Fluidized bed processes form an important part of the pharmaceutical industry. Fluidized beds are used for operations such as granulation, spray coating, drug layering and pellet formation. One of the problems associated with the use of the fluidized bed processes is the variability in the quality of products between various batches. It is estimated that 5-10% of the product batches have to be reworked or discarded because they fail to meet the quality standards in some way1. This, and the fact that manufacturing costs are sometimes as high as 40%, in the top pharmaceutical companies, while research costs are below 16%2, points to the fact that the manufacturing processes must be improved in order to decrease costs and achieve the intended quality. This can only be achieved if a detailed understanding of the process is available. This, in essence is also the aim of the PAT initiative of the FDA.

In this talk we highlight how detailed flow modeling techniques can be used as an enabling technology to complement understanding gained from other means. Different modeling techniques are demonstrated on the fluidized bed processes considered in this study. The modeling results help gain insight into the relative effect of the various parameters affecting the quality of the final product. By providing a detailed visual map of the processes in the various sections of the bed, CFD can provide the engineer with insights into the inner workings of his processes, that can otherwise be gained, if at all, by costly experimentation.

REFERENCES. 1. Abboud, L. and Hensley, S., 3-9-2003. New prescription for drug makers: update the plants. Wall Street Journal.

2. Anna Jorgensen, Increasing process understanding of wet granulation by spectroscopic methods and dimension reduction tools, PhD thesis, University of Helsinki, Finland.