Wetting of binary powder mixtures.

The wetting process involved when a liquid droplet comes into contact with a mixture of particles is a complex phenomenon which is often understood by reference to Cassie-Baxter theory. However, various authors have applied the Cassie-Baxter theory for the prediction of contact angles on two-component mixtures without success. We hypothesise that the main difficulty in applying the Cassie-Baxter theory to mixtures is that if the particles differ in size, it is possible for the small particles to coat the large particles, so reducing the available surface area of the large particles.

Implementation of an online thermal imaging to study the effect of process parameters of roller compactor.

During roller compaction, not only the properties of the primary powder affect the product quality but also the process parameters. Any change in the process parameters during roller compaction will result in changing the properties of the ribbon. In this study, the temperature of the ribbon during production was monitored online using a thermal camera.

Investigating the effect of processing parameters on pharmaceutical tablet disintegration using a real-time particle imaging approach.

Tablet disintegration is a fundamental parameter that is tested in vitro before a product is released to the market, to give confidence that the tablet will break up in vivo and that active drug will be available for absorption. Variations in tablet properties cause variation in disintegration behaviour. While the standardised pharmacopeial disintegration test can show differences in the speed of disintegration of different tablets, it does not give any mechanistic information about the underlying cause of the difference.

Roller compaction: Effect of relative humidity of lactose powder.

The effect of storage at different relative humidity conditions, for various types of lactose, on roller compaction behaviour was investigated. Three types of lactose were used in this study: anhydrous lactose (SuperTab21AN), spray dried lactose (SuperTab11SD) and α-lactose monohydrate 200M. These powders differ in their amorphous contents, due to different manufacturing processes.

Twin screw wet granulation: Effect of process and formulation variables on powder caking during production.

This work focuses on monitoring the behaviour and the mass of the built up/caking of powder during wet granulation using Twin Screw Granulator (TSG). The variables changed during this work are; powder (α-lactose monohydrate and microcrystalline cellulose (MCC)), the screw configuration (conveying and kneading elements) and the weight percentage of hydroxypropyl-methyl cellulose (HPMC) dissolved in the granulation liquid (i.e.

Roller compaction: Effect of morphology and amorphous content of lactose powder on product quality.

The effect of morphology and amorphous content, of three types of lactose, on the properties of ribbon produced using roller compaction was investigated. The three types of lactose powders were; anhydrous SuperTab21AN, α-lactose monohydrate 200 M, and spray dried lactose SuperTab11SD. The morphology of the primary particles was identified using scanning electron microscopy (SEM) and the powder amorphous content was quantified using NIR technique.

Roller compactor: The effect of mechanical properties of primary particles.

In this study, the nano-indentation hardness of a single primary particle was measured for six different materials; microcrystalline cellulose, hydroxypropyl methylcellulose, maltodextrin, lactose, sodium carbonate and calcium carbonate. This was linked to the properties of the ribbons produced by roller compactor at different hydraulic pressures in the range of 30-230 bar. The main investigated ribbon properties were strength, porosity and width.

Twin screw wet granulation: Binder delivery.

The effects of three ways of binder delivery into the twin screw granulator (TSG) on the residence time, torque, properties of granules (size, shape, strength) and binder distribution were studied. The binder distribution was visualised through the transparent barrel using high speed imaging as well as quantified using offline technique. Furthermore, the effect of binder delivery and the change of screw configuration (conveying elements only and conveying elements with kneading elements) on the surface velocity of granules across the screw channel were investigated using particle image velocimetry (PIV).

A mechanistic model for amorphous protein aggregation of immunoglobulin-like domains.

Protein aggregation is associated with many debilitating diseases including Alzheimer's, Parkinson's, and light-chain amyloidosis (AL). Additionally, such aggregation is a major problem in an industrial setting where antibody therapeutics often require high local concentrations of protein domains to be stable for substantial periods of time. However, despite a plethora of research in this field, dating back over 50 years, there is still no consensus on the mechanistic basis for protein aggregation.

Twin screw granulation: steps in granule growth.

The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying powder feed rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated.

An investigation of the influence of process and formulation variables on mechanical properties of high shear granules using design of experiment.

Being able to predict the properties of granules from the knowledge of the process and formulation variables is what most industries are striving for. This research uses experimental design to investigate the effect of process variables and formulation variables on mechanical properties of pharmaceutical granules manufactured from a classical blend of lactose and starch using hydroxypropyl cellulose (HPC) as the binder. The process parameters investigated were granulation time and impeller speed whilst the formulation variables were starch-to-lactose ratio and HPC concentration.