α-Gluco-oligosaccharide in the research and development of a polymeric material for modified drug delivery.

This research aimed to analyse the influence of the incorporation of α-gluco-oligosaccharide (GOS-α) in the formation of isolated films of different combinations of polymethyl by applying physicochemical analyses such as Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). Polymer films were prepared by evaporation associating Eudragit® RS30D with α-GOS. FTIR results confirmed the incorporation of α-GOS. The intermolecular interaction involving carbonyl and hydroxyl groups of Eudragit® with α-GOS was not detected. By TG and DSC, it was possible to detect that there were no changes in the thermal properties between the proposed combinations and the standard film. Upon SEM analysis, the appearance of pores for the association 90:10 was evidenced. Possibly, these pores act as output ports for the drug. These results sharpen the perspective of applying this material to the coating of pharmaceutical formulations of modified drug delivery.

Evaluation of the treatment with resveratrol-loaded nanoparticles in intestinal injury model caused by ischemia and reperfusion.

The gastrointestinal tract is extremely sensitive to ischemia and reperfusion (I/R). Studies have reported that resveratrol (RSV) is able to combat damage caused by intestinal I/R. Because of its effectiveness in increasing the permanence and bioavailability of resveratrol in the intestinal epithelium, we investigated whether the effect of resveratrol-loaded in poly(anhydride) nanoparticles reduce oxidative stress and promote myenteric neuroprotection in the ileum of rats subjected to I/R. Physicochemical evaluations were performed on nanoparticles. The animals were divided into nine groups (n = 6/group) and treated every 48 h. Treatments with resveratrol (7 mg/kg of body weight) were applied 5 days before surgery and continued for 7 days after surgery (reperfusion period). The superior mesenteric artery was occluded to cause I/R injury. Oxidative stress, myeloperoxidase, nitrite, aspartate aminotransferase, alanine aminotransferase, immunolabeling of myenteric neurons and glial cells, and gastrointestinal transit was evaluated. Both nanoparticle formulations presented negative charge with homogeneous distribution, and the payload, showed an encapsulation efficiency of 60%. Resveratrol administered in free form prevented alterations that were caused by I/R. The results of the groups treated with RSV-loaded nanoparticles presented similar results to the group treated with free resveratrol. Treatment with empty nanoparticles showed that poly(anhydride) is not an ideal nanocarrier for application in in vivo models of intestinal I/R injury, because of hepatotoxicity that may be caused by epithelial barrier dysfunction that triggers the translocation of nanoparticles.

Evaluation of Rosin Gum and Eudragit® RS PO as a Functional Film Coating Material.

Polymers are essential tools in the research and development of new therapeutic devices. The diversity and flexibility of these materials have generated high expectations in the composition of new materials with extraordinary abilities, especially in the design of new systems for the modified release of pharmaceutically active ingredients. The natural polymer rosin features moisture protection and pH-dependent behavior (i.e., it is sensitive to pH > 7.0), suggesting its possible use in pharmaceutical systems. The synthetic polymer Eudragit® RS PO is a low-permeability material, the disintegration of which depends on the time of residence in the gastrointestinal tract. The present study developed a polymeric material with desirable physicochemical characteristics and synergistic effects that resulted from the inherent properties of the associated polymers. Isolated films were obtained by solvent evaporation and subjected to a water vapor transmission test, scanning electron microscopy, calorimetry, Fourier transform-infrared (FT-IR) spectroscopy, micro-Raman spectroscopy, and mechanical analysis. The new polymeric material was macroscopically continuous and homogeneous, was appropriately flexible, had low water permeability, was vulnerable in alkaline environments, and was thermally stable, maintaining an unchanged structure up to temperatures of ∼400°C. The new material also presented potentially suitable characteristics for application in film coatings for oral solids, suggesting that it is capable of carrying therapeutic substances to distal regions of the gastrointestinal tract. These findings indicate that this new material may be added to the list of functional excipients.

Development and characterization of pullulan-polymethacrylate free films as potential material for enteric drug release

ABSTRACT Free films of pullulan-polymethacrylate associations were produced by casting process to develop a novel target-specific material. For characterization, tests of water vapor permeability, swelling index, infrared absorption spectroscopy, thermogravimetric analysis, scanning electron microscopy and mechanical analysis were performed. The polysaccharide concentration directly influenced vapor permeability and swelling, increasing the values of the latter up to five times when added in a proportion of 20% (per weight). The individual properties of each polymer were maintained, and chemical interactions were not detected. The films were found to be thermally stable and they had unaltered mechanical properties with the addition of the polysaccharide. The microscopic analysis revealed rugosity that was proportional to pullulan and disorganization of the polymer network at pH 6.8. These results suggest that this novel material has potential for enteric drug release because of synergism between pH and enzyme dependence.

