DFT/TDDFT calculations of geometry optimization, electronic structure and spectral properties of clevudine and telbivudine for treatment of chronic hepatitis B.

Chronic hepatitis B remains a worldwide health concern. Presently, many drugs, such as Clevudine and Telbivudine, are recommended for the treatment of chronic hepatitis B disease. For this purpose, the quantum chemical analysis of ELUMO-HOMO (Egap), ionization potential (IP), electron affinity (EA), electronegativity (EN), chemical hardness (η), chemical potential (µ), chemical softness (S), electrophilicity index (ω), electron accepting capability (ω+), electron-donating capability (ω-), Nucleophilicity index (N), additional electronic charge (∆Nmax), Optical softness (σ0) and Dipole Moment, IR and UV-Vis spectra, molecular electrostatic potential (MEP) profile, Mulliken charge analysis, natural bond orbital (NBO) were examined in this study. The dipole moment of the compounds suggests their binding pose and predicted binding affinity. The electrophilic and nucleophilic regions were identified, and techniques such as NBO, UV-Vis, and IR were used to gain insights into the molecular structure, electronic transitions, and potential drug design for Hepatitis B treatment. Calculations for this study were carried out using the Gaussian 09 program package coupled with the DFT/TDDFT technique. The hybrid B3LYP functional method and the 6-311++G(d, p) basis set were used for the calculations.

DFT study of the spectroscopic behaviour of different iron(II)-terpyridine derivatives with application in DSSCs.

Through a comprehensive computational analysis utilizing Density Functional Theory (DFT), we clarify the electronic structure and spectroscopic properties of modified iron(II)-terpyridine derivatives, with the aim of enhancing the efficiency of Dye-Sensitized Solar Cells (DSSCs). We optimized a series of nineteen iron(II)-terpyridine derivatives and related compounds in acetonitrile (MeCN) as the solvent using TDDFT, evaluating their potential as dyes for DSSCs. From the conducted computations on the optimized geometries of the nineteen [Fe(Ln)2]2+ complexes, containing substituted terpyridine and related ligands L1-L19, we determined the wavelengths (λ in nm), transition energy (E in eV), oscillator strength (f), type of transitions, excited state lifetime (τ), light harvesting efficiency (LHE), frontier orbital character and their energies (ELUMO/EHOMO), natural transition orbitals (NTOs), injection driving force of a dye (ΔGinject), and regeneration driving force of a dye (ΔGregenerate). Results show that the theoretically calculated values for assessing dye efficiency in a DSSC correlate with available experimental values. The UV-visible spectra of [Fe(Ln)2]2+ exhibited a peak above 500 nm (λmax) in the visible region, attributed to the ligand-to-metal charge transfer band (LMCT) in literature, and a significant absorbance peak at approximately 300 nm (λA,max) in the UV region. The M06-D3/CEP-121G method replicated all reported λmax and λA,max values with a mean absolute deviation (MAD) of 21 and 18 nm, respectively. Our findings underscore the connections between electronic modifications and absorption spectra, emphasizing their impact on the light-harvesting capabilities and overall performance of DSSCs. This research contributes to the advancement of fundamental principles governing the design and optimization of novel photovoltaic materials, facilitating the development of more efficient and sustainable solar energy technologies.

Multiple spectroscopic and computational studies on binding interaction of 2-phenylamino-4-phenoxyquinoline derivatives with bovine serum albumin.

