MANUFACTURING PROCESS ENVIRONMENTAL CONTROL
Geoff sits at his office PC reviewing data and adjusting setpoints as he monitors the manufacturing process. "Everything looks
good here," he says as Julie walks in. "What do the chart recorders show?"
Jonathan T. Whitney
Julie hands him a pile of charts, and Geoff frowns as he scans the wandering lines on one chart and then on the next. "What's
going on here?" he says. "I tweaked the system after the recordings you gave me yesterday, and now I have even more rooms
out of tolerance."
Trying to be helpful, Julie offers, "I think Bob also tried to make some adjustments."
With growing concern, Geoff looks up. "What did Bob do? This isn't getting better — it's getting worse! Beth in QA is going
to have my head for this!"
Geoff's concern about room conditions is well-founded, as production environments in many cases directly affect manufacturing
processes and product quality, and as such, require calibration and validation. The relevant question is not whether space
conditions are within specification at a given moment, but whether the process is under continuous control and the conditions
Building automation systems (BAS) can deliver that measure of control and documentation. A well-designed and well-implemented
BAS essentially functions as a sub-process of a current good manufacturing practice (cGMP) process. It uses inline acquisition
of critical quality data parameters to provide closed-loop feedback control and analysis of the process of manufacturing a
quality environment with optimum temperature, humidity, pressure, and particle count.
THE PAT APPROACH
The use of a BAS is fully consistent with the Food and Drug Administration new Process Analytical Technology (PAT) Initiative,1 which provides a framework and regulatory guidance for an innovative approach to pharmaceutical manufacturing and quality
assurance. In its simplest terms, PAT is a methodology for designing, analyzing, and controlling manufacturing by using timely
measurements of critical quality and performance attributes of raw and in-process materials. Crucial to a successful implementation
of PAT is a good scientific knowledge of the manufacturing process in which all critical sources of variability are well-understood
and explained, variability is managed by the process, and product quality attributes can be accurately and reliably predicted.
PAT provides a process whereby product quality is a function of process design, not of final testing.
This contrasts with the previous scenario, which is perhaps an extreme example but illustrates a common concern. Geoff's trial-and-error
approach shows lack of understanding of the manufacturing process. To make matters worse, others are making ad hoc, uncontrolled,
and undocumented changes to the process based on end-of-process measurements provided by chart recorders.
PAT charts a course to better process control and more consistent product quality. Outside the heavily regulated pharmaceutical
industry, one can find many settings where PAT is well-accepted. Many industries have evolved from batch processing to continuous
processes that use process analytical technology. Industries such as petrochemical, nuclear power, and steel manufacturing
apply PAT concepts to improve product quality, operate more safely, reduce waste, increase facility utilization, and increase
speed to market.
Building automation systems are another case in which a PAT framework has been used successfully. BAS have been applied with
substantial benefit in numerous industries and are already making strong contributions in pharmaceutical production.