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Determining the compression behaviour of fillers and magnesium stearate
Szwedová, Lenka ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
1 Abstract The energy of tablets compaction is obtained from the force-distance record. The aim of this work was to determine accumulated energy in a tablets (plastic energy), to determine energy released from a tablet after compaction (elastic energy) and summation of these two energies. Mixtures of magnesium stearate 0%, 0,5% and 1% were prepared in a blending cube. The T1 - FRO 50 compacting machine was used for compacting tablets (weight of each tablets was 500 mg). Compacting forces were 5, 10 and 15 kN. In the first procedure the compaction was ceased after reaching the maximal compaction force, in the second procedure the upper punch was stopped when the maximal compaction force was reached and during 180 s dwell time of decreasing compacting force was recorded while the tablet height was kept constant. The results show that increasing concentration of lubricant leads to a decrease of accumalated energy in a tablet and on the contrary it leads to an increase of energy released from a tablet. The 180 s dwell time with a tablet height kept constant increases plastic energy because of forming more bonds. Microcrystalline cellulose is characterized by higher plastic and lower elastic energy than lactose monohydrate.
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Determining the compression behaviour of microcrystalline cellulose and magnesium stearate
Smékalová, Petra ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
This thesis deals with the characterisation of a specific compression process by monitoring the viscoelastic properties of pressed material. The theoretical part of the thesis describes the substances - microcrystalline cellulose and magnesium stearate. It also describes methods for the assessment of tablet viscoelasticity using the force-displacement diagram and factors influencing the viscoelasticity of tablets. The aim of the experimental part of the work is to characterise the viscoelastic properties of microcrystalline cellulose as well as a mixture of microcrystalline cellulose and magnesium stearate lubricant of various lubricant concentrations using the force-displacement diagram and calculation of tablet relaxation. Tablets were pressed from a mixture of aggregates of microcrystalline cellulose and magnesium stearate lubricant using a T1-FRO 50 machine at 11 molding pressures in the range of 1,9 -113,0 MPa with lubricant concentration in the range of 0 % - 2,50 %. The height and diameter of each tablet were measured immediately after pressing and the measurements were repeated 24 hours later. Measurements determined viscoelastic parameters E1, E2, E3, Elis, and P1, and the volumes of the tablets, both at time 0 and after 24 hours. The result of the study was to determine the effect of...
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Determining the compression behaviour of fillers and talc.
Hofmanová, Tereza ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Determining the compression behaviour of fillers and talc Abstract The aim of this study was to determine how do the type of filler, presence of lubricant, size of compression force and compression with dwell time or without dwell time influence values of energy compression of tablets. Materials used were microcrystalline cellulose (Avicel PH 200), lactose monohydrate (Tablettose® 70) and talc. Mixtures with the 0%, 0,5% and 1% concentration of talc were prepared in a blending cube. Tablets with a weight of 500 mg were compacted in the compaction machine T1 - FRO 50 with the compaction force of 5 kN, 10 kN and 15 kN. Force-displacement curves were obtained from the resulting values of measurements of individual compaction processes, and numerical values of a plastic energy (E2), an elastic energy (E3), and Elis (E2 + E3) were calculated from them. Obtained data were statistically evaluated according to the Stats-Otto method. It results from these calculated values that the plasticity increases and the elasticity decreases during the compression with dwell time. Parameters E2, E3 and Elis increase with an increasing applied pressure. As expected, energy E2 and Elis did not decrease and energy E3 did not increase with the raising concentration of lubricant. This is caused by the character of the used...
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Determining the plasticity of mannitolum
Votava, Jakub ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
The visco-elastic characteristics and knowledge of them are the important factors that influence pressability of materials. These characteristics differ for every material and it is possible to determine them by variety of methods. In our thesis (chapter Experiments) we evaluated the relationship "force - travel" and determined elasticity and plasticity of materials. The test of relaxation of tense is another way to determine plasticity of materials. The results are parameters of FminA, FminB, FPL and parameters of single-parametric equation that describes decrease of preassure in a tablet during the relaxation period. These parameters and their evaluation are the goal of this thesis. We determined the Young's modulus of elasticity from the tablet dilatation measure restults. The value of Young's modulus of elasticity for mannitol is 413,36 MPa. The value of total plasticity Pc is 91,34177 MPa.s. Generally: increasing value of total plasticity determines increase of tablet material pressability.
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Determining the plasticity of calcium hydrogen phosphate
Hořínková, Pavla ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The essential condition for a compaction of materials are their viscoelastic properties. There are many methods how to determine them. During a compaction process we can obtain elastic and plastic energies or energy of particle friction from a force-displacement record. After compaction the Young's modul of elasticity can be calculated from the tablet dilatation's values. The stress relaxation test is used for working out the plasticity of a compacted material. Using this test we get values of the methods FminA, FminB, Fpl and parameters of first order equation describing the pressure decrease during the stress relaxation. The viscoelastic properties of calcium hydrogenphosphate dihydrate were evaluated in this work by above mentioned methods except for energies. The results obtained by these methods were 288,080 MPa for the Young's modul of elasticity and 700,5167 MPa.s for the total plasticity Pc. The greater this value is, the better compaction properties the material has.
