Perfectly formed

The development of new oral products is placing additional demands on tablet handling technology. Ron Garwood of Electro-mec looks at some of the latest challenges and how blisterpack feed systems are responding to them

In the pharmaceutical industry the rewards for finding the next blockbuster drug are enormous. Yet for every product that succeeds in breaking into the market, there are many that don't make it, which means manufacturers need to maximise their production throughput and efficiencies.

The competitive marketplace, coupled with continuing advances in science and technology, means new products are being brought to market in greater numbers than ever before.

This brings another challenge to the pharmaceutical packing operation, since production runs today are often short, with more frequent changeovers.

For tablets and capsules, the preferred type of packaging remains the blisterpack. It is convenient, easy to use and its measured method of dispense makes it an excellent means of ensuring that a patient takes the right amount of product over the right period. Naturally there has never been a standard blister pack format – and after all, its flexibility is one of its greatest advantages. Nevertheless, as products have become increasingly sophisticated, so the variety of blisterpack layouts has continued to grow.

For example, chevron-shaped blisterpacks, where the forms are at an angle, enable more product to be packed into one blister, a useful benefit for larger sized tablets and capsules. Some packs now have to accommodate two or more different products – which can also be different shapes – that need to be taken on specific days. There are also certain drugs where there is one tablet that must be taken first and which therefore needs to be isolated and highlighted on the pack.

careful handling

Similarly, products do not come in standard shapes or sizes either. These can vary from standard round bi-convex, which roll easily during the packing process, to flat or elliptical and multi-faceted shapes that need a degree of agitation to aid feeding.

Many products manufactured today can be quite brittle or fragile, causing them to shingle or break if not handled carefully during the packing process, which can lead to unacceptably high reject rates.

Meeting these new challenges while maintaining accuracy, speed and efficiency and minimising rejects has changed the face of blisterpacking in recent years.

Until about 10 years ago, the most common method of handling tablets was with a 'brush box'. Product is deposited on the web where the blisters are created and 'brushed' along into the forms. While this method remains in use today and, apart from limiting line speeds, is still perfectly acceptable for most standard shaped tablets and capsules, it is often not flexible or adaptable enough to deal with the more complicated products or applications.

The brush box method relies on product finding its own way into each blister form; it does not, therefore, take into account products that do not move easily. It is also less able to cope with blisterpack layouts. And in the 'free for all' that precedes product reaching the forms, there is a high risk of tablets chipping or breaking.

In the past, the only obvious alternative to meet the twin requirements of accuracy and careful handling for awkwardly shaped products or layouts would be to pack by hand. But such a method is very time-consuming – with a corresponding drop in product throughput – while high labour costs mean it can never be considered as a long-term solution.

The challenge of finding a machine to combine the accuracy and gentleness of hand packing with maximum machine speeds was taken up by manufacturers during the early 1990s.

preventing damage

Electro-mec's solution was to develop a range of feeders featuring individual feed tubes which precisely position a single tablet or capsule in each form every cycle, reducing misfilled rejects and allowing rapid, intermittent motion packing. It also prevents shingling, chipping and damage caused by excessive agitation of the tablets.

Individual change-part tooling is devised for each separate tablet or capsule to enable fast and easy changeovers. Indeed, machines are now being designed that can alternate easily between different filling methods, depending on the product being packed.

Product trials are an essential part of bringing a new product to market, and this too can often involve complicated or challenging packing requirements.

space restriction

Clinical trials, for example, not only mean short packing runs, but can often involve patients taking different products in different combinations on different days. This requires placing a number of tablets or capsules into one blister form while a different combination may be needed for the one immediately next to it – all of which need to be presented in a form that ensures patient compliance.

In these circumstances space restrictions may prevent an individual feeder being dedicated to each product, so machines have to be adapted to handle more than one product at the same time.

