Simple and Rapid Method by Ultra High-Performance Liquid Chromatography (UHPLC) with Ultraviolet Detection for Determination of Efavirenz in Plasma: Application in a Preclinical Pharmacokinetic Study

Analytical approaches for determination of COVID-19 candidate drugs in human biological matrices

Since the outbreak of the COVID-19 pandemic, the use of antiviral and other available drugs has been considered to combat or reduce the clinical symptoms of patients. In this regard, it would be necessary to choose sensitive and selective analytical techniques for pharmacokinetic and pharmacodynamic studies, monitoring of drug concentration in biological fluids, and determination of the most appropriate dose to achieve the desired effect on the disease. In the present study, the analytical techniques based on spectroscopy and chromatography with different detectors for diagnosis and determination of candidate drugs in the treatment of COVID-19 in human biological fluids are reviewed during the period 2015-2022. Moreover, various sample preparation and extraction techniques, are being used for this purpose, such as protein precipitation (PP), solid-phase extraction (SPE), liquid-liquid extraction (LLE), and QuEChERS (quick, easy, cheap, effective, rugged, and safe) are investigated.

Insights into the Design of An Enzyme Free Sustainable Sensing Platform for Efavirenz

In this study, a new hybrid sensor was developed using titanium oxide nanoparticles (TiO2-NPs) and nafion as an anchor agent on a glassy carbon electrode (GCE/TiO2-NPs-nafion) to detect efavirenz (EFV), an anti-HIV medication. TiO2-NPs was synthesized using Eucalyptus globulus leaf extract and characterized using ultraviolet–visible spectroscopy (UV–VIS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS). The electrochemical and sensing properties of the developed sensor for EFV were assessed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The current response of GCE/TiO2-NPs-nafion electrode towards the oxidation of EFV was greater compared to the bare GCE and GCE/TiO2-NPs electrodes. A linear dynamic range of 4.5 to 18.7 µM with 0.01 µM limit of detection was recorded on the electrode using differential pulse voltammetry (DPV). The electrochemical sensor demonstrated good selectivity and practicality for detecting EFV in pharmaceuticals (EFV drugs) with excellent recovery rates, ranging from 92.0–103.9%. The reactive sites of EFV have been analyzed using quantum chemical calculations based on density functional theory (DFT). Monte Carlo (MC) simulations revealed a strong electrostatic interaction on the substrate-adsorbate (GCE/TiO2-NPs-nafion-EFV) system. Results show good agreement between the MC computed adsorption energies and the experimental CV results for EFV. The stronger adsorption energy of nafion onto the GCE/TiO2-NPs substrate contributed to the catalytic role in the signal amplification for sensing of EFV. Our results provide an effective way to explore the design of new 2D materials for sensing of EFV, which is highly significant in medicinal and materials chemistry.