Binding characteristics of potent non-nucleoside HIV-1 reverse transcriptase inhibitors, 4-(2',6'-dimethyl-4'-formylphenoxy)-2-(5″-cyanopyridin-2″ylamino) quinoline (1) and 4-(2',6'-dimethyl-4'-cyanophenoxy)-2-(5″-cyanopyridin-2″ylamino) quinoline (2), to bovine serum albumin (BSA) under simulative physiological conditions were investigated by multiple spectroscopic and computational methods. The experimental results demonstrated that (1) and (2) bound to BSA at site III (subdomain IB), and quenched BSA fluorescence through a static quenching process. The binding interaction of (1) or (2) to BSA forms stable complexes with the binding constants (Kb) at the level of 104 L/mol and the number of binding site was determined to be 1 for both systems, indicating that new synthesized compounds occupied one site in BSA with moderate binding affinities. Based on the analysis of the thermodynamic parameters, it can be indicated that the main binding forces for interaction between BSA and both compounds were hydrogen bonding and van der Waals force. Synchronous fluorescence results revealed that the interaction of two compounds with BSA led to modifications in the microenvironment surrounding tryptophan residue of BSA. Circular dichroism spectra demonstrated alterations in the secondary structure of BSA induced by (1) and (2). Moreover, the experimental data of molecular docking and molecular dynamics (MD) simulations supported the results obtained from multiple spectroscopic techniques, confirming the binding interactions between both compounds and BSA.

Spectroscopic, computational, cytotoxicity, and docking studies of 6-bromobenzimidazole as anti-breast cancer agent.

6-Bromobenzimidazole (6BBZ) has been calculated in this study utilizing the 6-311++G(d,p) basis set and the Becke-3-Lee-Yang-Parr density functional approaches. The basic frequencies and geometric optimization are known. FTIR, FT-Raman, and UV-Vis spectra of the substance are compared between its computed and observed values. The energy gap between highest occupied molecular orbital-lowest unoccupied molecular orbital and molecule electrostatic potentials has been represented by charge density distributions that may be associated with the biological response. Time-dependent density functional theory calculations in the gas phase and dimethyl sulfoxide were carried out to ascertain the electronic properties and energy gap values using the same basis set. Molecular orbital contributions are investigated using the overlap population, partial, and total densities of states. Natural bond analysis was found to have strong electron delocalization by means of π(C4-C9) → π*(C5-C6), LP (N1) → π*(C7-C8), and LP(Br12) → π*(C5-C6) interactions. The Fukui function and Mulliken analysis have been explored on the atomic charges of the molecule. The nuclear magnetic resonance chemical shifts for 1 H and 13 C have been computed using the gauge-independent atomic orbital technique. With the highest binding affinity (-6.2 kcal mol-1 ) against estrogen sulfotransferase receptor (PDB ID: 1AQU) and low IC50 value of 17.23 µg/mL, 6BBZ demonstrated potent action against the MCF-7 breast cancer cell line. Studies on the antibacterial activity and ADMET prediction of the molecule have also been carried out.

Hypothetical confirmation for the anti-bacterial compound potassium succinate-succinic acid in comparison with certain succinate derivatives.

The development of antibacterial medications has recently been promoted due to the non- effective usage of antibiotics and the rise in severe bacterial infections. The effectiveness of antimicrobial therapy alternatives is constrained due to the prevalence of germs that are resistant to medications. Our current study's goal is to favor metallic compounds for antibiotic delivery in order to increase the effectiveness of the antibacterial regimen. Due to its bioactivity, potassium succinate-succinic acid is preferred because in general, the succinic acid compound has the greatest potential against microbial infections and a natural antibiotic because of its relative acidic nature. In the current study, the molecular geometry, band gap energies, molecular electrostatic interactions and potential energy distribution of the molecule were compared with those of certain succinate derivatives. The potential compound potassium succinate succinic acid was probed using FT-IR and FT-Raman analyses. Vibrational assignments pertaining to different modes of vibration with potential energy distribution have been improved by normal coordinate analysis. The chemical bond stability which is largely important for biological activity is studied using NBO analysis. The molecular docking study suggests that the molecule possesses antibacterial action and displays a minimal binding energy of -5.3 kcal/mol which can be endorsed for the prevention of any bacterial illness. From the results of our studies, the material would be stable and bioactive according to the FMO study, which indicates a band gap value of 4.35 eV and the pharmacokinetic features of the molecule, was predicted using the ADMET factors and the drug-likeness test.Communicated by Ramaswamy H. Sarma.

