimental conditions, calibration and partial validation studies were realized for bare and modified electrodes. As a result, the values of limit of detection and quantification were determined as be 2.38 × 10⁻¹⁰ and 7.93 × 10⁻¹⁰ M for bare and 1.06 × 10⁻¹⁰ and 3.52 × 10⁻¹⁰ M for modified glassy carbon electrodes, respectively. The applicability of the bare and modified electrodes was demonstrated for the determination of pramipexole in pharmaceutical dosage forms. The selectivity of the developed method was considered in the presence of Ca²⁺, Na⁺, K⁺, and glucose, ascorbic acid, uric acid, and dopamine. Interfering agents except uric acid did not affect pramipexole determination considerably.

     

Voltammetric behavior and determination of antidepressant drug paroxetine at carbon-based electrodes

Ionics - Simple, rapid, sensitive, and reproducible methods were developed for the assay of paroxetine in tablets. The electrooxidative behavior and determination of paroxetine on boron-doped...