Aspects Concerning the Scale-up

As far as other chemical engineering aspects are concerned, the scaling-up of the newer proposals for a multiphasic operation ought to be scrutinized. Once more, the commercial processes are out of the discussion. All new processes, ionic liquids, SCCO2, and fiuorous systems, should be able to be scaled up without problems. Unless serious developments occur, this seems to be valid also for polymer-bound systems - with the prerequisite of membrane devices for the separation of the products from the composite of polymer and catalyst. Moreover, imdustrial interest in soluble polymer-bound catalysts has been closely linked to the development of membranes with sufficient long-term stability in organic solvents. The discoveries attained with polymer-bound catalysts may fertilize new... 

To summarize, the significant aspects of pharmaceutical scale-up are presented in this book in order to illustrate potential concerns, theoretical considerations, and practical solutions based on the experience of the contributing authors. In no way do we claim a comprehensive treatment of the subject. A prudent reader may use this handbook as a reference and an initial resource for further study of the scale-up issues. 

If the scale-up is performed in the pi-space with variable physical properties, the requirement idem also concerns the form of the dimensionless formulated material function. This aspect can make the choice of the model material system considerably more difficult. This requirement is fulfilled, a priori, only if the interesting range Au in the standard representation w = (u) lies close to the standardization point, see the explanation concerning Fig. 9 b in the text. 

To this point, only the aspects concerning the technical success of the scale-up process have been treated, but it is evident that the final production process will only be successful if the catalyst can be produced in a cost-effective way. Therefore, it is important to select from the first development work the manufacturing routes that can give the lowest cost and concentrate the R D effort accordingly in the future development and test period. The raw material cost normally constitutes 60-80% of the direct cost and, therefore, the selection of raw material is an important task. The initial experiments are perhaps made on analytical... 

We are concerned primarily here with the process filter - its selection and design, and calculations for simulation and scale-up. During preparation of the current text a conscious decision was taken to largely limit the contents to cake filtration. However, although most chapters concentrate on cake filtration, it is not possible to give a balanced account of the practical aspects of filtration without some presentation of other separation techniques. To present information to a similar depth about all of these other processes would have made the book encyclopaedic. While there is certainly a technical need for such a book, or series of books, the authors did not set out to include all solid/liquid separation techniques in the current volume. This should not be seen as an attempt to diminish the importance of depth filtration, crossflow filtration or other solid/liquid separation techniques it is... 

This type of assignment had come to Marco many times before and always caused him concern. Achieving a successful scale-up always requires development of multiple steps that are easy to operate in the laboratory but can be very difficult to translate to manufacturing. In many cases a direct scale-up of the chemists procedure is possible, but in others, mixing differences between large- and small scale equipment result in reduced yield and selectivity. One of Marco s first objectives was to determine the scalability of the new process in each of the reaction, purification, and isolation steps. In order to focus on the mixing issues of interest, the aspects of this process that require feasibility and optimization stndies are not addressed in this discussion. 

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