Solid dispersion systems for enhanced dissolution of poorly water-soluble candesartan cilexetil: In vitro evaluation and simulated pharmacokinetics studies.

BACKGROUND: Candesartan cilexetil (CC) is a selective angiotensin II receptor antagonist widely used to treat hypertension. CC is a substrate of P-glycoprotein (P-gp), causing its efflux to the intestinal lumen. It is also practically insoluble in water and has low oral bioavailability (14%). Thus, the current study aims to improve the in vitro dissolution of CC by developing solid dispersion systems (SDSs) and corroborating the in vitro results using a simulated pharmacokinetics study. METHODS: The SDSs were prepared using polyvinyl pyrrolidone (PVP) as a water-soluble polymer, Eudragit E100 (EE100) as a pH-dependent soluble carrier, and a combination of these two polymers. The saturation solubility and the dissolution rate studies of the prepared systems in three dissolution media were performed. The optimized system SE-EE5 was selected for further investigations, including DSC, XRD, FTIR, FESEM, DLS, TSEM, IVIVC convolution study, and stability studies. RESULTS: The solubility of CC significantly increased by a factor of 27,037.344 when formulated as a solid dispersion matrix using EE100 at a ratio of 1:5 (w/w) drug to polymer (SE-EE5 SD), compared to the solubility of the pure drug. The mechanism of solubility and dissolution rate enhancement of CC by the optimized SDS was found to be via the conversion of the crystalline CC into the amorphous form as well as nanoparticles formation upon dissolution at a pH below 5. The instrumental analysis tests showed good compatibility between CC and EE100 and there was no chemical interaction between the drug and the polymer. Moreover, the stability tests confirmed that the optimized system was stable after three months of storage at 25°C. CONCLUSION: The utilization of the solid dispersion technique employing EE 100 polymer as a matrix demonstrates significant success in enhancing the solubility, dissolution, and subsequently, the bioavailability of water-insoluble drugs like CC.

Active control of pharmacokinetics using light-responsive polymer-drug conjugates for boron neutron capture therapy.

In boron neutron capture therapy (BNCT), boron drugs should exhibit high intratumoral boron concentrations during neutron irradiation, while being cleared from the blood and normal organs. However, it is usually challenging to achieve such tumor accumulation and quick clearance simultaneously in a temporally controlled manner. Here, we developed a polymer-drug conjugate that can actively control the clearance of the drugs from the blood. This polymer-drug conjugate is based on a biocompatible polymer that passively accumulates in tumors. Its side chains were conjugated with the low-molecular-weight boron drugs, which are immediately excreted by the kidneys, via photolabile linkers. In a murine subcutaneous tumor model, the polymer-drug conjugate could accumulate in the tumor with the high boron concentration ratio of the tumor to the surrounding normal tissue (∼10) after intravenous injection while a considerable amount remained in the bloodstream as well. Photoirradiation to blood vessels through the skin surface cleaved the linker to release the boron drug in the blood, allowing for its rapid clearance from the bloodstream. Meanwhile, the boron concentration in the tumor which was not photoirradiated could be maintained high, permitting strong BNCT effects. In clinical BNCT, the dose of thermal neutrons to solid tumors is determined by the maximum radiation exposure to normal organs. Thus, our polymer-drug conjugate may enable us to increase the therapeutic radiation dose to tumors in such a practical situation.

Therapeutic activity and biodistribution of a nano-sized polymer-dexamethasone conjugate intended for the targeted treatment of rheumatoid arthritis.

