|Reader in Particle Technology, Department of Chemical Engineering, Imperial College London|
|EPSRC Manufacturing the Future Early Career Fellow|
|Senior Lecturer, Department of Chemical Engineering, Imperial College London|
|2007-2011||Lecturer, Department of Chemical Engineering, Imperial College London|
|2006||Research Associate, Department of Chemical Engineering, Imperial College London, UK|
|2002-2006||PhD in Chemical Engineering, "Anisotropic Surface Properties of Crystalline Pharmaceutical Solids" Department of Chemical Engineering, Imperial College London, UK|
|1998-2002||B.Eng (Hons), Department of Chemical Engineering, Universiti Teknologi Malaysia, Malaysia|
Principal areas of research:
- Develop approaches to control nucleation and crystallisation of small molecule organic organic solids (polymorphism).
- Develop biocrystallisation as a downstream bioseparation for purification and isolation of biopharmaceuticals
- Study the role of surface properties in processability and manufacturability of powders, including the effect of processing on powder properties.
- Developing methods to experimentally measure powder surface energy heterogeneity and models to determine surface energy distributions.
Area 1: Approaches to Control Nucleation and Crystallisation of Small Molecules
My research group has demonstrated how the interface can be engineered to control crystallisation of polymorphs. The engineered surfaces we prepare have a combined feature of topography and surface chemistry. In this area of work, a polymorphic occurrence domain concept, TiPOD concept has been proposed to account for the influence of the interactions at the interface on the crystallisation of polymorphs.
Area 2: Biocrystallisation as a Downstream Separation Step
Progress has been made in the upstream production of biopharmaceuticals, though bottlenecks in downstream separations (DSB) of biopharmaceuticals still remains. Crystallisation of proteins, including biopharmaceuticals, has evolved to a stage where it is feasible to develop biocrystallisation as a downstream bioseparation for purification and isolation (increasing titer concentrations). Our work has demonstrated a “selective nucleation” concept, and coupled with flow crystallisation, can allow for the development of continuous biocrystallisation as an alternative to conventional DSB.
Area 3: Surface Properties in Processability and Manufacturability
A crystalline particle is typically assumed to be spherical and isotropic in surface properties. My work has demonstrated the highly facet specific properties of crystalline solids (anisotropic), evidenced experimentally for the first time for pharmaceutical solids. This area of work leads to an insight into the effect of processing (eg milling, crystallisation) on powder properties, the impact on processing (eg seeding, granulation, drying), and on the product performance (dissolution rate, fine particle fraction).
Area 4: Surface Energy Heterogeneity
My research here has developed approaches to determine powder surface energy heterogeneity and thermodynamics models to describe the surface energy site distribution. This gas chromatographic based technique is a more robust approach and provides a more complete description of the powder surface energy.
Shah UV, Williams DR, Heng JYY, 2012, Selective Crystallization of Proteins Using Engineered Nanonucleants, Crystal Growth & Design, Vol:12, ISSN:1528-7483, Pages:1362-1369
et al., 2011, Effects of Oscillatory Flow on the Nucleation and Crystallization of Insulin, Crystal Growth & Design, Vol:11, ISSN:1528-7483, Pages:4353-4359
et al., 2010, Influence of fines on the surface energy heterogeneity of lactose for pulmonary drug delivery, International Journal of Pharmaceutics, Vol:388, ISSN:0378-5173, Pages:88-94
Ho R, Wilson DA, Heng JYY, 2009, Crystal Habits and the Variation in Surface Energy Heterogeneity, Crystal Growth & Design, Vol:9, ISSN:1528-7483, Pages:4907-4911