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Panama, like most Latin American countries, has insufficient regulatory safeguards to ensure the safety and efficacy of all pharmaceutical products in the market, a situation that results in a two-tier system, where affluent citizens can afford innovator products while poor citizens must consume 'generics' of uncertain quality. Given that one lot of each drug product is analyzed every five years during registration while commercial lots are not, and since most products are not bioequivalent but simply copies or similars, there is a concern that commercial and registration lots of these 'generics' may not be of the same quality. The objective of this study was to assess the ability of various in vitro quality control tests to detect difference among five amlodipine products available in the Panamanian market: four 'generics', made in various countries, and the innovator, made in Germany and used as reference listed drug in Panama (Pan-RLD). The innovator manufactured in the United States (US-RLD) was used to compare the two RLDs. The Content Uniformity test, 30-min Dissolution test and multiple-pH Dissolution Profiles did not show any difference among the products. However, the in vitro dissolution absorption system 1 (IDAS1) showed a statistically significant difference in the amount dissolved between Pan-RLD and three out of the four 'generics', and significantly lower permeated amount for all the 'generics' compared with Pan-RLD; only US-RLD was similar to Pan-RLD. Thus, IDAS1 showed promise as a potential tool that authorities in weakly regulated markets can use to monitor for possible lot-to-lot product changes, which can help improve the quality of pharmaceutical products available to their entire populations. The significance of the similarity between the innovators made in Germany and the United States and their difference from the 'generics' (manufactured in other countries) is not known but deserves investigation.

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Metronidazole (MT) is an important drug available for Helicobacter pylori infection treatment. However, in the past few years, this drug has presented effective reduction for infection control, one of the most important reasons is attributed to the reduction of retention time in the stomach environment. Mucoadhesive nanostructured polyelectrolyte complexes (nano PECs) based on chitosan (CS) and hypromellose phthalate (HP) were rationally developed using a full factorial design (21 × 21 × 31), for the incorporation of MT based on the enhancement of the antimicrobial potential against active Helicobacter pylori, in the stomach. Different mass ratios of CS:HP (w/w) were tested, reaching the most promising ratios of 1:0.1, 1:0.5, and 1:1, and two methods of polymers addition (pouring-I and drip-II) were also evaluated. From method I, the obtained particles presented a diameter in the range of 811-1293 nm (Z-average) and a polydispersity index (PDI) between 0.47 and 0.88. By method II, there was a significant reduction in diameter and PDI to 553-739 nm and 0.23 at 0.34, respectively. The drug incorporation also resulted in a reduction in the diameter and PDI of the nano PECs. All samples showed positive zeta potential, about 20 mV, and a high percentage of MT incorporation (±95%). The method factor presented a greater influence on the nano PECs characteristics. Interactions in the system constituents were indicated by the FTIR data. Nano PECs mucoadhesiveness was observed and the composition and charge density were responsible for this phenomenon. MT dissolution evaluation showed the similarity of the dissolution profiles of free and loaded MT, in which almost 100% of the drug was in the simulated gastric medium in 120 min of testing. The in vitro antimicrobial potential against H. pylori of loaded nano PECs were measured and the minimum inhibitory concentration observed for free MT was >2000 µg/mL, while for the incorporated MT lower values were observed, showing an increase in the encapsulated MT activity.