Rheumatoid arthritis is a chronic inflammatory autoimmune disease caused by alteration of the immune system. Current therapies have several limitations and the use of nanomedicines represents a promising strategy to overcome them. By employing a mouse model of adjuvant induced arthritis, we aimed to evaluate the biodistribution and therapeutic effects of glucocorticoid dexamethasone conjugated to a nanocarrier based on biocompatible N-(2-hydroxypropyl) methacrylamide copolymers. We observed an increased accumulation of dexamethasone polymer nanomedicines in the arthritic mouse paw using non-invasive fluorescent in vivo imaging and confirmed it by the analysis of tissue homogenates. The dexamethasone conjugate exhibited a dose-dependent healing effect on arthritis and an improved therapeutic outcome compared to free dexamethasone. Particularly, significant reduction of accumulation of RA mediator RANKL was observed. Overall, our data suggest that the conjugation of dexamethasone to a polymer nanocarrier by means of stimuli-sensitive spacer is suitable strategy for improving rheumatoid arthritis therapy.

Polymeric nanoparticles in dermocosmetic / Nanopartículas poliméricas en dermocosmética

Recent advances in the fields of biomaterials and nanotechnology have allowed the development of advanced nanoparticles for biomedical applications. Despite a vast number of nanostructures such as liposomes, solid­lipid nanocapsules, polymeric and hybrid lipid­polymer nanoparticles have been studied as carriers for drug delivery for different pathologies with remarkable promising results; the use of polymeric nanoparticles in dermocosmetic still has not been widely explored. The evolution of cosmetic into the care skin and dermatology represents novel technological challenges. Also, the increasing knowledge about normal skin physiology and advances in nanotechnology provide an attractive environment for the creation of innovative dermocosmetic formulations. In this work, we discuss the state of the art of polymeric nanoparticles formulated for dermocosmetics, its mechanisms of action, and diffusion into the skin.

Los recientes avances en el campo de los biomateriales y la nanotecnología han permitido el desarrollo de nanopartículas avanzadas para aplicaciones biomédicas. A pesar de que un gran número de nanoestructuras tales como liposomas, nanocápsulas lípido-sólidas, nanopartículas poliméricas y lípido-polímero híbridas han sido estudiadas como vehículos para la administración de fármacos en diferentes patologías con notables resultados prometedores, el uso de nanopartículas poliméricas en dermocosmética todavía no ha sido ampliamente explorado. La evolución de la cosmética en el cuidado de la piel y la dermatología nos enfrentan a nuevos retos tecnológicos. Además, el aumento de los conocimientos sobre la fisiología de la piel normal y los avances en la nanotecnología proporcionan un entorno atractivo para la creación de formulaciones dermocosméticas innovadoras. En este trabajo se discute el estado del arte de las nanopartículas poliméricas desarrolladas para dermocosmética, sus mecanismos de acción y la difusión en la piel.

Formulation and Evaluation of Sustained Release Tablets of Metformin Hydrochloride by Solid Dispersion Technique Using pH dependent and pH independent Eudragit Polymers

Objectives: The purpose of the present investigation was to evaluate the influence of solid dispersion of pH dependent and pH independent Eudragit polymers on the sustained release metformin hydrochloride matrix tablets. Materials and methods: Matrix formulations were prepared by direct compression techniques. The excipients used in this study did not alter physicochemical properties of the drug, as tested by FTIR and DSC. All the batches were evaluated various physical parameters. The in vitro drug dissolution and SEM studies were also carried out. Mean dissolution time is used to characterize drug release rate from a dosage form. Results and discussion: Among the different examined polymer blends, Eudragit RLPO with S100 and Ll00 matrix tablets based on solid dispersion showed highly sustained release pattern. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled to anomalous type. Conclusions: Fitting the data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release(AU)

Objetivos: El propósito de la presente investigación ha consistido en evaluar la influencia de la dispersión sólida de polímeros pH dependientes y pH independientes de Eudragit en los comprimidos de matriz de liberación prolongada de clorhidrato de metformina. Métodos: Las formulaciones de matriz se han preparado a través de técnicas de compresión directa. Los excipientes utilizados en este estudio no han modificado las propiedades fisicoquímicas del fármaco, tal y como se ha probado mediante FTIR y DSC. Todos los lotes se han evaluado en varios parámetros físicos. También se ha llevado a cabo la disolución del fármaco in vitro y estudios de SEM (Microscopio electrónico de barrido). El tiempo medio de disolución se utiliza para describir el índice de liberación del fármaco de una forma farmacéutica. Resultados y Discusión: Entre las distintas mezclas de polímeros examinadas, los comprimidos de matriz de Eudragit RLPO con S100 y Ll00 basados en una dispersión sólida han mostrado un patrón de liberación muy prolongado. El modelado cinético de los perfiles de la disolución in vitro ha revelado el margen de mecanismo de liberación del fármaco desde una difusión controlada hasta un tipo anómalo. Conclusiones: La adecuación de los datos con la ecuación de Korsmeyer ha indicado que la difusión junto con la erosión podría ser el mecanismo de la liberación del fármaco(AU)