Development and characterization of crosslinked hyaluronic acid polymeric films for use in coating processes.

The aim of this work was to develop and characterize new hyaluronic acid-based responsive materials for film coating of solid dosage forms. Crosslinking of hyaluronic acid with trisodium trimetaphosphate was performed under controlled alkaline aqueous environment. The films were produced through casting process by mixing crosslinked or bare biopolymer in aqueous dispersion of ethylcellulose, at different proportions. Films were further characterized regarding morphology by scanning electron microscopy, robustness by permeation to water vapor transmission, and ability to hydrate in simulated gastric and intestinal physiological fluids. The safety and biocompatibility of films were assessed against Caco-2 and HT29-MTX intestinal cells. The permeation to water vapor transmission was favored by increasing hyaluronic acid content in the final formulation. When in simulated gastric fluid, films exhibited lower hydration ability compared to more extensive hydration in simulated intestinal fluids. Simultaneously, in simulated intestinal fluids, films partially lost weight, revealing ability for preventing drug release at gastric pH, but tailoring the release at higher intestinal pH. The physiochemical characterization suggests thermal stability of films and physical interaction between compounds of formulation. Lastly, cytotoxicity tests demonstrated that films and individual components of the formulations, when incubated for 4h, were safe for intestinal cells Overall, these evidences suggest that hyaluronic acid-based responsive films, applied as coating material of oral solid dosage forms, can prevent the premature release of drugs in harsh stomach conditions, but control the release it in gastrointestinal tract distal portion, assuring safety to intestinal mucosa.

Levan as a new additive for colon-specific films: a new approach in the use of exopolysaccharides in time-dependent free films (Aminoalkyl Methacrylate Copolymer RS).

Time-dependent films, augmented with prebiotics, offer potential strategy for colon-specific controlled drug release. In this study, we produced films containing levan (L) and Aminoalkyl Methacrylate Copolymer RS (ER). Free films of ER combined with levan were produced by the casting process and characterized by the mobility of the polymeric matrix, hydration, differential scanning calorimetry (DSC) and thermogravimetry (TGA). The results of this study suggest that the exopolysaccharide levan can be used in combination with ER for colon specific materials. No evidence of incompatibilities between the levan and the synthetic polymer were detected, and levan improved the mobility of the polymeric matrix and the hydrophilicity of the system. Levan may have positively altered the density of the polymeric matrix, as visualized by thermal characterization. The endothermic decomposition peak was shifted with increasing amounts of levan. This new barrier polymer utilized a combination of time-dependent enzymatic mechanisms and can be considered promising for use in the coating of solid oral drugs for specific release.

Levan in the developing of new colon-specific polymer material: evaluation of the permeability, moisture and thermal analyses in free films of Eudragit® FS 30 D / Levana no desenvolvimento de novo material polimérico cólon-específico: avaliação da permeabilidade, intumescimento e análises térmicas de filmes isolados de Eudragit® FS 30 D

Levan was used as agent in the synthesis of new colon-specific polymeric matrix together with Eudragit® FS 30 D. Eudragit® FS 30 D films incorporated with levan were made by casting process and characterized to: water vapour transmission, sweeling index, differential scanning calorimetry and thermogravimetric. The levan increased the films permeability (p < 0.001) however did not influenced in the sweeling index of the formulations (p > 0.05). The thermal analyses of the films indicated a glass transition temperature approximate at 47°C and thermal decomposition at 400°C. The results indicated that there is potential for using such site-specificity blend as pharmaceutical coating material.

Levana foi utilizada na síntese de novo material polimérico cólon-específico conjuntamente com o Eudragit® FS 30 D. Filmes de Eudragit® FS 30 D aditivados de levana foram feitos pelo método de "casting process" e caracterizados quanto à transmissão de vapor de água, índice de intumescimento, calorimetria diferencial de varredura e termogravimetria. A levana aumentou a permeabilidade dos filmes (p < 0,001), entretanto não influenciou no índice de intumescimento das formulações (p > 0,05). As análises térmicas dos filmes indicaram uma temperatura de transição vítrea aproximada de 47°C e temperatura de decomposição de 400°C. Os resultados indicaram que há potencial de uso desta nova blenda sítio-específica como material de revestimento farmacêutico.

