5 research outputs found

    Preparaci贸n de comprimidos de desintegraci贸n r谩pida de clorhidrato de ondansetr贸n mediante el m茅todo de compresi贸n directa

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    To make rapidly disintegrating tablets containing 8 mg ondansetron hydrochloride with suffi cient mechanical integrityas well as a pleasant taste, microcrystalline cellulose (MCC), lactose anhydrous, mannitol and croscarmellose wereformulated. Tablets were prepared by a direct compression method. Tablets properties such as tensile strength, disintegrationtime, wetting time and friability were determined. The two-factor spherical second order composite experimentaldesign was used for the preparation of preliminary batches and the desirability function was employed for theoptimization of preliminary batches. For preparation of the rapidly disintegrating tablets, simplex lattice design withconstraints on the proportion of excipients was utilized. In later design, tensile strength and disintegration time wereselected as dependent variables and concentration of microcrystalline cellulose, concentration of lactose anhydrous andconcentration of mannitol were selected as controlling factors. Mathematical equations and contour plots were usedto relate independent variables with tensile strength and disintegration time. Furthermore, the composite index which聽considers a positive or negative deviation from an ideal value was calculated for the optimization of the formulation.Contour plots of tensile strength and disintegration time were superimposed to fi nd out the optimized region at whichtablets with an acceptable crushing strength and disintegration time can be produced. The concept of similarity factorsf2 and Sd were used to prove similarity of dissolution in distilled water and simulated saliva (pH 6.8). Rapidly disintegratingtablets with durable structure and desirable taste could be prepared by selecting proper level of MCC, lactoseanhydrous, mannitol, croscarmellose and compression force.Para elaborar comprimidos de desintegraci贸n r谩pida con un contenido de 8 mg de clorhidrato de ondansetr贸n, consufi ciente integridad mec谩nica y buen sabor, se prepar贸 una formulaci贸n de celulosa microcristalina (CM), lactosaanhidra, manitol y croscarmelosa. Los comprimidos se elaboraron mediante el m茅todo de compresi贸n directa. Sedeterminaron propiedades tales como la resistencia a la fractura, el tiempo de desintegraci贸n, el tiempo de humidificaci贸n y la friabilidad. Para la preparaci贸n de los primeros lotes se utiliz贸 el dise帽o experimental de compuestode segundo orden esf茅rico de dos factores, y para su optimizaci贸n se emple贸 la funci贸n de deseabilidad. Para lapreparaci贸n de los comprimidos de desintegraci贸n r谩pida se utiliz贸 un dise帽o en ret铆culos simple con restriccionesen la proporci贸n de los excipientes. En un dise帽o posterior, se seleccionaron como variables independientesla resistencia a la fractura y la concentraci贸n de celulosa microcristalina, de lactosa anhidra y de manitol. Pararelacionar las variables independientes con la resistencia a la fractura y el tiempo de desintegraci贸n, se utilizaronecuaciones matem谩ticas y representaciones gr谩fi cas. Adem谩s, para optimizar la formulaci贸n, se calcul贸 el 铆ndicesint茅tico que considera una desviaci贸n positiva o negativa a partir de un valor ideal. Se superpusieron las representacionesgr谩fi cas de la resistencia a la fractura y el tiempo de desintegraci贸n para encontrar la regi贸n optimizadaen la que se pueden producir comprimidos con resistencia al aplastamiento y tiempos de desintegraci贸n aceptables.Para demostrar la similitud de la disoluci贸n en agua destilada y saliva simulada (pH 6,8) se utiliz贸 el concepto delos factores de similitud f2 y Sd. Se podr铆an preparar comprimidos de desintegraci贸n r谩pida con una estructuraduradera y un sabor agradable si se selecciona el nivel adecuado de CM, lactosa anhidra, manitol, croscarmelosay fuerza de compresi贸n

    M茅todo de cromatograf铆a l铆quida de alta resoluci贸n para la determinaci贸n simult谩nea de fosinopril s贸dico e hidroclorotiazida en formulaciones de comprimidos

