Carbon nanomaterials as electrochemical sensors for theophylline: a review

Abstract

Theophylline (TP) is a methylxanthine derivative, which serves as a valuable compound in treating respiratory disorders and acts as a bronchodilator agent. However, TP has a limited therapeutic range (20-100 μmol L^-1), demanding precise monitoring to prevent potential drug toxicity even with slight level fluctuations during treatment. Thus, to overcome this limitation, electrochemical methods have been extensively used due to their efficacy in achieving sensitivity, selectivity, and accuracy. In the context of electrochemical sensors, nanocarbon-based materials have gained widespread recognition for their extensive applications. Therefore, this review aims to explore the latest advancements in carbon-based electrodes particularly used for the precise determination of TP through electrochemical methods. The results are expected to provide insights into the profound significance of the methods in enhancing the accuracy and sensitivity for the detection of TP.

Fig. 1. Structure of theophylline.

Scheme 1. Various forms of CNM including 0D, 1D, 2D, and 3D carbon nanostructures.

Scheme 2. Some respiratory diseases are treated using TP and body fluids containing drug residues.

Fig. 2. Plausible reaction mechanism of TP. Reprinted with permission from ref. , Copyright (2021), Elsevier.

Fig. 3. Procedure for the preparation of (a) B/RGO nano-sheet, (b) TiO₂@CuO-B/RGO nanocomposites, and (c) design of electrochemical sensor for the simultaneous detection of UA and TP by the PAMT/AuNPs/TiO₂@CuO-B/RGO nanocomposite. Reprinted with permission from ref. . Copyright (2023), Elsevier.

Fig. 4. (a) DPV of 40 μM TP on different electrodes in 10 mM H₂SO₄. Reprinted with permission from ref. . Copyright (2021), Elsevier and (b) DPV of 0.1 M TP current response on ZnONPs-MWCNTs-Cyt c-GCE electrode with the addition of various interfering species. Reprinted with permission from ref. . Copyright (2020), Elsevier.

Fig. 5. (a) CV of blank (a) and TP (b) in H₂SO₄ on the BDD electrode. Reprinted with permission from ref. , Copyright (2015), The Royal Society of Chemistry. (b) CV of the blank (0.1 M PBS) for the BDD electrode (blue), BDD (red) and BDD/NiNP electrode (purple) in 60 μM TP, (c) CV of bare recorded at GCE (blue) and GCE/Chi-CDs (red), and (d) CV of CPE on PBS pH 3.0 (a), CPE/MB on PBS pH 3.0 (b), CPE on PBS containing TP (c), and CPE/MB on PBS containing TP (d). Reprinted with permission from ref. Copyright (2018), Elsevier.