Effect of piroxicam on lipid membranes : Drug encapsulation and gastric toxicity aspects

Uptake of piroxicam, a non-steroidal anti-inflammatory drug, from the intestines after oral intake is limited due to its low solubility and its wide use is associated with several side effects related to the gastrointestinal tract. In this study, all-atom molecular dynamics (MD) simulations and fluorescent spectroscopy were employed to investigate the interaction of piroxicam in neutral, zwitterionic, and cationic forms with lipid bilayers composed of phosphatidylcholine, cholesterol, and PEGylated lipids. Our study was aimed to assess the potential for encapsulation of piroxicam in liposomal carriers and to shed more light on the process of gastrointestinal tract injury by the drug. Through both the MD simulations and laser scanning confocal microscopy, we have demonstrated that all forms of piroxicam can associate with the lipid bilayers and locate close to the water-membrane interface. Conventional liposomes used in drug delivery are usually stabilized by the addition of cholesterol and have their bloodstream lifetime extended through the inclusion of PEGylated lipids in the formulation to create a protective polymer corona. For this reason, we tested the effect of these two modifications on the behavior of piroxicam in the membrane. When the bilayer was PEGylated, piroxicam localize to the PEG layer and within the lipid headgroup region. This suggests that PEGylated liposomes are capable of carrying a larger quantity of piroxicam than the conventional ones. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

The First Four Ursuline Principals of Saint Bernard Academy

Starting in 1920, four women from rural western Kentucky came to Nebraska City, Nebraska, to serve as principals of St. Bernard Academy. These women were part of a religious community known as the Company of St. Ursula, or Ursulines. Following the spirituality of St. Angela Merici, they had consecrated themselves to serve God as “Brides of Christ” and, through a vow of obedience, they were sent to Nebraska. Their work as educational leaders enabled the school to flourish. This historical study tells their story. The narrative begins with St. Angela and the foundation of the Ursulines, follows the community to its foundation in Kentucky, and describes how they obtained possession of St. Bernard Academy. Then, through correspondence and personal documents found in the archives of the Motherhouse of Mt. St. Joseph, Kentucky, and the Diocese of Lincoln, Nebraska, a snapshot is provided into the joys, sorrows, tribulations, and triumphs of their lives

The release of hydrophilic compounds from the liposomes.

Celem pracy było zamykanie w liposomach formy utlenionej dinukleotydu nikotynamidoadeninowego (NAD+), zbadanie jego przenikalności przez błonę lipidową, oraz zwiększenie stabilności badanego układu liposomalnego.Związek ten ze względu na występowanie we wszystkich reakcjach zachodzących podczas procesu oddychania komórkowego ma potencjalne zastosowanie w leczeniu łuszczycy, jednakże jego niestabilność termiczna utrudnia przechowywanie, a hydrofilowy charakter nie pozwala na łatwe wnikanie do komórek. Jako nośnik leku ułatwiający jego przenikanie do wnętrza komórek zastosowano liposomy, których wykorzystanie możliwe jest dzięki ich wysokiej biokompatybilności oraz biodegradowalności.W związku z trudnością prowadzenia badań nad NAD+, który nie wykazuje fluorescencji, a jego roztwory są bezbarwne, do badań przenikalności przez błony biologiczne zastosowano hydrofilowe związki modelowe takie, jak kalceina oraz chlorek sodu.Wzrost stabilności liposomów próbowano osiągnąć przez zastosowanie metody layer-by-layer do pokrycia ich powierzchni ultracienkimi warstwami polimerów. W tym celu zastosowano hydrofobowo modyfikowany poli(chlorek allilotrimetyloamoniowy) oraz (poli(N-allilosulfaminian sodu).The aim of this thesis was encapsulation oxidized form of nicotinamide adenine dinucleotide (NAD+) in liposomes, investigation of the permeability through lipid membrane, and improvement of the stability of the liposomal system.This compound, due to participation in all the process of cellular respiration, has potential use in treating psoriasis. However, its thermal instability makes difficult to storage, and its hydrophilic nature does not allow for easy penetration to cells. Liposomes are used as a drug vehicles to facilitate cells penetration of the drug. It is possible due to their high biocompatibility and biodegradability.Since NAD+ shows no fluorescence and its solutions are colorless, the study of this compound is very difficult. As a results, in the studies of the permeability through biological membranes we have used also hydrophilic model compounds such as calcein and sodium chloride.The increase of liposome stability was achieved by the layer-by-layer method, which results in ultrathin polymeric layers coating the surface of liposome vesicles. A hydrophobically modified poly(allyltrimethylammonium chloride) and poly(sodium N-allylsulfamate) were used for this purpose

