Influence of compression forces on tablets disintegration by AC Biosusceptometry

Analysis of physical phenomena that occurs during tablet disintegration has been studied by several experimental approaches; however none of them satisfactorily describe this process. The aim of this study was to investigate the influence of compression force on the tablets by associating the AC Biosusceptometry with consolidated methods in order to validate the biomagnetic technique as a tool for quality control in pharmaceutical processes.Tablets obtained at five compression levels were submitted to mechanical properties tests. For uncoated tablets, water uptake and disintegration force measurements were performed in order to compare with magnetic data. For coated tablets, magnetic measurements were carried out to establish a relationship between physical parameters of the disintegration process. According to the results, differences between the compression levels were found for water uptake, force development and magnetic area variation measurements. ACB method was able to estimate the disintegration properties as well as the kinetics of disintegration process for uncoated and coated tablets. This study provided a new approach for in vitro investigation and validated this biomagnetic technique as a tool for quality control for pharmaceutical industry. Moreover, using ACB will also be possible to test these parameters in humans allowing to establish an in vitro/in vivo correlation (IVIVC). (C) 2007 Elsevier B.V. All rights reserved.

Porosity measurement of solid pharmaceutical dosage forms by gamma-ray transmission

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A load cell for grain-propelled ballistic rocket thrust measurement

A 1000-kgf resistive strain-gauge load cell has been developed for quality testing of rocket propellant grain. A 7075-T6 aluminum alloy has been used for the elastic column, in which 8 uniaxial, 120-Ω strain gauges have been bonded and connected to form a full Wheatstone bridge to detect the strain. The chosen geometry makes the transducer insensitive to moments and, also, to the temperature. Experimental tests using a universal testing machine to imposed compression force to the load cell have demonstrated that its behavior is linear, with sensitivity of 2.90 μV/kgf ± 0.34%, and negligible hysteresis. The designed force transducer response to a dynamic test has been comparable to that of a commercial load cell. © 2005 IEEE.

Força de compressão e umidade no perfil de dissolução da hidroclorotiazida

The aim of this work was to evaluate the influence of compression force and humidity in the dissolution profile of tablets formulation. As hidroclorotyiazide presents real problems of bioavailability, it was incorporate as standard drug in a formulation of tablets to study the mechanical resistance, time of disintegration and dissolution profile in function of humidity and compression force. The time of disintegration was not affected by the compression force, but it was influenced by humidity. The dissolution profile was altered by the compression force and for the humidity as well. Both factors can alter the bioavailability of drugs dispensed in the form of tablets.

Influência do graute e da taxa de armadura no comportamento da alvenaria de blocos de concreto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo multi-instrumental do processo de desintegração de comprimidos envolvendo três classes de desintegrantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito do tratamento térmico nos fios ortodônticos de aço inoxidável

Pós-graduação em Odontologia - FOA

Aspectos ergonômicos do levantamento manual de carga em mulheres: relação com equação de NIOSH

Pós-graduação em Engenharia Mecânica - FEG

Estudo da aromatização pré-extrusão e das condições de extrusão sobre as características físicas e retenção de aroma em proteína isolada de soja

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Pre-extrusion aromatization of a soy protein isolate using volatile compounds and flavor enhancers: Effects on physical characteristics, volatile retention and sensory characteristics of extrudates

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Exact Solution of the Elastica with Transverse Shear Effects

A new derivation of Euler's Elastica with transverse shear effects included is presented. The elastic potential energy of bending and transverse shear is set up. The work of the axial compression force is determined. The equation of equilibrium is derived using the variation of the total potential. Using substitution of variables an exact solution is derived. The equation is transcendental and does not have a closed form solution. It is evaluated in a dimensionless form by using a numerical procedure. Finally, numerical examples of laminates made of composite material (fiber reinforced) and sandwich panels are provided.