Design and evaluation of lornoxicam bilayered tablets for biphasic release

The objective of the present investigation was to develop bilayered tablets of lornoxicam to achieve biphasic release pattern. A bilayered tablet, consisting of an immediate and controlled release layer, was prepared by direct compression technique. The controlled release effect was achieved by using various hydrophilic natural, semi synthetic and synthetic controlled release polymers such as xanthan gum, hydroxypropyl methylcellulose (HPMC) and polyethylene oxide (PEO) to modulate the release of the drug. The in vitro drug release profiles showed the biphasic release behavior in which the immediate release (IR) layer containing the lornoxicam was released within 15 minutes, whereas the controlled release (CR) layer controlled the drug release for up to 24 h. All the bilayered tablets formulated have followed the zero order release with non-Fickian diffusion controlled release mechanism after the initial burst release. FTIR studies revealed that there was no interaction between the drug and polymers used in the study. Statistical analysis (ANOVA) showed no significant difference in the cumulative amount of drug release after 15 min, but significant difference (p < 0.05) in the amount of drug released after 24 h from optimized formulations was observed. Based on the release kinetic parameters obtained, it can be concluded that xanthan gum polymer was suitable for providing a biphasic release of lornoxicam.

O objetivo do presente trabalho foi desenvolver comprimidos bicamada de lornoxicam para atingir padrão de liberação bifásica. Preparou-se, por compressão direta, comprimido bicamada, consistindo de uma camada de liberação imediata e uma de liberação controlada. A liberação controlada foi obtida pelo uso de vários polímeros naturais hidrofílicos, semi-sintéticos e sintéticos, tais como goma xantana, hidroxipropilmetil celulose (HPMC) e óxido de polietileno (PEO) para modular a liberação do fármaco. Os perfis de liberação in vitro mostraram comportamento bifásico em que a camada de liberação imediata (IR) contendo lornoxicam foi liberada em 15 minutos, enquanto a camada de liberação controlada (CR) liberou o fármaco em mais de 24 horas, Todos os comprimidos bicamada formulados seguiram a liberação de ordem zero com mecanismo de liberação controlada por difusão não fickiana após a liberação inicial por erupção. Os estudos de FTIR revelaram que não há interação entre o fármaco e os polímeros utilizados no estudo. A análise estatística (ANOVA) não mostrou diferença significativa na quantidade acumulada de fármaco após 15 minutos de liberação, mas observou-se diferença significativa (p<0,05) na quantidade de fármaco liberado após 24 h nas formulações otimizadas. Com base nos parâmetros de cinética de liberação obtidos, pode-se concluir que a goma xantana foi adequada para se atingir liberação bifásica de lornoxicam.

Polímeros biodegradables en el transporte selectivo de moléculas antitumorales / Biodegradable polymers in the selective delivery of antitumor molecules

