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Solution blow spinning was used to prepare nonwoven bicomponent fibers constituted by poly (ethylene oxide)-Polysulfone (PEO-PSF). As a new material, deep characterization was carried out to have a database to understand final performance regarding its multiple functions as a potential material for biomedical applications. The morphology was studied by field emission scanning electron and transmission electron microscopy and optical profilometry. Structural characterization was carried out by Fourier transform infrared spectroscopy and thermal degradation by thermogravimetric analysis. Additionally, wettability and mechanical behavior were studied by contact angle measurements and tensile tests, respectively. The bicomponent material was constituted of fibers with a structure mainly described by a core-shell structure, where the PSF phase is located at the center of the fibers, and the PEO phase is mainly located at the outer parts of the fibers, leading to a kind of shell wall. The study of possible interactions between different phases revealed them to be lacking, pointing to the presence of an interface core/shell more than an interphase. The morphology and roughness of the bicomponent material improved its wettability when glycerol was tested. Indeed, its mechanical properties were enhanced due to the PSF core provided as reinforcement material.

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The application of mesenchymal stem cells (MSC) in bone tissue regeneration can have unpredictable results due to the low survival of cells in the process since the lack of oxygen and nutrients promotes metabolic stress. Therefore, in this work, polymeric membranes formed by organic-inorganic hybrid materials called ureasil-polyether for modified glucose release were developed in order to overcome the problems posed by a of lack of this nutrient. Thus, membranes formed by polymeric blend of polypropylene oxide (PPO4000) and polyethylene oxide (PEO500) with 6% glucose incorporation were developed. Physical-chemical characterization techniques were performed, as well as tests that evaluated thermal properties, bioactivity, swelling, and release in SBF solution. The results of the swelling test showed an increase in membrane mass correlated with an increase in the concentration of ureasil-PEO500 in the polymeric blends. The membranes showed adequate resistance when subjected to the application of a high compression force (15 N). X-ray diffraction (XRD) evidenced peaks corresponding to orthorhombic crystalline organization, but the absence of glucose-related peaks showed characteristics of the amorphous regions of hybrid materials, likely due to solubilization. Thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses showed that the thermal events attributed to glucose and hybrid materials were similar to that seen in the literature, however when glucose was incorporated into the PEO500, an increase in rigidity occurs. In PPO400, and in the blends of both materials, there was a slight decrease in Tg values. The smaller contact angle for the ureasil-PEO500 membrane revealed the more hydrophilic character of the material compared to other membranes. The membranes showed bioactivity and hemocompatibility in vitro. The in vitro release test revealed that it is possible to control the release rate of glucose and the kinetic analysis revealed a release mechanism characteristic of anomalous transport kinetics. Thus, we can conclude that ureasil-polyether membranes have great potential to be used as a glucose release system, and their future application has the potential to optimize the bone regeneration process.

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Jussara pulp (Euterpe edulis Mart.) is rich in bioactive compounds known to be protective mediators against several diseases. In this context, nevertheless, anthocyanins, the most abundant natural pigment in jussara, are sensitive to temperature, pH, oxygen, and light conditions, leading to instability during food storage or digestion, and, thus jeopardizing the antioxidant proprieties retained by these flavonoids and limiting industrial application of the pulp. The production of nanostructures, from synthetic and natural polymers, containing natural matrices rich in bioactive compounds, has been widely studied, providing satisfactory results in the conservation and maintenance of the stability of these compounds. The current work aimed to compare uniaxial and coaxial electrospinning operation modes to produce core-shell jussara pulp nanofibers (NFs). Additionally, the parameters employed in the electrospinning processes were optimize using response surface methodology in an attempt to solve stability issues for the bioactive compounds. The best experimental conditions provided NFs with diameters ranging between 110.0 ± 47 and 121.1 ± 54 nm. Moreover, the coaxial setup improved jussara pulp NF formation, while further allowing greater integrity of NFs structures.

