Advances in Twin-Screw Granulation

Twin-screw granulation (TSG) is a pharmaceutical process that has gained increased interest from the pharmaceutical industry for its potential for the development of oral dosage forms. The technology has evolved rapidly due to the flexibility of the equipment design, the selection of the process variables and the wide range of processed materials. Most importantly, TSG offers the benefits of both batch and continuous manufacturing for pharmaceutical products, accompanied by excellent process control, high product quality which can be achieved through the implementation of Quality by Design (QbD) approaches and the integration of Process Analytical Tools (PAT). Here, we present basic concepts of the various twin-screw granulation techniques and present in detail their advantages and disadvantages. In addition, we discuss the detail of the instrumentation used for TSG and how the critical processing paraments (CPP) affect the critical quality attributes (CQA) of the produced granules. Finally, we present recent advances in TSG continuous manufacturing including the paradigms of modelling of continuous granulation process, QbD approaches coupled with PAT monitoring for granule optimization and process understanding.

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The Influence of Equipment Design and Process Parameters on Granule Breakage in a Semi-Continuous Fluid Bed Dryer after Continuous Twin-Screw Wet Granulation

Pharmaceutics ◽

10.3390/pharmaceutics13020293 ◽

2021 ◽

Vol 13 (2) ◽

pp. 293

Author(s):

Alexander Ryckaert ◽

Michael Ghijs ◽

Christoph Portier ◽

Dejan Djuric ◽

Adrian Funke ◽

...

Keyword(s):

Process Development ◽

Wet Granulation ◽

Major Goal ◽

Drying Time ◽

Process Step ◽

Manufacturing Line ◽

Fluid Bed ◽

Twin Screw ◽

Filling Phase ◽

Twin Screw Granulation

The drying unit of a continuous from-powder-to-tablet manufacturing line based on twin-screw granulation (TSG) is a crucial intermediate process step to achieve the desired tablet quality. Understanding the size reduction of pharmaceutical granules before, during, and after the fluid bed drying process is, however, still lacking. A first major goal was to investigate the breakage and attrition phenomena during transport of wet and dry granules, the filling phase, and drying phase on a ConsiGma-25 system (C25). Pneumatic transport of the wet granules after TSG towards the dryer induced extensive breakage, whereas the turbulent filling and drying phase of the drying cells caused rather moderate breakage and attrition. Subsequently, the dry transfer line was responsible for additional extensive breakage and attrition. The second major goal was to compare the influence of drying air temperature and drying time on granule size and moisture content for granules processed with a commercial-scale ConsiGma-25 system and with the R&D-scale ConsiGma-1 (C1) system. Generally, the granule quality obtained after drying with C1 was not predictive for the C25, making it challenging during process development with the C1 to obtain representative granules for the C25.

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Effects of a Twin-Screw Extruder Equipped with a Molten Resin Reservoir on the Mechanical Properties and Microstructure of Recycled Waste Plastic Polyethylene Pellet Moldings

Polymers ◽

10.3390/polym13071058 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1058

Author(s):

Hikaru Okubo ◽

Haruka Kaneyasu ◽

Tetsuya Kimura ◽

Patchiya Phanthong ◽

Shigeru Yao

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Value Added ◽

Industrial Applications ◽

Twin Screw Extruder ◽

Screw Extruder ◽

Polymer Properties ◽

Wide Range ◽

Twin Screw ◽

Recycled Plastics

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.

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Mechanistic understanding of the effects of process and design parameters on the mixing dynamics in continuous twin-screw granulation

Powder Technology ◽

10.1016/j.powtec.2021.05.071 ◽

2021 ◽

Author(s):

Lalith Kotamarthy ◽

Rohit Ramachandran

Keyword(s):

Design Parameters ◽

Mixing Dynamics ◽

Twin Screw ◽

Mechanistic Understanding ◽

Twin Screw Granulation

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3D Flow Simulation of a Twin-Screw Pump for the Analysis of Gap Flow Characteristics

Journal of Fluids Engineering ◽

10.1115/1.4051730 ◽

2021 ◽

Author(s):