Study of the binding interaction of salmon sperm DNA with nintedanib, a tyrosine kinase inhibitor using multi-spectroscopic, thermodynamic, and in silico approaches.

The study of the intermolecular binding interaction of small molecules with DNA can guide the rational drug design with greater efficacy and improved or more selective activity. In the current study, nintedanib's binding interaction with salmon sperm DNA (ssDNA) was thoroughly investigated using UV-vis spectrophotometry, spectrofluorimetry, ionic strength measurements, viscosity measurements, thermodynamics, molecular docking, and molecular dynamic simulation techniques under physiologically simulated conditions (pH 7.4). The obtained experimental results showed that nintedanib and ssDNA had an apparent binding interaction. Nintedanib's binding constant (Kb) with ssDNA, as determined using the Benesi-Hildebrand plot, was 7.9 × 104 M-1 at 298 K, indicating a moderate binding affinity. The primary binding contact forces were hydrophobic and hydrogen bonding interactions, as verified by the enthalpy and entropy changes (ΔH0 and ΔS0), which were - 16.25 kJ.mol-1 and 39.30 J mol-1 K-1, respectively. According to the results of UV-vis spectrophotometry, viscosity assays, and competitive binding interactions with ethidium bromide or rhodamine B, the binding mode of nintedanib to ssDNA was minor groove. Molecular docking and molecular dynamic simulation studies showed that nintedanib fitted into the B-DNA minor groove's AT-rich region with high stability. This study can contribute to further understanding of nintedanib's molecular mechanisms and pharmacological effects.

Inflammatory Studies of Dehydroandrographolide: Isolation, Spectroscopy, Biological Activity, and Theoretical Modeling.

Dehydroandrographolide (DA) was isolated and experimentally characterized utilizing FT-IR, UV-Vis, and NMR spectroscopy techniques along with detailed theoretical modelled at the DFT/B3LYP-D3BJ/6-311 + + G(d,p) level of theory. Substantially, molecular electronic property investigations in the gaseous phase alongside five different solvents (ethanol, methanol, water, acetonitrile and DMSO) were comprehensively reported and compared with the experimental results. The globally harmonized scale (GHS), which is used to identify and label chemicals, was also utilized to demonstrate that the lead compound predicted an LD50 of 1190 mg/kg. This finding implies that consumers can safely consume the lead molecule. Notable impacts on hepatotoxicity, cytotoxicity, mutagenicity, and carcinogenicity were likewise found to be minimal to nonexistent for the compound. Additionally, in order to account for the biological performance of the studied compound, in-silico molecular docking simulation analysis was examined against different anti-inflammatory target of enzymes (3PGH, 4COX, and 6COX). From the examination, it can be inferred that DA@3PGH, DA@4COX, and DA@6COX, respectively, showed significant negative binding affinities of -7.2 kcal/mol, -8.0 kcal/mol, and - 6.9 kcal/mol. Thus, the high mean binding affinity in contrast to conventional drugs further reinforces these results as an anti-inflammatory agent.

Biophysical insights on the interaction of anticoagulant drug dicoumarol with calf thymus-DNA: deciphering the binding mode and binding force with thermodynamics.