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Hybrid encapsulation structures based on ß-carotene-loaded nanoliposomes incorporated within the polymeric ultrathin fibers produced through electrospinning were developed to improve the photostability of the antioxidant. These novel materials were intended to incorporate ß-carotene into water-based food formulations, overcoming the existing limitations associated with its hydrophobic character. Initially, both empty and antioxidant-loaded nanoliposomes were developed and incorporated into polyvinyl alcohol (PVOH) and polyethylene oxide (PEO) solutions. The changes in the solution properties were evaluated to determine their effects on the electrospinning processing. The mixed polymer solutions were subsequently electrospun to produce hybrid nanoliposome-loaded ultrathin fibers. FTIR analysis confirmed the presence of phospholipid molecules inside the electrospun fibers. These ultrathin fibers were evaluated regarding their morphology, diameter, internal ß-carotene distribution and stability against UV irradiation. Liposomal release studies from the electrospun fibers were also undertaken, confirming the presence of the liposomal structures after dissolving the electrospun fibers in water.

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The aim of the present research is to formulate and evaluate the gastroretentive floating drug delivery system of antihypertensive drug, propranolol HCl. Gastroretentive floating tablets (GRFT) were prepared by using a synthetic hydrophilic polymer polyethylene oxide of different grades such as PEO WSR N-12 K and PEO 18 NF as release retarding polymers and calcium carbonate as gas generating agent. The GRFT were compressed by direct compression strategy and the tablets were evaluated for physico-chemical properties, in vitro buoyancy, swelling studies, in vitro dissolution studies and release mechanism studies. From the dissolution and buoyancy studies, F 9 was selected as an optimized formulation. The optimized formulation followed zero order rate kinetics with non-Fickian diffusion mechanism. The optimized formulation was characterised with FTIR studies and observed no interaction between the drug and the polymers.

O objetivo da presente pesquisa é o de formular e avaliar o sistema de liberação de fármaco gastrorretentivo flutuante, contendo o anti-hipertensivo, cloridrato de propranolol. Comprimidos gastrorretentivo flutuantes (GRFT) foram preparados utilizando um polímero hidrofílico sintético, o óxido de polietileno, de diferentes graus, tais como GE WSR N-12 K e GE 18 NF, como polímeros de retardamento de liberação, e carbonato de cálcio, como agente gerador de gases. Os GRFT foram comprimidos por compressão direta e avaliados para determinação das propriedades físico-químicas, flutuabilidade in vitro, estudos de inchamento, de dissolução in vitro e de mecanismo de liberação. Dos testes de dissolução e de flutuabilidade, selecionou-se F 9 como formulação otimizada. A formulação otimizada seguiu cinética de ordem zero, com mecanismo de difusão não-Fickiano. Essa formulação foi caracterizada por estudos de FTIR, não se observando interação entre o fármaco e os polímeros.

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The aim of the present research was to prepare and evaluate a gastroretentive drug delivery system for metformin HCl, using synthetic and semi-synthetic polymers. The floating approach was applied for preparing gastroretentive tablets (GRT) and these tablets were manufactured by the direct compression method. The drug delivery system comprises of synthetic and semi-synthetic polymers such as polyethylene oxide and Carboxymethyl ethyl cellulose (CMEC) as release-retarding polymers. GRT were evaluated for physico-chemical properties like weight variation, hardness, assay friability, in vitro floating behaviour, swelling studies, in vitro dissolution studies and rate order kinetics. Based upon the drug release and floating properties, two formulations (MP04 & MC03) were selected as optimized formulations. The optimized formulations MP04 and MC03 followed zero order rate kinetics, with non-Fickian diffusion and first order rate kinetics with erosion mechanism, respectively. The optimized formulation was characterised with FTIR studies and it was observed that there was no interaction between the drug and polymers.