Ali Hassannejadmoghaddam ◽

Boris Kutschelis ◽

Frank Holz ◽

Tomas Börjesson ◽

Romuald Skoda

Keyword(s):

Flow Rate ◽

Volume Flow Rate ◽

Overset Grid ◽

3D Flow ◽

Screw Pump ◽

Pump Performance ◽

Gap Flow ◽

Wide Range ◽

Twin Screw ◽

Pump Head

Abstract Unsteady 3D flow simulations on a twin-screw pump are performed for an assessment of the radial, circumferential and flank gap flow effect on the pump performance. By means of the overset grid technique rigid computational grids around the counter-rotating spindles yield a high cell quality and a high spatial resolution of the gap backflow down to the viscous sublayer in terms of y^+ < 1 . An optimization of the hole-cutting process is performed on a generic gap flow and transferred to the complex moving gaps in the pump. Grid independence is ensured, and conservation properties of the overset grid interpolation technique are assessed. Simulation results are validated against measured pump characteristics. Pump performance in terms of pressure build-up along the flow path through the spindles and volume flow rate is presented for a wide range of spindle speed and pump head. Flow rate fluctuations are found to depend on head but hardly on speed. By a profound assessment of the respective radial, circumferential and flank gap contribution to the total backflow, the importance of the most complex flank gap is pointed out. Backflow rate characteristics in dependence on the pump head and the pump speed are presented.

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Twin screw granulation: Understanding the mechanism of granule formation along the barrel length

Chemical Engineering Research and Design ◽

10.1016/j.cherd.2016.03.008 ◽

2016 ◽

Vol 110 ◽

pp. 43-53 ◽

Cited By ~ 16

Author(s):

Sushma V. Lute ◽

Ranjit M. Dhenge ◽

Michael J. Hounslow ◽

Agba D. Salman

Keyword(s):

Granule Formation ◽

Twin Screw ◽

Twin Screw Granulation

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Sputter Synthesis of Ferroelectric Films and Heterostructures

MRS Bulletin ◽

10.1557/s0883769400046042 ◽

1996 ◽

Vol 21 (6) ◽

pp. 25-30 ◽

Cited By ~ 33

Author(s):

O. Auciello ◽

A.I. Kingon ◽

S.B. Krupanidhi

Keyword(s):

Ion Beam ◽

Random Access ◽

Chemical Vapor ◽

Ferroelectric Materials ◽

Process Technology ◽

Ferroelectric Films ◽

Pyroelectric Properties ◽

Wide Range ◽

High Dielectric ◽

New Generation

Ferroelectric films can display a wide range of dielectric, ferroelectric, piezoelectric, electrostrictive, and pyroelectric properties. The potential utilization of these properties in a new generation of devices has driven the intensive studies on the synthesis, characterization, and determination of processing-microstructure-property relationships of ferroelectric thin films during the last five years. In addition there has been an increased drive for integrating ferroelectric film-based heterostructures with different substrate materials to demonstrate numerous devices that exploit the dielectric, ferroelectric, piezoelectric, electrostrictive, and pyroelectric properties of these materials. For example the high dielectric permittivities of perovskite-type materials can be advantageously used in dynamic random-access memories (DRAMs), while the large values of switchable remanent polarization of ferroelectric materials are suitable for nonvolatile ferroelectric random-access memories (NVFRAMs).Various vapor-phase deposition techniques such as plasma and ion-beam sputter deposition (PSD and IBSD, respectively), pulsed laser-ablation deposition (PLAD), electron-beam or oven-induced evaporation for molecular-beam epitaxy (MBE), and chemical vapor deposition (CVD) have been applied to produce ferroelectric films and layered heterostructures. See References 4–7 for recent reviews. However, work is still necessary to optimize the techniques to produce device-quality films on large semiconductor substrates in a way that is fully compatible with existing semiconductor process technology. Therefore research efforts should be focused on the optimization of suitable process methods and on the investigation of processing-composition-microstructure property relationships. These efforts are the focus of this article with emphasis on PSD and IBSD techniques.

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