The biological activity of drugs is exhibited due to their interactions with bio-receptors. Dicoumarol (DIC) is a natural hydroxycoumarin and a well-known anticoagulant. DNA is the genetic material and one of the targets of numerous drugs. The interaction of DIC with calf-thymus DNA (ct-DNA) has been studied using different biophysical techniques and docking studies. The binding constant in the order of 103 to 104 M-1 was observed from spectroscopic studies. Thermodynamic studies at 4 different temperatures revealed the spontaneity of the interaction with the entropy-driven process. Marker displacement studies with competitive markers of intercalators (ethidium bromide) and groove binders (Hoechst 33258) confirmed the groove-binding nature of DIC in DNA. The groove-binding mode of DIC was complemented by different studies like viscosity measurements, DNA melting, and the effect of KI on the binding. A minor perturbation in the DNA viscosity and no significant change in the DNA melting temperature (Tm) after binding with DIC further confirms the groove binding mode. The effect of KI on the DIC and DIC-DNA system suggested the absence of DIC intercalation. The absence of significant electrostatic force was revealed from the ionic-strength effect study. Binding-induced conformational variation in ct-DNA was absent in circular dichroism studies. Molecular docking studies suggested the position of DIC within the minor groove of ct-DNA, covering three base pairs long. The outcome of this report may help in understanding the pharmacodynamics and pharmacokinetics of dicoumarol analogs and related molecules.Communicated by Ramaswamy H. Sarma.

Intercalation of anticancer drug Palbociclib with calf-thymus DNA: new insights from molecular spectroscopic, molecular dynamic simulations and cleavage studies.

The interaction between the anti-cancer drug Palbociclib (PAL) and calf-thymus DNA (CT-DNA) was investigated using various biophysical techniques in a physiological buffer (pH 7.4). It was found that PAL intercalated into the base pairs of CT-DNA as evidenced from the results of UV-Vis, fluorescence, circular dichroism (CD), competitive binding assay with ethidium bromide (EB) and Hoechst 33258, KI quenching study, the effect of denaturing agent and viscosity measurements. The magnitude of binding constants (106 M-1) at different temperatures suggested strong binding between PAL and CT-DNA during complexation. The observed ΔHo > 0 and ΔSo > 0 indicated that the binding process is primarily driven by hydrophobic interactions. Molecular docking studies indicated partial intercalation of pyridopyrimidine ring between the base pairs of DNA. Free energy surface (FES) analysis derived from metadynamics simulation studies revealed the PAL-induced cleavage of DNA, which was confirmed by gel electrophoresis experiments.Communicated by Ramaswamy H. Sarma.

Probing binding mode between sodium acid pyrophosphate and albumin: multi-spectroscopic and molecular docking analysis.

Sodium acid pyrophosphate (SAPP) food additive is widely used as a preservative, bulking agent, chelating agent, emulsifier and pH regulator. It is also used as an improver of color and water retention capacity in the processing of various types of seafood, canned food, cooked meat and flour products. For the first time, we evaluated the SAPP interaction with bovine serum albumin (BSA) using spectroscopic methods including UV-Vis absorption, fluorescence spectroscopy, and surface plasmon resonance, and docking analysis to understand the mechanisms of complex formation and binding. The fluorescence intensity of BSA reduces when titrated with various concentrations of SAPP by forming a complex with BSA via a static quenching mechanism. The binding constant between BSA and SAPP decreased from 123,300 to 15,800 (M-1) with rising temperature, which indicates a decrement in complex formation owing to the interaction of SAPP with BSA. A negative ΔG° value means that SAPP binds spontaneously to BSA at all temperatures, and both ΔH° and ΔS° negative values indicate that hydrogen bonds (H-bonding) and van der Waals forces are the primary forces involved in the binding processes. The UV-Vis spectrum of BSA reduced upon increasing SAPP concentrations due to forming a new ground state complex between SAPP and BSA. Molecular docking study shows that residues Arg256, Ser259, Ser286, Ile 289 and Ala 290 play an important role in SAPP binding process to site I (subdomain IIA) of BSA through H-bonding and van der Waals forces, which is supported by the thermodynamic study.Communicated by Ramaswamy H. Sarma.

Augmented least squares, a powerful chemometric approach for the spectroscopic analysis of the antiretroviral therapy abacavir, lamivudine and dolutegravir in their ternary mixture.

