Application of Electrical Resistance Tomography Technology to Pharmaceutical Processes

Francois Ricard1, Clemens Brechtelsbauer1, Chris Lawrence2, Yun Xu2 and Anne Pannier1

1GlaxoSmithKline R&D, Strategic Technologies Department, Old Powder Mills, Near Leigh, Tonbridge, Kent, TN11 9AN, UK, Francois.X.Ricard@gsk.com

2Department of Chemical Engineering and Chemical Technology, Imperial College London, SW7 2AZ, UK

ABSTRACT

Recent developments in the use of non-intrusive, electrical measurements to interrogate mixing processes in batch vessels have triggered a joint GSK / Imperial College project aimed at assessing the applicability of Electrical Resistance Tomography (ERT) to pharmaceutical process development. A jacketed 3.5 L glass reactor was fitted with 64 platinum sensors arranged on 4 planes and linked to an ITS P2000 data acquisition system. Several vessel / stirrer configurations aimed at mimicking typical plant reactor geometries were investigated in connection with typical process scenarios in the pharmaceutical industry. Variations in local and bulk conductivity measurements were monitored, and the data obtained were compared with spectroscopic on-line monitoring information as well as kinetic and computational fluid dynamics modelling results. Very encouraging results were achieved for model and industrial processes. This approach shows promise for on-line control of process mixing performance as well as efficiency evaluation and optimisation of reactor geometries. This allows us to conclude that ERT is a valuable tool for the development of robust manufacturing processes for Active Pharmaceutical Ingredients.

Keywords Electrical resistance tomography, mixing, retreat curve impeller, pharmaceutical