Dr Sarah Rough
M.Phil. ACE Programme Manager
|Qualifications/honours||MEng, MA (Cantab), PhD (DIC)|
|Address|| Department of Chemical Engineering and Biotechnology
University of Cambridge
New Museums Site
CB2 3RA, UK
|Telephone||+44 (0)1223 (3)34772|
My current main research interests lie in the extrusion-spheronisation of pharmaceutical pastes. Many pharmaceutical drugs are administered in the form of a controlled release dose. An effective way of achieving this is by using spherical pellets (about 1 to 2 mm in diameter) of powder/binder. The spheres consist of an excipient, such as lactose or microcrystalline cellulose, and are coated with or contain a small amount of active ingredient. These spheres can be subsequently pressed into tablets or filled into capsules for oral administration. The spheres are usually produced via paste extrusion/spheronisation. Extrudates obtained from a screen extruder are loaded onto a rotating frictional plate and the paste segments are thus broken up and rounded into spherical pellets. It is important that well-formed spheres of narrow size distribution are generated in order to achieve product dose uniformity and reproducibility.
Part of my research looks at the effect of extrudate fracture on the process of spheronisation for water-based microcrystalline cellulose (MCC) pastes. The work shows that the type of fracture occurring during ram extrusion affects the morphology, size and size distribution of the spheronised pellets. By considering the effects of process and design parameters, such as extrusion velocity and die geometry, the mechanisms involved in extrudate fracture can also be alluded to. Thus the processing conditions required to form an extrudate, and hence spheres, of a given quality may be established.
Research keywordsPaste, powder, extrusion, spheronisation
Rough, S.L., Bridgwater, J. and Wilson., D.I. (2000) Effects of liquid phase migration on extrusion of microcrystalline cellulose pastes Int. J. Pharm., 204, 117-126.
Rough, S.L. and Wilson, D.I. (2005) Extrudate fracture and spheronisation of microcrystalline cellulose pastes J. Mat. Sci., 40, 4199-4219.
Murray, T., Rough, S.L. and Wilson D.I. (2007) The effect of drying technique on tablets formed from extrusion-spheronization granules Chem. Eng. Res. Des., 85(A7), p.996-1004.
Wilson, D.I. and Rough S.L. (2007) Extrusion-Spheronisation In “Granulation and Coating of Fine Powders”, AD Salman et al. (Eds.), Elsevier.
Dr Rough has been teaching and researching within the Department since the late 1990s. She is also the Programme Manager for the M.Phil. in Advanced Chemical Engineering