Augmented least squares models such as concentration residual augmented classical least squares (CRACLS) and spectral residual augmented classical least squares (SRACLS) are powerful chemometric approaches that can be applied for spectroscopic analysis of many pharmaceutical compounds. Herein, both CRACLS and SRACL have been employed for UV spectral analysis of three antiretroviral therapy namely abacavir (ACV), lamivudine (LMV) and dolutegravir (DTG) in their ternary mixture. A partial factorial design has been utilized for calibration set construction then both CRACLS and SRACLS models have been optimized regarding the number of iterations and principal components, respectively, using a leave-one-out cross-validation procedure. It was found that a higher number of iterations and principal components were required for modelling the minor component DTG indicating more augmentation procedures to improve the models' accuracy. Validation of the proposed models was performed using external validation set of 13 mixtures and different validation parameters have been evaluated regarding models' predictive abilities. Both models showed excellent performance for analyzing ACV and LMV with relative root mean square error of prediction (RRMSEP) below 2 %. However, higher RRMSEP values around 5 % were observed for the minor component DTG suggesting that these models should be utilized with caution when analyzing minor components in mixtures. Furthermore, the suggested models have been applied for analyzing ACV, LMV and DTG in their pharmaceutical formulation and excellent agreement was observed between the suggested models and the reported chromatographic method posing these models as powerful chemometric approaches for quality control analysis of many pharmaceutical compounds.

Exploring the interaction of tepotinib with calf thymus DNA using molecular dynamics simulation and multispectroscopic techniques.

In recent times, there has been a surge in the discovery of drugs that directly interact with DNA, influencing gene expression. As a result, understanding how biomolecules interact with DNA has become a major area of research. One such drug is Tepotinib (TPT), an FDA-approved anti-cancer medication known as a MET tyrosine kinase inhibitor, used in chemotherapy for metastatic non-small cell lung cancer (NSCLC) with MET exon 14 skipping alterations. In our study, we adopted both biophysical and in-silico methods to investigate the binding relationship of TPT and ctDNA. The absorption spectra of ctDNA exhibited a hypochromic effect when titrated with TPT and the binding constant of TPT-ctDNA complex was calculated, Ka = 9.91 × 104 M-1. By computing bimolecular enhancement constant (KB) and thermodynamic enhancement constant (KD) in fluorometric investigations, it was found that the fluorescence enhancement is a result of a static process involving the ctDNA-TPT complex formation in the ground state, as opposed to a dynamic process. The displacement assay results further supported this finding, showing that TPT exhibits a binding preference for minor groove of ct-DNA and was also demonstrated by KI quenching and CD spectroscopy. The molecular docking and molecular dynamic simulations validated TPT's groove binding nature and binding pattern with ctDNA, respectively. Thus, the results of our present investigation offer valuable insights into the interaction between TPT and ctDNA. It is evident that TPT, as an anti-cancer medication, binds to the minor groove of ctDNA.

Potential toxic effects of perfluorobutanesulfonyl fluoride analysis based on multiple-spectroscopy techniques and molecular modelling analysis.

Perfluorobutanesulfonyl fluoride (PBSF) has been used in the manufacture of fluorochemicals. Since PBSF is not biodegradable, the predicted environmental levels of PBSF are also expected to rise over time. In recent years, there has been a rise in the levels of PBSF in humans. In order to clarify the impact of PBSF on the accumulation of substances in the human body, we examined the interaction mechanism between PBSF and bovine serum albumin (BSA). To investigate the interaction mechanism between PBSF and BSA, we utilized a range of methods including UV-visible spectrophotometry, fluorescence spectroscopy, circular dichroism, molecular docking simulation, and molecular dynamics (MD) simulation. The inherent fluorescence of BSA was effectively suppressed by PBSF through fluorescence quenching analysis, using a static mechanism. The Ka value of 1.34 × 105 mol-1 L indicated a strong binding between PBSF and BSA. Further analysis of the interaction between PBSF and BSA involved examining thermodynamic parameters, fluorescence resonance energy transfer, and conducting other theoretical calculations. These investigations produced results that were in strong accordance with the experimental observations. The participation of hydrophobic interactions between BSA and PBSF was uncovered through molecular docking and MD simulation investigations. Furthermore, this investigation explored the impact of copper ions (Cu2+) and calcium ions (Ca2+) on the interaction between PBSF and BSA, establishing a vital basis for comprehending the mechanism by which PBSF affects proteins in the human surroundings.

