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Physico-chemical characteritazion of microcrystalline celluloses
Gregor, Stanislav ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Charles Univerzity in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Student: Mgr. Stanislav Gregor Supervisor: Doc. RNDr. Milan Řehula, CSc. Physico-chemical characteritazion of microcrystalline celluloses Microcrystalline cellulose is very important pharmaceutical excipient. The aim of the study was to evaluate the different types by using physico-chemical charakteristics. Particle size was evaluated by optical microscopy. The flow properties were evaluated by flowability and by the angle of repose. Bulk and tapped properties were evaluated by bulk and tap density and by compressibility index. Temperatute and heat of fusion, glass transitive temperature and specific heat improvers were evaluated by DSC. Compaction process was evaluated by compaction equations, stress relaxation test and record the force-displacement. The compressed tablets were evaluated by kinetics crushing tablets and had fixed radial strength. Particle sizes correspond to the declared values stated by the manufacturer. The largest deviation was found for Avicel PH-200 (difference 20,0 mm). With increasing particle size reduces fiction between particles and increases the flowability. The tapped density is higher than the bulk density and the copies. From the results of three- exponential...
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Characterization of Compaction Process According to New Equation Parameters of Compaction
Rysl, Tomáš ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee) ; Rabišková, Miloslava (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department: Department of galenic pharmacy Candidate: Mgr. Tomáš Rysl Supervisor: doc. RNDr. Milan Řehula CSc. Title of Doctoral Thesis: Characterization of compaction process according to new equation parameteres of compaction. The thessis deals with comparation of excipients used for production of tablets using new equations of tablet compaction. A lot of mathematical interpretations exist for determination of excipient behaviour during compaction process of tablet production. Obtained parameters of them express more or less possible behaviour of these excipients during compaction. The new mathematical interpretation was proposed for crystallic and polymeric materials. It seems to be very exact method to express compation process very correctly. 40 materials was evaluated according to this new proposed equation of compaction. Zwick/Roell Z050 was used to obtain this equation. Different behaviour of polymeric and crystallic materials has been found out. Behaviour of crystallic materials is interpreted by 2 phases, expressed by biexpoinencial equation. Behaviour of polymeric materials is interpreted by 3 phases, expressed by triexponencial equation. According to obtained paramateres, excipients have been described in term of...
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Compressibility of the powder mixture with microcrystalline cellulose.
Hrdinová, Petra ; Řehula, Milan (advisor) ; Ďoubal, Stanislav (referee)
Compressing process can be evaluated by the parameters that are acquired from the record of force-run, stress relaxation or compaction equation. Compac- tion equation expresses the dependency on height, volume or density compression moulded material by pressure. In these thesis is pressing process characterized by parameters of compaction equation. Original Heckel equation declared range of pressing pressures, which caused plastic deformation of materials. Simultaneously pressed material is characterized by rate constant, expressing the rate of reduction of material in the plastic deformation. In these thesis is used triple - exponential equation, which was created at the Department of Pharmaceutical Technology and which is based on Cooper-Eaton equation. In a comparison between the Cooper- Eaton equation, the triple-exponential equation is not based on genuine values of density and detailed interpretation of the meaning of individual parameters. These thesis evaluates the granulate produced from a mixture of lactose monohydrate and microcrystalline cellulose and starch in mixtures where the microcrystalline cellulose is added at the concentration of 10, 20, 30, 40 %. The work results showed that with increasing reduction of volume, at the same time increases the volume of energy consumption 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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Evaluation of compressibility of acetylsalicylic acid
Pavelková, Petra ; Řehula, Milan (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Petra Pavelková Consultant: Doc. RNDr. Milan Řehula, CSc. Evaluation of compressibility of acetylsalicylic acid The aim of this thesis was evaluation of stability of acetylsalicylic acid from crystallographic aspect during compression process and to determine compressibility of this medical substance in the same time. For this purpose it was performed measurement of differential scanning calorimetry in range from - 30 žC to 220 žC by a speed of heating 10 žC/min. and cooling - 20 žC/min.. Further, the compaction equation, force-displacement record at compression forces ranging from 5 to 40 kN, and the stress relaxation at compression forces of 5, 10 and 15 kN were used. Measurement took place in specific conditions, which are described below. The experimental results showed following conclusions: The relation between the parameter E3 and compression force (LS) is non- linear and described by the equation: ESD3 = 0,086 LS + 0,013 LS2 - 0,211 R2 = 0,9999 The relation between plasticity and compression force (LS) is also non-linear and described by the equation: Pl = - 3,603 LS + 0,049 LS2 + 85,506 R2 = 0,9903 Values of the parameter PL show that ASA has a poor compressibility. At a...