Los transportadores poliméricos de fármacos con propiedades adecuadas aseguran el transporte de los agentes quimioterápicos hasta el tumor en concentraciones activas mediante diversos mecanismos de acción. Los materiales poliméricos más ampliamente utilizados para la preparación de estos sistemas son los poli (alquilcianoacrilatos) (PACA), la poli (e-caprolactona) (PCL), el chitosan, la poli(D,Llactida-co-glicolida) (PLGA). Sin embargo, otros polímeros, como el alginato, la poli(D,L-lactida), el Eudragit Ò, la gelatina, el poli (glutaraldehído), la poliacrilamida o los dendrímeros, por citar sólo algunos ejemplos, también han sido propuesto con el mismo objetivo, obteniendo resultados muy prometedores. En este trabajo se investigan las posibilidades reales que ofrecen las nanoplataformas de tipo polimérico en el transporte de fármacos antineoplásicos. Se analiza también la superioridad de chitosan, PACA, PLGA y PCL como transportadores de moléculas antitumorales a la masa cancerosa sobre otro tipo de polímeros biodegradables(AU)

Polymeric drug carriers with adequate properties assure the delivery of chemotherapy agents to the tumor sites at active concentrations by several mechanisms. The biodegradable polymers most widely employed to prepare these colloids are poly (alkylcyanoacrylate) (PACA), poly(e-caprolactone) (PCL),chitosan, and poly(D,L-lactide-co-glycolide) (PLGA). However, other polymers have been also investigated with that aim, such as alginate, poly(D,L-lactide), Eudragit Ò, gelatin, poly (glutaraldehyde), polyacrylamide, and dendrimers, to cite just a few. In this work, an extensive investigation of the real capabilities of polymer-based nanoplatforms in drug delivery is carried out. It is also analyzed the superiority of chitosan, PACA, PLGA, and PCL in the delivery of antitumor molecules to the cancer mass over other biodegradable polymers(AU)

Dermatitis de contacto a acrilatos en una industria de fabricación de ascensores. A propósito de 8 casos / Contact Dermatitis Caused by Acrylates Among 8 Workers in an Elevator Factory

Introducción: Los acrilatos son sustancias químicas de bajo peso molecular, con una amplia utilización en la industria (desde su introducción en los años treinta), la medicina y el medio doméstico, que destacan por sus propiedades de polimerización. Los compuestos acrílicos más utilizados son los cianoacrilatos, los metacrilatos y los acrilatos. Objetivo: Establecer el diagnóstico de sospecha de enfermedad profesional en un grupo de trabajadores de una fábrica de ascensores. Material y métodos: Se estudian un total de 8 pacientes que presentan clínica de dermatitis en las manos, así como pulpitis en los dedos, y que trabajan en contacto con acrilatos. Se realizaron pruebas epicutáneas con batería de acrilatos (BIAL-Aristegui, Bilbao, España). Resultados: El 87,5% mostró positividad frente al dimetacrilato de etilenglicol al 1%. También mostraron positividad el hidroxietilmetacrilato al 2% (62,5%), el dimetacrilato de trietilenglicol al 1% (50%), el monómero de metil metacrilato al 10% (25%) y el monómero de etil metacrilato al 10% (37,5%), el acrilato de etilo al 1% (12,5%) y el ácido acrílico al 0,1% (12,5%). Conclusiones: Destacamos el alto poder sensibilizante de los acrilatos y la importancia de extremar las medidas preventivas en las distintas industrias, así como la evitación del contacto con el producto en los casos de sensibilización demostrada (AU)

Introduction: Acrylates are widely used low-molecular-weight substances, initially introduced in industry in the 1930s and subsequently applied also in medicine and the home. One of their main features is the ability to undergo polymerization. The most commonly used acrylic compounds are cyanoacrylates, methacrylates, and acrylates. Objective: To confirm suspicion of occupational disease in a group of workers in an elevator factory. Material and methods: We studied 8 patients with dermatitis of the hands and finger pads. In their work, the patients came into contact with acrylates. Patch testing was applied with an acrylate panel (BIAL-Aristegui, Bilbao, Spain). Results: Seven of the patients (87.5%) had a positive result with 1% ethylene glycol dimethacrylate. Positive results were also observed for 2% hydroxyethyl methacrylate (5 patients, 62.5%), 1% triethylene glycol dimethacrylate (4 patients, 50%), 10% ethyl methacrylate monomer (3 patients, 37.5%), 10% methyl methacrylate monomer (2 patients, 25%), 1% ethyl acrylate (1 patient, 12.5%), and 0.1% acrylic acid (1 patient, 12.5%). Conclusions: We highlight the strong sensitizing capacity of acrylates and the importance of taking all necessary preventive measures in industries where these substances are used. Such measures should include avoidance of contact with the product in cases where sensitization has been confirmed (AU)