Elucidation of binding mechanism of rhodanine derivative P4OC on bovine serum albumin.

Rhodanine is an important scaffold in medicinal chemistry and it act as potent anticancer agent and other pharmacological effects. In pharmacokinetics and pharmacodynamics studies of the drug, the drug binding properties on serum protein is crucial for producing better drug. This study was designed to explore the binding interactions between the Rhodanine derivative (P4OC) on Bovine Serum Albumin (BSA). The interactions between P4OC and BSA were investigated using biophysical approach and molecular docking. The quenching mechanism and binding constants of P4OC on BSA were determined by biophysical approach through fluorescence spectroscopic experiments. Circular dichroism (CD) spectroscopy was used to study the secondary structural changes of BSA upon P4OC binding. The fluorescence experiments of P4OC binding on BSA show good drug binding with static quenching constants using stern Volmer plot and found the quenching constant value KP4OC = 1.12762 × 1013 M-1 with corresponding binding free energy (ΔG) -2.303 kcal/mol. The molecular displacement fluorescence emission on BSA-P4OC complex by site specific markers shows that P4OC binds at I A sub-domain of BSA further confirmed peak shift by synchronous fluorescence of P4OC on BSA with tyrosine, tryptophan and phenylalanine amino acids. Increasing concentration of P4OC on BSA found secondary structural changes, the percentage of α-helix was decreased as well increase percentage of ß-sheet and random coil. The binding of P4OC to BSA was computationally studied by molecular docking methods. Thus, results obtained are in excellent agreement with experimental and theoretical results with respect to the binding mechanism and binding constant of P4OC on BSA. We concluded that, the rhodanine derivative P4OC possesses good drug binding properties on BSA. Further P4OC may be evaluated its potential pharmacological activities on clinical trial.Communicated by Ramaswamy H. Sarma.

Non-covalent binding interaction of bioactive coumarin esculetin with calf thymus DNA and yeast transfer RNA: A detailed investigation to decipher the binding affinities, binding location, interacting forces and structural alterations at a molecular level.

Esculetin is a well-known coumarin derivative found abundantly in nature possessing an extensive array of pharmacological and therapeutic properties. Consequently, to comprehend its molecular recognition mechanism, our objective is to conduct a complete investigation of its interactions with the nucleic acid, specifically ct-DNA, and t-RNA, using spectroscopic and computational techniques. The intrinsic fluorescence of esculetin is quenched when it interacts with ct-DNA and t-RNA, and this occurs through a static quenching mechanism. The thermodynamic parameters demonstrated that the interaction is influenced by hydrogen bonding and weak van der Waals forces. CD and FT-IR results revealed no conformational changes in ct-DNA and t-RNA structure on binding with esculetin. Furthermore, competitive displacement assay with ethidium bromide, melting temperature, viscosity measurement, and potassium iodide quenching experiments, reflected that esculetin probably binds to the minor groove of ct-DNA. The molecular docking results provided further confirmation for the spectroscopic findings, including the binding location of esculetin and binding energies of esculetin complexes with ct-DNA and t-RNA. Molecular dynamics simulation studies demonstrated the conformational stability and flexibility of nucleic acids.

Unraveling the underlying mechanism of interactions between astaxanthin geometrical isomers and bovine serum albumin.