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Determining the plasticity of microcrystalline celulose
Skálová, Marie ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Important properte of pressed (compacting) materials is their energy and plasticity. For their calculation is used several methods. One of values elasticity or plasticity energy from record power-line, in another metod is used elastic recovery, which is used for calculation of Young's elastic modul and the third one value stress relaxation of tenseness. In this analyze we can get parameters as FminA, FminB, Fpl and also characterization of ralation dependence compression in the time. In this dissertation is valueted one of the most common excipient microcrystaline celulose by all these methods. Basic characteristic is Young's elastic modul ,which is 253,794MPa and total plasticity is 995,48. We can say, that values of total plasticity means good compressible material and that plasticity increases with increasing of total plasticity.
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Determining the plasticity of lactose
Patočková, Simona ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The aim of this work was to take charakteristic of lactose and their influence on compressibility. Plastic properties ensuring better compressibility of material, whereas elastic properties make difficult for compressibility. Plasticity and elasticity are important characteristics of compacting materials. Several methods are commonly used for calculation of these parameters. One of the methods utilizes elastic recovery. On the base of relation between elastic recoveries and compression pressure, the Young's modul of elasticity is counted. Elastic and plastic energy is acquired from measurement force - displacement representing continuance of pressing process. Force - displacement curves are obtained from measurements of punch force and displacement. Energy is needed for the compression of material and formation of strong compacts. The properties of the compact are correlated with the energy input. The force - displacement profiles as such may be useful as a material charakteristic. Furthermore, the stress relaxation test is exploited for calculation of plasticity. By this test the parameters F min A, F min B, FPL and also characteristics of single parametric relation dependence of compacting pressure on time are counted. In this work, the lactose was evaluated by all mentioned methods. The basic...
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Determining the compression behaviour of hypromelloses.
Palounková, Zuzana ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
The diploma work is concerned with a study of mechanical resistance which is assessed through the tablet crushing force and tensile strenght.In this work there was used tablet measuring method resulting from the recording of force - path, while the crushing process is assessed not only by crushing strenght but also by the path of crushing. Using the crushing force, crushing path and tablet crushing force is possible to compute next parameteres of crushing process detailing tablet properties as are volume crushing force, volume crushing energy and weight crushing energy. Assessed tablets were compacted of microcrystalline cellulose, hydroxypropylmethylcelulos, lactose and calcium hydrogen phosphate. From the result of work follows that crushing force (possibly tensile strenght) is decreasing in assessed adjuvants microcrystalline cellulose Ceolus, hydroxypropylmethycellulose HPMC K4, hydroxypropymethylcellulose HPMC K100, calcium hydrogen phosphate Emcompress, lactose Tablettosa respectively. Tablet breakage kinetics parameteres were decreasing with used substances in order microcrystalline cellulose Ceolus, hydroxypropymethylcellulose HPMC K100, hydroxypropylmethycellulose HPMC K4, and the lowest results were registered with lactose Tablettossa and calcium hydrogen phosphate Emcompress.
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Determining the compression behaviour of mannitol and sorbitol.
Svačinová, Petra ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
This diploma thesis is summarize the tablet's parameters such as pressing, crushing and the kinetics of the tablets. Moreover, the crushing force, tensile strenght, volume crushing force, trajectory, crushing energy, volume crushing energy and relations between compression force and compression pressure, crushing force and influence of compression force onto the tensile strenght, crushing force and volume crushing force. These characteristics have been investigated by using tablets made of microcrystalline celulosis called Avicel 103 and Avicel 301, saccharosis, sorbitole and mannitole (Pearlitole). Tablets were pressed with the using of various pressing pressures and then crushed. Parameters and relations inbetween them are followed by the force-trajectory data record, that has been acquired during the process of crushing. As the results are, the dependance among crushing and pressing forces is linear in the latitude of 4 - 15 kN, therefore for other enumerations I used the values gained during these measurements. Parameters of the destructing process for the numbers of crushing force, tensile strenght ans volume destruction energy were the highest with usage of Avicel 103 and then descending through Avicel 301, sorbitole, pearlitole and saccharose. Tensile strenght was descending in order:...
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Determining the compression behaviour of celluloses.
Ondrejček, Pavel ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
Mechanical resistance of tablets is usually described by crushing force, or by tensile strength. Method used in this thesis records crushing force and path of crushing. This force-path record can be used to calculate crushing energy. Crushing force, crushing path and crushing energy can be used to calculate other parameters that characterize tablet properties. This thesis uses crushing force, volume crushing force, tensile strength, crushing energy, volume crushing energy and crushing energy related to tablet weight to describe tablets compressed of powdered cellulose, microcrystalline cellulose, hydroxypropylcellulose and lactose monohydrate. Results of this thesis shows descent of tensile strength in this order: microcrystalline cellulose Avicel PH-112, microcrystalline cellulose Avicel PH-101, hydroxypropylcellulose, powdered cellulose and lactose monohydrate. Kinetic characteristics of tablets descent in this order: hydroxypropylcellulose, microcrystalline cellulose Avicel PH-101, microcrystalline cellulose Avicel PH-112, powdered cellulose and lactose monohydrate.
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