Investigation on molecular and biomolecular spectroscopy of the novel 2BCA molecule to analyse its biological activities and binding interaction with nipah viral protein.

The molecule of 2-Biphenyl Carboxylic Acid (2BCA), which contains peculiar features, was explored making use of density functional theory (DFT) and experimental approaches in the area of quantum computational research. The optimised structure, atomic charges, vibrational frequencies, electrical properties, electrostatic potential surface (ESP), natural bond orbital analysis and potential energy surface (PES) were obtained applying the B3LYP approach with the 6-311++ G (d,p) basis set.. The 2BCA molecule was examined for possible conformers using a PES scan. The methods applied for spectral analyses included FT-IR, FT-RAMAN, NMR, and UV-Vis results. Vibrational frequencies for all typical modes of vibration were found using the Potential Energy Distribution (PED) data. The UV-Vis spectrum was simulated using the TD-DFT technique, which is also seen empirically. The Gauge-Invariant Atomic Orbital (GIAO) approach was employed to model and study the 13C and 1H NMR spectra of the 2BCA molecule in a CDCL3 solution. The spectra were then exploited experimentally to establish their chemical shifts. To predict the donor and acceptor interaction, the NBO analysis was used. The electrostatic potential surface was employed to anticipate the locations of nucleophilic and electrophilic sites. Hirshfeld surfaces and their related fingerprint plots are exploited for the investigation of intermolecular interactions. Reduced Density Gradient (RDG) helps to measure and illustrate electron correlation effects, offering precise insights into chemical bonding, reactivity, and the electronic structure of 2BCA. According to Lipinski and Veber's drug similarity criteria, 2BCA exhibits the typical physicochemical and pharmacokinetic properties that make it a potential oral pharmaceutical candidate. According to the findings of a molecular docking study, the 2BCA molecule has promise as a treatment agent for the Nipah virus (PDB ID: 6 EB9), which causes severe respiratory and neurological symptoms in humans.

Experimental and computational study of hydrolysis and photolysis of antibiotic ceftriaxone: Degradation kinetics, pathways, and toxicity.

In this work, we have experimentally and computationally investigated the process of hydrolysis and photolysis of cephalosporin antibiotics with ceftriaxone (CEF) as a model compound. The CEF hydrolysis was investigated in ultrapure and natural water, at 25 ± 1 °C and 4 ± 1 °C in the dark. It was found that CEF after 100 and 900 days at 25 ± 1°C and 4 ± 1 °C, respectively practically completely removed from ultrapure water. The CEF hydrolysis in natural water was five and three times slower at 25 ± 1 °C and 4 ± 1 °C, respectively than in ultrapure water. Further, the efficiency of direct photolysis (solar/UVA-B) and solar/H2O2 treatment of CEF was investigated. Under UVA-B radiation 95.6% of CEF was removed after 60 min, while for the same time of solar radiation degradation was practically not observed (only 3.2%). Also, the effects of different concentrations of H2O2 (0-150 mM) in the presence/absence of solar radiation were studied. The most efficient solar/H2O2 treatment was in the presence of 90 mM H2O2, whereby 66.8% of CEF was removed after 60 min (41.8% by indirect photolysis, 21.8% by H2O2-oxidation, and 3.2% by direct photolysis). Radial distribution functions (RDF) provided information about the distribution of water around the CEF molecule. Aside from the RDF, investigation of intramolecular noncovalent interactions and calculations of bond dissociation energies for hydrogen abstraction enabled understanding of degradation mechanism of CEF. In order to investigate sensitivity of CEF towards the radical attacks, the concept of Fukui functions was used. The structures of intermediates and degradation pathways were suggested by UHPLC-LTQ OrbiTrap MS and density functional theory calculations. Toxicity assessments showed that intermediates formed during hydrolysis exerted only mild cell growth effects in selected cell lines.

Kinetics, mechanism and toxicity of intermediates of solar light induced photocatalytic degradation of pindolol: Experimental and computational modeling approach.

In this work, we have investigated the stability of pindolol (PIN), a non-selective ß1-blocker detected in the river and wastewater of hospitals, in water solution under solar irradiation. Further, detailed insights into the stability of PIN were obtained by the density functional theory (DFT) calculations and molecular dynamics simulations. The kinetics of PIN photocatalytic degradation and mineralization has been studied using four commercial photocatalysts ZnO and TiO2 (P25, Hombikat, and Wackherr). It was found that the major role in degradation of PIN play the reactive hydroxyl radicals. The structures of degradation intermediates were suggested by LC-ESI-MS/MS and DFT calculations. Also, DFT calculations were used to refine molecular structures of intermediates and obtain their geometries. Toxicity of PIN and its mixtures formed during photocatalytic degradation were investigated using mammalian cell lines (H-4-II-E, HT-29, and MRC-5). The H-4-II-E cell line was the most sensitive to PIN and its photodegradation mixtures. The computational results were combined with the experimental data on the amounts of degradation intermediates for determination of the intermediates that were principally responsible for the toxicity. Intermediate with two hydroxyl groups, positioned on indole ring in meta and para positions, was proposed as the one with the highest contribution to toxicity.

