In Vitro Pharmacokinetic Profiling of Thiourea Derivatives of Naproxen With Anti-Inflammatory and Anticancer Activity Nikola Nedeljković, Vladimir Dobričić, Marina Vesović, Ratomir Jelić, Bojan Marković, et al. Chemistry and Biodiversity, 2026 Pharmacokinetic deficiencies account for nearly 40% of clinical drug candidate failures, emphasising the importance of early in vitro evaluation. Following the 3Rs principle, this study assessed the in vitro pharmacokinetic properties of thiourea derivatives of naproxen ( 1 – 14 ). Permeability assessment using the parallel artificial membrane permeability assay method revealed that derivatives 4 (‐logPe = 4.13, p = 0.0859) and 7 (‐logPe = 3.94, p = 0.2291) exhibited the highest passive gastrointestinal absorption potential, comparable to naproxen. Evaluation of binding affinity to human serum albumin (HSA) using the high‐performance affinity chromatography method identified two groups of compounds: high‐binding aromatic amine derivatives (except derivative 5 ) and low‐binding aromatic amino acid ester derivatives. Microsomal stability assays indicated that compound 7 underwent the most extensive metabolic degradation (65.83% decrease). These findings suggest that further structural optimisation of compound 7 , such as esterification with higher or branched alcohols, should lead to the improvement of HSA binding and reduction of metabolic susceptibility. Conversely, compound 4 combines favorable biological activity with a pharmacokinetic profile closely resembling that of naproxen. Although limited by the exclusive use of in vitro models and the absence of in vivo validation, this study provides valuable insights for the rational design of naproxen‐based thiourea derivatives with enhanced anti‐inflammatory and anticancer potential.
Analysis of the Lipophilicity and HSA Binding Profile of Biologically Relevant 2-Mercaptobenzoic Acid Derivatives Miloš Nikolić, Ratomir Jelić, Nikola Nedeljković, Marina Vesović, Gordana Radić, et al. Chemistry and Biodiversity, 2025 One of the key factors determining a compound's distribution, metabolism, and therapeutic properties is its binding affinity to human serum albumin (HSA). This study investigated the binding interaction between potential biologically active S‐alkyl (methyl‐[L1], ethyl‐[L2], propyl‐[L3], butyl‐[L4], and benzyl‐[L5]) derivatives of 2‐mercaptobenzoic acid and HSA using various spectroscopic methods and molecular docking simulations. The protonation constants (βn) of the investigated ligands were determined potentiometrically in aqueous solutions, whereas their lipophilicity was assessed using different experimental methods and software packages. An increase in the absorption intensity of HSA upon interaction with the investigated compounds indicates static quenching and the formation of a complex between HSA and the ligands. The incorporation of alkyl groups into the ligand molecules results in a slight increase in the protonation constants of the tested compounds, as well as an enhancement lipophilicity compared to 2‐mercaptobenzoic acid. In silico analyses demonstrated that multiple amino acid residues are crucial for the binding process in Sudlow site I, situated within subdomain IIA, with salt bridges being the predominant interaction.
Quercetin, Catechin, and Diosmin as Modulators of Haloperidol–HSA Interactions: A Biophysical and Computational Study Aleksandar Petrušić, Emina Mrkalić, Ratomir Jelić, Aleksandar Kočović, Miloš Milosavljević, et al. International Journal of Molecular Sciences, 2025 Potential interactions of haloperidol with food ingredients such as flavonoids may be of great importance both for understanding the pharmacokinetic interactions of xenobiotics with human serum albumin and for clinical practice itself. In this study, the effect of the flavonoids quercetin, catechin, and diosmin on the interaction of haloperidol and human serum albumin was examined. These flavonoids are very common in foods of plant origin. Haloperidol is a typical antipsychotic that has a pronounced binding affinity for human serum albumin. Fluorescence spectroscopy, molecular docking analysis, and molecular dynamics simulations were used for these tests. Previous studies have shown that all test substances bind to the same binding site on human serum albumin (Sudlow site I, Subdomain IIA). Fluorescence spectroscopy revealed that the tested flavonoids reduce the value of the haloperidol binding constant to human serum albumin (from 4.45 × 103 in the binary system to 3.75 × 102, 5.40 × 102 and 6.24 × 102 in the ternary systems, respectively), due to competition for the same binding site. Experimental results were confirmed by molecular docking analysis and molecular dynamics simulations.