Quantificação da desintegração de comprimidos por fluxo ótico em seqüências de imagens de biosusceptometria AC

AC Biosusceptometry (ACB) is a low-cost biomagnetic tool that has been successfully applied on pharmaceutical research to evaluate performance of solid dosage forms. The aim of this work was to evaluate the Horn & Shunck method to access tablet disintegration. To evaluate the HS results was record on video a test with a objet moving in a rail with a constant velocity. The desintegration was recorded on video and ACB, which used have seven pairs of detection coils and a pair of excitation coils to mensure the magnetic ux variation. The signals were ampli ed and digitalized to create images, which were restored by Wiener lter, while the video images are converted to gray scale, both are normalized and binarized and had the optical ow estimation calculated by Horn & Schunck (HS) algorithm. All signals and images are processed and developed algorithm on Matlab. During the tests the ve tablets (500mg ferrite, 375mg excipients, compression 10 to 50 kN) were on a becker between of the ACB system and of the video system, and only touching the surface of the water. With all OF maps calculated was realized the sum of the resultants of each, to get a disintegration process resultant for each compression. Whit that was possible observed the disintegration behaves. For the compression force study the HS components of each sequence was sum, take mean and normalized for sequence's max modulo, therefore can be observed a high growing on less compression tablets. We can conclude the HS algorithm is viable to tablets disintegration data collection and whit that was possible to create a tablets disintegration analyzes protocol, which would be useful on desintegration kinetics study

Natural rubber/leather waste composite foam: A new eco-friendly material and recycling approach

This article describes a new approach of recycling the leather waste (shavings) using it as filler in natural rubber foams composites. The foams were prepared using different amounts of leather waste (0-60 parts per hundred of rubber) and submitted to morphological (SEM microscopy) and mechanical analyses (cyclic stress-strain compression). The increase of leather shavings on the composite causes an increase of viscosity in the mixture, which reflects in the foaming process. This results in smaller and fairly uniform cells. Furthermore, expanded rubber has the biggest cell size, with more than 70% of cell with 1000 mu m, while the composite with the higher concentration of leather has around 80% of total number of cells with 100-400 mu m. The mechanical parameters were found to depend on the leather dust concentration. Moreover, the stiffness rises with the increase of leather shavings; consequently, the compression force for expanded rubber was 0.126 MPa as well as the composite with higher concentration of leather was 7.55 MPa. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41636.

Effect of veneering material on the deformation suffered by implant-supported fixed prosthesis framework

The aim of this study was to evaluate the deformation suffered by cantilevered implant-supported fixed prostheses frameworks cast in silver-palladium alloy and coated with two occlusal veneering materials: acrylic resin or porcelain. Material and Methods: Two strain gauges were bonded to the inferior surface of the silver-palladium framework and two other were bonded to the occlusal surface of the prosthesis framework covered with ceramic and acrylic resin on each of its two halves. The framework was fixed to a metallic master model and a 35.2 N compression force was applied to the cantilever at 10, 15 and 20 mm from the most distal implant. The measurements of deformation by compression and tension were obtained. The statistical 2-way ANOVA test was used for individual analysis of the experiment variables and the Tukey test was used for the interrelation between all the variables (material and distance of force application). Results: The results showed that both variables had influence on the studied factors (deformation by compression and tension). Conclusion: The ceramic coating provided greater rigidity to the assembly and therefore less distortion compared with the uncoated framework and with the resin-coated framework. The cantilever arm length also influenced the prosthesis rigidity, causing higher deformation the farther the load was applied from the last implant.

Influence of the yielding criterion on total forming force in metallic junctions using elastomers

The production of metallic junctions employing elastomers is an unconventional technique that has been in development in the last 20 years. The forming process gets successfull just if a simultaneous compression between the elastomers and the tube takes place. Exact solutions for problems involving forming with elastomers are quite difficult to determine. However, the upper-bound theory can be used in order to predict the necessary load for junctions forming. Thus, it is necessary to develop a model capable to provide an estimate of the total forming force, which is useful to set-up tools and equipments required for the process. In this work, Von Mises, Hill's 1948 and Hill's 1979 associated yielding theories, and the Hosford's theory (1979) as well, were used in order to study the anisotropic behaviour on total forming force of junctions using elastomers, insuring the functionality of the proposed model. (c) 2006 Elsevier B.V. All rights reserved.