Selenium-capped cyclic peptide nanoparticles for penicillamine drug delivery: A DFT Study

Using a model for performance of penicillamine (PCA) anti-cancer drug on selenium-cyclic peptide nanoparticle (CPSeNP), 11 noncovalent configurations have been investigated. Se8 ring model and cyclooctaglycine were used for selenium nanoparticle (SeNP) and cyclic peptide (CP), respectively. Binding energies, quantum molecular descriptors and solvation energies were studied in gas phase and water at M06-2X /6-31G** level of theory. The calculated energies represent the high-energy stability of CPSeNP/PCA 1-11 configurations. Solvation energies showed that drug solubility increases, which is a major factor for their use in drug delivery. Regarding to quantum molecular descriptors such as hardness and electrophilic power, the drug reactivity increases in the vicinity of SeNP. The QTAIM analysis revealed that intramolecular interaction Se-L (L =O, H , S, C , N) plays an important role in the system. Se-L interaction in all configurations is relevant to weak interactions. The configurations that PCA drug is located in parallel with the carrier (CPSeNP) are more stable than penicillamine-CP or penicillamine-SeNP systems

Experimental sensing and density functional theory study of an ionic liquid mediated carbon nanotube modified carbon-paste electrode for electrochemical detection of metronidazole

A new highly sensitive sensor was prepared for metronidazole (MNZ) employing single-walled carbon nanotube (SWCNT) and 1-butyl-3-methylimidazolium tetrafluoroborate as ionic liquid (IL). The utilization of IL as a binder in the paste increased the response of the electrode. The performance of the obtained carbon paste electrode was examined by differential pulse voltammetry. Various factors like electrode composition, types of supporting electrolyte, pH, stirring rate, scan rate were studied and optimized. The modified sensor demonstrated high recognition ability and sensitivity for MNZ when compared with the unmodified sensor. Moreover, the sensor also demonstrated good stability and acceptable reproducibility for the determination of MNZ. In the optimum experimental conditions, the current response of the electrochemical sensor studied for metronidazole solution and linearity was obtained in the range of 5.00×10–5 to 5.00×10–3mgL–1, with a detection limit of 1.238×10–5mgL–1. The method was successfully used for the analysis of MNZ in the milk and egg samples with acceptable recoveries of 90.33–108.0 %. In addition, the non-covalent interactions of the metronidazole with the SWCNT were investigated employing the density functional theory (DFT) method.Keywords: Carbon paste electrode, metronidazole, differential pulse voltammetry, single-walled carbon nanotube, density functional theory, 1-butyl-3-methylimidazolium tetrafluoroborat

Geometry, tautomerism and non-covalent interactions of the drug halofuginone with the carbon-nanotube and γ-Fe2O3 nanoparticles: A DFT study

Halofuginone is a potential anti-malarial drug, which could exist as three possible tautomers. Herein, using density functional theory (DFT), and handling the solvent effects with the PCM model, the tautomerism of halofuginone was investigated. Intramolecular H-bonds play an important role in the stability of the tautomers. The conformer H1a is the most stable. Noncovalent interactions of the H1a conformer with the armchair (5,5) single-wall carbon nanotubes and γ-Fe2O3 nanoparticles were explored in several manners. The most stable form of them was determined. The intermolecular H-bonds play a substantial role in the energy behavior of the interaction between γ-Fe2O3 nanoparticles and halofuginone

Tautomerism and non-covalent interactions of flucytosine with armchair (5,5) SWCNT and γ-Fe₂O₃ nanoparticles: A DFT study

626-632The structural parameters, energetic behavior and natural bond orbital analysis of flucytosine, as well as its tautomerization mechanism are explored theoretically using density functional theory calculations. The PCM model has been adopted to consider the solvent effects. Due to the large HOMO-LUMO energy gap, the flucytosine molecule is highly stable. The non-covalent interactions of the most stable tautomer of flucytosine with the armchair (5,5) single wall carbon nanotube and the magnetic γ-Fe2O3 nanoparticle have been explored. In each case, the most stable form is determined. Intramolecular hydrogen bonds play an essential role in stability of the non-covalent interactions between the flucytosine molecule and the γ-Fe2O3 nanoparticle

Mesoporous materials, Mesoporous silica, Silica, SBA-15, Functionalized SBA-15, Drug delivery

The structural parameters, energetic behavior and natural bond orbital analysis of flucytosine, as well as its tautomerization mechanism are explored theoretically using density functional theory calculations. The PCM model has been adopted to consider the solvent effects. Due to the large HOMO-LUMO energy gap, the flucytosine molecule is highly stable. The non-covalent interactions of the most stable tautomer of flucytosine with the armchair (5,5) single wall carbon nanotube and the magnetic γ-Fe2O3 nanoparticle have been explored. Intramolecular hydrogen bonds play an essential role in stability of the non-covalent interactions between the flucytosine molecule and the γ-Fe2O3 nanoparticle.