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    A simple, specifi c, accurate and precise reversed phase HPLC method with UV detection for the simultaneous determinationof fosinopril sodium and hydrohclorthiazide in pharmaceutical formulations was developed. The drug solutionwas prepared in mobile phase and was injected into a C18 column with UV detection at 208 nm. The mobile phasewas a mixture of 0.2%w/v phosphoric acid in water and acetonitrile (30:70) delivered at a fl ow rate of 0.5 ml/min at29 0C. The calibration graphs were linear in the range of 10-50 渭g/ml (r2 > 0.99) for fosinopril sodium and 6.25-31.35 渭g/ml for hydrochlorthiazide (r2 > 0.99). The detection limit was 0.5渭g/ml for fosinopril sodium and 1.0 渭g/mlfor hydrochlorthiazide with quantitation limit of 10 渭g/ml and 6.25 渭g/ml for fosinopril sodium and hydrochlorthiazide,respectively. The statistical evaluation of the method was examined by performing intra-day (n=5) and inter-day calibration(n=5) and was found to be satisfactory, with high accuracy, and precision results. Application of the suggestedmethod was successfully applied to the simultaneous determination of fosinopril sodium and hydrochlorthiazide intablets formulation, with high percentage of recovery, good accuracy with precision.Se ha desarrollado un m茅todo HPLC de fase inversa con detecci贸n de UV sencillo, espec铆fi co, exacto y preciso parala determinaci贸n de fosinopril s贸dico e hidroclorotiazida en formulaciones farmac茅uticas. La soluci贸n de f谩rmacose prepar贸 en fase m贸vil y se inyect贸 en una columna C18 con detecci贸n de UV a 208 nm. La fase m贸vil era unamezcla de 0,2% p/v de 谩cido fosf贸rico en agua y acetonitrilo (30:70) a帽adida a una velocidad de fl ujo de 0,5 ml/mina 29 0C. Los gr谩fi cos de calibraci贸n fueron lineales en el rango de 10-50 渭g/ml (r2 > 0,99) para el fosinopril s贸dicoy de 6,25-31,35 渭g/ml para la hidroclorotiazida (r2 > 0,99). El l铆mite de detecci贸n fue de 0,5 渭g/ml para el fosinoprils贸dico y de 1,0 渭g/ml para la hidroclorotiazida, con un l铆mite de cuantifi caci贸n de 10 渭g/ml y 6,25 渭g/ml para elfosinopril s贸dico y la hidroclorotiazida, respectivamente. La evaluaci贸n estad铆stica del m茅todo se examin贸 mediantecalibraci贸n intrad铆a (n=5) e interd铆a (n=5) y result贸 satisfactoria, con una exactitud y precisi贸n elevadas. El m茅todosugerido se aplic贸 con 茅xito en la determinaci贸n simult谩nea de fosinopril s贸dico e hidroclorotiazida en formulacionesde comprimidos, con un elevado porcentaje de recuperaci贸n, buena exactitud y precisi贸n

    Pepsina capturada en gr谩nulos gelificados de 魏-carragenato reticulados mediante actividad ionotr贸pica para una mejora de la estabilidad: Optimizaci贸n y caracterizaci贸n fisicoqu铆mica mediante el dise帽o de Box-Behnken

