Under Continuous Consideration

Continuous manufacturing is increasingly noted as an important long-term objective for the pharmaceutical industry. PTE talks with Tim Freeman, Director of Operations at Freeman Technology, about some of the central issues involved in this transition, as well as the supporting role of relevant analytical technology.
Nov 01, 2011
Volume 23, Issue 11

What do you think are the main factors that explain the current focus on continuous manufacturing?

Tim Freeman
The pressures currently faced by the pharmaceutical industry are well-documented. Time-to-market is a major issue, as is the current health of the drug pipeline. With the time to commercialisation for a new product now estimated at around ten to twelve years, patent cover no longer necessarily provides a lengthy period in which to recoup the steadily increasing costs of R&D (1). Notably, the generics sector is now very active.

This prevailing environment has brought the efficiency of manufacture under much scrutiny. Similarly, the regulatory focus on reducing risk has prompted questions about how well understood manufacturing processes are and how best to secure product quality. Within this context, a shift away from batch operation to continuous processing is seen as increasingly attractive.

Continuous processing is an intrinsically more efficient approach, with a number of benefits:
  • more consistent product quality
  • reduced manufacturing costs
  • easier scale up
  • reduced waste
  • improved asset utilisation
  • lower CAPEX
  • better containment.

That said, batch processing has some advantages too; an important point being that it simplifies the containment and isolation of an operating problem (an essential aspect of product recall). It is likely that some processes may always remain in batch mode rather than transitioning to continuous. This is exemplified by the chemical sector, which continues to successfully apply both strategies.

The scale up process for continuous processing is very different when compared with batch, could you explain some of the advantages?

One major advantage of continuous processing is that scaling up from lab to commercial-scale quantities is usually achieved by simply running the process for a greater length of time. While this may involve the addition of upgraded ancillary equipment, it essentially avoids the complications associated with changes in equipment geometry and size, which can be considerable. Meeting commercial production targets by operating a smaller unit continuously may, therefore, be much more straightforward than the alternative of persisting with batch production and scaling up by a considerable amount.

However, the aspiration of the industry is not just to switch from batch to continuous operation, but, perhaps more importantly, to extend processing knowledge, and to learn how to engineer and precisely control a manufacturing plant so as to achieve the very highest levels of efficiency and quality. This demands an in-depth understanding of those variables that define clinical performance and how to control them—the approach enshrined in quality by design.

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