A pH/enzyme-responsive polymer film consisting of Eudragit FS 30 D and arabinoxylane as a potential material formulation for colon-specific drug delivery system.

Polymer film based on pH-dependent Eudragit FS 30 D acrylic polymer in association with arabinoxylane, a polysaccharide issued from gum psyllium, was produced by way of solvent casting. Physical-chemical characterization of the polymer film samples was performed by means of thermogravimetry (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Furthermore, water-equilibrium swelling index (I(s)) and weight loss of the films in KCl buffer solution of pH 1.2, in KH(2)PO(4) buffer solution of pH 5.0, or in KH(2)PO(4) buffer solution of pH 5.0 consisting of 4% enzyme Pectinex 3X-L (w/v) were also carried out for the film characterization. No chemical interactions between the Eudragit FS 30 D and the arabinoxylane polymer chains were evidenced, thus suggesting that the film-forming polymer structure was obtained from a physical mixture of both polymers. The arabinoxylane-loader films showed a more pronounced weight loss after their immersion in buffer solution containing enzyme Pectinex 3X-L. The introduction of the arabinoxylane makes the film more susceptible to undergo an enzymatic degradation. This meant that the enzyme-dependent propriety issued from the arabinoxylane has been imprinted into the film formulation. This type of polymer film is an interesting system for applications in colon-specific drug delivery system.

Avaliação da pectina fosfatada aplicada na formação de filmes isolados: material candidato a novos sistemas para liberação modificada de fármacos / Phosphated pectin application in the development of films for drug delivery systems: evaluation of permeability properties and swelling

Pectina fosfatada (Pect-TMFT) juntamente com o α-Gluco-oligossacarídeo (Bioecolians®) foram incorporados à dispersão aquosa de polimetacrilato (Eudragit® RS 30 D) para obtenção de filmes isolados pelo processo "casting" (50 ºC) em placa de Teflon®. A Pect-TMFT e o Bioecolians® foram adicionados à dispersão de Eudragit® RS 30 D nas concentrações: 90: 05: 05, 80: 10: 10 e 70: 20: 10 (4 por cento p/v). Citrato de trietila (TEC) foi utilizado como plastificante (20 por cento da massa do polimetacrilato). As dispersões propostas apresentaram habilidades filmogênicas. Os filmes isolados foram caracterizados pela determinação da permeabilidade ao vapor d'água (TVA), pelo índice de intumescimento (Ii por cento) em fluidos de simulação gástrica (FSG) e intestinal (FSI) e por microscopia eletrônica de varredura (MEV). O aumento do polissacarídeo modificado e do Bioecolians® nos filmes favoreceram a permeabilidade ao vapor d'água e o grau de hidratação quando em FSI (pH= 6,8). Dessa forma, o filme 70: 20: 10, poderá impedir a liberação prematura do fármaco em regiões superiores do TGI quando aplicado como revestimento de sistemas sólidos orais. Além disso, a presença da Pect-TMFT e do Bioecolians®, poderá favorecer a degradação específica da película por enzimas produzidas pela microflora colônica, possibilitando uma cinética de liberação modificada de fármacos apesar das variações inter-individuais de pH que possam existir.

Phosphated pectin (Pect-TMFT) together with α-gluco-oligossacaride (Bioecolians®) were incorporated into aqueous dispersion of polymethacrylate (Eudragit® RS 30 D) to obtain free films by the casting process (50ºC) in Teflon® plate. Pect-TMFT and Bioecolians® were added into dispersions of Eudragit ® RS 30 D at different rates: 90:05:05, 80:10:10 and 70:20:10 (4 percent p/v). Triethyl citrate (TEC) was used as plasticizer (20 percent of mass of the polymethacrylate). The proposed dispersions showed film formation ability. The free films were characterized by the determination of water vapour transmission (WVT), by the swelling index (Ii percent) in fluids of gastric simulation (FGS) and intestinal (FIS) and by scanning electron microscopy (SEM). The increase of modified polysaccharide and Bioecolians® in the films favored their permeability to the water vapour and their hydration degree when in FIS (pH = 6.8). In that way, the obtained film in the concentration 70:20:10, can prevent the premature release of the drug in the up GIT when applied to develop oral solid systems coating. Besides, the presence of Pect-TMFT and Bioecolians® can contribute to the specific membrane degradation by colonic microflora enzymes, making possible a modified release kinetics of drugs even with the existence of inter-individual variations of pH.

