When manufacturers are developing a tablet designed to be scored or subdivided, what tests are necessary to ensure stability?
How does patient compliance factor into these decisions?
Stability raises issues around the mechanical properties of the tablet, for example, can it be broken into two equally useful
doses without crumbling, and is the finished product stable despite the score? Once again, powder characterisation can play
a useful role here in product and process optimisation. For instance, one of the factors that influences tablet hardness and
friability is the consistency of the die filling, which in turn is impacted by the characteristics of the powder blend. Even
if the die can be filled uniformly at a commercially viable press speed, it is vital that the entrained air is rapidly released
during compression and compaction, as retention can lead to capping and lamination. Retention is especially a problem for
larger tablets that are more likely to be scored. The ability of the blend to release air can be quantified using parameters
such as permeability and through dynamic characterisation of aerated powders. Finally, the response of the powder to compression
can be directly measured via compressibility testing. In summary, comprehensive multifaceted powder characterisation supports
the development of optimised formulations and more exacting processes, both of which are required to produce well-engineered,
mechanically stable scored tablets that are easy for patients to use.
FDA is currently working on draft guidance for tablet scoring. If implemented, how could such guidance affect analytical approaches
for scored tablets, both in terms of new developments and demands from the industry?
Increased focus by the FDA on scored tablets intensifies the requirement for manufacturers to adopt a rigorous quality-by-design
(QbD) approach to their tablet development processes. Analytical approaches that can lead to a better understanding of critical-to-quality
parameters, such as content uniformity and mechanical stability as outlined above, are therefore likely to become increasingly
important. Properties that predict blending performance and how the blend will subsequently perform in the tableting press
are especially valuable. For example, returning to the issue of air entrainment and release, processing powders with low permeability
at high rates can ultimately lead to trapped air building up in the powder at all stages of the press due to fast powder flow
rates and recycle. The net result is an eventual degradation in tablet quality. This is just one of many illustrations of
how powder property data can help processors make sound decisions about what equipment to use and what production rates to
target for efficient scored tablet manufacture.
1. Blending white paper at: http://www.freemantech.co.uk/en/literature-and-downloads/articles-and-white-papers.html#white-papers