(JOHN-FOXX/GETTY IMAGES)

Continuous processing is not a new concept. Outside of the pharmaceutical industry, in the petrochemical, chemical and food industries, for example, companies have been steadily switching their manufacturing operations to continuous processes, primarily for cost and quality purposes. The pharmaceutical industry has, however, been slower off the mark. Although there is a rising interest in the continuous processing concept, the industry, which is synonymous with batch manufacturing procedures, has been reluctant to take the leap. The typical 'watch and wait' approach that is often seen in the pharmaceutical industry, coupled with the reluctance to invest in new technologies, processes and personnel training are primary reasons for this lethargy. With manufacturers coming under increasing and continuing pressure to reduce costs and increase efficiencies, however, the appeal of continuous processing technologies is most certainly on the up.

To gain some insights into the industry's current view of continuous processing, to understand the challenges and the rewards of implementing continuous processing technology, and to gauge some opinion on its future role in pharmaceutical manufacturing, Pharmaceutical Technology Europe conducted a roundtable meeting of experts in the field.

Q. PTE: In your opinion, has continuous processing been sufficiently proven to improve manufacturing efficiency and reduce costs? If so, why is the pharmaceutical industry being so slow to adopt the technology?

Kevin Nepveux

Nepveux (Pfizer): Continuous processing has been proven in high volume applications where capital investment avoidance and/or incremental productivity improvements carry significant value. In the drug product arena, there have been fewer examples where continuous processing was employed because it affords improved quality or functionality to the product or process. In the drug substance arena, there are more examples where continuous processing supports chemistries that are more effective than in batch mode.

Schoeters (GEA): Continuous processing techniques are not so uncommon in the pharmaceutical industry as one seems to think. Certain unit operations, such as tabletting or roller compaction, are in fact continuous operations, which are handled in a batch fashion. Similarly, we believe that certain technologies have been successfully proven to manufacture more efficiently and reduce costs compared with traditional batch systems.

I believe there are a number of reasons why the industry has been quite slow to adopt the technology:

• General concerns about start-up and shutdown and waste related to these phases.
• Perception on limited use, for example, that it is only suitable for large volumes.
• Regulatory concerns.
• Installed base of existing (older) equipment in many companies, causing them to question why they should change.

All of the abovementioned concerns are, however, not an issue with certain continuous processing technologies. Further, switching from traditional processes in general does not lead to a big regulatory impact.

Weiler (SAFC): Continuous processing (including Simulated Moving Bed or SMB) has been shown to improve efficiency by generating less waste through solvent recycling, producing better volumetoyield ratios and, in most cases, it is more energy efficient. In addition to these economic improvements there are exciting examples of reactions that can be performed using continuous processing technology, such as fluorinations, direct oxidations, azideforming reactions, copperorganic chemistry, which have been impossible to scaleup in batch mode without dedicated expensive installations.

Further, all major pharmaceutical companies have been using classical continuous processing technologies for decades and today most of them are active in the field of multipurpose continuous flow process research. However, as the pharmaceutical industry is highly regulated, and most projects are covered by confidentiality, many applications are not immediately visible. We are convinced that in 5–10 years we will see a lot more continuous processes implemented.

Whitfield (Inprotech): Continuous processing is well established in other industries, such as food & drink, personal care & cosmetics, petrochemical, chemicals and household detergents, and is proven to significantly improve manufacturing efficiency and reduce costs, but it is much less demonstrated in the pharma sector. The theories point to similar efficiency improvement and cost reduction benefit potential, substantiated by pockets of successfully implemented continuous processing within the pharma industry, both within primary (API) and secondary (drug product) manufacturing. A greater level of adoption is still required before we can truly state that continuous processing has been sufficiently proven in our industry but the signs are nonetheless very encouraging.

There are many regulatory, technological, economical and philosophical based reasons for the slow adoption of continuous processing within the industry but fundamentally we should not forget an important fact. The key enabling technologies, which now make it possible to manufacture pharmaceutical products with the required high levels of process understudying, control and demonstrable capability, at the most optimum scale (throughput) for the majority of business needs, did not exist until relatively recently. That said the industry has undoubtedly been slow to embrace these evolving technologies and adopt continuous processing.