|
|
Influence of lubricants on viscoelastic parameters of compaction process
Svačinová, Petra ; Rabišková, Miloslava (advisor) ; Kubová, Kateřina (referee) ; Zámostný, Petr (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department Pharmaceutical technology Candidate Mgr. Petra Svačinová Supervisor Prof. PharmDr. Miloslava Rabišková, CSc. Title of Doctoral Thesis Influence of lubricants on viscoelastic parameters of compaction process This thesis deals with an evaluation of lubricant's influence on viscoelastic parameters of compaction process. The force-displacement record and stress relaxation test were used for this evaluation. This study evaluates the viscoelastic parameters on three fillers intended for direct compression, i.e. microcrystalline cellulose Avicel PH-200, lactose Lactochem Fine Crystals and calcium hydrogen phosphate dihydrate Emcompress. Magnesium stearate and modified colloidal silica Syloid were used as lubricants at concentrations of 0.5 % and 1 %. Particle size and shape and specific surface area were determined for all used excipients. Flow properties were studied for individual fillers and also for their mixtures with lubricants. Subsequently, tablets were compressed from fillers and mixtures using force-displacement record and stress relaxation test, and viscoelastic parameters were evaluated. The applied compression forces for both methods were 5 kN, 10 kN and 15 kN. The hardness of tablets was measured. The results show...
|
|
|
The influence of the die size on the compaction process
Marcinková, Nikola ; Ondrejček, Pavel (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradci Králové Department of: Department of Pharmaceutical Technology Consultant: Mgr. Pavel Ondrejček, Ph.D. Student: Nikola Marcinková Title of Thesis: The influence of the die size on the compaction process This diploma thesis is focused on exploration the influence of the die size on the compaction process. That was evaluated by parameters of three-exponential equation. Compressibility was studied by using force-displacement record. In this work was also observed an effect of die size on the tensile strength. In processing the experimental part of this work were used four different model materials. Microcrystalline cellulose and dicalcium phosphate are used as model fillers and theophylline and paracetamol as model active substances. Compaction of these materials was carried out in dies of size 7 mm, 9 mm, 11 mm, 13 mm and 15 mm. The results of the work showed that the die size significantly affects all parameters force-displacement record. With the growing size of the die there was a reduction of energy parameters. Most of the compaction parameters were statistically influenced. Increasing die size caused reducing volume reduction and energy consumption and increased speed of volume reduction at the stage of pre- compression and elastic...
|
|
|
A study of a novel dry binder composed of α-lactose monohydrate, microcrystalline cellulose and corn starch
Srbová, Alena ; Mužíková, Jitka (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department Pharmaceutical Technology Candidate Mgr. Alena Srbová Consultant PharmDr. Jitka Mužíková, Ph.D. Title of the Thesis A study of a novel dry binder composed of α-lactose monohydrate, microcrystalline cellulose and corn starch This paper deals with a study of the novel dry binder Combilac® , which contains 70 % of α-lactose monohydrate, 20 % of microcrystalline cellulose and 10 % of native starch. These tests include flow properties, compressibility, lubricant sensitivity, tensile strenght and disintegration time of tablets. Compressibility is evaluated by means of the energy profile of compression proces and tablet strenght. The above-mentioned parameters are also evaluated in the physical mixture of α-lactose monohydrate, microcrystalline cellulose and native corn starch and results are compared. Combilac® and physical mixture cannot be compressed without lubricants due to high friction and sticking to the matrix. Combilac® shows much better flowability than the physical mixture of the used dry binders, its compressibility is better and the total energy is higher. Tablets possess a higher tensile strength and higher lubricant sensitivity. Disintegration time of Combilac® tablets is comparable with the disintegration time...
|
|
|
The evaluation of stress relaxation of lactose and calcium hydrogen phosphate mixtures intended for the preparation of tablets with theophylline.
Le, Thanh Tra ; Svačinová, Petra (advisor) ; Ondrejček, Pavel (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: Mgr. Petra Svačinová, PhD. Student: Le Thanh Tra Title of Thesis: Evaluation of stress relaxation of mixtures of lactosum and calcii hydrogenphosphate for preparation tablets with theophylline This thesis studies viscoelastic behavior of fillers and tensile strength of tablets with theophylline. Used material are described in theoretical part: Laktosum SpheroLac 100, microcrystalline cellulose Comprecel 102, calcium hydrogenophosphate anhydrate Di-Cafos A150, calcium hydrogenophosphate dihydrate Di-Cafos D160, theophylline and magnesium stearate. Thesis also describes the stress relaxation test, methods of evaluation and it's application. Experimental part evaluates viscoelastic behavior and tensile strength through the test of stress relaxation with maximal compression force 10 kN and dwell time 180 s. The tensile strength of tablets is also evaluated. Experimental part evaluates parameters of elasticity Ai and plasticity Pi, which were obtained from the test of stress relaxation. It evaluates effect of different fillers on these parameters. The highest values were measured at mixtures E (Spherolac 100 a Comprecel 102), further at mixtures D (Spherolac 100 a Di-Cafos A150) and...