Avaliação da pectina-HPMC no processo de revestimento por compressão: I - Estudo da propriedade de intumescimento em núcleos revestidos / Evaluation of pectin-hpmc as compression coating: I - A study of the swelling properties of coated tablet

Neste estudo, comprimidos de teofilina anidra foram revestidos através do processo de revestimento por compressão aplicando sistema binário pectina-HPMC. O método aplicado gerou comprimidos revestidos com características físicas adequadas aos padrões farmacopeicos. Foram avaliadas as características físicas dos comprimidos obtidos em diferentes proporções (80:20, 60:40, 50:50, 40:60, 20:80, 0:100) de pectina-HPMC respectivamente, e estabelecido o perfil de intumescimento desses sistemas nos fluidos de simulação gástrico (pH 1,2) e intestinal (pH 6,8). O método aplicado gerou a formação de comprimidos revestidos que apresentaram variação nos perfis de hidratação in vitro, entretanto, a análise estatística revelou que estas diferenças não foram significativas quando comparadas entre si. O sistema formado apresenta elevada expectativa sobre o gerenciamento da liberação de fármacos, todavia, só a partir do teste de dissolução que constitui a segunda etapa deste projeto poderemos definir qual das formulações propostas será mais eficaz no controle da cinética de liberação.

In this study, core tablets of dry theophylline were compressed coated using the system pectin-HPMC for controlled drug delivery. The methodology applied produced coated tablets with suitable physical characteristics according to Brazil Pharmacopeia 4th edition. The physical properties were evaluated for different ratios (80:20, 60:40, 50:50, 40:60, 20:80, 0:100) of pectin-HPMC, respectively, and the swelling test was carried out in simulated gastric fluid (pH 1.2) and in simulated intestinal fluid (pH 6.8). The method applied gave origin to coated tablets with high expectation in the kinetics control of drug release. From the statistics analyses of the results obtained, it was observed that results were not significant between different ratios.

Reaction of pectin and glycidyl methacrylate and ulterior formation of free films by reticulation.

In this work, low-methoxyl pectin was chemically modified by reaction with glycidyl methacrylate (GMA) to give a material with low hydrosolubility. After physio-chemical characterization by FT-IR, DSC, and TGA analyses, the methacrylated/modified pectin (Pect-GMA) was crosslinked after the addition of sodium persulfate (SP), that actuates as initiator, at 50 degrees C for 24 and 48h either in the presence or not of aqueous polymethacrylate dispersion (Eudragit RS 30 D) to obtain free films by Teflon plate "casting" process. Different Pect-GMA/Eudragit RS 30 D ratios and SP concentrations were used. The free films were characterized by the determination of water vapor transmission (WVT), the swelling index (Ieq%) in simulated gastric (SGF) and intestinal (SIF) fluids, and by scanning electron microscopy (SEM). The presence of ionized groups in Pect-GMA turned the films pH-dependent because Ieq% of swollen crosslinked Pect-GMA films was larger at pH 6.8 than at pH 1.2. This was confirmed by the large pore size observed in the micrographs of SIF-swollen lyophilized films. In this way, films containing Pect-GMA and Eudragit RS 30 D, a time-dependent polymer, may present a synergistic action that favors specific biodegradation of the film in distal end of the gastrointestinal tract (GIT) by enzymes produced by the colonic microflora, enabling the modification of the release kinetics of drugs.

Avaliação das propriedades de intusmescimento e permeabilidade de filmes isolados de polimetacrilato contendo polissacarídeo da raiz de Lótus (Nelumbo nucifera) / Evaluation of sweeling and permeability properties of films isolated from polymethacrylate containing polysaccharide from Lotus root (Nelumbo nucifera)

Polissacarídeo extraído da raiz de Lótus (Nelumbo nucifera) adicionado a polimetacrilato foi utilizado para a obtenção de filmes isolados, constituindo material candidato ao revestimento de formas farmacêuticas sólidas orais, sendo estas voltadas à liberação modificada de fármacos, potencialmente suscetíveis à degradação pela microflora presente exclusivamente na região distal do trato gastrinstestinal. A adição do polissacarídeo ao polímero de base, dispersão aquosa Eudragit®RS 30D, ocorreu em diferentes proporções: 100:0, 90:10, 80:20, 70:30. Os filmes isolados foram caracterizados pela determinação do índice de intumescimento e pela transmissão de vapor de água...