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Los ensayos de equivalencia terapéutica tienen como objetivo demostrar que los medicamentos genéricos aportan la misma cantidad de principio activo en comparación con el medicamento innovador. El objetivo de la investigación fue evaluar la equivalencia terapéutica del medicamento enalapril maleato en tabletas de 20 mg, según la clasificación biofarmacéutica que le corresponde, ya que este es un medicamento representativo de la clase III, para demostrar que tienen un perfil de tolerabilidad adecuado y que son eficaces para su prescripción médica. Por otro lado, al demostrarse la equivalencia terapéutica se puede recurrir con toda seguridad al medicamento genérico y reducir los costos de los tratamientos, con lo cual la población tendrá una oferta de medicamentos confiables, seguros y a precios económicos. Se utilizó un medicamento innovador y tres de los ocho medicamentos genéricos de fabricación y comercialización nacional, a los cuales se les determinó perfiles de disolución (F2: 45.41, 92.42, 71.04), uniformidad de contenido (AV: 7.37, 2.97, 2.50) y valoración de principio activo (%: 107.14, 98.89, 101.71) para determinar la cantidad de principio activo en las muestras. Los análisis se realizaron con base en los criterios establecidos en la Farmacopea de los Estados Unidos. Se aplicó un modelo estadístico independiente, y se estableció que dos de los tres lotes analizados de los medicamentos genéricos son equivalentes terapéuticos con el lote del medicamento innovador. Con las pruebas de disolución in vitro realizadas a lo largo de este estudio, se puede concluir que los tres lotes analizados de dos medicamentos genéricos pueden ser considerados intercambiables con respecto al lote del medicamento innovador.

The therapeutic equivalence essays to demonstrate that generic medicine can provide the same amount of active ingredient compared to the innovative medicine. The objective of this research was to evaluate the therapeutic equivalence of enalapril maleate 20 mg, according to the biopharmaceutical classification, given that this is a representative class III drug. This to demonstrate that it has an acceptable tolerability profile and that it is effective for medical prescription. Once the therapeutic equivalence is stablished, the use of therapeutic bioequivalence products can reduce treatment costs, so that the general public can have access to reliable, safe and affordable medicines. For this study an innovative medicine and three of the eight generic medicines of national manufacture and commercialization were used for each medicine, the dissolucion profiles (F2: 45.41, 92.42, 71.04), the uniformity of content (AV: 7.37, 2.97, 2.50) and percentage of active ingredient (%: 107.14, 98.89, 101.71) were determined. The essays were performed based on the criteria established in The United States Pharmacopeia and were satisfactory in all the analyzed batches. An independent statistical model was carried out it was established, that two of the three analyzed batches for generic medicine are therapeutic equivalents with the batch of the innovative drug. In vitro dissolution tests obtained throughout this study, concluded that the three analyzed batches of two generic medicines can be considered interchangeable in respect to the batch of the innovative medicine.

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The purpose of this study was to investigate the effect on solubility and dissolution rate of binary complexes of ß-(ßCD), methyl-(MßCD) and hydroxypropyl-ß-cyclodextrin (HPßCD) with diloxanide furoate (DF). The complexation in solution was evaluated by phase solubility studies and 1H nuclear magnetic resonance (NMR). Enhanced water solubility of DF was obtained with the DF:MßCD system (61-fold). The mode of inclusion was supported by NMR experiments, which indicated that real inclusion complexes were formed between DF and MßCD or HPßCD. Solid state analysis was performed using infrared and thermal methods, which suggested the formation of true inclusion complexes of DF with two derivatized cyclodextrins, MßCD and HPßCD, and an exclusion complex with ßCD when the systems were prepared by freeze-dried technique. Dissolution studies conducted in simulated gastric fluid (2 h) and subsequent simulated intestinal fluid (next 4 h) showed increased dissolution rate of DF from the freeze-dried systems with ßCD, MßCD, and HPßCD (85; 77 and 75% of dissolved drug at 5 min, respectively) and 100% of the drug dissolved at 150 min for the three systems. The enhancement of the solubility and the dissolution of DF observed make these complexes promising candidates for the preparation of oral pharmaceutical formulations.

