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A central composite design was applied to design a novel gastric floating drug delivery system comprising propranolol HCl in Terminalia catappa gum and to evaluate the buoyancy, in vitro drug release behavior, and pharmacokinetic parameters. All formulations exhibited good buoyancy properties in vitro reflected by floating lag time of 1-110 sec, total floating time of 9-16 h and prolonged release behaviour (upto 12 h). Statistically optimised formulation (PBGRso) was orally administered to human volunteers under both fasted and fed conditions to evaluate gastric floating behavior under different food conditions by X-ray evaluation. In vivo studies of optimised formulations revealed that the gastric residence time of floating tablets was enhanced in the fed but not in the fasted state. Pharmacokinetic studies of the optimised Terminalia catappa formulation and a commercial product (Ciplar LA 80) carried out on healthy human volunteers showed a significant improvement in the bioavailability (132%) of propranolol HCl released from from the experimental Terminalia catappa formulations compared with Ciplar LA 80.

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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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As the main intent of delivering maximum concentration of drug available from the dosage form, an oral compression coated tablet (CCT) was intended to develop with a predetermined lag time of 6 hrs before immediate release of drug to target circadian rhythms of rheumatoid arthritis. Solid dispersions are promising approach to enhance drug release, which later will be developed as core tablet formulation and compression coated with polyethylene oxide (PEO WSR 303). Solid dispersions were formulated with different ratio of drug and carrier (sucrose fatty acid esters 1811) using solvent evaporation and melt granulation technique, optimized solid dispersion was formulated as core tablet with different diluents. Optimized core tablet was compression coated with PEO WSR 303 along with a channeling agent (DCL 21, mannitol, HPMC 5 cps and starch 1500). Lag time before immediate release of drug was markedly dependent on weight ratios of polymer and channeling agent used, which ranged from 4 to 12 hrs. Optimized solid dispersion (S9) was used for formulating optimized core tablet formulation (C8). CCT (T8) prepared with core tablet (C8) along with mannitol provided a lag time of 6 hrs with minimum concentration of channeling agent used, which was also supported from the permeability study results. Incompatibility and characterization was confirmed from DSC, XRD, FTIR and SEM studies. Unaltered Cmax and AUC0-t but delayed Tmax following oral ingestion of optimized formulation (T8) to human volunteers indicated clear lag time before immediate release of drug, which is suitable for treating rheumatoid arthritis following circadian rhythm.

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BACKGROUND AND THE PURPOSE OF THE STUDY: The purpose of the present investigation was to characterize and evaluate solid dispersions (SD) of indomethacin by using a novel carrier sucrose fatty acid ester (SFE 1815) to increase its in vitro drug release and further formulating as a tablet. METHODS: Indomethacin loaded SD were prepared by solvent evaporation and melt granulation technique using SFE 1815 as carrier in 1:0.25, 1:0.5 1:0.75 and 1:1 ratios of drug and carrier. Prepared SD and tablets were subjected to in vitro dissolution studies in 900 mL of pH 7.2 phosphate buffer using apparatus I at 100 rpm. The promising SD were further formulated as tablets using suitable diluent (DCL 21, Avicel PH 102 and pregelatinised starch) to attain the drug release similar to that of SD.. The obtained dissolution data was subjected to kinetic study by fitting the data into various model independent models like zero order, first order, Higuchi, Hixon-Crowell and Peppas equations. Drug and excipient compatibility studies were confirmed by fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. RESULTS: The in vitro dissolution data exhibited superior release from formulation S(6) with 1:0.5 drug and carrier ratio using solvent evaporation technique than other SDs prepared at different ratio using solvent evaporation and melt granulation technique. The in vitro drug release was also superior to that of the physical mixtures prepared at same ratio and also superior to SD prepared using common carriers like polyvinyl pyrollidone and PEG 4000 by solvent evaporation technique. Tablets (T(8)) prepared with DCL21 as diluent exhibited superior release than the other tablets. The tablet formulation (T(8)) followed first order release with Non-Fickian release. CONCLUSION: SFE 1815 a novel third generation carrier can be used for the preparation of SD for the enhancement of in vitro drug release of indomethacin an insoluble drug belonging to BCS class II.

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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 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.

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