Room for further innovation
Given the way that manufacturing is changing within the industry, real-time, on- and/or in-line instrumentation is becoming
increasingly preferred, where its application is feasible. With respect to granulation, on-line NIR detection for moisture
content measurement and on- or in-line particle size analysis are both commercially available and applied. As BFE has proven
to be a particularly relevant and sensitive tool for monitoring granulation applications, its evolution as an on-line as opposed
to at-line method would be a welcome innovation.
As manufacturers increasingly choose to use BFE as part of the specification for granule properties, it is inevitable that
more published data correlating BFE with tabletting performance will emerge.
The benefits of accurate endpoint determination
As discussed earlier, if we define endpoint by saying "add x litres of granulation solution and process at an impeller speed
of y rpm for z minutes", then each new scale presents a new optimisation challenge because the values of x, y and z will depend
on the scale of the granulation process. If, on the other hand, we can define endpoint in terms of a granule property independent
of scale, then moving from development to full production is easier. Considering the measurement of granule flow properties,
at each stage we are targeting the same BFE as granules made at a small scale that made ideal tablets, rather than using conditions
that work only at that smaller scale. This iterative process to reach acceptable processing conditions is therefore accelerated
at each scale.
Efficient endpoint detection is, of course, essential for consistent product quality. More than that though, it maximises
equipment utilisation, where granulating for just long enough to meet a specification ensures that a unit is not tied up unproductively.
Tim Freeman is Director of Operations at Freeman Technology.
This article is part of a special feature on granulation that was published in the March issue of PTE Digital, available at
http://www.pharmtech.com/ptedigital0311
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