Current Analytical Chemistry - Volume 20, Issue 7, 2024

Biophysical techniques include various methodologies applied in studying biological systems at the molecular and cellular level for the drug discovery process. Various methods like isothermal calorimetry, electron microscopy, XRD (X-ray diffraction), electron microscopy, mass spectrometry, atomic force microscopy, differential scanning calorimetry, surface plasmon resonance, and nuclear magnetic resonance are important techniques for drug discovery. Out of these techniques, XRD is widely employed in structure-based drug discovery, whereas FBDD (fragment-based drug discovery) is widely used in the different phases of drug discovery. XRD was considered one of the most important tools for structure determination of biomolecules and peptides. Consistent development and advancement in XRD improved the various aspects of data processing, collection, sample loading, and increased throughput. This advancement is crucial in obtaining highly resolved protein and other biomolecule crystal structures. The structure obtained from XRD forms the core of structure-based drug discovery and FBDD. This review article focuses on the different roles of biophysical techniques with special emphasis on advancement, data collection, and XRD's role in different drug discovery phases.

Background: Tetracycline (TC), a commonly used antibiotic, is extensively utilized in the medical sector, leading to a significant annual discharge of tetracycline effluent into the water system, which harms both human health and the environment. Objective: A novel technique was developed to address the issues of photogenerated carrier complexation and photocatalyst immobilization. Compared to traditional photocatalytic photoelectrodes, the suspended catalyst used in the photovoltaic synergy field is more stable and increases the solidliquid contact area between the catalyst and the pollutant. Methods: This paper uses sol-gel-prepared Ag-TiO2 materials for the photoelectric synergistic fieldcatalyzed degradation of TC. The study examined how the Ag doping ratio, calcination conditions, catalyst injection, pH, electrolytes, and electrolyte injection affected photoelectric synergistic fieldcatalyzed degradation. The experiments were performed in a photocomposite field with a constant 50 mA current and a 357 nm UV lamp for 60 minutes. The composites underwent characterization using XRD, TEM, and XPS techniques. Results: Ag-TiO2 photoelectric synergistic field-catalyzed reaction with 357 nm ultraviolet lamp irradiation for 60 min and a constant current of 50 mA degraded 5 mg/LTC under preparation conditions of molar doping ratio of Ti: Ag=100:0.5, roasting temperature of 500 °C, and roasting time of 2 h. The photoelectric synergistic field-catalyzed degradation process achieved a degradation rate of 90.49% for 5 mg/L TC, surpassing the combined degradation rates of electrocatalysis and photocatalysis. The quenching experiments demonstrated that the degradation rate of TC decreased from 90.49% in the absence of a quencher to 53.23%, 42.58%, and 74.52%. The presence of •OH had a more significant impact than h⁺ and •O2^-. Conclusion: The findings suggest that Ag-TiO2 significantly enhanced the efficacy of photoelectric synergistic field-catalyzed degradation and can be employed to treat high-saline and lowconcentration TC. This establishes a benchmark for using photoelectrocatalytic materials based on titanium in treating organic wastewater.

Introduction: A simple, precise, and sensitive UV spectrophotometric method was developed to estimate Imipramine and Ferulic acid in bulk and polymeric micelles formulation. Moreover, imipramine and ferulic acid showed maximum absorbance at 237 nm and 216 nm. Methods: The method was validated for linearity, accuracy, precision, robustness, and ruggedness. The detector response for the imipramine and ferulic acid was linear over the selected range of 2 to 12 μg/ml with a correlation coefficient of 0.996 and 0.997. The accuracy was 99.4 and 101.02%. The precision (RSD) among six sample preparations was 0.68% and 0.85%. The method was validated as per the ICH guidelines. A polymeric micelle formulation was developed containing Vitamin E TPGS and F-127 as a surfactant and block co-polymer using different solvents. The optimized formulation containing 40 mg of F-127 and 30 mg of TPGS yielded the desired attributes of the optimized formulation. Results: The optimized formulation was subjected to freeze-drying and yielded nanoparticulate size and excellent flowability. In vitro, the release of both drugs from the polymeric micelles was evaluated using dissolution, and multi-fold enhancement in release behavior was demonstrated compared to pure drugs. Both drugs were simultaneously detected successfully with accuracy and precision in bulk form and during in vitro analysis. Conclusion: The developed method can be adopted in routine analysis of imipramine and ferulic acid in bulk, and it involves relatively low-cost solvents with no complex extraction techniques.