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La epilepsia es la enfermedad neurológica más frecuente en el mundo, esta situación impulsó el desarrollo de nuevos fármacos anticonvulsivantes (FAE) como lamotrigina (LMT) que presenta un elevado costo económico para la población con crisis convulsivas. El propósito del estudio fue comparar los perfiles de disolución de comprimidos de LMT de 25 mg (Test) comercializados en Paraguay y la Referencia (Lamictal®). Se tomaron productos de LMT 25mg comprimidos, con registros sanitarios vigentes y comercializados en Paraguay, realizándose los controles de calidad acorde a criterios generales de las farmacopeas oficiales. Posteriormente, se determinó la cinética de disolución de los productos Test y Referencia, en los 3 medios de disolución recomendados (pHs 1,2 ; 4,5 y 6,8). Los perfiles de disolución de los productos evaluados de LMT, presentaron comportamientos similares a los diferentes pHs, liberando más del 85% a los 15 minutos en los 3 medios de disolución, no siendo necesario la comparación con la prueba f1 y f2. Se concluye que la cinética de disolución de los comprimidos de LMT de 25mg analizados, mostraron un comportamiento in vitro semejante entre las formulaciones. Estos resultados son orientadores, permitiendo tan sólo guiar prospectivamente la puesta en marcha del ensayo de bioequivalencia entre el medicamento Test y Referencia evaluado in vitro. Se pretende que estos ensayos llevadosa cabo con LMT, constituyan el paso inicial, para estudiar el comportamiento de las cinéticas de disolución de otros medicamentos Test y sus correspondientes Referencias del mercado paraguayo.

Epilepsy is the most common neurologic disease in the world, this situation boosts the development of new anticonvulsant drugs (AEDs) as lamotrigine (LMT) having, the latter, ahigh economic cost for the population with seizures. The aim of the study was to comparethe dissolution profiles of LMT tablets of 25 mg (Test) marketed in Paraguay and the Reference or innovator (Lamictal®). LMT 25mg tablets were chosen with the current health register sold in Paraguay and performing the quality controls according to general criteria ofthe official pharmacopoeia. Subsequently, the kinetics of dissolution of the Test and Reference products were determined in the three recommended dissolution media (pH 1,2 ; 4,5 and 6,8). The dissolution profiles of LMT products evaluated presented similar behaviorat the three different pHs, releasing more than 85% within 15 minutes in the three dissolution media. No comparison with the f1 and f2 test was necessary. The kinetics of dissolution of the tablets of LMT 25 mg analyzed showed a similar in vitro behavior between the formulations. These results constitute only a guide for the implementation of bioequivalence studies between the Test and the Reference assayed in vitro. These tests carried out with LMT could emerge as an initial step in order to study the behavior of dissolution profiles of the Test product and the corresponding references in the Paraguayan market.

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Objetivo: evaluar los perfiles de disolución decomprimidos de Lamotrigina 100mg (Test) con laReferencia (Lamictal®) comercializados en Paraguay.Material y Métodos: Se utilizaron comprimidosde Lamotrigina de 100mg comercializados enParaguay. Se determinaron los perfiles de disoluciónde los productos Test y Referencia, en los tresmedios de disolución recomendados (pHs 1,2 ; 4,5y 6,8). El método analítico se basó en HPLC condetector PDA a 277nm, usando una PhenomenexLuna C18 a 40ºC, con fase móvil de buffer fosfatode sodio 0.05M pH4.0-acetonitrilo (80:20), flujode 1.3mL/min y tiempo de retención de 5 min.Resultados: Los perfiles de disolución del productoTest de Lamotrigina 100mg, fueron similaresen los diferentes pHs al producto de Referencia,liberando más del 85% a los 15 minutos en los 3medios de disolución, no siendo necesaria la comparacióncon el factor f2.Conclusión: Los perfiles de disolución de los comprimidosde Lamotrigina de 100mg Test muestranun comportamiento in vitro semejante al productode Referencia, lo que sugiere que su comportamientoin vivo podría ser también semejante.

Objectives: to evaluate the dissolution profiles ofLamotrigine tablets of 100 mg (Test) and Reference(Lamictal®) marketed in Paraguay.Material and Methods: Tablets of Lamotrigine100 mg marketed in Paraguay were used. Dissolutionprofiles of the Test and Reference productswere determined in the three recommended dissolutionmedia (pH 1.2; 4.5 and 6.8). The HPLCmethod used consisted of a Phenomenex Luna C18column, with mobile phase of 0.05M sodium phosphatebuffer pH4.0-acetonitrile (80:20), flow rateof 1.3mL / min and retention time of 5 min. Thecolumn compartment was kept at 40ºC, and thewavelength detection was 277 nm.Results: The dissolution profiles of the Test productof Lamotrigine 100mg, showed similar behavior tothe Reference product at the three different pHs,releasing more than 85% in 15 minutes in the threemedia dissolution. No calculation using the similarityfactor f2 was needed.Conclusion: Dissolution profiles of the two formulationsof Lamotrigine 100mg were similar in thedifferent pH dissolution media, thus a similar invivo behavior could be expected.