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    This work examines the infl uence of process parameters, namely 魏-carrageenan concentration, potassium chloride concentration,and hardening time, on pepsin entrapped in ionotropically crosslinked 魏-carrageenan beads for improvementof its stability using response surface methodology. A Box-Behnken design was employed to investigate the effect ofprocess variables on the entrapment, time required for 50% enzyme release (T50), time required for 90% enzyme release(T90), and particle size. The beads were prepared by dropping the 魏-carrageenan containing pepsin into a magneticallystirred potassium chloride solution. In vitro enzyme release profi le of the beads was fi tted to various release kineticsmodels in order to understand the release mechanism. Topographical characterization was carried out by SEM, andentrapment was confi rmed by FTIR and DSC. Stability testing was carried out according to the ICH guidelines forzones III and IV. A polymeric matrix prepared by 3.0% w/v 魏-carrageenan and 0.3 M potassium chloride using theionotropic gelatin method, with a hardening time of 10 min resulted in the production of beads characterized by aspherical disk shaped with a collapsed center, an absence of aggregates, an entrapment of more than 80%, and a T90of less than 40 min. The shelf-life of the pepsin-loaded beads was found to increase to 3.24 years compared with 0.97years for the conventional formulation. It can be inferred that the proposed methodology can be used to prepare pepsinloaded魏-carrageenan beads for stability improvement. In addition, the proper selection of rate-controlling carrageenanconcentration and their interactive potential for crosslinking is important, and will determine the overall size and shapeof beads, the duration and pattern of dissolution profi les, and the enzyme loading capacity.En este trabajo se examina la infl uencia de los par谩metros de proceso, particularmente la concentraci贸n de 魏-carragenato,la concentraci贸n de cloruro pot谩sico y el tiempo de endurecimiento, en pepsinas capturadas en gr谩nulos de魏-carragenato reticulados mediante actividad ionotr贸pica para la mejora de su estabilidad mediante la metodolog铆ade superfi cie de respuesta. Se utiliz贸 un dise帽o de Box-Behnken para investigar el efecto de las variables de procesoen la captura, el tiempo necesario para la liberaci贸n del 50% de las enzimas (T50), el tiempo necesario para laliberaci贸n del 90% de las enzimas (T90) y el tama帽o de part铆cula. Los gr谩nulos se prepararon mediante el vertidode gotas de 魏-carragenato con pepsina en una soluci贸n de cloruro pot谩sico agitada magn茅ticamente. El perfi l deliberaci贸n enzim谩tica in vitro de los gr谩nulos se ajust贸 a varios modelos cin茅ticos de liberaci贸n para comprender elmecanismo de liberaci贸n. La caracterizaci贸n topogr谩fi ca se realiz贸 mediante microscop铆a electr贸nica de barrido (SEM)y la captura se confi rm贸 a trav茅s de espectrometr铆a infrarroja por transformada de Fourier (FTIR) y calorimetr铆adiferencial de barrido (DSC). La prueba de estabilidad se realiz贸 seg煤n las indicaciones de ICH para las zonas IIIy IV. Una matriz polim茅rica preparada con un 3,0% p/v de 魏-carragenato y 0,3 M de cloruro pot谩sico medianteel m茅todo de gelifi caci贸n ionotr贸pica, con un tiempo de endurecimiento de 10 minutos provoc贸 la producci贸n degr谩nulos caracterizados por un disco esf茅rico con un centro aplanado, una ausencia de agregados, una captura dem谩s del 80% y un valor T90 inferior a 40 minutos. Se observ贸 que la vida de almacenamiento de los gr谩nulos cargadoscon pepsina aument贸 hasta los 3,24 a帽os en comparaci贸n con los 0,97 a帽os de la formulaci贸n convencional.Se puede concluir que la metodolog铆a propuesta se puede utilizar para preparar gr谩nulos de 魏-carragenato cargadosde pepsina para la mejora de la estabilidad. Adem谩s, se concluy贸 que la selecci贸n adecuada de la concentraci贸n decarragenato con control de la velocidad de liberaci贸n y su potencial interactivo para la reticulaci贸n es importante,y determinar谩 el tama帽o y la forma general de los gr谩nulos, la duraci贸n y el patr贸n de los perfi les de disoluci贸n yla capacidad de carga de la enzima

    Surface-Enhanced Raman Scattering for Imaging Biological Cells

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    Nanotoxicology and challenges of translation

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    This paper focuses on the processes of translation in nanomedical research practices and contributes to a context- and object-centred research agenda in Science and Technology Studies. In particular, it addresses how nano-specific issues in medical research are exacerbated by uncertainty and unpredictability. Analyzing the relationship between nanomedicine and nanotoxicology I discuss how scientists are involved in highly uncertain processes, which require a contingent and experimental approach to nano-objects in everyday laboratory practices. Consequently, the dealings with nanomedical materials evoke a reformulation of numerous traditional forms of toxicological knowledge and knowledge practices, and challenge the self-concept of toxicology as a testing discipline
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