El objetivo del presente trabajo consistió en preparar y evaluar un sistema de administración gastro-retentivo de metformina HCl, utilizando polímeros sintéticos y semisintéticos. Se aplicó el método de flotación para la elaboración de los comprimidos de retención gástrica (CRG) y éstos se prepararon mediante el método de compresión directa. El sistema de suministro del fármaco estaba constituido por polímeros sintéticos y semisintéticos, tales como el óxido de polietileno y la carboximetil etil celulosa, como agentes retardadores de la liberación del fármaco. Se evaluaron las propiedades físico-químicas de los CRG, tales como: variación de peso, dureza, friabilidad, comportamiento flotante in vitro, capacidad de inflación, estudios de disolución in vitro y su tasa de orden cinético. Se seleccionaron dos fórmulas (MP04 y MC03), sobre la base de la liberación del fármaco y las propiedades de flotabilidad, como fórmulas óptimas. Estas fórmulas MP04 y MC03 optimizadas siguieron cinéticas de velocidad de orden cero, con difusión no-Fickian y tasa cinética de primer orden con mecanismo de erosión, respectivamente. Las fórmulas óptimas se caracterizaron con estudios FTIR y se observó que no hubo interacción entre el fármaco y los polímeros.

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The aim of this study was to develop and evaluate a multiparticulate modified release system, composed of minitablets with a sustained release matrix system coated with a pH-dependent release polymer, using mesalamine as a model drug. Polyox® WSR 1105 was the polymer used in the matrix system and Eudragit® L30D55 was used as a pH-dependent polymer. The minitablets (with 20%, 30% or 40% Polyox® concentration) were prepared by dry granulation, which led to good quality minitablets. The developed minitablets were coated in a fluidized bed at 8% of the coating level. Dissolution studies were performed in media that simulated the gastrointestinal tract (pH 1.4, 6.0 and 7.2) and showed that formulations with higher Polyox® concentrations were capable of retaining the drug release in pH 1.4. All formulations prolonged the drug release and presented zero-order kinetic behaviour. The Korsmeyer-Peppas model demonstrated that formulations with 20% or 30% of polymer exhibited anomalous transport behaviour, whilst the 40% sample exhibited super case II model transportation. Dissolution efficiency showed that only the formulations containing 20% and 40% polymer could be considered statistically different.

O presente trabalho teve como objetivo desenvolver e avaliar um sistema multiparticulado de liberação modificada, composto por minicomprimidos com sistema matricial de liberação prolongada revestidos com polímero de liberação pH-dependente, utilizando mesalazina como fármaco modelo. Polyox® WSR 1105 foi o polímero utilizado no sistema matricial e Eudragit® L30D55 foi utilizado como polímero pH-dependente. Os minicomprimidos (com 20%, 30% e 40% de concentração de Polyox®) foram preparados por granulação via seca, gerando minicomprimidos de boa qualidade. Os minicomprimidos desenvolvidos foram revestidos em leito fluidizado a 8% de nível de revestimento. Efetuou-se o estudo de dissolução em meios que simulam o trato gastrointestinal (pH 1,4, 6,0 e 7,2) e as formulação contendo maiores concentrações de Polyox® foram capazes de reter a liberação do fármaco em pH 1,4. Todas as três formulações apresentaram liberação prolongada e comportamento cinético de ordem zero. O modelo de liberação de Korsmeyer-Peppas mostrou que as formulações com 20% e 30% de polímero apresentam comportamento de transporte anômalo, enquanto a com 40%, transporte super caso II. A eficiência de dissolução mostrou que somente as formulações com 20% e 40% de concentração do polímero foram consideradas estatisticamente diferentes.

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The aim of the present investigation was to formulate thermally sintered floating tablets of propranolol HCl, and to study the effect of sintering conditions on drug release, as well as their in vitro buoyancy properties. A hydrophilic polymer, polyethylene oxide, was selected as a sintered polymer to retard the drug release. The formulations were prepared by a direct compression method and were evaluated by in vitro dissolution studies. The results showed that sintering temperature and time of exposure greatly influenced the buoyancy, as well as the dissolution properties. As the sintering temperature and time of exposure increased, floating lag time was found to be decreased, total floating time was increased and drug release was retarded. An optimized sintered formulation (sintering temperature 50°C and time of exposure 4 h) was selected, based on their drug retarding properties. The optimized formulation was characterized with FTIR and DSC studies and no interaction was found between the drug and the polymer used.

