|
|
Determining the compression behaviour of fillers IX.
Linková, Markéta ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
The process of tablets compression can be described by compression equations. Compression equations express dependence of compressed material volume on compression force. Parameters brought from compression equations are used for compressed material characteristic or for study of compression process mechanism. In this study is evaluated compression process by new compression equations, which have been reveal in Faculty of Pharmacy at Hradec Kralove. There have been used two groups of excipients with different behavior during compression. First group is represented by polymers based on cellulose which have in its structure intapartiular pores. The compression of polymers was carried out in three steps. Interparticular pores, intraparticular pores and solid substance without pores had been reduced. The process of polymers compression was evaluated by the three - exponential equoation. Second group of excipients is crystaline substances in this case has been used lactose. The compression has had two phases. Interparticular pores and solid substance without pores were reduced. Compression process can be evaluated by parameters AR , LTP , E, EP.
|
|
|
Determining the compression behaviour of microcrystalline celluloses.
Coufal, Libor ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
Coufal Libor, diploma paper, June 2009 Tablets are a very expanded dosage form. All new investigation in their technology are worth. While in pharmacopoeial method of measurement of mechanical strength of tablets evaluate by means of the strength at which the tablet breaks. This paper is based on the strength - course record. From this record, it is possible to ascertain other parameters of crushing process, such as the course of crushing, the crushing force and deformation energy. The radial strength, the volume deformation energy and deformation energy related to tablet weight are calculated from them. Tablets prepare from microcrystalline celluloses, hydroxyehylcelulose, powdered lactose monohydrate and substance called PharmDry (maltodextrine) were evaluated by means of these parameters. Results of this thesis shows descent of tensile strength in this order: microcrystalline cellulose Avicel PH-200, microcrystalline cellulose Avicel PH-102, maltodextrine, hydroxyethylcellulose and powdered lactose monohydrate. Kinetic characteristics of tablets descent in this order: microcrystalline cellulose Avicel PH-102, hydroxyethylcellulose, maltodextrine, microcrystalline cellulose Avicel PH-200 and powdered lactose monohydrate. Key words: strength - course record, course of crushing, crushing force,...
|
|
|
Determination of Residual Plasticity in Tablets from Microcrystalline Cellulose
Filipčíková, Michaela ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Determination of Residual Plasticity in Tablets from Microcrystalline Cellulose Michaela Filipčíková, 2007 Abstract Microcrystalline cellulose is an important pharmaceutical excipient. Ceolus KG 802 is one type of microcrystalline cellulose. The aim of this Diploma thesis was the determination of plasticity in tablets from microcrystalline cellulose (Ceolus KG 802) and to valuate the influence of compression force on plasticity. The influence of both a type of microcrystalline cellulose and different compression conditions on the second section of the graph curve showing the relation of the plasticity to the compression force was investigated as well. Test Xpert V9.01, Microsoft Excel and Origin Professional 7.5 were used for processing compaction data. The plasticity was determined from graphs showing the decreasing trend of force on the time. We used methods which were based on identification of maximum and minimum forces and then method which was based on valuation of the area. Considering to uncertainty in the scope of plasticity is the plasticity considered as a residual one. We found that these three methods gave comparable results. We were able to distinguish two sections of the curve from graphs showing the relation of the plasticity to the compression force. The first section characterizes the...
|
|
|
Determination of Plasticity in Tablets from Microcrystalline Cellulose
Křivková, Blanka ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
Determination of plasticity in tablets from microcrystalline celullose Blanka Křivková, 2007 Microcrystalline celullose is widely used as a filler for direct compression. Avicel PH 102 is very often used because of its size of particles (100 μm), appropriate, bulk volume, compressibility. The aim of Diploma thesis was to determine plasticity, to describe influence of the compression force on the plasticity and influence of the type of microcrystalline cellulose and compression conditions on plasticity. The plasticity was determined from graphs showing the decreasing trend of force on the time.Three methods using "one-point" evaluation put into rate value of maximal and minimal forces. The third method evaluate rate of area. These three methods gave comparable result. Two sections of curve from graphs showing the dependence of the plasticity on the compression force can be distinguished. The first one characterized the phase of precompression second one characterized the plastic deformacion of tablets. We can also confirmed the influence of different compression conditions on the second section of the curve. Type of microcrystalline celullose on this section was minimal.
|
|
|
Study of factors influencing weight of oral drops. 2.
Šímová, Sandra ; Šklubalová, Zdeňka (advisor) ; Řehula, Milan (referee)
Ten commercial packages of oral drops with seven different dropper tips have been tested in this thesis. The mass of a drop has been investigated in the dependence on density, surface tension, dynamic viscosity and dispensing angle. Physical and chemical properties of oral formulations influence significantly the dropping ability of dispensing systems as well as the mass of a drop. An explicit dropping condition has been deduced. It formulates relations among characteristic dimensions of the dispensing system, surface tension and density of the liquid. The validity of the dropping condition has been verified for all original commercial packages. A linear relationship between drop mass and viscosity has been determined experimentally; a weak decreasing dependence between necking diameter and viscosity has been found. A combined influence of density and surface tension on diameter of a drop has been explained. The mass of drop decreases significantly when the dispensing angle decreases from 90ř to 70ř. However, the variability of dose increases simultaneously due to wetting of dropper tip and possible formation of bigger drops. A patient should be informed about the necessity to drop the oral formulation upon strictly vertical position. This information has been missing at seven from ten original...