DFT STUDY ON THE MECHANISTIC, ENERGETIC AND STRUCTURAL ASPECTS OF ADSORPTION OF TIRAPAZAMINE ONTO PRISTINE AND FUNCTIONALIZED CARBON NANOTUBES

Using density functional theory, noncovalent interactions and two mechanisms of covalent functionalization of drug tirapazamine with pristine, COOH and COCl functionalized carbon nanotube (NT, NTCOOH and NTCOCl) have been investigated. Quantum molecular descriptors of noncovalent configurations were studied. It was specified that binding of drug tirapazamine with NTCOOH has more binding energy than NTCOCl and NT, so NTCOOH can act as a favorable system for tirapazamine drug delivery within biological and chemical systems (noncovalent). NTCOOH and NTCOCl can bond to the amino group of tirapazamine through OH (COOH mechanism) and Cl (COCl mechanism) groups, respectively. The activation parameters of two pathways were calculated and compared with each other. The activation parameters related to COOH mechanism are higher than those related to COCl mechanism and therefore COCl mechanism is suitable for covalent functionalization. These results could be generalized to other similar drugs

Catalytic performance of Preyssler heteropolyacids and synthesis, experimental, theoretical characterizations, fluorescence properties of 1,8-dioxodecahydroacridine derivative

715-721Two Preyssler heteropolyacids, H14[NaP5W29MoO110] (HPA1) and H14[NaP5W30O110] (HPA2) have been studied for catalytic performance in the synthesis of 1,8-dioxodecahydroacridines. These green, heterogeneous, efficient and environment-friendly catalysts have been utilized in a one-pot three-component reaction of dimedone, aromatic aldehydes and ammonium acetate under solvent and solvent-free conditions. The results showed that 0.03 g of each catalysts at 110°C under solvent-free conditions could be the best conditions for the synthesis of products. In addition, a new derivative of 1,8-dioxodecahydroacridines has been synthesized. The structure of the new compound has been studied both experimentally and theoretically. DFT calculations have been carried out using B3LYP/6-31+G(d,p) level of theory. The theoretical 1H NMR data are found to be in accordance with the experimental data. Furthermore, the fluorescence properties of the new compound have been evaluated in different solvents and temperatures

Наноструктуры дендримеров ПАМАМ в системе доставки лекарств для 5-фторурацила

In this article, we studied five noncovalent structures for adsorption of 5 fluorouracil drug (5 FL) on poly(amidoamine) G0 generation dendrimer (PAMAMG0) carrier using M06-2X and B3LYPfunctionals. We investigate the quantum molecular descriptors and the binding and solvation energies in gas phase and aqueous solution. The energetic stability of non-bonded species (PAMAMG0/5-FL1-5) was shown through evaluation of binding free energies. The solvation free energies of PAMAMG0/5-FL1-5 are negative, indicating that the solvation process is spontaneous. We considered quantum molecular descriptors such as electrophilicity power and global hardness and found reduced toxicity of 5-FL drug near PAMAMG0 carrier as well as facilitated drug release. The AIM (Atoms In Molecule) analysis for all PAMAMG0/5-FL1-5 structures demonstrated that the pseudo-hydrogen and hydrogen bonds are essential in the functionalization of PAMAMG0 with 5-FL drug. We found thatthe structure in which 5-FL drug interacts with CO functional groups of PAMAMG0 is the most stable configurationВ этой статье мы изучили пять нековалентных структур для адсорбции лекарственного средства 5-фторурацила (5 FL) на носителе дендримеров поколения поли (амидоамина) G0 (PAMAMG0) с использованием функционалов M06-2X и B3LYP. Мы исследуем квантовые молекулярные дескрипторы и энергии связывания и сольватации в газовой фазе и водном растворе. Энергетическая стабильность несвязанных частиц (PAMAMG0 / 5-FL1-5) была показана путем оценки свободных энергий связи. PAMAMG0 / 5-FL1-5 отрицательны, что указывает на самопроизвольный процесс сольватации. Мы рассмотрели квантовые молекулярные дескрипторы, такие как мощность электрофильности и общая жесткость, и обнаружили сниженную токсичность препарата 5-FL вблизи носителя PAMAMG0, а также облегчение высвобождения лекарства. Анализ AIM (атомы в молекуле) для всех структур PAMAMG0 / 5-FL1-5 продемонстрировал, что псевдоводородные и водородные связи важны для функционализации PAMAMG0 лекарственным средством 5-FL. Мы обнаружили, что структура, в которой препарат 5-FL взаимодействует с функциональными группами CO PAMAMG0, является наиболее стабильной конфигурацие