|
|
|
The evaluation of the influence of lubricants on the compaction process of tableting mixtures with microcrystalline cellulose
Motlová, Tereza ; Svačinová, Petra (advisor) ; Ondrejček, Pavel (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Consultant: PharmDr. Petra Svačinová, Ph.D. Student: Mgr. Tereza Motlová Title of Thesis: Evaluation of the influence of lubricants on the compaction process of tableting mixtures with microcrystalline cellulose This thesis evaluates the influence of various lubricants on the compaction process of tableting. Microcrystalline cellulose Avicel® PH 102 was used as filler. This cellulose was mixed with 2 % of magnesium stearate, Aerosil® 200, Syloid® AL-1 FP and Syloid® 244 FP EU, respectively. The evaluation was carried out using a compaction equation and stress relaxation tests. Parameters for evaluation of compaction equation were obtained by calculation from three-exponential equation. It is possible to determine the different phases of the compression process, its mechanism or to evaluate the compressed material using these parameters. The compression process is divided into three phases - pre-compression phase, the phase of elastic deformation and plastic deformation phase. The results show, that all lubricants accelerate the first stage of rearrangement of the particles and also the phase of elastic deformation. The speed of volume reduction in the phase of plastic deformation is similar...
|
|
|
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...
|
|
|
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 %).
|
|
|
A study of co-processed dry binders with lactose and microcrystalline cellulose.
Nezbedová, Andrea ; Mužíková, Jitka (advisor) ; Svačinová, Petra (referee)
The thesis compares two coprocessed dry binders with identical content MicroceLac® 100 and DisintequikTM MCC 25. The substances content α-lactose monohydrate and microcrystalline cellulose in the same ratio 3:1. They were evaluated from the aspect of powder's properties, compressibility and mechanical properties of compressed tablets (tensile strength and disintegration time). The influence factors were the compression force and the addition of the lubricants magnesium stearate and sodium stearyl fumarate in 1 % concentration. DisintequikTM MCC 25 showed higher flowability and higher bulk and tapped density than MicroceLac® 100. The value of all evaluated energies increased with compression force, but the plasticity decreased. MicroceLac® 100 indicated higher values of total energy of compression and energy of friction. DisintequickTM MCC 25 showed higher values of plasticity energy, energy of compression and plasticity. The elasticity energy was comparable in both substances. The addition of lubricants didn't affect the tested energies or plasticity. The tensile strength and the disintegration time increased with compression force. The tensile strength of tablets from both coprocessed dry binders was almost identical and was reduced by lubricants. The disintegration time was significantly longer...
|
|
|
A study of the compaction process and the properties of tablets from different types of calcium hydrogen phosphate.
Koryťáková, Lenka ; Mužíková, Jitka (advisor) ; Svačinová, Petra (referee)
The thesis evaluates anhydrous and dihydrate calcium hydrogen phosphate from the view point of the tensile strength, disintegration time of tablets depending on the compression force. Two firm products - Anhydrous Emcompress® and Di-Cafos® A 60 are used as anhydrate and Emcompress® is used as dihydrate. A compression force together with lubricants (magnesium stearate, sodium stearyl fumarate) and an addition of microcrystalline cellulose (Vivapur® 102) are the influential factors. In addition to the characteristics of tablets, the energy balance of compression is also evaluated. Used compression forces were 12, 16 and 20 kN. The compression force 12 kN was used for the mixtures containing Vivapur® 102. Total energy of compression, energy for friction and energy accumulated by tablet after compression increased with compression force. The highest values were at Anhydrous Emcompress® , an addition Vivapur® 102 increased these values. There weren't more significant differences among the values of decompression energy. Plasticity decreased with the growing compression force, the highest values were at Anhydrous Emcompress® , Vivapur® 102 increased that. Tensile strength increased with compression force, Emcompress® provided the strongest tablets, Di-Cafos® A 60 provided at least strong tablets. Vivapur...
|
|
|
A study of the compaction process and the properties of tablets containing microcrystalline cellulose and colloidal silicon dioxide
Louženská, Markéta ; Mužíková, Jitka (advisor) ; Svačinová, Petra (referee)
The thesis deals with the comparison of compressibility and properties of tablets containing silicified microcrystalline cellulose and physical mixtures of microcrystalline cellulose with different types of colloidal silicon dioxide. The used excipients were silicified microcrystalline cellulose Prosolv® SMCC 90, microcrystalline cellulose Avicel® PH-102 and colloidal silicon dioxide Aerosil® 200 and 255. Tablets were compressed at three compression forces 2.5, 3 and 3.5 kN. The energy profile of compression, the tensile strength of tablets and the disintegration time of tablets were evaluated. The effect of 1 % magnesium stearate on these parameters under various mixing conditions and its homogenity in the tablet were evaluated. Total energy of compression increased with the growing compression force, it was the highest at Prosolv® SMCC 90. Plasticity decreased with compression force, mixtures of Avicel® PH-102 with both types of Aerosil showed its the highest values. These mixtures provided tablets with lower strength than Avicel® PH-102 and Prosolv® SMCC 90. Disintegration time of tablets increased with the growing compression force and it was longer in the case of tablets from Prosolv® SMCC 90 and Avicel® PH-102. The addition of magnesium stearate decreased tensile strength of tablets most in...
|
guest ::
