Electrochemical Behaviour Study and Determination of Guanine, 6‐Thioguanine, Acyclovir and Gancyclovir on Fluorine‐doped SnO₂Electrode. Application in Pharmaceutical Preparations

Abstract

An electroanalytical method using square wave voltammetry (SWV) is proposed for the quantification of Guanine (G), 6‐Thioguanine (TG), Acyclovir (Acy) and Ganciclovir (Gan) in different types of pharmacological samples. In addition, for the first time, a study of the electrochemical behavior (using cyclic voltammetry, CV) of guanine and its pharmacological derivatives on fluoride doped oxide (FTO) electrodes was carried out. The study of CV potential scanning demonstrated the charge transfer process was diffusion controlled and the diffusion coefficient was determined for all the studied products. Besides, electrochemical parameters, such as transfer coefficient, heterogeneous charge transfer constant and the number of electrons transferred (e) were determined namely, 4e for TG and 2e for G, Acy and Gan. SWV studies at pH 4 for G and 2 for TG, Acy and Gan showed linear ranges between 4.0×10−6 and 40.0×10−6 mol L−1, with detection limits of 0.91×10−6 for G, and 1.50×10−6 for TG, 1.25×10−6 for Acy and 0.45×10−6 mol L−1 for Gan. The method presents sensitivity and stability appropriate to be employed in quality control and routine quantification of drugs in pharmaceutical formulations.

Improved Performance for the Electrochemical Sensing of Acyclovir by Using the rGO–TiO2–Au Nanocomposite-Modified Electrode

“…The detection limit is 0.3 μM based on a signal-to-noise ratio of 3. The rGO–TiO 2 –Au/GCE showed a comparable or better dynamic range and detection limit for ACV compared to other electrochemical sensors, such as Cu nanoparticle-modified carbon paste electrode (2.64 μM) ( Heli et al, 2010 ), pencil graphite electrode (0.3 μM) ( Dilgin and Karakaya, 2016 ), nanoporous nickel microsphere-modified carbon paste electrode (40 μM) ( Heli et al, 2012 ), fluorine-doped SnO 2 electrode (1.25 μM) ( Martínez-Rojas et al, 2017 ), and CdO/Fe 3 O 4 -modified carbon paste electrode (0.3 μM) ( Naghian et al, 2020 ).…”

Voltammetric Mixture Analysis of 6-thioguanine and Folic Acid Using Ionic Liquid-Carbon Paste Electrode Modified by Nano Petal-Like MoWS2 and N-(ferrocenylmethylidene)fluoren-2-amine

“…The detection limit (3σ) was determined at 0.09 μm for 6-TG. The present modified electrode was compared with other previous works 20,[55][56][57][58][59][60] for the detection of 6-TG and results are summarized in Table I. According to these results it is possible to conclude that the developed electrode shows comparable or superior analytical performance to most of the other electrochemical techniques.…”

First Acyclovir Determination Procedure via Electrochemically Activated Screen-Printed Carbon Electrode Coupled with Well-Conductive Base Electrolyte

“…According to the data in the literature and the results obtained, the process of acyclovir oxidation relies on deprotonation and cleavage of the double bond in the imidazole ring between the N (7) = C (8) atoms. The described process of ACY electrooxidation into an oxoguanine analogue is shown in Figure 4 [ 4 , 27 , 28 ].…”