Perovskite La1-xSrxFeO3 Thin Films Deposited by Laser Ablation Process

The aim of the research was to investigate the influence of strontium on the structure of thin films La1-xSrxFeO3 (x = 0; 0,1; 0,2). The LaFeO3 and Sr-doped LaFeO3 films were produced by pulsed laser deposition (PLD) on Si (100) substrate using the Nd-YAG (λ = 266 nm) laser. SEM, AFM and XRD methods were used to characterize the structure and morphology of the thin films. X-Ray Diffraction analysis showed only the LaFeO3 phase in the undoped thin film and the La0.9Sr0.1O3 and La0.8Sr0.2O3 phases in thin films doped by Sr. The mean crystallite size, calculated by Williamson-Hall method, was smaller (of the order of 18 nm) in films doped by Sr. SEM analysis showed small droplets in thin films doped by Sr. Highly developed surface layer was observed using the AFM microscope for thin films doped by Sr

Perovskite La1-xSrxFeO3 Thin Films Deposited by Laser Ablation Process

The aim of the research was to investigate the influence of strontium on the structure of thin films La1-xSrxFeO3 (x = 0; 0,1; 0,2). The LaFeO3 and Sr-doped LaFeO3 films were produced by pulsed laser deposition (PLD) on Si (100) substrate using the Nd-YAG (λ = 266 nm) laser. SEM, AFM and XRD methods were used to characterize the structure and morphology of the thin films. X-Ray Diffraction analysis showed only the LaFeO3 phase in the undoped thin film and the La0.9Sr0.1O3 and La0.8Sr0.2O3 phases in thin films doped by Sr. The mean crystallite size, calculated by Williamson-Hall method, was smaller (of the order of 18 nm) in films doped by Sr. SEM analysis showed small droplets in thin films doped by Sr. Highly developed surface layer was observed using the AFM microscope for thin films doped by Sr

Structural Characterization of La1−xSrxCoO3La_{1-x}Sr_xCoO_3 Thin Films Deposited by Pulsed Electron Deposition Method

The aim of the presented research was to investigate the influence of strontium dopant on the structure and composition of $La_{1-x}Sr_{x}CoO_3$ (x=0, 0.1, 0.2) perovskite thin films. Pure and Sr doped LaCoO₃ thin films were grown by pulsed electron deposition technique on crystalline epi-polished Si/MgO substrates. Numerous analytical techniques (scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction) were applied to characterize their phase/chemical composition, structure and surface morphology. X-ray diffraction analysis showed the presence of pure LaCoO₃ perovskite phase in the undoped thin film. For Sr doped thin films $La_{0.8}Sr_{0.2}CoO_3$ (x=0.2), $La_{0.9}Sr_{0.1}CoO_3$ (x=0.1) small contents of La₂ O₃ and LaSrCoO₄ phases were noticed. The crystallite sizes, calculated from the Williamson-Hall plots, were about 18 nm for all analyzed films. According to scanning electron microscopy/atomic force microscopy observations, obtained thin films were free from defects and cracks. Atomic force microscopy (tapping mode) analysis revealed the differences in the shape and quantity of surface crystallites for all thin films as a result of Sr doping and different deposition parameters. Atomic force microscopy technique also allowed measurement of roughness parameters for analyzed samples. X-ray photoelectron spectroscopy analyses of chemical states of elements of thin films showed that their chemical state was stable across the film thickness and even at the interface with the MgO substrate. X-ray photoelectron spectroscopy analysis also allowed to evaluate chemical states and atomic concentration of La, Co, and Sr elements within cross-sections of deposited thin films

The Effect of Strontium Doping on LaFeO3 Thin Films Deposited by the PLD Method

The aim of the presented investigations was to deposit the thin films La1−xSrxFeO3 (x = 0, 0.1, 0.2) on (100) Si substrate by using the Pulsed Laser Deposition (PLD) method. Structure was exanimated by using XRD, SEM, AFM, TEM and XPS methods. The catalytic properties were analyzed in 4 ppm acetone atmosphere. The doping of Sr thin films La1−xSrxFeO3 (x = 0, 0.1, 0.2) resulted in a decrease in the size of the crystallites, the volume of the elemental cell and change in the grain morphology. In the LaFeO3 and La0.9Sr0.1FeO3, clusters around which small grains grow are visible in the structure, while in the layer La0.8Sr0.2FeO3, the visible grains are elongated. The TEM analysis has shown that the obtained thin films had a thickness in the range 150–170 nm with triangular or flat column ends. The experiment performed in the presence of gases allowed us to conclude that the surfaces (101/020) in the triangle-shaped columns and the plane (121/200) faces in flat columns were exposed to gases. The best properties in the presence of CH3COCH3 gas were noted for LaFeO3 thin film with triangle columns ending with orientation (101/020)