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Title: Twin screw granulation : granule property optimisation
Author: Ai, Qing
ISNI:       0000 0004 7233 8641
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2018
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This thesis aims to design granule properties with narrower size distributions and controlled bulk strength through the optimisation of formulation parameters and processing parameters in twin screw granulation with a consideration of binder in solid and liquid forms, respectively. In this thesis, lactose (soluble) and microcrystalline cellulose (insoluble) were chosen as the objective powders. Hydroxypropyl cellulose was used as the main binding excipient. From a perspective of formulation development, a novel approach to predict the optimal L/S ratio for twin screw granulation was developed through the study of single drop behaviour, which reduces the waste from trial and error in formulation development process, in order to producing the granule with narrower size distribution. In addition, the solid binder particle size in formulation was studied. Through evaluating the binding capability of different sized HPC and sieved lactose, it was found that the solid binder with smaller particle size could achieve better binding capabilities which is important on granule size distribution and strength. Moreover, a new solid binder-micronized lactose was evaluated and examined for twin screw granulation. Due to its instant dissolution rate, it was proved to be excellent in binding capability and also leads to a produce of more uniformed granule for both materials. On the other hand, investigations from processing parameter to design the granule properties was also carried out. At first, granulation temperature, especially the liquid temperature was studied. It was found to be effective to enhance the binding capability of HPC in both forms. In addition, more uniformed granule for both material could be obtained when a high temperature applied, especially when HPC solution was used. In addition, process parameters including screw speed and configurations was studied with a constant materials mass in the barrel (Barrel loading, g). This study clarified the effect of process parameter especially screw speed on granule properties which is quite contradictory in the literature. It was found that similar to the use of kneading elements, the screw speed is quite important in narrowing granule size distribution and enhance granule strength especially when kneading elements were used.
Supervisor: Salman, Agba Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available