Q. What has been the greatest innovation in the tabletting industry during the past few years?
Prideaux: It is difficult to single out one innovation because there have been a number that have had a significant influence on the
industry, including direct compression, which is an extremely efficient process in terms of process control and tableting
parameters. In-line process inspection is another technology that has significantly impacted tablet production processes by
helping to control variability. Tablet coating technologies have also developed considerably and can provide innovative solutions
for drug dissolution and controlled release. From a tablet compression tooling perspective, we have seen multi-tip tooling
(increasing the number of tablets produced from a single punch), die segments (increasing the number of punches in the tablet
press) and tool coatings, all of which have had a positive impact on tablet manufacturing.
Natoli: The tablet compression industry has seen many innovations in recent years, such as wash/clean in place technology, product
containment, exchangeable die disc and die shells, die segments and tablet-in-tablet technology, to name but a few. In my
opinion, the greatest is not so much a new innovation but rather a new acceptance of an older technology: multi-tip tooling.
Although multi-tip tooling has been used in tablet compression for over a century, it's only in the past couple of years that
it has now been refined and accepted by the pharmaceutical industry. Multi-tip tooling can help manufacturers to significantly
increase production; for instance, one tablet manufacturer we were working with was producing six to seven thousand tablets/min
using a single tip, but became capable of producing 24 to 30 thousand tablets/min after switching to 4 tip. The number of
punch tips per tool is typically related to the punch size and tablet size. Companies can contact their tooling manufacturers
to find out if their product is a candidate for multitip tooling.
Chesnoy: The demand for reduced costs and simpler formulations has led to further development of the direct compression technique.
In this technique, powder characteristics are critical. The need for improved powder properties, without having to develop
a new chemical entity, has been met by the development of co-processed excipients, where several excipients are processed
simultaneously to obtain synergistic effects in functionalities. A number of articles have been published that highlight the
advantages of co-processed excipients for tabletting.2,3
Q. What features/improvements would you like to see in future tabletting methods/processes?
Prideaux: As a supplier of tablet compression tooling, we would welcome tablet press manufacturers embarking on some degree of standardisation
(e.g., key positions) in line with global tooling standards across all types of tablet press. This would benefit the end users
by increasing the potential for interchangeability of tooling across tablet presses and individual production sites/markets
worldwide. Lubrication-free tablet presses would also help tablet manufacturers to minimise product loss caused by contamination.
Finally, we would welcome innovation around the in-line monitoring of formulations prior to compression (e.g., humidity and
granule size), which could do much to mitigate process variation throughout the tablet production process.
Natoli: There is a strong need for integrated temperature monitoring and controls for high-speed output tablet presses. A growing
number of tablet formulas and granulations are sensitive to tablet press operating temperature and the heat generated by tablet
compression.
Sensing functions would also be useful for both new and retrofit tablet presses to give feedback on whether a product has
started to pick or stick on the lower punch before producing a barrel of tablets. Also, detecting the necessary forces required
to remove a tablet from the lower punch could set new guidelines to eliminate question marks over differences between development
and production. Although, maybe this isn't possible!
Chesnoy: Simplification is the key word! Simplification of formulas and processes will ultimately help save time and costs.
Among compression techniques, direct compression remains the simplest technique available and requires less time and energy.
On the other hand, this technique is highly demanding in the number of required excipient properties. The ideal excipient
for direct compression should exhibit constant particle sizes and shapes as these have a strong influence on density and compressibility.
Compactability is also affected by tablet size and weight, and the type of press used in manufacture. In the end, in-depth
excipient knowledge linked to process equipment will be a win–win strategy for developing innovative excipients for the tabletting
industry.
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