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El propósito de los estudios in vitro es comparar las características de liberación del principio activo contenido en una forma farmacéutica sólida oral mediante la cantidad, o porcentaje de la dosis, disuelta en función del tiempo en condiciones controladas y validadas. Se realizó una comparación de disolución in vitro de flunitrazepam (Rohypnol®, Somnidual® e Inervon®) y de lamotrigina (Lamictal® y Epilepax®). Para los perfiles de disolución de flunitrazepam, una de las marcas comerciales tuvo un perfil de disolución muy diferente a las otras dos marcas. Para el caso de lamotriginano existió diferencia para aquellos pH que se consideran fundamentales para la disolución del comprimido en el tracto gastrointestinal. Los resultados obtenidos de los estudios in vitro son simplemente orientadores, permiten tan solo guiar la puesta en marcha del ensayo de bioequivalencia entre el test evaluado in vitro y la referencia utilizada en el mismo ensayo. No obstante, estos resultados pueden constituirse en un elemento de apoyo a la presunción de bioinequivalencia como causa de un evento adverso (ineficacia o toxicidad) detectado en los programas de farmacovigilancia actualmente en marcha.

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El propósito de los estudios in vitro es comparar las características de liberación del principio activo contenido en una forma farmacéutica sólida oral mediante la cantidad, o porcentaje de la dosis, disuelta en función del tiempo en condiciones controladas y validadas. Se realizó una comparación de disolución in vitro de flunitrazepam (Rohypnol®, Somnidual® e Inervon®) y de lamotrigina (Lamictal® y Epilepax®). Para los perfiles de disolución de flunitrazepam, una de las marcas comerciales tuvo un perfil de disolución muy diferente a las otras dos marcas. Para el caso de lamotriginano existió diferencia para aquellos pH que se consideran fundamentales para la disolución del comprimido en el tracto gastrointestinal. Los resultados obtenidos de los estudios in vitro son simplemente orientadores, permiten tan solo guiar la puesta en marcha del ensayo de bioequivalencia entre el test evaluado in vitro y la referencia utilizada en el mismo ensayo. No obstante, estos resultados pueden constituirse en un elemento de apoyo a la presunción de bioinequivalencia como causa de un evento adverso (ineficacia o toxicidad) detectado en los programas de farmacovigilancia actualmente en marcha.

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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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Introducción: el raloxifeno es un modulador selectivo del receptor estrogénico perteneciente a la familia de los benzotiofenos. Varios ensayos clínicos han mostrado que el raloxifeno reduce la pérdida del hueso en la espina dorsal y puede aumentar la masa de hueso en ciertos sitios. Objetivo: determinar la estabilidad física y química de las tabletas de raloxifeno. Métodos: se prepararon tres lotes a escala piloto de 5 kg cada uno. Se realizaron estudios de disolución in vitro, estabilidad química, fotoestabilidad y humedad. Se colectaron las muestras al tiempo 0, 1, 2, 3 y 6 meses para el estudio de estabilidad acelerado y a tiempo 0, 6, 12, 18 y 24 meses para la estabilidad por vida de estante. Se determinó la estabilidad química aplicando un método de análisis por cromatografía líquida de alta resolución, desarrollado y validado previamente. Resultados: en estudio de estabilidad acelerada, el ensayo de disolución in vitro mostró disolución del ingrediente activo en concentraciones mayores al 90 por ciento, mientras que la concentración se mantuvo entre el 90 y 110 por ciento. Los estudios en condiciones de humedad afectaron la estabilidad química del medicamento. Conclusiones: todos los lotes de la formulación de tabletas de raloxifeno resultaron estables por 24 meses en los envases estudiados, almacenados a la temperatura de 32 ± 2 ºC y protegidos de la humedad. Las tabletas presentan una buena disolución in vitro durante los 24 meses