Photocatalytic decomposition of selected biologically active compounds in environmental waters using TiO2/polyaniline nanocomposites: Kinetics, toxicity and intermediates assessment.

A comprehensive study of the removal of selected biologically active compounds (pharmaceuticals and pesticides) from different water types was conducted using bare TiO2 nanoparticles and TiO2/polyaniline (TP-50, TP-100, and TP-150) nanocomposite powders. In order to investigate how molecular structure of the substrate influences the rate of its removal, we compared degradation efficiency of the initial substrates and degree of mineralization for the active components of pharmaceuticals (propranolol, and amitriptyline) and pesticides (sulcotrione, and clomazone) in double distilled (DDW) and environmental waters. The results indicate that the efficiency of photocatalytic degradation of propranolol and amitriptyline was higher in environmental waters: rivers (Danube, Tisa, and Begej) and lakes (Moharac, and Sot) in comparison with DDW. On the contrary, degradation efficacy of sulcotrione and clomazone was lower in environmental waters. Further, of the all catalysts applied, bare TiO2 and TP-100 were found to be most effective in the mineralization of propranolol and amitriptyline, respectively, while TP-150 appeared to be the most efficient in terms of sulcotrione and clomazone mineralization. Also, there was no significant toxicity observed after the irradiation of pharmaceuticals or pesticides solutions using appropriate catalysts on rat hepatoma (H-4-II-E), mouse neuroblastoma (Neuro-2a), human colon adenocarcinoma (HT-29), and human fetal lung (MRC-5) cell lines. Subsequently, detection and identification of the formed intermediates in the case of sulcotrione photocatalytic degradation using bare TiO2 and TP-150 showed slightly different pathways of degradation. Furthermore, tentative pathways of sulcotrione photocatalytic degradation were proposed and discussed.

Photocatalytic degradation of 4-amino-6-chlorobenzene-1,3-disulfonamide stable hydrolysis product of hydrochlorothiazide: Detection of intermediates and their toxicity.

In this work we have investigated in details the process of degradation of the 4-amino-6-chlorobenzene-1,3-disulfonamide (ABSA), stable hydrolysis product of frequently used pharmaceutical hydrochlorothiazide (HCTZ), as one of the most ubiquitous contaminants in the sewage water. The study encompassed investigation of degradation by hydrolysis, photolysis, and photocatalysis employing commercially available TiO2 Degussa P25 catalyst. The process of direct photolysis and photocatalytic degradation were investigated under different type of lights. Detailed insights into the reactive properties of HCTZ and ABSA have been obtained by density functional theory calculations and molecular dynamics simulations. Specifically, preference of HCTZ towards hydrolysis was confirmed experimentally and explained using computational study. Results obtained in this study indicate very limited efficiency of hydrolytic and photolytic degradation in the case of ABSA, while photocatalytic degradation demonstrated great potential. Namely, after 240 min of photocatalytic degradation, 65% of ABSA was mineralizated in water/TiO2 suspension under SSI, while the nitrogen was predominantly present as NH4+. Reaction intermediates were studied and a number of them were detected using LC-ESI-MS/MS. This study also involves toxicity assessment of HCTZ, ABSA, and their mixtures formed during the degradation processes towards mammalian cell lines (rat hepatoma, H-4-II-E, human colon adenocarcinoma, HT-29, and human fetal lung, MRC-5). Toxicity assessments showed that intermediates formed during the process of photocatalysis exerted only mild cell growth effects in selected cell lines, while direct photolysis did not affect cell growth.

Theoretical investigation of loratadine reactivity in order to understand its degradation properties: DFT and MD study.

