Development and control of pharmaceutical solids using extrusion and granulation

  • Laura Martinez Marcos

Student thesis: Doctoral Thesis


Nowadays, the pharmaceutical industry is seeking manufacturing processes that enable the delivery of high quality medicines with less cost and delivery time. The introduction of flexible manufacturing equipment such as twin-screw equipment can be used for these purposes and be part of a continuous manufacturing platform. Hot-Melt Extrusion (HME) and Twin-Screw Granulation (TSG) are two applications that can be used with the same processing equipment and reduce the number of stages involved in the manufacturing process. In this thesis the use of HME to produce amorphous solid dispersions of the poorly water soluble drug albendazole is investigated. HME enabled the transformation of the drug solid state from crystalline to amorphous by optimised processing parameters and the use of two suitable hydrophilic polymers as carriers. Amorphous solid dispersions showed an increase of albendazole dissolution properties. Differences in drug release rate indicated possible molecular interactions between the drug molecule and one of the polymers studied. Further studies are required to investigate the type of possible interactions. Computed tomography was used to determine the density differences and the internal structure properties of the extruded materials. This thesis studied the impact of screw element design, processing parameters and mechanism behind granule formation in twin-screw wet granulation. The use of conveying elements only achieved a poor liquid distribution due to the low shear applied. Combined screw configurations of mixing and conveying elements resulted in better liquid distribution properties. Excess of fines production was attributed to a breakage mechanism caused by the use of the distributive feed screw. These results can contribute towards the design of space of TSG processes. Overall, this thesis showed that the optimisation of processing parameters in HME and TSG can lead to the enhancement of product properties which would be beneficial for continuous manufacturing platforms.
Date of Award2 Jun 2017
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)
SupervisorGavin Halbert (Supervisor) & Dimitrios Lamprou (Supervisor)

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