|
|
|
Determining the compression behaviour of microcrystalline cellulose and aluminium stearate
Skopalová, Gabriela ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
This graduation theses delas with determination of compactibility of microcrystalline cellulose and aluminium stearate and their viscoelastic properties during the tablet formation. The force-distance record was used. The theoretical part concerns with characterization of microcrystalline cellulose and aluminium stearate and describes individual evaluation procedures and the influence of single materials to elastic recovery. The aim of experimental part was the determination of compaction pressure to compaction energy, compaction pressure to tablet relaxation and aluminium stearate concentration to compaction energy. Tablets were compacted in the T1 FRO machine, the preload was 2N, speed of preload 2mm/s and cycle rate 2mm/s.
|
|
|
Plasticity in Tablets from Microcrystalline Cellulose
Reich, Filip ; Řehula, Milan (advisor) ; Musilová, Marie (referee)
A study of parameters (power, speed), affect on force - displacement profile, microcrystalline celulose (AVICEL PH - 102® ) and other types of excipients in direct compression 2007, s. 1 - 73 Filip Reich Charles univerzity in Prague, Fakulty of Pharmacy, Institute of Pharmaceutical technology, Heyrovského street 1203, 500 05, Hradec Králové accepted 15th. may 2007 Abstract Compression behaviour, plasticity, of a direct compression excipient, microcrystalline celulose (AVICEL PH - 102), was studied in this work. The compaction property, plasticity, has been acquired with three methods,two procession with the "one-point" plotting, the last one with the "area" plotting. In this work avicel was tableting with slower and more even increase of the compacting power. Yielded results were compared with results from the studies of other laborers, who were solving the same problem by using different compaciton properties, including the speed of tableting 2 mm/s, and using also the same excipients. The acquired plasticity indicated, that these methods gave compareable results. In the force - plasticity profile we can find two apparent slots, the first characterize the phase before the start of compaction, the second one shows the phase of plastic deformation. The character of the force - plasticity curve in the phase...
|
|
|
Study of factors influencing weight of oral drops
Franzová, Pavla ; Šklubalová, Zdeňka (advisor) ; Řehula, Milan (referee)
10 SUMMARY The factors influencing weight of peroral drops were investigated in this dissertation. During this work six commercial available plastic dropper tips for peroral drops and model mixtures of hydrophil solvents were used. It was determined that the most suitable mixture for testing dropper charakteristics (depending on design of dropper tip) was the mixture of five parts of 96% ethanol and ninetyfive parts of purified water or the mixtureof sixty parts of 85% glycerol and forty parts of purified water. The weight of drop was influenced by the diameter of outer orifice of dropper tip. The final weight of drop is also affected by the other charakteristics - inner diameter of dropper part, inner aperture diameter of dropper capilary, design of dropper tip, design of compensatory capilary. The drop weight of mixture of water with glycerol increased with decreasing density of mixture. The reduction of dropper angle from 90ř (vertical) to 45ř (transversal) lead to decisive reduction of drop weight. The uncontrolled wettion of dropper surface by the liquid was observed in some cases. On the base of optimal dispending of peroral drops we should recommend the producer following: there should be the instruction about the right holding of dropper bottle in upright position (upside-down, 90ř vertical)
|
|
|
Viscoelastic properties of microcrystalline cellulose and lactose
Sosvorová, Lucie ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The aim of this work was to evaluate the use of creep test during the compaction of microcrystalline celluloce Avicel PH 102, lactose FlowLac 100 and their mixtures in rates of 75:25, 50:50 and 25:75. Individual substances or mixtures were compressed by compression forces 0,25; 0,5; 1; 2; 3; 4; 5; 7,5; 10 and 15 kN. After the compression of each tablet a report describing the process of compression was procured. These dates were obtained by software connected with compression machine. Obtained relation bethween displacement and time was transfered to the relation bethween parameter J (creep compliance) and time. This relation was finally characterized by four basic parameters: E1 (immediate elasticity), E2 (retardet elasticity), P1 (plasticity) and FP (factor of plasticity). From the results we can see that microcrystalline celluloce Avicel PH 102 compared to lactose FlowLac 100 has lower elasticity and higher plasticity. With the decreasing value of microcrystalline celluloce Avicel PH 102 in the mixture the elasticity is inceased and plasticity decreased. Further was proved, that creep test method is usable in praxis for evaluation of pharmaceutical supplementary substances (fillers) used in the tablet manufacture. This test clearly valued the elasticity and plasticity by way of concrete numerical...
|
|
|
Viscoelastic properties of microcrystalline cellulose of Avicel PH 200
Skálová, Marie ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
In this dissertation the viscoelasticity of the most common excipient microcrystaline celulose was valuated and viscoelasticite parametres were compared to three substances. Viscoelasticity was valuated by two methods..The first method is Creep test. In this analyze the compression force is constant and hold for 180s. During this time height of the tablet was lowered. The diffrences of tablet height was noted and used for calculation in Crčel test. Parameters of elasticity got by this method are FCT1,FCT2 and parameters of plasticity are PCT1,FP. When the parameters of elasticity increase the elasticity decrease. When the parameter FP increases the plasticity increases too. The higher the value of PCT1 is the lower is the plasticity. Stress relaxation is the second method. In this analyze hight of tablet is constant and decline compression force is recorded. In this analyze we noted the decline for 180 sec. In this way we get parameters of elasticity ESR1, ESR2, ESR3 and parameters of plasticity PSR1, PSR2, PSR3. The plasticity increases when parameter P increases. Comparing three substances the elasticity increases in-line Emcompress, Avicel, Flowlac and the elasticity decreases in-line Emcompress, Avicel, Flowlac.
|
guest ::