Influência da adição da goma arábica em filmes isolados de polímero acrílico. Estudo das propriedades de intumescimento e de permeabilidade / Influence of arabic gum in acrylic polymer isolated films. Study of swelling properties and permeability

Goma arábica associada ao polímero acrílico Eudragit RS30D® na formação de filmes isolados foram obtidos e investigados como material potencialmente adequado à liberação modificada de fármacos. Foram preparadas dispersões aquosas de 4 por cento (p/v) e o citrato de trietila (20 por cento massa polímero acrílico) foi usado como plastificante. Dispersões foram vertidas em placa de Nylon revestida com Teflon® e colocadas em estufa a 60 °C. A determinação do índice de intumescimento (Ii por cento) em fluidos de simulação gástrica (FSG) e intestinal (FSI), além da permeabilidade ao vapor d'água (TVA) foram avaliadas. As dispersões propostas apresentaram habilidades filmogênicas...

Desenvolvimento de comprimidos de AAS 500 mg: influência do Amido 1500® na compressão direta / Development of AAS 500 mg tablets influenced by direct compression (CD) process

O experimento teve por objetivo demonstrar a viabilidade tecnológica do desenvolvimento de comprimidos de AAS 500 mg (Ácido Acetil Salicílico), empregando processo de compressão direta (CD). O Amido 1500® foi usado como excipiente no desenvolvimento das formulações, visando investigar suas propriedades de compressibilidade, desintegração, agregação e lubrificação. Usando metodologias previstas em Farmacopéias, foram realizados ensaios tecnológicos e físico-químicos. Os resultados evidenciaram que a mistura dos pós apresentou características de fluxo e compressibilidade adequadas ao rol de excipientes para compressão direta disponíveis no mercado. A presença do Amido 1500® também interferiu no tempo de desintegração. Dentre as formulações propostas neste trabalho, a fórmula contendo 6,35 por cento de Amido 1500® foi eleita a mais adequada por apresentar maior proximidade em relação aos produtos disponíveis no mercado brasileiro

Polysaccharides as excipients for colon-specific coatings. Permeability and swelling properties of casted films.

Oligosaccharides such as inulin (In) and polysaccharides such as galactomannans, combined with polymethacrylates on isolated films for film coatings, were obtained from aqueous-based solvents and investigated as potential vehicles for colonic drug delivery. These compositions, which are susceptible to fermentation by colonic microflora, constitute promising excipients for the development of new colon-specific therapeutic systems. The characteristics of several compositions have been demonstrated in permeability and swelling studies on isolated films composed of a polymethacrylate associated with In or galactomannans of mesquite seed gum (MSG). Results reported prove a dependency of the properties of mixed films on the polymethacrylate-polysaccharide concentration ratio and on the composition of the dissolution media. An increase in permeability through the mixed films was observed in a simulated colonic environment for the following compositions: Eudragit RS30D-MSG 70:30 w/w; Eudragit RS30D-In 90:10 w/w; Eudragit RS30D-In 76:24 w/w.

Excipientes farmacêuticos: perspectivas dos polissacarídeos na pesquisa e desenvolvimento de novos sistemas de liberação / Pharmaceutical excipients: perspectives for polysaccharides in the research and development of new drug delivery systems

Excipientes em geral são conceituados como substâncias auxiliares diretamente envolvidas na composição das diversas formulações farmacêuticas. Constituintes de diferentes sistemas terapêuticos viabilizam o sucesso da forma farmacêutica final, apresentando características e propriedades diferentes daquelas pertinentes aos fármacos. Excipientes farmacêuticos constituem elementos de elevado destaque na formulação dos medicamentos, uma vez que, exercem efetivo papel na garantia de obtenção da forma farmacêutica adequada ao uso e ao efeito terapêutico desejado, regendo e influenciando de maneira significativa a cedência do princípio ativo contido no medicamento. Polissacarídeos são polímeros de monossacarídeos, encontrados abundantemente na natureza, a baixo custo, e devido as suas propriedades, de baixa toxicidade, biodegradabilidade, características filmogênicas, facilidade de derivatização, disponibilidade a baixo custo, têm constituído elementos de elevado interesse e destaque nas pesquisas farmacêuticas. Estes polímeros naturais encontram vasto campo de aplicação incluindo a melhoria de diversas propriedades das formulações de formas farmacêuticas sólidas tradicionais, sendo estas representadas pela facilidade de escoamento dos granulados, boa uniformidade de peso e otimização da dureza em comprimidos. Prioritariamente, encontram posição de destaque na pesquisa e desenvolvimento de novos sistemas para liberação modificada de fármacos quando aplicados nos sistemas reservatórios (revestimento farmacêutico), sistemas matriciais, ou como ôcarregadoresö macromoleculares e/ou biodegradáveis