Mucoadhesive drug delivery systems / Sistemas de entrega de drogas mucoadesiva

Drug actions can be improved by developing new drug delivery systems, such as the mucoadhesive system. These systems remain in close contact with the absorption tissue, the mucous membrane, releasing the drug at the action site leading to a bioavailability increase and both local and systemic effects. Mucoadhesion is currently explained by six theories: electronic, adsorption, wettability, diffusion, fracture and mechanical. Several in vitro and in vivo methodologies are proposed for studying its mechanisms. However, mucoadhesion is not yet well understood. The aim of this study was to review the mechanisms and theories involved in mucoadhesion, as well as to describe the most-used methodologies and polymers in mucoadhesive drug delivery systems.

O efeito de fármacos pode ser potencializado através do desenvolvimento de novos sistemas de liberação como os sistemas mucoadesivos. Estes sistemas permanecem em contato íntimo com o tecido de absorção, as mucosas, liberando o fármaco no local de ação, com o consequente aumento da biodisponibilidade, podendo promover efeitos locais e sistêmicos. A mucoadesão, atualmente, é explicada por seis teorias, a eletrônica, da adsorção, da molhabilidade, da difusão, da fratura e a mecânica. Para estudar seus mecanismos e quantificá-la, são propostas várias metodologias in vitro e in vivo. Porém, a mucoadesão ainda não é totalmente compreendida. Esse trabalho tem por objetivo revisar os mecanismos e as teorias envolvidas na mucoadesão, além de descrever as metodologias e os polímeros mais utilizados em sistemas mucoadesivos para liberação de fármacos.

Extended release promethazine HCl using acrylic polymers by freeze-drying and spray-drying techniques: formulation considerations / Liberação prolongada prometazina HCl utilizando polímeros acrílicos por liofilização e técnicas de secagem por aspersão: consideração de formulação

The present study investigated a novel extended release system of promethazine hydrochloride (PHC) with acrylic polymers Eudragit RL100 and Eudragit S100 in different weight ratios (1:1 and 1: 5), and in combination (0.5+1.5), using freeze-drying and spray-drying techniques. Solid dispersions were characterized by Fourier-transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), Powder X-ray diffractometry (PXRD), Nuclear magnetic resonance (NMR), Scanning electron microscopy (SEM), as well as solubility and in vitro dissolution studies in 0.1 N HCl (pH 1.2), double-distilled water and phosphate buffer (pH 7.4). Adsorption tests from drug solution to solid polymers were also performed. A selected solid dispersion system was developed into capsule dosage form and evaluated for in vitro dissolution studies. The progressive disappearance of drug peaks in thermotropic profiles of spray-dried dispersions were related to increasing amount of polymers, while SEM studies suggested homogenous dispersion of drug in polymer. Eudragit RL100 had a greater adsorptive capacity than Eudragit S100, and thus its combination in (0.5+1.5) for S100 and RL 100 exhibited a higher dissolution rate with 97.14 percent drug release for twelve hours. Among different formulations, capsules prepared by combination of acrylic polymers using spray-drying (1:0.5 + 1.5) displayed extended release of drug for twelve hours with 96.87 percent release followed by zero order kinetics (r²= 0.9986).

