Multi-scale solids processing in Pharmaceuticals, batch to continuous
Special Symposium - EPIC-1: European Process Intensification Conference - 1
EPIC-1: Poster Session (EPIC - Poster) - P2
Keywords: Multiscale processing, process intensification, solids processing, pharmaceuticals, batch to continuous
The IMPULSE project [1] aims at effective, targeted integration of innovative process equipment such as microreactors, compact heat exchangers, thin–film devices and other micro and/or meso-structured components, to attain radical performance enhancement for whole processes, thereby contributing to significant improvements in supply–chain sustainability for the chemical industry.
Solids processing plants in pharmaceuticals face many operational problems. The need for short time to market and lack of full understanding of phenomena at particle and bulk solids scales have resulted in the domination of batch or semi batch modes of operation. The pharmaceutical industry is highly regulated and receives extensive regulatory oversight by relevant authorities. This has increasingly focussed on process robustness and understanding. As a result of this, as well as the potential for significant performance improvements, there is a strong desire in the industry to move to continuous manufacturing processes.
Relatively little has been done on the process system engineering of pharmaceutical solids processes, despite the economic significance of solid dosage forms. The approach within IMPULSE has been to bring more science into the field in order to establish useful links between various relevant length-scales, i.e. from plant size down to particle size. This presents an alternative to the use of past experience and rule-based algorithms that are much prevalent in the field for the “design” of processes. It is also valuable in the identification of opportunities to move from batch to continuous processing.
In this work, underlying physics of solids handling and processing as well as algorithms of solids processing synthesis were studied; the IMPULSE philosophy was applied to equipment selection and design. A new methodology is proposed in which various critical decision-making steps in each unit should be identified and relevant product specifications, operating conditions, parameters and solids properties and behaviours are linked to those steps, as below (input data are in brackets). More sub-steps might be required between steps 4 and 5 and back itteration may be required between steps.
1) Identifying fundamental parts of equipment and the sequence of each part in design/selection (Specified duty or duties)
2) Identifying parameters influencing decision making for each part of the equipment (Feed data, Product specification, constraints of the process/operation; Physical and chemical properties of the materials)
3) Linking the parameters and underlying science to create knowledge for decision making (Feed data, Product specification, constraints of the process/operation; Physical and chemical properties of the materials)
4) Gathering more data, identifying possible experiments as well as controlling parameters (to push for multi-time/scale approach)
5) Overall equipment selection and design (available knowledge on equipment, business, SHE, etc.)
The conceptual model above (excluding the fifth step) was applied to equipment selection and design of a drying process, leading to better understanding of the process, linking various length scales, delivering more precise conditions to the materials and revealing the opportunities for process intensification, continuous operation etc.. This approach also enables a designer to specify a dryer which is not already available “on the shelf”, opening the possibility of targeted innovation in the field.
Major gaps in multi-scale approach to solids processing synthesis were identified. Solids handling and flowability in equipment as well as between units are major key areas to explore, and also crucial to the move from batch to continuous operation. Finally, novel suggestions were made to tackle the gaps.
------------------------
[1] This research is a part of the EU FP6 IMPULSE (Integrated Multi-scale Process Units with Locally Structured Elements) project. http://www.impulse-project.net/
Presented Thursday 20, 13:30 to 14:40, in session EPIC-1: Poster Session (EPIC - Poster) - P2.