Introduction: Raloxifene is a selective estrogen receptor modulator from the benzothiophene family. Several clinical trials have shown that raloxifene reduces bone loss rate in the spinal column and may increase bone mass at certain sites.Objective: to determine the physical and chemical stabilities of raloxifene tablets. Methods: three pilot scale batches of 5 kg each were prepared. In vitro dissolution, chemical stability, photostability and humidity studies were carried out. Samples were collected at 0, 1, 2, 3 and 6 months for the accelerated stability study and at 0, 6, 12, 18 and 24 months for the shelf life stability study. Chemical stability was determined using high performance liquid chromatography analytical method, which was developed and validated prior to the study.Results: in the accelerated stability study, the percentages of dissolved drug were more than 90 percent and drug content porcentages were between 90 percent and 110 percent. Humidity conditions affected the chemical stability of the tablets. Conclusions: All raloxifene tablet batches formulations were stable for 24 months in the studied containers stored at 32 ± 2 ºC and waterproof. In vitro drug release dissolution showed good results for 24 months

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El presente estudio se realizó con el objetivo de establecer mediante pruebas de disolución in vitro, si dos formas farmacéuticas multifuente de liberación inmediata, de administración peroral con metformina como principio activo, son equivalentes en relación con su producto de referencia. Los datos de porcentaje de disolución obtenidos en tres niveles de pH (1,2; 4,5 y 6,8) y en dos equipos de disolución diferentes, se analizaron mediante el método de modelo independiente para comparar los perfiles de disolución de los productos a través del cálculo de los factores de diferencia (f1) y de similitud (f2), según las recomendaciones de la Food and Drug Administration (FDA). Para evaluar la cinética de liberación del fármaco, se aplicaron tres modelos matemáticos (ecuación de orden cero, de primer orden e Higuchi); además, para la comparación de los productos se aplicó un método basado en análisis multivariado para un diseño de medidas repetidas. Los resultados mostraron que existen diferencias estadísticamente significativas entre los productos, razón por la cual en este estudio no se demostró la equivalencia de los productos B y C con relación al producto A, con base en pruebas de disolución in vitro.

The objective of the study was to determine the equivalence of two multisource drug products of metformin tablets using in vitro testing. The in vitro dissolution profiles were done in phosphate buffer (pH 6.8), acetate buffer (pH 4.5), hydrochloric acid (pH 1.2) and two dissolution apparatus were used. Multivariate analysis for repeated measures design was employed to compare the percentage dissolved of the drug products. According to Food and Drug Administration (FDA) guidance for dissolution data equivalence, model independent approach was applied. This involves the use of difference factor (f1) and similarity factor (f2). The drug release from drug products was analyzed by various mathematical models such as zero order, firs order and Higuchi. The results showed that there were significant differences between the drug products, and for this reason it was not possible to demonstrate equivalence based in vitro assays.

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Este trabalho teve como objetivo principal comparar, através do estudo de equivalência farmacêutica e do perfil de dissolução in vitro, oito medicamentos genéricos contendo paracetamol 750 mg, comercializados na região central do Rio Grande do Sul. As análises foram realizadas em conformidade com a monografia do paracetamol comprimidos, descrita na Farmacopeia Brasileira (2010). Os genéricos A, B, D, E, F, G e H são equivalentes farmacêuticos do medicamento referência, pois foram aprovados em todos os testes a que foram submetidos. O Genérico C, no entanto, foi reprovado no doseamento. Quando avaliados em relação ao perfil de dissolução, pelos critérios descritos na RDC 31/2010, somente o genérico E não possui o mesmo perfil de dissolução que o medicamento referência, porém quando comparados pela eficiência de dissolução (ED) podemos verificar que somente os Genéricos G, H, F e A possuem a mesma ED que o medicamento referência.