The health benefits of astaxanthin (AST) are related to its geometric isomers. Generally, functional activity is realized by the interactions between active substances and transporters. Hereto, bovine serum albumin (BSA), as a model-binding protein and transporter, is able to recognize and transport isomers of active substances through binding with them. However, differences in the binding mechanism of isomers to BSA may affect the functional activities of isomers through the "binding-transport-activity" chain reaction. Thus, this study sought to elucidate the interactions between AST geometrical isomers and BSA using multi-spectroscopy, surface plasmon resonance and molecular docking. The results showed that Z-AST displayed more interacting amino acid residues and lower thermodynamic parameters than all-E-AST. Meanwhile, the order of binding affinity to BSA was 13Z-AST (1.56 × 10-7 M) > 9Z-AST (2.70 × 10-7 M) > all-E-AST (4.01 × 10-7 M), indicating that Z-AST possessed stronger binding ability to BSA. Moreover, AST isomers were located at the junction between subdomains ⅡA and ⅢA of BSA, and showed the same interaction forces (hydrogen bond and van der Waals force) as well as kinetic processes (slow combination, slow dissociation). These interaction parameters provide valuable insights into their pharmacokinetics in vivo, and it was of great significance to explain the potential differences among AST isomers in functional activities.

Interaction mechanism of a pesticide, Azoxystrobin with bovine serum albumin: Assessments through fluorescence, UV-Vis absorption, electrochemical and molecular docking simulation techniques.

The current study's objective was to investigate how an antifungal pesticide Azoxystrobin (AZO) interacts with bovine serum albumin (BSA) under conditions that simulate a physiological medium (pH 7.4). This investigation was carried out using various experimental (UV-Vis absorption, steady-state fluorescence and 3-D fluorescence spectroscopies, and electrochemical) and theoretical (molecular docking and molecular dynamics simulations) methods. The fluorescence quenching data demonstrated that AZO caused fluorescence quenching in BSA, and this quenching process was attributed to the static quenching mechanism. By examining the fluorescence quenching of BSA at three different temperatures, it was determined that the binding constants for the AZO-BSA complexes were approximately 104 M-1 in magnitude, while the same magnitude of the binding constant was found by the electrochemical method. This indicates that the interaction between AZO and BSA was of moderate strength. This was further validated by the changes observed in the UV-Vis spectrum of BSA following the addition of AZO. The thermodynamic information, including ΔH and ΔS, revealed that the interaction forces primarily involved van der Waals forces as well as hydrogen bonds. The negative Gibbs free energy indicated that the reaction is spontaneous. In the theoretical investigation, the comparison highlights a remarkable consistency in how AZO interacts with the BSA active site over various time points. Hydrogen bonding and hydrophobic interactions consistently play a role in ensuring the stable and specific binding of the ligand. Moreover, the 3-D fluorescence spectral findings revealed alterations in the surrounding microenvironment of protein fluorophores when AZO binds. Upon analyzing the electrochemical data, it was observed that there was a consistent decrease in the peak currents of AZO when BSA was added to solutions containing AZO. The primary cause of this decrease in the peak currents was the reduction in the equilibrium concentration of AZO due to the addition of BSA. Furthermore, the formation of a non-electroactive complex between BSA and AZO, which impedes electron transport between AZO and the working electrode, accounts for these decreases. As a result, it can be said that the understanding of how AZO binds to BSA offers valuable insights that can be applied in the food, human health, and environment sectors.

Computational simulation on the study of Tacrolimus and its improved dermal retention using Poly(Ԑ-caprolactone) nanocapsules.

