166 research outputs found

    Drug delivery from liposomes in different biorelevant media

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    Liposomes provide ideal vesicular systems for controlled release and vectorization of drugs through pulmonary administration, due to their similarity to cell membranes and their great versatility./nSildenafil citrate, represents an optimal model of drug to be incorporated into these lipid vesicles for the treatment of pulmonary hypertension./nThe objective of the work was to characterize the behavior of liposomes loaded with sildenafil and evaluate the transfer of the drug in different bio-resistant media./nLiposomes of two sizes (0.45 and 0.20 microns) were developed by sonication. Subsequently, the drug release test was carried out in different biorelevant media (simulated plasma fluid SBF, simulated pulmonary fluid SPF and PBS)./nAccording to the results obtained, a more sustained and consistent rate of release of the drug was observed over time in the case of liposomes, regardless of the medium. In PBS and SPF media, a greater amount of drug was released from the larger liposomes (0.45 microns), however, in the SBF the transfer kinetics of both liposome sizes (0.45µm and 0.20 µm) are very similar, with no significant differences in the time or amount of drug releasedLos liposomas constituyen sistemas vesiculares ideales para la liberación controlada y vectorización de fármacos a través de su administración pulmonar, debido a su similitud con las membranas celulares y su gran versatilidad./nEl citrato de sildenafilo, representa un óptimo modelo de fármaco para ser incorporado en estas vesículas lipídicas para el tratamiento de la hipertensión pulmonar./nEl objetivo del trabajo fue caracterizar el comportamiento de los liposomas cargados con sildenafilo y evaluar la cesión del fármaco en distintos medios biorrelevantes./nSe elaboraron liposomas de dos tamaños (0.45 y 0.20 micras) mediante sonicación. Posteriormente se llevó a cabo el ensayo de liberación del fármaco en diferentes medios biorrelevantes (fluido plasmático simulado SBF, fluido pulmonar simulado SPF y PBS)./nSegún los resultados obtenidos se observó una velocidad de liberación del fármaco más sostenida y constante a lo largo del tiempo en el caso de los liposomas, independientemente del medio. En los medios PBS y SPF, se liberó una mayor cantidad de fármaco desde los liposomas con mayor tamaño (0,45 µm), sin embargo, en el SBF las cinéticas de cesión de ambos tamaños de liposomas (0,45 y 0,20 µm) son muy similares, no encontrándose diferencias significativas en el tiempo o cantidad de fármaco liberada

    Design of a liposomal formulation aimed to vaccines administration

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    Antigen is not the single component involved in the pharmacological response for vaccines but additional factors such as formulation and adjuvant compounds play a relevant role. Several strategies based on the use of liposomes are currently assayed in this field. According to this, the aim of the present work was the design, preparation and characterization of a pharmaceutical vehicle able to produce a rapid delivery of adjuvants and a slow release of antigen. From the know-how a theoretical vehicle was design and proposed as optimal formulation and this was then prepared and characterized. The “proposed formulation” is based on albumin coated liposomes made of egg phosphatidylcholine, cholesterol and diethyldodeccyiamonium. The applied procedure carried out in absence of organic solvents allowed for obtaining liposomes with a 20-70 nm aerodynamic diameter range and a zeta potential mean value of 61.9 ±2.08 mV and also for its coating with albumin. Coated particles showed a spherical shape and a size range of 2-10 µm which does not fulfil parenteral formulations requirements but are optimal for nasal or dermatological administration routes.Los efectos de una vacuna dependen no solo del antígeno, sino también de factores relacionados con la formulación; la elección del sistema de liberación junto con el empleo de potenciadores inmunológicos son aspectos de gran relevancia. Actualmente existen numerosas estrategias en desarrollo en este campo basados en la utilización de liposomas. El objetivo de este  trabajo ha sido el diseño y la preparación de un vehículo para la administración de vacunas, capaz de liberar inmediatamente el coadyuvante y más lentamente el antígeno.  Analizando los conocimientos previos se realizó, en una primera fase,  el diseño teórico del vehículo y seguidamente la preparación y caracterización del mismo. La “formulación propuesta” se basa en la microencapsulación de liposomas, constituidos por fosfatidilcolina, colesterol y dimetildioctadecil amonio, con albumina bovina. El procedimiento experimental aplicado, que transcurre en ausencia de disolventes orgánicos,  permite obtener liposomas con un potencial zeta de  61,9 ±2,08 mV y tamaño entre 20 y 70 nm así como su inclusión en partículas esféricas de albúmina, cuyo rango de tamaño resultó ser de 2-10 µm. Con estas características el vehículo no podría administrarse por vía parenteral pero si nasal o transdérmica