The aim of this study was to compare, by testing their pharmaceutical equivalence and dissolution profiles in vitro, eight generic medicines containing 750 mg paracetamol, marketed in the central region of Rio Grande do Sul (Brazil). Analyses were carried out in accordance with the monograph on paracetamol tablets in the Brazilian Pharmacopoeia (2010). The generic medicines A, B, D, E, F, G and H are pharmaceutically equivalent to the drug reference, since they passed all the tests they underwent. Of all the samples analyzed, only drug E did not have the same dissolution profile as the reference drug, a fact that may interfere with the interchangeability of these products, which is required of a drug being marketed as a generic. Regarding dissolution efficiency (DE), the ANOVA showed a significant difference between the products, so the Tukey test was applied, showing that only the generics A, F, G and H have the same DE as the reference drug.

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The aim of present study was the assessment of antimicrobial activity of prepared time-dependent release bilayer tablets of amoxicillin trihydrate and in vitro evaluation of drug release by antimicrobial assay using agar plate diffusion method. The bilayer tablets comprised of a delayed and sustained release layer. Direct compression method was used for the preparation of bilayer tablets containing Eudragit-L100 D55 as delayed release polymer, and HPMCK4M and HPMCK15 as sustained release polymers. The prepared bilayer tablets containing amoxicillin trihydrate were evaluated for hardness, thickness, friability, weight variation and drug content. Further, in vitro drug release was assessed by antimicrobial assay using S. aureus and E. coli as test microorganisms. The aliquot samples of in vitro drug release study were found to be effective against both microorganisms for 16 hours due to sustained action. The in vitro drug release study and antimicrobial assay showed that bilayer tablets have sustained release profile of drug delivery with time-dependent burst release after a lag-time of 2 hours. The lower MIC value (2 µg/mL) of prepared bilayer tablets vis-à-vis marketed preparation (5 µg/mL) represented its good antimicrobial activity.

O objetivo do presente estudo foi avaliar a atividade antimicrobiana de formulações de comprimidos de dupla camada contendo amoxicilina triidratada para liberação tempo dependente e avaliação da liberação in vitro do fármaco pelo ensaio de atividade antimicrobiana utilizando o método de difusão em placa de ágar. Os comprimidos de dupla camada consistem em uma camada para liberação retardada e outra sustentada. O método de compressão direta foi usado para a preparação dos comprimidos de dupla camada contendo Eudragit-L 100 D55 como polímero para liberação retardada e HPMCK4M ou HPMCK15 como polímeros para liberação sustentada. As formulações de comprimidos de dupla camada contendo amoxicilina triidratada foram avaliadas quanto a dureza, espessura, friabilidade, variação de peso e conteúdo de fármaco. Além disso, a liberação do fármaco in vitro foi avaliada por ensaio de atividade antimicrobiana usando S. aureus e E. coli como microrganismos teste. A alíquota das amostras do estudo de liberação do fármaco in vitro demonstrou ser efetiva contra ambos os microrganismos por um período de 16 horas devido à ação sustentada. O estudo de liberação do fármaco in vitro e o ensaio de atividade antimicrobiana mostraram que os comprimidos de dupla camada tiveram um perfil de liberação sustentada do fármaco com um pico de liberação após 2 horas de ensaio. O menor valor de MIC (2 ug/mL) dos comprimidos de dupla camada quando comparados à formulação comercial (5 ug/mL) representa uma boa atividade antimicrobiana.

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RESUMO

The objective of the present study is to develop a colon targeted drug delivery systems for Aceclofenac using xanthan gum as a carrier. In this study, multilayer coated system that is resistant to gastric and small intestinal conditions but can be easily degraded by colonic bacterial enzymes was designed to achieve effective colon delivery of Aceclofenac. The xanthan gum, the drug and the physical mixture were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). All the formulations were evaluated for hardness, drug content uniformity and other physical properties. Release aspects of Aceclofenac in simulated gastrointestinal fluid and colonic fluid with enzymes were investigated. From these results, Eudragit coated system exhibited gastric and small intestinal resistance to the release of Aceclofenac. The rapid increase in release of Aceclofenac in SCF was revealed as due to the degradation of the xanthan gum membrane by bacterial enzymes. The designed system could be used potentially as a carrier for colon delivery of Aceclofenac by regulating drug release in stomach and the small intestine.

