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