O presente trabalho compreendeu estudo de um novo sistema de liberação prolongada de cloridrato de prometazina (PHC) com polímeros acrílicos Eudragit RL100 e Eudragit S100 em diferentes proporções em massa (1:1 e 1:5) e em combinação (0,5+1,5), utilizando técnicas de liofilização e de secagem por aspersão As dispersões sólidas foram caracterizadas por espectrofotometria no infravermelho por transformada de Fourier (FT-IR), calorimetria diferencial de varredura (DSC), difratometria de raios X (PXRD), Ressonância Magnética Nuclear (RMN), microscopia eletrônica de varredura (SEM) e, também, por estudos de solubilidade e de dissolução in vitro em HCl 0,1 N (pH 1,2), água bidestilada e tampão fosfato (pH 7,4). Realizaram-se, também, testes de adsorção da solução do fármaco nos polímeros sólidos. Desenvolveu-se sistema de dispersão sólida exclusiva dentro das cápsulas, que foi avaliado por meio de estudos de dissolução in vitro. Relacionou-se o desaparecimento progressivo de picos do fármaco em perfis termotrópicos de dispersões secas por spray à quantidade aumentada de polímero, enquanto os estudos de SEM sugeriram dispersão homogênea do fármaco no polímero. O Eudragit RL100 apresentou maior capacidade de adsorção do que o Eudragit S100 e, dessa forma, a combinação de (0,5+1,5) para S100 e para RL100 mostrou taxa de dissolução maior, com liberação de 94,17 por cento de fármaco em 12 horas. Entre as várias formulações, as cápsulas preparadas pela combinação de polímeros acrílicos utilizando secagem por aspersão (0,5+1,5) apresentou liberação prolongada do fármaco em 12 horas, com 96,78 por cento de liberação, seguindo cinética de ordem zero (r² = 0,9986).

Determinación de la estabilidad de Kollicoat MAE 30D mediante medidas de calorimetría diferencial de barrido / Determination of the stability of Kollicoat MAE 30D by means of differential scanning calorimetry

Se estudia la estabilidad de Kollicoat MAE 30D mediante determinaciones calorimétricas y microscópicas. Se estudian los efectos que producen pH, temperatura y agitación sobre las propiedades fisicoquímicas de las partículas de este látex comercial. Se comprueba que el factor que más influencia ejerce es el pH, siendo máxima la estabilidad a pH ácidos, y modificándose con un decrecimiento de la misma, a partir de pH 6. Se determina la forma y tamaño de partícula mediante medidas microfotográficas de SEM, realizando el recuento de 200 partículas de una muestra del látex previamente desecado. Se comprueba que la dispersión acuosa de Kollicoat MAE 30 D a su pH natural(2.5), da lugar a una población de partículas con un diámetro medio de 1.56 nm (AU)

The stability of Kollico at MAE 30 D was studied with differential scanning calorimetric, and scanning electron microscopy. We investigated the effects of pH, temperature and shaking on physicochemical properties of the latex particles. Stability of the polymer as most strongly affected by pH; hence, we conclude that the stability of this latex reaches a maximum at acid pH values, whereas stability is lost to pH 6.The particle shape and the mean diameter were determined by means of SEM microphotographs on 200 particles in a sample of dry latex. The aqueous Kollico at MAE 30 D dispersion, at its natural pH (2.5), presented one population of particles with a mean diameter of 1.56 nm (AU)

Microencapsulación: aplicaciones, métodos y caracterización / Microencapsulation: applications, methods and characterization

Se hace una revisión general de la microencapsulacióncomo recurso tecnológico en farmaciapara el desarrollo de medicamentos. Lamicroencapsulación es un campo interdisciplinarioque requiere tecnología de la emulsión,en la mayoría de los casos y de la estabilizaciónde principios activos y proteínas. Se empleanmuchas técnicas con gran variedad demateriales formadores de cubierta para la obtenciónde microcápsulas a nivel comercial, enespecial el recubrimiento en lecho fluido, laatomización y la atomización con congelación.En esta revisión también se consideran aspectossobre la caracterización de dichas microcápsulas

A revision of the microencapsulation as apharmaceutical technology for the drug developmentis made. Microencapsulation is an interdisciplinaryfield that requires knowledge ofpolymer science, emulsion technology in mostcases and an understanding of drug and proteinstabilization. Many techniques using a largevariety of coating materials are employed tomanufacture such microcapsules, in particularairsuspension coating and spray-drying orspray-congealing on a commercial scale. Aspectsof the characterization of drug-containingmicrocapsules will be considered in this review