    Xanthan Gum–Konjac Glucomannan Blend Hydrogel for Wound Healing

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    Hydrogels are considered to be the most ideal materials for the production of wound dressings since they display a three-dimensional structure that mimics the native extracellular matrix of skin as well as a high-water content, which confers a moist environment at the wound site. Until now, different polymers have been used, alone or blended, for the production of hydrogels aimed for this biomedical application. From the best of our knowledge, the application of a xanthan gum-konjac glucomannan blend has not been used for the production of wound dressings. Herein, a thermo-reversible hydrogel composed of xanthan gum-konjac glucomannan (at different concentrations (1% and 2% w/v) and ratios (50/50 and 60/40)) was produced and characterized. The obtained data emphasize the excellent physicochemical and biological properties of the produced hydrogels, which are suitable for their future application as wound dressings.info:eu-repo/semantics/publishedVersio

    Aliento de justos, espejo de perfectos, consuelo de pecadores y fortaleza de flacos en los trabajos de Maria Santisima

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    Sign. : A-Z4, 2A-2V4.Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

    The diagnostic value of pleural fluid homocysteine in malignant pleural effusion

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    Background Pleural fluid homocysteine (HCY) can be useful for diagnosis of malignant pleural effusion (MPE). There are no published studies comparing the diagnostic accuracy of HCY with other tumour markers in pleural fluid for diagnosis of MPE. The aim was to compare the accuracy of HCY with that of carcinoembryonic antigen (CEA), cancer antigen (CA) 15.3, CA19.9 and CA125 in pleural fluid and to develop a probabilistic model using these biomarkers to differentiate benign (BPE) from MPE. Methods Patients with pleural effusion were randomly included. HCY, CEA, CA15.3, CEA19.9 and CA125 were quantified in pleural fluid. Patients were classified into two groups: MPE or BPE. By applying logistic regression analysis, a multivariate probabilistic model was developed using pleural fluid biomarkers. The diagnostic accuracy was determined by receiver operating characteristic (ROC) curves and calculating the area under the curve (AUC). Results Population of study comprised 133 patients (72 males and 61 females) aged between 1 and 96 years (median = 70 years), 81 BPE and 52 MPE. The logistic regression analysis included HCY (p< 0.0001) and CEA (p = 0.0022) in the probabilistic model and excluded the other tumour markers. The probabilistic model was: HCY+CEA = Probability(%) = 100x( 1 +e(-z))(-1), where Z = 0.5471x[ HCY]+0.3846x[ CEA]-8.2671. The AUCs were 0.606, 0.703, 0.778, 0.800, 0.846 and 0.948 for CA125, CA19.9, CEA, CA15.3, HCY and HCY+CEA, respectively. Conclusions Pleural fluid HCY has higher accuracy for diagnosis of MPE than CEA, CA15.3, CA19.9 and CA125. The combination of HCY and CEA concentrations in pleural fluid significantly improves the diagnostic accuracy of the test

    Analysis of the nutritional state and body composition of school children in Granada (Spain)

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    Los objetivos de este estudio fueron determinar el estado nutricional de la población de escolares estudiada. En segundo lugar, analizar el patrón de distribución de la grasa subcutánea entre dicha población. La muestra estaba constituida por 977 escolares de Granada capital y provincia (524 chicas y 452 chicos), todos ellos con edades comprendidas entre los 9 y los 17 años. Para el estudio del estado nutricional y distribución del componente graso subcutáneo se realizó una evaluación antropométrica completa incluyendo una valoración del peso, estatura, índice de masa corporal, pliegues cutáneos y perímetros corporales. Los resultados obtenidos muestran la existencia de una prevalencia de sobrepeso del 23,01% en chicas frente a un 20,81% en chicos. Asimismo, se encontró una prevalencia de obesidad del 12,70% entre las chicas frente a un 4,98% en chicos. El análisis del patrón de distribución de la grasa subcutánea evidenció una distribución del componente graso de predominio eminentemente central. La existencia de una prevalencia importante de sobrepeso y obesidad unida al desarrollo de un patrón de distribución graso de predominio central, ponen de manifiesto el potencial riesgo cardiovascular al que se encuentran expuestos dichos alumnos.The objective of this study was to first determine the nutritional state of a sample population of school children, and then analyze the distribution pattern of their subcutaneous fat layer. The sample was composed of 977 school children from the city and province of Granada (Spain). All of the children (524 girls and 452 boys) were 9-17 years of age. To study their nutritional state and the distribution of the subcutaneous fat layer, they were given a complete anthropometric evaluation, which included measuring their weight, height, body mass index, skin folds, and body perimeters. The results obtained showed a 23.01% prevalence of overweight in the female subjects and 20.81% in the male subjects. Furthermore, the female subjects had an obesity prevalence of 12.70% in comparison to the male subjects, whose obesity prevalence was 4.98%. The distribution pattern of subcutaneous fat was found to be mainly located in the central part of body. The high percentage of overweight and obesity along with the development of a central fat distribution pattern (neck, chest, and abdomen) in these school children is clear evidence of potential cardiovascular risk
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