O presente estudo teve como objetivo o desenvolvimento de sistema de liberação cólon-alvo de aceclofenaco empregando goma xantana. Nesse trabalho, o revestimento de múltiplas camadas com característica de resistência às condições do intestino delgado além de gastrorresistência oferece como vantagem a rápida degradação desse sistema por enzimas bacterianas colônicas. Dessa forma, o planejamento de tal sistema possibilitou a liberação específica do aceclofenaco no cólon. A goma xantana e o fármaco, além da mistura física desses dois componentes, foram caracterizados por espectroscopia no infravermelho com transformada de Fourier (FTIR) e calorimetria diferencial exploratória (DSC). Todas as formulações foram avaliadas no que se refere à dureza, à uniformidade de conteúdo do fármaco além de outras propriedades físicas. Os perfis de liberação do aceclofenaco no fluido gástrico simulado e fluido colônico simulado contendo enzimas foram investigados. Os resultados revelaram que o sistema revestido com Eudragit® exibiu resistência gástrica e intestinal à liberação de aceclofenaco. O rápido aumento na liberação de aceclofenaco no fluido colônico simulado foi atribuido à degradação da goma xantana por enzimas bacterianas. O sistema apresenta aplicação potencial no desenvolvimento de produtos para a liberação cólon-alvo de aceclofenaco.

Assuntos

RESUMO

The present study was initiated with the objective of studying the in vitro dissolution behavior of gliclazide from its solid dispersion with polyethylene glycol 6000. In this work, a solid dispersion of gliclazide with polyethylene glycol was prepared by the fusion method. In vitro dissolution study of gliclazide, its physical mixture and solid dispersion were carried out to demonstrate the effect of PEG 6000. Analytical techniques of FT-IR spectroscopy, differential scanning calorimetry and X-ray diffractometry were used to characterize the drug in the physical mixtures and solid dispersions. The dissolution studies of solid dispersion and physical mixture showed greater improvement compared to that of the pure drug. The mechanisms for increased dissolution rate may include reduction of crystallite size, a solubilization effect of the carrier, absence of aggregation of drug crystallites, improved wettability and dispersbility of the drug from the dispersion, dissolution of the drug in the hydrophilic carrier or conversion of drug to an amorphous state. The FT-IR spectra suggested that there was no interaction between gliclazide and PEG 6000 when prepared as a solid dispersion. DSC and XRD study indicated that the drug was converted in the amorphous form.

O presente trabalho foi realizado com o objetivo de estudar o comportamento in vitro da dissolução da gliclazida a partir da sua dispersão sólida com polietileno glicol 6000. Neste trabalho, as dispersões sólidas de gliclazida com polietileno glicol foram preparadas pelo método de fusão. Os estudo de dissolução in vitro da gliclazida, na mistura física e nas dispersões sólidas foram realizados para demonstrar o efeito de PEG 6000. Técnicas analíticas como espectroscopia FT-IR, calorimetria diferencial de varredura e difração de raios-X foram empregadas para caracterizar o fármaco nas misturas físicas e nas dispersoes sólidas. Os estudos de dissolução demonstraram maior melhoria. Os mecanismos para aumentar a velocidade de dissolução podem incluir a redução do tamanho dos cristais, a solubilização do carreador, a ausência de agregação dos cristais do fármaco, a melhoria da molhabilidade e dispersibilidade do fármaco a partir da dispersão, a dissolução do fármaco no carreador hidrofílico ou conversão da forma cristalina do fármaco para estado amorfo. Os espectros de FT-IR sugeriram que não houve interação entre gliclazide PEG 6000 e na sua combinação. Os estudos de DSC e DRX indicaram que o fármaco foi convertido para a forma amorfa.

Assuntos