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Viscoelastic properties of calcium hydrogenphosphate dihydrate of Emcopress
Hořínková, Pavla ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The important condition for materials compression are their viscoelastic properties. Two methods are used in this work for determination viscoelastic parameters of calcium hydrogephosphate dihydrate - the Creep test and the Stress relaxation test. Both methods provide us with elastic and plastic constants. During the Creep test the compaction pressure is kept constant for 180s and a decrease of tablet height is measured. This tablet decreasing allows us to calculate viscoelastic parameters. The most important result is the factor of total plasticity FPC, which is equal to 0,89441. The greater this value is the better compaction properties the material has. A constant height of tablet is held for 180s in the Stress relaxation test and a decrease of pressure within the tablet is recorded. This pressure decrease is caused by three different processes. The third process is most important for the tablet plasticity and is expressed by the total parameter of third process PSR3C = 328,86916 MPas. Again, the greater this value is the better compaction properties the material has.
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Calculation of elasticity and plasticity of microcrystalline cellulose Avicel PH 103
Reich, Filip ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Calculation of Elasticity and Plasticity of Microcrystalline Cellulose Avicel® PH - 103 Mgr. Filip Reich, Hradec Králové 2008 Avicel® PH - 103, well-known type of microcrystalline cellulose, is an important pharmaceutical excipient. Solid technological forms use to contain Avicel for its ability to reduce addition amount of pharmaceutical powders, tablets especially. Avicel also facilitates tableting of pressing power, this fact is important for therapeutical agents, that are sensitive for high pressure. The aim of this work was the definition and calculation of elasticity and plasticity of microcrystalline cellulose Avicel® PH - 103. The plasticity was determined from the "force - time" profile with three different methods. The first one was based on the proportion of the highest and the lowest pressing force. The second one used "one - parameter" evaluation of the "force - time" profile and the last one was established by using "three - parameter" rate. Further we had to determine Young's modulus, the elasticity character of system. The value equals 100,75023 MPa. From the "plasticity - force" profile we were able to distinguish the all compression phases with eventual progressing changes. Exactly there was the phase of precompression followed by the elastic and then the plastic deformation. This...
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Viscoelastic properties of lactose Flow Lacu 100
Patočková, Simona ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The aim of this work was to obtain viscoelastic charakteristics of one of the most used auxiliary pharmaceutical material. The testing material was lactose Flow Lac 100. Its viscoelastic properties were valued by two tests: Creep test and test Stress relaxation. Plastic properties are necessary to ensure good compressibility of material, whereas elastic properties can make difficulties during a compaction. In the theoretic part I dealt with energy of a tablet compaction. Elastic and plastic energy is acquired from measurement force - displacement, which represents continuance of a compaction process. The process of compaction can be classify into three parts according to the energy consumption: E1 is energy needed to prepressing, E2 is energy used for tablet forming and E3 means energy released from the tablet after compacting. Creep test: tablets were compressed to the defined compacting pressure and this pressure was held constant for a period of 180 s. In process of this period changes in height of a tablet was recorded. The decreasing height of the tablet was used for a determination of parameters of plasticity and elasticity: ECT1C = 72,1235 [s], ECT2C = 0,0117 [s], PCT1C =1,0623.107 [MPa.s], FPCTC =0,4828. Stress relaxation test: tablets were compressed to the defined compaction pressure and...