The Molecular Recognition of Lurasidone by Human Serum Albumin: A Combined Experimental and Computational Approach Nevena Živković, Emina Mrkalić, Ratomir Jelić, Jovica Tomović, Jadranka Odović, et al. Molecules, 2025 Lurasidone (LUR) is an antipsychotic drug whose interaction with human serum albumin (HSA) plays a crucial role in its pharmacokinetic and pharmacodynamic properties. A thorough understanding of LUR’s binding mechanism to HSA is crucial for predicting its transport, distribution, and potential drug interactions. Methods: The interaction between LUR and HSA was investigated using fluorescence and circular dichroism (CD) spectroscopy, followed by molecular docking simulations. Binding characteristics were analyzed through quenching mechanisms, thermodynamic parameters, and competitive site marker experiments. Results: This study revealed a systematic decrease in HSA fluorescence intensity with increasing LUR concentration, indicating a static quenching mechanism driven by non-fluorescent complex formation. Binding constants suggest enhanced complex stability at higher temperatures, with thermodynamic analysis confirming an endothermic, hydrophobic interaction. Competitive site marker assays and synchronous fluorescence spectra confirmed that LUR primarily binds to site I (subdomain IIA) near tryptophan residues. Conformational changes in HSA, observed as a decrease in α-helix content, further demonstrate the structural impact of LUR binding. Conclusions: These findings offer key insights into the molecular interactions between LUR and HSA, enhancing our understanding of LUR’s pharmacokinetics and its potential interactions with other drugs. Understanding these binding characteristics can aid in optimizing LUR’s clinical application and predicting possible interactions with other biomolecules.
Investigation of the interaction between S-isoalkyl derivatives of the thiosalicylic acid and human serum albumin Marina Vesović, Ratomir Jelić, Miloš Nikolić, Nikola Nedeljković, Ana Živanović, et al. Journal of Biomolecular Structure and Dynamics, 2025 S-isoalkyl derivatives of thiosalicylic acid (isopropyl-(L1), isobutyl-(L2) and isoamyl-(L3)) were selected in order to investigate the binding interaction with the human serum albumin (HSA) using different spectroscopic methods and molecular docking simulation. Association constants and number of binding sites were used to analyze the quenching mechanism. The experimental results showed that the fluorescence quenching of HSA by L1, L2 and L3 occurs because of static quenching and that binding processes were spontaneous, with the leading forces in bonding by hydrogen bonding, hydrophobic interactions, and electrostatic interactions. Fluorescence spectroscopy, UV-Vis spectroscopy and synchronous fluorescence spectroscopy showed that ligands (L1, L2 and L3) can bind to HSA and that the binding of ligands induced some microenvironmental and conformational changes in HSA. The calculated distance between the donor and the acceptor according to fiFörster's theory confirms the energy transfer efficiency between the acceptor and HSA. Results of site marker competitive experiments showed that the tested compounds bind to HSA in domain IIA (Site I). Molecular dynamics and docking calculations demonstrated that L3 binds to the Sudlow site I of HSA with lower values of binding energies compared to L1 and L2, indicating the formation of the most stable ligand-HSA complex. Understanding the binding mechanisms of S-isoalkyl derivatives of the thiosalicylic acid to HSA may provide valuable data for the future studies of their biological activity and application as potential antitumor drugs.Communicated by Ramaswamy H. Sarma.
Linamarin Binding to Human Serum Albumin. A Spectroscopic and Molecular Docking Approach Ratomir Jelić, Emina Mrkalić, Marina Ćendić‐Serafinović, Jadranka Odović, Miroslav Sovrlić Chemistryselect, 2024 The interaction between linamarin (LIN), a cyanogenic glycoside, and human serum albumin (HSA) was studied by multiple spectroscopic techniques and molecular docking simulation. All measurements were performed under physiological conditions. The obtained results (including the binding constants, effective quenching constant and a number of binding sites) showed that the complex of HSA‐LIN is formed. The values of Stern‐Volmer constants (6.70×103, 5.53×103 and 1.95×103) indicate that fluorescence quenching of HSA was static. Results of site marker experiments showed that the binding site of LIN is mainly located in site I (subdomain IIA) of HSA. The thermodynamic parameters showed that binding process occurs spontaneously through hydrophobic interactions. Molecular docking results are in good agreement with experimental data. Furthermore, computational results revealed LIN binds in the cavity of TRP 214, that is, subdomain IIA (site I) of HSA. This comprehensive study provides a deeper insight into ligand binding in HSA which may be useful in drug design and pharmacology.
Determination of moxifloxacin in human plasma by derivative UV spectrophotometry in a micellar medium Canadian Journal of Analytical Sciences and Spectroscopy, 2007