Tacrolimus (TAC) is a drug from natural origin that can be used for topical application to control autoimmune skin diseases such as atopic dermatitis, psoriasis, and vitiligo. Computational simulation based on quantum mechanics theory by solving Schrödinger Equation for n-body problem may allow the theoretical calculation of drug geometry, charge distribution and dipole moment, electronic levels and molecular orbitals, electronic transitions, and vibrational transitions. Additionally, the development of novel nanotechnology-based delivery systems containing TAC can be an approach for reducing the dose applied topically, increasing dermal retention, and reducing the reported side effects due to the controlled release pattern. Firstly, this paper was devoted to obtaining the molecular, electronic, and vibrational data for TAC by using five semi-empirical (SE) methods and one Density Functional Theory (DFT) method in order to expand the knowledge about the drug properties by computational simulation. Then, this study was carried out to prepare TAC-loaded poly(ԑ-caprolactone) nanocapsules by interfacial polymer deposition following solvent displacement and investigate the in vitro drug permeation using the Franz diffusion cell and the photoacoustic spectroscopy. Computational simulations were compared in the three schemes SE/SE, SE/DFT, and DFT/DFT, where the first method represented the procedure used for geometry optimization and the second one was performed to extract electronic and vibrational properties. Computational data showed correspondence with TAC geometry description and electronic properties, with few differences in HOMO - LUMO gap (Δ) and dipole values. The SE/DFT and DFT/DFT methods presented a better drug description for the UV-Vis, Infrared, and Raman spectra with low deviation from experimental values. Franz cell model demonstrated that TAC was more delivered across the Strat-M® membrane from the solution than the drug-loaded poly(ԑ-caprolactone) nanocapsules. Photoacoustic spectroscopy assay revealed that these nanocapsules remained more retained into the Strat-M® membranes, which is desirable for the topical application.

Preanalytical Quality Evaluation of Citrate Evacuated Blood Collection Tubes-Ultraviolet Molecular Absorption Spectrometry Confronted with Ion Chromatography.

We previously enabled a direct insight into the quality of citrate anticoagulant tubes before their intended use for specimen collection by introducing an easy-to-perform UV spectrometric method for citrate determination on a purified water model. The results revealed differences between the tubes of three producers, Greiner BIO-ONE (A), LT Burnik (B), and BD (C). It became apparent that tubes C contain an additive, which absorbs light in the ultraviolet range and prevents reliable evaluation of citrate anticoagulant concentration with the suggested method. In this research, we re-evaluate the quality of citrate-evacuated blood collection tubes by complementing UV spectrometry with ion chromatography. (1) Comparable results were obtained for tubes B at 220 nm. (2) Citrate concentrations determined with ion chromatography were lower for tubes A and C. Chromatograms reveal additional peaks for both. (3) Influences of heparin on absorption spectra and chromatograms of citrate were studied. Some similarities with the shape of the anticoagulant spectra of tubes A and C were observed, and the lithium heparin peak in chromatograms is close to them, but a confident judgment was not possible. (4) Contamination of anticoagulant solution with potassium, magnesium, and calcium was confirmed for all the brands, and contamination with lithium for B and C.

Spectral Physics of Stable Cu(III) Produced by Oxidative Addition of an Alkyl Halide.

In this paper, we theoretically investigated spectral physics on Cu(III) complexes formed by the oxidative addition of α-haloacetonitrile to ionic and neutral Cu(I) complexes, stimulated by recent experimental reports. Firstly, the electronic structures of reactants of α-haloacetonitrile and neutral Cu(I) and two kinds of products of Cu(III) complexes are visualized with the density of state (DOS) and orbital energy levels of HOMO and LUMO. The visually manifested static and dynamic polarizability as well as the first hyperpolarizability are employed to reveal the vibrational modes of the normal and resonance Raman spectra of two Cu(III) complexes. The nuclear magnetic resonance (NMR) spectra are not only used to identify the reactants and products but also to distinguish between two Cu(III) complexes. The charge difference density (CDD) reveals intramolecular charge transfer in electronic transitions in optical absorption spectra. The CDDs in fluorescence visually reveal electron-hole recombination. Our results promote a deeper understanding of the physical mechanism of stable Cu(III) produced by the oxidative addition of an alkyl halide.