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Determination of the Kinetics of the Crushing Process of Tablets Containing Acetylsalicylic Acid
Gallová, Zuzana ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Gallová Zuzana- Diplomová práce - 2006 The graduation theses deal with the evaluation of tablet strength. The work uses the record force - displacement . The method determines destructive force and energy of compression. Theoretical part of the work deals with the characterization of granules and tablets, theory of destruction of tablets and parameters of the mechanical resistance of tablets. The aim of the experimental work was the determination of an optimal cycle and the height of preloading. The basic configuration of the pressing operation: test speed 1 mm/s, preload 0.05 N, preloading rate 0.1 mm/s . Commercially produced Acylpyrine tablets were evaluated. It follows from the results that the optimal configuration for the measurement of tablet resistance with T1-FRO instrument is the test speed 0.6 mm/s and higher. Suitable preloading is 0.1N
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Determination of the Kinetics of the Crushing Process of Tablets Containing Paracetamol
Juhaňáková, Jana ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Juhaňáková Jana - diplomová práce - 2006 The diploma theses deal with the measurement of mechanical resistance of tablets on basis of force - displacement record. The new method compared to the classical method characterizes mechanical resistance by means of destruction and destructive energy. Theoretical part of the work describes characterization and distribution of granules and tablets, characterization of additives used for production of tablets. It deals with the starch group in detail as well. The aim the experimental work was the determination of optimal parameters for measurement of the kinetics of destruction of tablets, preloading, rate of preloading a cycle. Commercially produced tablets of Paralen 500 were evaluated. The optimal parameters for the measurement of mechanical resistance of tablets by means of T1 - FRO 50 by differential record method are the following: preloading 0.1 N, preloading rate 0.1 mm/s, cycle rate 1.0 mm/s
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Determination of the Kinetics of the Crushing Process of Tablets Containing Isosorbide-5-mononitrate
Šulková, Petra ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Šulková Petra - diplomová práce - 2006 The diploma theses deal with the determination of optimal parameters for measurement of the kinetics of destruction on basis of force - displacement record. Theoretical part of the work discusses questions of fillers in direct tablet compression. It describes lactose in detail. Besides it describes the methods of evaluation of mechanical resistance of tablets and parameters destructive process. The aim of the experimental work was the evaluation of the destructive process by differential method without zero setting. The minimum value of preloading and cycle rate was to be determined. The tablets of Isosorbit-5-mononitrate were evaluated. The result of the work was the determination of the optimal parameters for the measurement of mechanical resistance of tablets by means of T1 - FRO 50. Minimum value of preloading is 0.1 N, cycle rate and preloading rate 1.0 mm/s. Simultaneously, it was found out that the decrease in force does not influence destructive force, displacement and energy.
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DSC analysis of pharmaceuticals
Zernerová, Alena ; Musilová, Marie (advisor) ; Řehula, Milan (referee)
A DSC calorimeter 200 Phox® was used for measurements of thermal behaviour of Tiaprofenic acid, Salicylic acid, Acetylsalicylic acid, Nimesulid, Phenacetine, Phenazone, Propyphenazone, Tribuzone, and Suppository mass Adeps neutralis.
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Determination of the plasticity of lactose
Juhaňáková, Jana ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Juhaňáková Jana - Rigorózní práce - 2006 This work deals with the determination of tablet plasticity made of Tablettose 70 using stress relaxation method. Theoretical part of the work describes preparation and characterization of the tablets. It deals in detail with the determination of residual plasticity of Tablettose 70, determination of the influence of the dwell time on residual plasticity and on the dependence of residual plasticity on compression force. Plasticity was measured by means of T1 - -FRO 50 device. From the results of the work it follows that the increase in dwell time results in residual plasticity of Tablettose 70. Tablettose 70 has the parameter A 49.679 % and tangent B -13.712% kN-1 .
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Energy of compressing and destructive energy of dry fillers
Červenková, Lucie ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Červenková Lucie - Rigorózní práce - 2006 This work deals with the evaluation of viscoelasticity on basis of force - displacement record. Theoretical part of the work characterizes tablets and fillers for direct compression, discusses the theory of destruction of tablets and presents the parameters of mechanical resistance of tablets. The aim of the work was the following of the influence of the type of a dry filler on displacement of the grinding process and to find out the dependence between the compression parameter E2 and parameter DE. The microcrystalline cellulose Avicel PH 102, mannitol, and lactose were used as fillers. It follows from the results that the destructive displacement in the case of microcrystalline cellulose is significantly longer than those of mannitol and lactose. Absolute or differential methods of record do not influence the destructive displacement. Microcrystalline cellulose in comparison with lactose and mannitol consumes less energy at compression and simultaneously has higher DE. Comparison of mannitol and lactose shows that mannitol consumes more energy at compressions and has also higher value of DE.
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