Antihistamines are frequently used pharmaceuticals that treat the symptoms of allergic reactions. Loratadine (LOR) is an active component of the second generation of selective antihistaminic pharmaceutical usually known as Claritin. Frequent usage of this type of pharmaceuticals imposes the need for understanding their fundamental reactive properties. In this study we have theoretically investigated reactive properties of LOR using both density functional theory (DFT) calculations and molecular dynamics (MD) simulations. DFT study is used for collecting information related to the molecule stability, structure, frontier molecular orbitals, quantum molecular descriptors, charge distribution, molecular electrostatic potential surfaces, charge polarization, and local reactivity properties according to average local ionization energy surfaces. Based on these results, N24 atom of pyridine ring and oxygen atom O1 were identified with nucleophilic nature. In order to collect the information necessary for the proposition of degradation compounds we also calculated bond dissociation energies (BDE) for hydrogen abstraction and single acyclic bonds as well. According to BDE, the oxidation is likely to occur in the piperidine and cycloheptane rings. MD simulations were used in order to understand the interactions with water through radial distribution functions (RDF). Based on RDFs the most important interactions with solvent are determined for carbon atom C5, chlorine atom Cl15, and oxygen atom O1. Collected results based on DFT calculations and MD simulations provided information important for suggestion of possible degradation compounds. Covalent and noncovalent interactions between LOR and (•)OH have also been investigated.

Efficient removal of sulcotrione and its formulated compound Tangenta® in aqueous TiO2 suspension: Stability, photoproducts assessment and toxicity.

The photocatalytic degradation of the herbicide sulcotrione (0.05 mM) and its formulated compound Tangenta® in aqueous suspensions of TiO2 Degussa P25 was examined as a function of the different operational parameters. The optimum of the catalyst loading was found to be 2.0 mg mL(-1) under UVA light. In the first stage of the reaction, the photocatalytic degradation of sulcotrione alone and in Tangenta® followed the pseudo-first order kinetics, in which the heterogeneous catalysis proceeds via OH and holes. Further, it can be concluded that degradation rate of sulcotrione alone is about two times higher compared to formulated compound. The results showed that the disappearance of sulcotrione led to the formation of three organic intermediates and ionic byproducts (Cl(-), SO4(2-), acetate and formate), whereas their mineralization was about 90% after 4 h. Tentative photodegradation pathways were proposed and discussed. Also, there was no significant toxicity observed after the irradiation of sulcotrione solution and Tangenta® formulation using TiO2 catalyst on three mammalian cell lines.

Toxicity assessment of metoprolol and its photodegradation mixtures obtained by using different type of TiO2 catalysts in the mammalian cell lines.

Toxicity of metoprolol (MET) alone and in mixtures with its photocatalytic degradation intermediates obtained by using TiO2 Wackherr and Degussa P25 under UV irradiation in the presence of O2 was evaluated in vitro in a panel of three histologically different cell lines: rat hepatoma (H-4-II-E), human colon adenocarcinoma (HT-29) and human fetal lung (MRC-5). Both catalysts promoted a time-dependent increase in the toxicity of the photodegradation products, and those obtained using Degussa P25 photocatalyst were more toxic. The most pronounced and selective toxic action of MET and products of its photodegradation was observed in the hepatic cell line. The higher toxicity of the mixtures obtained using Degussa P25 catalyst could be explained by a different mechanism of MET degradation, i.e. by the presence or higher concentrations of some intermediates. Although the concentrations of intermediates obtained using TiO2 Wackherr catalyst were higher, they did not affect significantly the growth of the examined cell lines, indicating their lower toxicity. This suggests that a treatment aiming at complete mineralization should be performed bearing in mind that the type of catalyst, the concentration of target molecule, and the duration of the process are significant factors that determine the nature and toxicity of the resulting mixtures. Although the EC50 values of MET obtained in mammalian cell lines were higher compared to the bioassays for lower trophic levels, the time-dependent promotion of toxicity of degradation mixtures should be attributed to the higher sensitivity of mammalian cell bioassays.

Photocatalytic degradation of the herbicide clomazone in natural water using TiO2: kinetics, mechanism, and toxicity of degradation products.

The photocatalytic degradation of the herbicide clomazone (0.05mM) in aqueous suspensions of TiO2 Degussa P25 was examined as a function of the different operational parameters. The optimum concentration of the catalyst was found to be 0.50mgmL(-1) under UV light at the pH 10.3. In the first stage of the reaction, the photocatalytic degradation of clomazone followed the pseudo-first order kinetics, with and the heterogeneous catalysis proceeding via OH radicals. The results also showed that the disappearance of clomazone led to the formation of a number of organic intermediates and ionic byproducts, whereas its complete mineralization occurred after about 55min. Tentative photodegradation pathways were proposed and discussed. A comparison of the evolution of toxicity that was evaluated in vitro in rat hepatoma (H-4-II-E) and human fetal lung (MRC-5) cell lines with the degradation kinetics indicates that the irradiation contributed to the decrease of the toxicity of the mixture that is no longer dominated by the parent compound. The study also encompassed the effect of the quality of natural water on the rate of removal of clomazone.

Degradation of thiacloprid in aqueous solution by UV and UV/H2O2 treatments.