Reología aplicada y sistemas poliméricos / Applied rheology and polymers

Se hace una revisión de las características de flujo de los sistemas poliméricos, tratando muy especialmente los aspectos prácticos de la Reología o Reología Aplicada. A partir de los conceptos generales, se profundiza en aquellos temas relativos a ciertos materiales cuyo comportamiento reológico complejo no puede describirse según los modelos clásicos, como es el caso de los sistemas poliméricos de tanta significancia y repercusión en Tecnología Farmacéutica y Cosmética. Se detiene además en explicar por qué determinadas medidas son importantes o la relación entre las fuerzas viscosas y la geometría molecular, y cuál es el significado real de la terminología reológica. Los polímeros se utilizan actualmente en muchas formas farmacéuticas semisólidas. El carácter reológico que imprimen a los sistemas dispersos, desempeña asimismo un importante papel en el mantenimiento de dichas preparaciones farmacéuticas en su lugar de aplicación. En los últimos años se han formulado muchas bases gelificadas hidrosolubles en la optimización de sistemas de liberación tópica de medicamentos, sin que se haya realizado previamente un exhaustivo estudio reológico. En nuestra opinión, el conocimiento de las propiedades reológicas de estos sistemas reviste la mayor importancia, y puede conducir al futuro empleo de los parámetros reológicos en la optimización de sistemas de liberación tópica a partir de formulaciones dermatológicas y dermocosméticas. Las propiedades reológicas y mecánicas de los sistemas poliméricos se encuentran entre sus características físicas más importantes, con un importante potencial de aplicación en estudios de biodisponibilidad; no sólo determinan su calidad sino también su posible utilidad como vehículos galénicos y excipientes dermatológicos (AU)

Desenvolvimemto e avaliação de micropartículas contendo microrganismos viáveias utilizados como bioinseticida / Development and evaluation of microparticles containing feasible microorganisms used as bioinsecticides

Neste trabalho foi feito um estudo para obtenção de formulações multiparticuladas, formadas por micropartículas de polímeros naturais, solúveis em água, não tóxicos e biodegradáveis. Os polímeros utilizados foram: Caseína, Hidroxietilcelulose (HEC), Hidroxipropilmetilcelulose (HPMC), Alginato de sódio e Quitosana. As técnicas utilizadas para obtenção das micropartículas foram o spray drying e a atomização de alginato de sódio em uma solução de CaCl2, para gelificação das gotículas formadas, com uma complexaço ou não com quitosana. O estudo de micropartículas secas de alginato de cálcio e alginato de cálcio recoberta com uma membrana de qutosana revelou que diferentes procedimentos e variáveis de processo influenciavam...

Histometric analysis of rat alveolar wound healing following immediate implantation of a biocompatible osteoconductive polymer (BOP) / Análise histométrica da cicatrizaçäo alveolar no rato após a implantaçäo imediata de um polímero osteocondutivo biocompatível (BOP)

O presente trabalho teve por objetivo avaliar quantitativamente a biocompatibilidade de grânulos do polímero osteocondutor biocompatível (BOP), implantados imediatamente após a extraçäo de incisivos superiores direitos de ratos, bem como a cronologia do preparo alveolar frente ao material implantado. Utilizou-se uma câmara clara para estimar a fraçäo de volume ocupada pelo polímero e pelos tecidos conjuntivo e ósseo, por um método diferencial de contagem de pontos, de 1 a 6 semanas após a cirurgia. O exame histológico mostrou grânulos regulares de BOP preenchendo parcialmente o terço médio alveolar. O materialfoi parcialmente reabsorvido e, sendo biocompatível, foi progressivamente integrado integrado no osso alveolar reparacional. A comparaçäo com alvéolos controles, no entanto, mostrou que a presença de BOP no terço médio provocou uma diminuiçäo pequena, porém estatisticamente significante, na neoformaçäo óssea nos terços apical e cervical