Improving Solid Dosage Forms With Dry Granulation

Although tablet manufacture is traditionally a batchbased wet granulation process, there are many advantages to be gained by adopting dry granulation, including lower costs and increased yields. The simplicity of dry granulation could also enable it to become one of the main technologies for continuous processing.
Mar 07, 2011
Volume 23, Issue 3

The pharma industry traditionally utilises batchbased manufacturing methods because of traceability requirements to ensure product safety. After several years of establishing new ways of analysing drug variability and quality in various manufacturing process stages (under the PAT initiative), the industry is moving away from conventional batch sampling and analysis to embrace more advanced techniques that analyse consistency in real time. The challenge now is for the industry to take this QbD concept and look at its manufacturing processes in lean terms to adapt for a more efficient future.

Continuous granulation processes

Sidebar 1: Key advances made by new roller compaction systems
Tablet manufacture is traditionally a batch-based wet granulation process. Dry granulation, on the other hand, can be used as a semibatch process but could also emerge as one of the main continuous processing solutions due to its simplicity. There are other forms of dry granulation, but the most commonly used is roller compaction, which is a continuous technology by design that has been significantly further developed in recent years. In particular, a number of important changes have been made that differentiate novel technologies from conventional roller compactors (Sidebar 1).

Combined with PAT techniques, roller compaction can help achieve a continuous granulation process. Depending on the objectives and site PAT strategy, measurements prior to the process can be taken to establish raw material consistency and blend uniformity. Essentially, this will enable a consistent processing window with established boundary limits to be achieved.

Sidebar 2: Terahertz pulsed imaging of pharmaceutical compacts
Sidebar 2 provides an example of PAT analysis data based on the measurement of terahertz wave forms, which are reflected from pharmaceutical roller compactions of various densities. The example demonstrates the potential for the technique as an in-line technology to analyse critical material attributes of compacted ribbons prior to milling to establish increased process understanding.

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