Material de acondicionamento e embalagem primário: avaliação da permeabilidade ao vapor d'água / Primary material for packing: evaluation of permeability to water vapor

A ampla diversidade dos materiais de acondicionamento e embalagem (MAE) disponíveis no mercado, considerados elementos de segurança, informação e facilidade na administração dos medicamentos, tem permitido a manutenção da integridade dos diferentes componentes das formulações farmacêuticas. Garantindo prioritariamente, a estabilidade do fármaco durante todo período de estocagem, isolando o produto final, dos fatores externos que podem alterar sua conservação (ar, luz, umidade). A escolha do MAE adequado para cada produto, representa argumento constante de estudos. A determinação da transmissão de vapor d/'água (TVA) constitui parâmetro capaz de estabelecer a permeabilidade em membranas poliméricas, sendo considerado método simples quando comparado com estudos tradicionais de difusão, permitindo prever o comportamento e a integridade do MAE. A proposta deste estudo foi determinar a TVA em diferentes composições poliméricas (MAE primário) destinados para formas sólidas orais. A TVA foi investigada aplicando método padrão recomendado pela ASTM (American Society for Testing Material - EUA). Utilizando cúpulas de alumínio, modelo Braive Instruments (Payne permeability cup); e micrômetro (Mitutoyo). Os resultados obtidos demonstram que a TVA foi mais elevada na ordem Pet/Pe < Pe < MB < MC 40/30 < Pet < MC 60/20, para todas as diferentes composições poliméricas testadas (associações de polímeros plásticos ou de celulose). Entretanto, a análise estatística (ANOVA) sobre o conjunto dos dados gerados, demonstraram que apesar dos diferentes valores de TVA registrados, estes resultados não foram estatisticamente significativos. Estes resultados sugerem, para as amostras testadas, que a escolha do MAE apropriado, poderá basear-se, no custo final do produto

Perspectivas dos sistemas de liberaçäo colo-específicos / Perspectives for the colon-specific drug delivery systems

A pesquisa e o desenvolvimentode novos dispositivos para liberaçäo de fármacos com elevado grau de especificidade, constituem estímulo e justificativas constantes na continuidade dos investimentos realizados nas últimas décadas em tecnologia farmacêutica. Neste contexto, várias pesquisas foram direcionadas à obtençäo de sistemas terapêuticos apresentando elevado grau de seletividade para liberaçäo de fármacos em regiöes específicas do trato gastrointestinal. Dentre esses, os sistemas terapêuticos colo-específicos destinados a via oral, voltados ao tratamento de afecçöes locais, aliado às perspectivas de administraçäo oral de peptídeos para absorçäo e açäo sistêmica, apresentam elevada posiçäo de destaque. O colo devido as suas particularidades (elevado tempo de residência e baixa atividade enzimática) tem sido amplamente explorado como ambiente adequado e promissor tanto para o tratamento local, como para a liberaçäo e otimizaçäo da biodisponibilidade de fármacos: corticosteróides, contraceptivos, hormônio do crescimento e insulina.

Polissacarídeos no desenvolvimento de filmes cólon-específicos e de sistemas matriciais para liberação modificada / Polysaccharides in the development of films colon-specifics and matrixes systems for modified liberation

Muitos polissacarídeos devido as suas propriedades e aprovação para uso como excipiente farmacêutico, são amplamente sugeridos na obtenção de sistemas para liberação modificada, os quais proporcionam manutenção das concentrações plasmáticas dos fármacos a níveis terapêuticos, podendo ainda, prevenir a inativação dos ativos sensíveis às condições fisiológicas do trato gastrintestinal (peptídeos), direcionando elevadas concentrações desses fármacos exclusivamente aos sítios de ação específicos. Neste trabalho proposta de desenvolvimento de membrana para revestimento cólon-específico foi realizada, associando polimetacrilatos aos polissacarídeos inulina e galactomanano (GSA). Valores das taxas de transmissão de vapor dïágua, índice de intumescimento, e coeficiente de permeabilidade à cafeína, em diferentes situações de simulação do trato gastrintestinal, foram influenciados principalmente pela participação dos polimetacrilatos...