Although some studies concerning flash photolysis and photocatalytic ozonation of thiacloprid have already been published, no complete investigation and explanation of the effects of thiacloprid photodegradation under the conditions of UV and UV/H(2)O(2) (high-pressure mercury lamp and H(2)O(2)) have been reported yet. The photochemical degradation of thiacloprid (0.32 mM) was studied under a variety of solution conditions, by varying the initial concentrations of H(2)O(2) from 0 to 162 mM and the pH from 2.8 to 9. In the UV/H(2)O(2) system, thiacloprid reacted rapidly, the maximum first-order rate constant (2.7 x 10(-2)min(-1), r=0.9996) being observed at the H(2)O(2)/thiacloprid molar ratio of 220 and pH 2.8. Under these conditions, 97% of the thiacloprid was removed in about 120 min. The thiacloprid degradation is accompanied by the formation of a number of ionic byproducts (Cl(-), acetate, formate, SO(4)(2-), and NH(4)(+)) and organic intermediates, so that after 35 h of irradiation, 17% of organic carbon remained non-degraded. The application of UV radiation, or H(2)O(2) alone, yielded no significant thiacloprid degradation. The study of the rate of removal of thiacloprid from natural water showed that it is dominantly influenced by the presence of HCO(3)(-).

Photocatalytic degradation of selected herbicides in aqueous suspensions of doped titania under visible light irradiation.

The aim of this work was to study the efficiency of Fe- and N-doped titania suspensions in the photocatalytic degradation of the herbicides RS-2-(4-chloro-o-tolyloxy)propionic acid (mecoprop, MCPP), (4-chloro-2-methylphenoxy)acetic acid (MCPA), and 3,6-dichloropyridine-2-carboxylic acid (clopyralid, CP) under the visible light (lambda > or = 400 nm) irradiation. The obtained results were compared with those of the corresponding undoped TiO(2) (rutile/anatase) and of the most frequently used TiO(2) Degussa P25. Computational modeling procedures were used to optimize geometry and molecular electrostatic potentials of MCPP, MCPA and CP and discuss the obtained results. The results indicate that the efficiency of photocatalytic degradation is greatly influenced by the molecular structure of the compound. Lowering of the band gap of titanium dioxide by doping is not always favorable for increasing photocatalytic efficiency of degradation.

Photodegradation of clopyralid in TiO2 suspensions: identification of intermediates and reaction pathways.

The work is concerned with the kinetics, identification of intermediates and reaction pathways of the photocatalytic degradation of the herbicide clopyralid (3,6-dichloropyridine-2-carboxylic acid) in UV illuminated aqueous suspensions of TiO(2) (Degussa P25). In the investigated concentration range (0.5-3.0 mM) the photocatalytic degradation kinetics of clopyralid in the first stage of the reaction follows approximately a pseudo-first kinetic order. The highest reaction rate was observed at 4 mg mL(-1)of catalyst concentration, the apparent activation energy of the reaction being 7.74 kJ mol(-1). The effect of the presence of hydrogen peroxide, potassium bromate, and ammonium persulfate, acting as electron acceptors along with molecular oxygen, were also studied. By studying the effect of ethanol as a hydroxyl radical scavenger it was shown that the heterogeneous catalysis takes place mainly via hydroxyl radicals. The reaction intermediates (3,6-dichloropyridin-2-ol, 3,6-dichloro hydroxypyridine-2-carboxylic acid, and 3,3',6,6'-tetrachloro-2,4'-bipyridine-2'-carboxylic acid) were identified and the kinetics of their appearance/disappearance was followed by LC-MS/MS (ESI+). Tentative photodegradation pathways were proposed and discussed.

Synthesis and Characterization of Rutile TiO(2) Nanopowders Doped with Iron Ions.

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5-7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO(2) into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence.

Phosphorus-doped and undoped glassy carbon indicator electrodes in controlled-current potentiometric titrations of bromide- or chloride-containing active ingredients in some pharmaceutical preparations.

Phosphorus-doped glassy carbon (as a novel material) and glassy carbon (Sigri commercial sample) were applied as potentiometric indicator electrodes in the titrimetric determination of active components with bromide or chloride in their molecules in different pharmaceutical preparations (Buscopan, Prostigmine, Isoptin, Bedoxin, Akineton and Trodon). After the necessary pre-treatment of the electrode surfaces and sample dissolution, the halide was titrated with a standard solution of silver nitrate (indirect determination). Amounts of 10-20 micromol of the investigated active ingredients per titration were determined with a relative standard deviation that, depending on the nature of indicator electrode, determined molecules and filler components, was in the range of 0.3-2.7%. The results obtained were compared with those of the official methods and with those obtained by potentiometric titrations using silver electrode. The titrimetric procedures developed are relatively fast, easy, economical and can be used to analyse of a large number of pharmaceutical products.