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Evaluation of compressibility of ibuprofen
Kolarczyková, Barbora ; Řehula, Milan (advisor) ; Svačinová, Petra (referee)
The aim of this study is to determine whether dissociation and a change of crystal modification of ibuprofen do not arise during the compression process. For this purpose an evaluation by means of equation of compression, evaluation by stress relaxation, evaluation by force-distance diagram and evaluation by differential scanning calorimetry is accomplished. The equation of compression developed by department of pharmaceutical technology describes the process of compression by parameters of three phases: phase before compression, phase elastic and plastic deformation. The test of stress relaxation was performed at compression force of 5, 10 and 15 kN. During the evaluation of a force-distance record phase of compression and relaxation of tablet was examined from energetic point of view at compression force of 5, 10, 15, 20, 25, 30, 35, 40 kN. These tablets were also evaluated by means of differential scanning calorimetry. Two basic conclusions arise out of the measured results: during the compression process dissociation or modification of crystal form if ibuprofen and simultaneously low plasticity of medicinal substance was found out (at compression force of 15kN plasticity was only 47 %).
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Determination of optimal compression force and speed of compression for the production aciclovir tablets
Vlachová, Hana ; Řehula, Milan (advisor) ; Ondrejček, Pavel (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Student: Vlachová Hana Consultant: Doc. RNDr. Milan Řehula, CSc. Determination of optimal compression forces and speed of compression for the production of aciclovir tablets. This thesis deals with the characterisation of impact compression process on hardness of the tablets. The theoretical part of the thesis describes the effective substance - aciclovir. It also describes compression equations which explain process of compression and factors influencing terminal weight and hardness of tablets. The aim of the experimental part of the work is to measure physical properties of the tablets and find compression forces and speed of compression which are suitable for compression tablets. Tablets were pressed using Kilian Synthesis 700 machine at six compression forces in the range from 4 kN to 14 kN. The height, weight and hardness of each tablet were measured immediately after dressing and note to help for later calculation. The result of the study was to determine the impact of compression forces and compression speed on tablet hardness and weight. Tablet weight decreses with increasing comppession forces. Hardness increases with increasing compression forces. The range of radial hardness...
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Evaluation of compressibility of paracetamol
Šorf, Aleš ; Řehula, Milan (advisor) ; Ondrejček, Pavel (referee)
The objective of this work was to evaluate the compressibility of paracetamol by determination of compression and viscoelastic properties of the active substance and also to detect eventual changes in crystal modification of the substance during the compression process. The parameters of the compression equation were determined using tree-exponential equation developed at the Department of pharmaceutical technology. Mutual interactions between particles were also studied by stress relaxation test using compression forces 5, 10 and 15 kN, as well as energetic parameters of a force-distance record using compression forces from 5 to 40 kN. Tablets made in the last mentioned test were used as samples for DSC analysis to seek potential changes in the crystal structure of paracetamol when undergoing the compression process. The evaluation of the executed tests suggested that compression ability of paracetamol in basic form I is very poor and its plasticity when being compressed by commonly used pressures is about 50%, which is considered as very low. It was also found out that any crystal structure changes of the active substance did not occur during compression.
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Physico-chemical characteritazion of microcrystalline celluloses
Gregor, Stanislav ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Charles Univerzity in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Student: Mgr. Stanislav Gregor Supervisor: Doc. RNDr. Milan Řehula, CSc. Physico-chemical characteritazion of microcrystalline celluloses Microcrystalline cellulose is very important pharmaceutical excipient. The aim of the study was to evaluate the different types by using physico-chemical charakteristics. Particle size was evaluated by optical microscopy. The flow properties were evaluated by flowability and by the angle of repose. Bulk and tapped properties were evaluated by bulk and tap density and by compressibility index. Temperatute and heat of fusion, glass transitive temperature and specific heat improvers were evaluated by DSC. Compaction process was evaluated by compaction equations, stress relaxation test and record the force-displacement. The compressed tablets were evaluated by kinetics crushing tablets and had fixed radial strength. Particle sizes correspond to the declared values stated by the manufacturer. The largest deviation was found for Avicel PH-200 (difference 20,0 mm). With increasing particle size reduces fiction between particles and increases the flowability. The tapped density is higher than the bulk density and the copies. From the results of three- exponential...
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Possibilities for in-vitro testing of controlled-release parenterals.
Kožák, Jan ; Řehula, Milan (advisor) ; Rabišková, Miloslava (referee)
The objective of this study was to start with the development of a gel-based medium simulating intramuscular environment for in-vitro drug release testing as an alternative to currently used water-based media. A pork meat was selected as a model of the muscle tissue. At the first part of the study, diffusion rate was proposed as the most determining factor of drug release in gel-based medium. Consequently, the diffusion rate of sodium fluorescein in pork meat was compared with the diffusion rate in various gels, namely gelatine, calcium alginate and different grades of hydroxypropyl methylcellulose (HPMC). The measurments were performed at 37řC with respect to recomendations for drug dissolution testing and in- vivo temperature. Gelatine however underwent a gel-sol transition at 37řC regardless to polymer concentration and showed to be unsuitable for measurement by selected method. The diffusion rate of fluorescein in all used gels was higher than the diffusion rate in the meat. Only 25% HPMC (Methocel E4M grade) showed acceptable similarity to meat, in terms of the diffusion rate, and was consequently selected for the second part of the study. In the second part of the study, the release of ibuprofen from ethylcellulose implants (ethylcelulose : ibuprofen weight ratio 9:1) in pork meat and 25%...
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