The most recent challenge the packing and filling industry has had to face is the continuing sophistication of the blisterpacking machines themselves. Today, many blisterforming machines work on the continuous as opposed to the intermittent motion method. This means that the web is continually moving and a feed system has had to be developed that synchronises with the web, maintaining the speed and accuracy of the filling process. Again, handling has to ensure the tablet is presented in optimum condition.

innovative design

Electro-mec has supplied an EMF to Pharmacia in Belgium, tailored to meet the demands of packing high compression tolerance elyptical bicon tablets, which are awkward to handle and prone to damage and shingling during the feeding process. Pharmacia was looking to increase productivity by using a more efficient method than brush feeding but the complexity of the tablet demanded a special solutions approach.

Electro-mec developed important new features for its EMF4D, which is installed over a UPS4MT blister machine, to meet the company's requirements. An innovative high frequency tapping motion is combined with a highly-polished interior surface of the feed tube to ensure that each tablet is placed quickly and accurately into the blister form, while at the same time ensuring a smooth and careful operation which dramatically reduces the risk of tablet damage.

This process has enabled the company to increase production speeds, feeding 140 tablets in one cycle.

'The high compression tolerance of this particular tablet makes it very awkward to feed,' explained Marc Sonck, PTS project engineer. 'Prior to installing the EMF machine, we were using the traditional brush box method backed up by a significant amount of hand filling to place each tablet into the blister without damage, which was time-intensive and did not meet our objective for increased production efficiency. The new machines have significantly increased the efficiency of our operation.'

Following the success of the new solution, Electro-mec was asked to supply two additional feeders – an EMF4D and a secondary system for use with a smaller EMF3 machine, which have just been delivered.

Vibrators aid Viagra

With the explosion in Viagra sales came problems with packing the diamond-shaped tablets. The tablet is not suitable for standard feeders, and the pockets are designed to be positioned very close together. The key to solving the problem for the maker, Pfizer Turkey, was to use a new vibratory feeder from Italian company IMA. The new feeding system eliminates the need for change parts on feeders and can handle tablets and capsules of various shapes and sizes without any adjustment. It is ideal for unusually shaped tablets and can also handle tablets with variations in dimensional tolerances. Hasan Sezer, operations manager, Pfizer Turkey, said: Viagra comes in three sizes, plus the related doctor sample sizes. We would have required six feeding size parts for the blister packer. However, using the new IMA vibrating feeder has enabled us to handle the different sizes with one system, The reason for this is that the vibrating elements bring the tablets right up to the table and the product recirculation system ensures that any unfed tablets are returned to the pre-feeder. The fact that tablets stay for a very short time inside the infeeder reduces the likelihood of chipping and damage. As Viagra tablets are coated and printed, reducing the time in the vibrating feeder reduces the chances of waste product," Sezer said. Handling a tablet or capsule at speed without damaging it is an aim for IMA's new C96 blister packing machine. Over the past three years the trend has been to increase investment in high speed machines," suggested Henk van der Ree, marketing manager – blister department, IMA Italy. He described the new machine during a seminar on blister packing, held at IMA's open house last October. It is due to be launched at Interpack 2002, will have an output of an incredible 1,200 blisters a minute. T +44 118 977 2323
F +44 118 977
3453 hotdesk@ima.co.uk

Manesty to launch mpower

Following its recent relocation to purpose-built premises, Manesty is set to launch a series of major products at interpack 2002. A new family of tablet presses incorporates mpower integrated technology - designed in collaboration with customers to achieve the lowest total cost of ownership - to maximise product yield and ease of use. These new presses are said to offer the fastest product-to-product changeover, with and without turret removal, and a Windows NT control system compliant with FDA CFR21 Part 11 requirements for electronic records and signatures. The next generation of the Accelacota tablet coating system has a new control system, which also complies with FDA CFR21 Part 11 requirements, and is an entirely modular design. It also has a new CiP system plus a range of new features to further improve standards of GMP and ease of use. An XL model advanced plug and play tablet coater for r&d applications has already been installed in leading laboratories around the world. T +44 151 547 8000
linda.cashmore@manesty.com Picture: To guarantee total quality control, all Menesty Diamond tableting presses can be equipped with a WHT (Weight/Hardness/Thickness) in-process controller.