Development of molecularly imprinted electrochemical sensor for selective and sensitive determination of antiviral drugs acyclovir, fosamprenavir, and lopinavir

Abstract

Viruses represent the primary pathogenic agents responsible for causing serious illnesses in humans and various other organisms. Antiviral drugs have been developed to prevent and cure viral infections since they are among the most common pathogens. These antiviral agents function by interrupting the viral replication cycle at different stages, thereby addressing the infection. Currently, antiviral therapies are available for a limited range of infections, primarily focusing on alleviating symptoms, curbing transmission, and reducing the duration of the illness. Therapeutic drug monitoring (TDM) has become an essential approach for enhancing the clinical efficacy of antiviral treatments, as numerous studies have indicated a significant relationship between drug effectiveness and their concentrations in biological fluids. Increasingly, standard treatment guidelines advocate for TDM through the measurement of antiviral drug levels in patient samples, which facilitates dosage modifications to attain optimal therapeutic results. Nevertheless, the widespread application of antiviral medications has raised environmental issues. These substances enter wastewater systems not only through the use of household pharmaceuticals and personal care products but also via discharges from the pharmaceutical sector and healthcare facilities. After administration, antivirals are frequently only partially metabolized or excreted in urine and feces as pharmacologically active metabolites, which then make their way to sewage treatment plants. Traditional wastewater treatment methods often do not completely eliminate these substances, resulting in their release into aquatic ecosystems. With the global increase in the consumption of antiviral drugs, their environmental burden is anticipated to rise significantly. This development presents potential ecological threats, as the persistence of antivirals in natural environments may disrupt the biological functions of non-target organisms and contribute to wider environmental disturbances. Consequently, the advancement of rapid, accurate, and dependable methods for examining biological samples or dose forms of antiviral medications is essential. Electroanalytical techniques have been frequently employed for this purpose, with electrochemical methods holding a significant position among analytical approaches bacuse of their distinctive advantages, including specificity, sensitivity, consistency, cost-effectiveness, straightforward sample preparation, and the absence of a pre-analysis requirement. In the context of my doctoral research, sensors utilizing molecularly imprinted polymers (MIPs) were created to enable the specific and ultrasensitive detection of the antiviral medications acyclovir (ACV), lopinavir (LPV), and fosamprenavir (FPV). In the context of this doctoral research, sensors that utilize MIPs were developed to facilitate the specific and ultrasensitive detection of the antiviral medications acyclovir (ACV), lopinavir (LPV), and fosamprenavir (FPV). The electrochemical properties and surface characteristics of these sensors were assessed through various techniques, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). An innovative electrochemical sensor constructed around MIP was developed to detect ACV, utilizing acrylamide (AM) as the functional monomer through a photopolymerization (PP) technique. To assess the analytical capabilities of the AM-ACV@MIP/GCE sensor, differential pulse voltammetry (DPV) was employed. The sensor demonstrated a linear working range for both pharmaceutical dosage forms and commercial serum samples, spanning from 1×10-11 to 1×10-10 M. The sensor is capable of detecting very low concentrations of ACV, as evidenced by its limit of detection (LOD) and limit of quantification (LOQ), which are 7.15 × 10−13 M and 2.38 × 10−12 M, respectively. Furthermore, the sensor exhibited remarkable selectivity when tested against other antiviral drugs with similar structures. To detect LPV, electrochemical sensors based on MIP were created utilizing various functional monomers, including methacrylic acid (MAA) and p-aminobenzoic acid (PABA), through thermal polymerization (TP) and electropolymerization (EP) methods, respectively. The analytical performance of the TP-LPV@MIP/GCE and EP-LPV@MIP/GCE sensors was assessed using DPV. When measuring LPV in tablet formulations and serum samples, both the TP-LPV@MIP/GCE and EP-LPV@MIP/GCE sensors demonstrated excellent recovery rates, ranging from 99.85% to 101.16% and 100.36% to 100.97%, respectively. Furthermore, the sensors were evaluated for their susceptibility to interference and their stability during storage. Electrochemical sensors designed around MIP were created to detect FPV, utilizing p-aminophenol (PAP) as a functional monomer in PP and PABA in the EP technique. Following the construction of the most effective MIP-integrated electrochemical sensors, their performance metrics were assessed and compared. The linear detection ranges for PP-FPV@MIP/GCE and EP-FPV@MIP/GCE were found to be 1.0-17.5 pM and 1.0-10.0 pM, respectively, in both standard and commercial human serum preparations. In standard conditions, the LOD for PP-FPV@MIP/GCE and EP-FPV@MIP/GCE were determined to be 2.84 × 10−13 M and 2.27 × 10−13 M, respectively, while in serum samples, these values were slightly altered to 2.48 × 10−13 M and 2.38 × 10−13 M. Furthermore, density functional theory (DFT) simulations were utilized to determine the ideal ratio of the template to the functional monomer, as well as to assess the interaction energies that exist between them. In this thesis, electrochemical sensors built around MIP are used for the first time to analyze antiviral medications. Furthermore, it offers a novel comparison between distinct molecular imprinting techniques for the first time. A comprehensive examination of these molecular imprinting methods has been undertaken to qualitatively/quantitative assess the presence of antiviral drugs in pharmaceutical and biological samples. This thesis study encourages the development of antiviral drug analysis options that exhibit greater selectivity than those reported in previous studies.