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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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