El propósito de la presente investigación fue la elaboración de tabletas flotantes de HCL propanolol térmicamente sinterizadas y estudiar los efectos de las condiciones de sinterización sobre la liberación de la droga, así como sobre sus propiedades de flotabilidad in vitro. Se seleccionó un polímero hidrofílico, el óxido de polietileno, como polímero sinterizado, para retardar la liberación de la droga. Las fórmulas se prepararon mediante un método de compresión directa y se evaluaron mediante estudios de disolución in vitro. Los resultados demostraron que la temperatura de sinterización y el tiempo de exposición tuvieron una gran influencia sobre las propiedades de flotabilidad y de disolución. Se encontró que el intervalo de retardo en la flotación disminuyó, el tiempo total de flotación aumentó y se retardó la liberación de la droga, a medida que aumentaron la temperatura de sinterización y el tiempo de exposición. Se seleccionó una fórmula óptima de sinterización (temperatura de sinterización de 50°C y tiempo de exposición de 4 h), basados en las propiedades retardativas sobre la droga. La fórmula sinterizada se caracterizó mediante estudios FITR y DSC y no se encontró ninguna interacción entre la droga y el polímero utilizado.

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The purpose of this research was to develop and evaluate effervescent gastric floating tablets of propranolol HCl. The oral delivery of antihypertensive propranolol HCl was facilitated by preparing an effervescent floating dosage form which could increase its absorption in the stomach by increasing the drug’s gastric residence time. In the present work, effervescent floating tablets were prepared with a hydrophilic carrier such as polyethylene oxide (PEO WSR N 60K and PEO WSR 303) as a release retarding agent and sodium bicarbonate as a gas generating agent. The prepared tablets were evaluated for all their physicochemical properties, in vitro buoyancy, drug release and rate order kinetics. From the results, P9 was selected as an optimized formulation based on their 12 h drug release, minimal floating lag time and maximum total floating time. The optimized formulation followed first order rate kinetics with erosion mechanism. The optimized formulation was characterized with FTIR studies and no interaction between the drug and the polymers were observed.

El propósito de la presente investigación fue desarrollar y evaluar tabletas flotantes, efervescentes de HCL propranolol. La administración oral del antihipertensivo HCL propranolol se facilitó mediante la preparación de una forma de dosificación flotante y efervescente que permitiría su absorción en el estómago, mediante el aumento del tiempo de residencia gástrico de la droga. En el presente trabajo, las tabletas flotantes efervescentes fueron preparadas con un portador hidrofílico, tal como el óxido de polietileno (PEO WSR N 60K and PEO WSR 303), como agente retardador y bicarbonato de sodio como un agente generador de gas. Se evaluaron todas las propiedades fisicoquímicas de las tabletas preparadas, su flotación in vitro y su tasa de orden cinético. Se seleccionó el P9 a partir de los resultados obtenidos, como una fórmula óptima, basados en la liberación de la droga a las 12 h, tiempo mínimo de retraso para flotación y máximo tiempo total de flotación. La formulación optimizada siguió una tasa cinética de primer orden con mecanismo de erosión. Esta fórmula óptima se caracterizó mediante estudios FITR y no se observó ninguna interacción entre la droga y los polímeros utilizados.

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In this work a different type of formulation, as disc, containing a selected mucoadhesive polymer, fillers, and binders were investigated for their potential as a mucoadhesive gastroretentive delivery system to deliver famotidine in the stomach. Various types of hydrophilic diluents were evaluated for their swelling and mucoadhesive property and one (polyvinylpyrrolidone, PVP) was selected to combine with the selected mucoadhesive polymer (polyethylene oxide, PEO). Discs with different ratios of PEO and PVP were prepared and evaluated for swelling, dissolution, and mucoadhesion. The swelling property of the discs increased as the concentration of PEO was increased and also did the mucoadhesion. These discs retained their integrity and adherence onto gastric mucosa for more than 10 h under in-vitro conditions. The PEO, in combination with PVP, yielded a non-disintegrating type mucoadhesive dosage form which was suitable for gastroretentive applications to achieve the desired release profile of the drug.