Introduction: This study synthesizes and characterizes a novel hybrid composite, SGdpm, to capture UO2²⁺ ions from water. The composite has successfully formed by hosting covalently diphenylmethane-1,3-dione (dpm) within an inorganic silica gel matrix, showing promising potential for environmental remediation and nuclear waste management. Methods: The preparation involved the reaction of tetraethylorthosilicate (TEOS) with diphenylmethane- 1,3-dione (dpm) under acidic conditions, resulting in white solids. The doped composite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), revealing the presence of siloxane and Si-O-C bonds. The application of SG-dpm for capturing UO2²⁺ ions from water was investigated, showing a shift in FTIR peaks and confirming the formation of SG-dpm-UO2²⁺ as inner-sphere complexes. Scanning Electron Microscopy (SEM) revealed a non-uniform distribution of particles, essential for consistent behavior in applications such as adsorption. Results and Discussion: Batch sorption experiments demonstrated temperature-dependent sorption behavior with increased efficiency at higher temperatures (T = 55°C). The study also explored the influence of pH and initial concentration on UO2²⁺ sorption, revealing optimal conditions at pH 5 and lower initial concentrations (1.0 mg L^-1). Kinetic studies using pseudo-second-order models indicated a high efficiency of UO2²⁺ ion removal (99%) as a chemisorption process. Intraparticle diffusion models highlighted three distinct sorption stages. Sorption isotherm studies favored the Langmuir model, emphasizing monolayer adsorption. The thermodynamic analysis suggested an endothermic (ΔH = + 16.120 kJ mol^-1) and spontaneous (ΔG = −25.113 to − 29.2449 kJ mol^-1) sorption process. Selectivity studies demonstrated high efficiency in capturing Cu²⁺, Co²⁺, and Cr³⁺ ions, high degree selectivity of UO2²⁺ ions (74%), moderate efficiency for Fe³⁺ and Zn²⁺, and lower efficiency for Pb²⁺, Ni²⁺, and Cd²⁺, and poor efficiency for Mn²⁺ ions. Conclusion: SG-dpm exhibits promising potential for selective UO2²⁺ ion removal, demonstrating favorable characteristics for various applications, including environmental remediation and nuclear waste management.

Introduction: Lung carcinoma presents an aggressive evolution, with its carriers having reduced survival. Late diagnosis is one of the main factors of death. In the neoplasia in question, there is an established correlation with increases in Alpha-Fetoprotein (AFP) serum concentrations. Methods: Commonly used diagnostic methods are invasive or inaccessible. Therefore, a low-cost, non-invasive method would be extremely promising, and biomarkers can be used to achieve this goal. Electrochemical biosensors are a promising approach for detecting analytes of clinical interest using innovative bioreceptors. In this work, we obtained an electrochemical biosensor based on a hybrid ligand metal-organic structure (ZIF-8-905%) and functionalized carbon nanotubes (MWCNTs- COOH) in association with the lectin Concanavalin A (ConA), as a biorecognition element for detecting AFP in human serum from patients with lung carcinoma. Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV), and Electrochemical Impedance Spectroscopy (EIS) were used to characterize the development of this biosensor. Microscopic analysis through Atomic Force Microscopy (AFM) revealed the formation of ConA-AFP complexes, pointing out the sensor's ability to identify the target analyte. Results: The blocking electron transfer effect in the electrode-redox pair interface assessed AFP detection. The ZIF-8-905%/MWCNTs-COOH/ConA platform exhibited a limit of detection (LOD) of 7.98 ng/mL, and a limit of quantification (LOQ) of 23.78ng/mL was also estimated. In addition, the biosensor showed excellent selectivity towards interfering biomolecules. Conclusion: Therefore, the biosensor represents an efficient form of detection, contributing to research that aims to detect tumor biomarkers and ensure better prognoses.

Background: Thyroid hormones play an important role in cognition and brain development. The determination of the content of levothyroxine, as well as related substances and dissolution test analysis, should be carried out by methods that are selective and highly sensitive due to the low concentration used in low dose orodispersible minitablets. Objectives: This study aims to develop and validate an analytical method by HPLC-UV for the quantification of levothyroxine and its related substances in pharmaceutical formulations; looking forward to being this method suitable for a future dissolution test analysis using tandem mass spectrometry detector. Methods: A Hypersil GOLD C18 (100 x 2.1 mm, 3 μm) column was used with 25°C column temperature, 5 μL injection volume, 0.3 mL/min flow rate and detection at 225 nm. The mobile phase consisted of methanol: 0.05% formic acid (55:45). The developed method was validated for specificity, linearity, precision, accuracy and robustness. Results: The method is linear within the range of 2-20 μg mL-1 (R2=0.9982), which makes the method suitable for the evaluation of levothyroxine in pharmaceuticals formulations. LOQ was 0.17 μg/mL (0.85 ng on column) and LOD 0.05 μg/mL (0.25 ng on column) of LT4. Therefore, in terms of efficiency (1671), retention factor, k (6.79), Tailing factor, T (1.09) and resolution, Rs (5.11) the chromatographic method was found to be suitable according to USP 43. Conclusion: The HPLC UV method was found to be linear, specific, precise, accurate and robust, therefore it is suitable for the quality control of levothyroxine in pharmaceutical ODMTs.