Olutayo A. Adeleye, Mbang N. Femi-Oyewo and Michael A. Odeniyi
Drug delivery to the proper site of action in the body is greatly influenced by the excipients used and some processing variables such as changes in compression force.
The aim of this investigation was to study the influence of changes in compression forces during tablet manufacturing on the mechanical and release properties of Tramadol matrix tablet. Hardness and friability were used as assessment parameters for mechanical properties while release properties were analysed using dissolution test. Data were analysed using One-way ANOVA at p < 0.05.
Tablet hardness and friability were typically compression pressure-dependent with a significant difference in tablet hardness and friability with increase in compression pressure (p < 0.001).
Drug release was best expressed by Korsmeyer-Peppas equation as the plots showed high linearity (r2) of 0.998 and 0.988 for formulations containing Xanthan gum and Sodium carboxymethylcellulose, respectively. Drug release from formulations containing Xanthan gum was mainly by diffusion while a combination of diffusion and chain relaxation was the mechanism of drug release from formulation containing Sodium Carboxymethylcellulose.
The release properties of tramadol matrix tablet were not significantly influenced by compression pressure but rather by the polymer and the material properties of the drug.
The presented research deals with the development of comfortable male underwear taking into account the development of pattern block methods and the analysis of the relationships existing between the compression pressure, the knitted materials properties, and some push-up effects. The main aim of this study is to achieve the technical selection of the materials based on KES-FB evaluations.The ease value has been used as the main index to connect the structural design of underwear, on one hand, and the body sizes, on other hand. A “bodyshell” system for testing the soft tissue of male bodies by FlexiForce sensor has been implemented. The pressures under the shells at six different places on the male body with ease changing have been tested.The collected results including maximum-possible pressure and material tensile indexes measured thanks to KES-FB have been analyzed in order to find the most relevant indexes of the material properties. A mathematical equations based on relationships combining theoretical model with practical application have been established. These equations will be helpful for the consumers and designers to select “the suitable knitting materials for male underwear” and they can be used too in the perspective of parameterization in CAD, in order to improve product developments efficiency.
Aleš Franc, Slavomir Kurhajec, Sylvie Pavloková, Dana Sabadková and Jan Muselík
The aim of this study was to find the optimal tablet composition with maximum content of dried fruits (Cornus mas L.). The effect of three different concentrations (12.5, 25 and 50 %) of two types of microcrystalline cellulose (Avicel® PH 101 and Avicel® PH 200) and three different compression pressures (20, 60 and 100 MPa) on the physical properties of tablet blends and tablets was studied. Tablets containing 50 % Avicel® PH 101 compressed under 100 MPa were found to have the best physical properties. This combination of composition and compression pressure resulted in stable tablets even after storage under accelerated stability conditions (6 months, 40 °C and 75 % RH).
Celia Cifuentes, Ángela Aguilar-de-Leyva, Ali R. Rajabi-Siahboomi and Isidoro Caraballo
Percolation theory has been applied to study the drug release behaviour in multicomponent inert matrices containing ethylcellulose as a matrix forming polymer. Global influence of major formulation factors such as polymer viscosity, polymer particle size, drug and filler solubility and porosity of the tablets in drug release kinetics has been studied for the first time. Batches containing three viscosity grades of Ethocel™, microcrystalline cellulose (MCC) and lactose as fillers, a lubricant and flow aid mixture and three drugs with different solubility have been manufactured. For some batches, compression pressure was varied in order to obtain matrices with five levels of initial porosity. The behaviour of inert matrices was explained based on the percolation ranges of the main components of the formulation. The effect of the porosity percolation threshold was observed and the existence of a tricoherent drug-polymer-filler system is hypothesized.
Determination of location of Top Dead Centre and compression ratio value on the basis of ship engine indicator diagram
In the polytropic model of compression process, exponent of polytropic compression curve was replaced with a power polynomial in which the piston travel was used as its argument. It was shown that 3rd order polynomial is optimum one. In the model were taken into account the following: design parameters of cylinder, influence of cylinder wear and gas blow-by on compression process, error in determining the piston's Top Dead Centre (TDC) location, measurement error due to indicator diagram's truncation. The presented solution of the non-linear model is based on its partial linearization, use of the least squares method as well as on application of the optimum determination methods known in the theory of experiment. The model makes it possible to determine TDC location on indicator diagram dealing with combustion, determination of total compresion ratio, pressure value of indicator diagram truncation, as well as determination of maximum values of compression pressure on the diagrams in which self-ignition occurs before reaching the TDC.
Ivan Struhár, Michal Kumstát and Dagmar Moc Králová
-exercise helped to recover contractile properties of muscles within 24 hours ( Perrey et al., 2008 ). Besides an impact of wear time, the range of delivered pressure is also very high among studies ranging from 1-34 mmHg at the ankle and 8-27 mmHg at the calf ( Beliard et al., 2015 ). To date, the ideal compressionpressure required to be beneficial to performance and recovery has not been defined ( Hill et al., 2015 ).
A common issue among CGs used in sports is related to the direction of the pressure. Gradual compression indicates that the applied pressure is highest when
T. Adinaveen, J. Judith Vijaya, R. Sivakumar and L. John Kennedy
the total pore volume.
Electrical conductivity studies
The DC electrical conductivity (σ) was measured at room temperature by a two-probe method. 1 g of porous carbon dried at 110 °C over night was compressed in a hollow Pyrex glass cylinder with an inner diameter of 10 mm between two metal plungers at compressionpressure ranging from 75.9 kPa to 742 kPa. The top and the bottom of the plungers were made of copper. They were connected to a Keithly 614 electrometer to measure the electrical conductivity of the samples. The compressionpressure
Michal Wilk, Michal Krzysztofik, Mariola Gepfert, Stanislaw Poprzecki, Artur Gołaś and Adam Maszczyk
, they seem to be very precise. However, it should be noted that not every athlete that follows RT-BFR training has an access to precise occlusion devices that monitor the restriction pressure. In order to promote a wider application of RT-BFR, the authors decided to evaluate the effectiveness of BFR using elastic wraps, without precise determination of the compressionpressure. Elastic knee wraps (~ 76 mm wide), which represent an inexpensive and easily available tool, were first used for BFR in 2009 ( Loenneke and Pujol, 2009 ). In the following years, a series of