RESUMEN
Thermal polymerization (TP) and electropolymerization (EP) are the two methods used in this study to explore the molecular imprinting process. To detect the antiviral medication lopinavir (LPV), an inhibitor of enzyme HIV-1 protease that is co-formulated with ritonavir (RTV) to extend its half-life in the body, with greater precision, these methods were merged with an electrochemical sensor. The sensors were created on glassy carbon electrodes (GCE) based on molecularly imprinted polymers (MIP) using TP with methacrylic acid (MAA) functional monomer and EP with p-aminobenzoic acid (PABA) functional monomer. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and electrochemical methods were utilized to examine the technical features of the suggested sensors. For both approaches, the necessary optimization investigations were carried out. Different LPV concentrations, ranging from 1.0 pM to 17.5 pM in drug solution and commercial human serum samples, were used to validate the analytical efficiency of the two sensors and compare their electroanalytical behaviour. For TP-LPV@MIP/GCE and EP-LPV@MIP/GCE, the corresponding limit of detection (LOD) was 2.68 × 10-13 M (0.169 pg mL-1) and 1.79 × 10-13 M (0.113 pg mL-1) in standard solutions, and 2.87 × 10-13 M (0.180 pg mL-1) and 2.91 × 10-13 M (0.183 pg mL-1) in serum samples. For the measurement of LPV in tablet form and serum samples, the proposed TP-LPV@MIP/GCE and EP-LPV@MIP/GCE sensors provide good recovery, demonstrating 99.85-101.16 % and 100.36-100.97 % recovery, respectively. The imprinting factor was utilized to demonstrate the selectivity of the suggested sensors by utilizing several anti-viral drugs that are structurally comparable to LPV. Additionally, the constructed sensors were examined for the potential impacts of interferences and the stability during the storage.
RESUMEN
Acyclovir (ACV), a synthetic nucleoside derivative of purine, is one of the most potent antiviral medications recommended in the specific management of varicella-zoster and herpes simplex viruses. The molecularly imprinted polymer (MIP) was utilized to create an effective and specific electrochemical sensor using a straightforward photopolymerization process to determine ACV. The polymeric thin coating was developed using the template molecule ACV, a functional monomer acrylamide, a basic monomer 2-hydroxyethyl methacrylate, a cross-linker ethylene glycol dimethacrylate, and a photoinitiator 2-hydroxy-2-methyl propiophenone on the exterior of the glassy carbon electrode (GCE). Scanning electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were employed for the purpose of characterizing the constructed sensor (AM-ACV@MIP/GCE). Differential pulse voltammetry and a 5 mM ferrocyanide/ferricyanide ([Fe(CN)6]3-/4-) redox reagent were used to detect the ACV binding to the specific cavities on MIP. The study involves density functional theory (DFT) calculations, which were conducted to investigate template-functional monomer interactions thoroughly, calculate template-functional monomer interaction energies, and determine the optimal template/functional monomer ratio. DFT calculations were performed using Becke's three-parameter hybrid functional with the Lee-Yang-Parr correlation functional (B3LYP) method and 6-31G(d,p) basis set. The sensor exhibits linear performance throughout the concentration region 1 × 10-11 to 1 × 10-10 M, and the limit of detection and limit of quantification were 7.15 × 10-13 M and 2.38 × 10-12 M, respectively. For the electrochemical study of ACV, the sensor demonstrated high accuracy, precision, robustness, and a short detection time. Furthermore, the developed electrochemical sensor exhibited exceptional recovery in tablet dosage form and commercial human blood samples, with recoveries of 99.40 and 100.44%, respectively. The findings showed that the AM-ACV@MIP/GCE sensor would effectively be used to directly assess pharmaceuticals from actual specimens and would particularly detect ACV compared to structurally similar pharmaceutical compounds.
RESUMEN
Atypical antidepressant mirtazapine (MIR) is mostly prescribed for the management of major depressive disorder. The identification of MIR in pharmaceutical dosage forms was made possible by developing a novel, quick, sensitive high-performance liquid chromatography (HPLC) approach that was verified in accordance with ICH recommendations. In the first part of this study, HPLC investigations were optimized with regard to variables including pH, working column, mobile phase, temperature, and flow rate. The limit of detection (LOD) was 0.013 ppm, the limit of quantification (LOQ) was 0.044 ppm, and the linear range was computed as 0.5-15 ppm (R2 = 0.9998). The recovery investigation assessed the method's accuracy, which was shown to range between 98.82 and 100.97 %. In the second part, by using UV-vis spectroscopy, HPLC, thermal denaturation, and viscosity measurements, the mechanism of binding interaction of MIR with double-stranded fish sperm deoxyribonucleic acid (dsDNA) has been thoroughly studied. The DNA binding constants (Kb) were determined using UV-Vis absorption and HPLC methods. To investigate the interactions of MIR with dsDNA, molecular docking calculations and additionally, molecular dynamics simulations were performed. Results showed that MIR is located in the minor groove of dsDNA, and in addition to hydrogen bonding, electrostatic interaction is also formed between the aromatic ring of MIR and phosphate oxygen of dsDNA. Finally, a binding characterization study using MIR tablets was also conducted in order to assess the interaction mechanism of the DNA with the drug using the validated analytical procedure developed for the MIR molecule.
