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Blister packs for pharmaceuticals is an emotive subject, understandably so when it is related to child protection. This method of packaging was first used in the US in the early 70s but it is still far from perfect. Rodney Abbott reports

Consumer watchdogs and the lawmakers have been pretty demanding over the years. Both suppliers and users have had a tough time of it but, with fresh EC legislation on the horizon, it is going to get a lot tougher.

According to Uhlmann’s Dieter Janek, who was one of the pioneers of blister packing, the concept of child resistance to blisters began in the US in 1970 with the Poison Prevention Packaging Act.

This produced many variations of the blister, including some that were complex to produce and open. As a result, only 20% of products in the US are packed in blisters.

In the UK the pharmaceutical blister is far more ubiquitous. Why? “Because it has never needed to be child resistant and has always been cheaper than reclosables,” asserts Stephen Wilkins of the Child-Safe Packaging Group.

Others argue that the blister pack offers improved patient compliance, notably calendar packs, product stability and protection, convenience, tamper evidence, hygiene and low cost, especially for small packs.

But, when fresh EC legislation materialises, many fear that costs could soar all the way down the packaging chain. Why? Because, whatever solutions for child resistance are implemented, the probability is that blister sizes will increase and be based on the German model involving higher gauge or different substrates and perforation of lidding foil.

Accordingly, the minimum workable space between pockets will be doubled and, for some, base substrates the pocket angle will need to be shallower, contributing to a significant increase in overall blister size.

Materials’ costs downstream as well as on the blister machine will increase, with larger cartons and cases required.

This will impact right through the supply chain, affecting transport, storage and distribution functions for both suppliers and retailers.

Another challenge facing the industry is how to achieve child-resistance and limit the frustration of those said to be in the third age [55-70].

No provision is made for the over 70s but there are many who believe that medication after this age should be supervised by a responsible adult!

Pago has solved this problem by deadening the adhesive in the centre and putting a perforation around the pocket. When the perforation is burst, a tab is exposed and peeled back so that the pill is accessible.

Outside of prescription drugs, the American market is still very much a bottle market.

In the meantime the lawmakers are busy tightening up the rules. In the UK the Medicines Control Agency updated guidelines on blister labelling at the beginning of last month.

And these guidelines make it clear that, where practicable, the name and strength of the product should appear over each blister pocket or be oriented centrally across the pack.

Why? Because it is important that the particulars remain available to the user up to the point at which the last dose is removed from the blister pack.

It is not possible to apply all the information over each blister pocket but, where a random display of the information is proposed, it should frequently appear across the pack.

In all cases it is acceptable to apply the batch number and expiry date to the end of the blister strip. If technically possible this should be applied to both ends of the strip.

Blister foils should be printed to ensure maximum legibility of the statutory information using a sufficiently large font.

Colour for the text and the font style should be chosen carefully as the legibility of the text on the foil is already impaired due to the nature of the material.

Non-reflective material or coloured foils should be considered to enhance the readability of the information presented and the correct identification of the medicine.

Only a month or two ago machinery maestro Romaco staged a conference in a bid to put together an overall picture of the effects of fresh legislation on the industry.

At that meeting it became apparent that current moves towards further legislation within BS8404 [currently best practice] were prompted by a child poisoning which took place over two years ago.

It was suggested that BS8404 could be implemented as early as October of this year, with transitional arrangements running for a 12-month period thereafter. Pharmaceutical industry representatives reported serious reservations about this timeframe, given the amount of development and testing required.

When amendments are incorporated in EU legislation, the re-licensing process could become unnecessarily complicated.

EU legislation or not, there are some who feel that the moment of truth where standardisation is concerned has arrived, albeit to the detriment of innovation.

Leading the charge is Pago managing director Mike Cooper who is convinced that, unless the following criteria is met, much of the stream of innovation that is currently flooding the marketplace will fail to meet the required standards.

“We need to establish a benchmark where surface tension, adhesive and mechanical configuration parameters fall within a range that will automatically pass the child test,” he says.

“The child test is expensive and encourages children to open blisters. For this reason it is not generally liked. A less flexible standard could reduce these costs.

“To some extent such a move will stifle innovation but this philosophy works in the States. Admittedly, it will slow blister lines down and it may affect profitability.

“The advantage of such a label lies in short runs and, unfortunately for the industry, orders are getting smaller and smaller and lead times are getting shorter and shorter.

“The label industry has an opportunity to offer a solution but it needs one of the major blister machinery players to agree to a joint development programme.”

Not everyone in the industry believes that standardisation is the market requirement. “There has recently been a vast increase in the variations of pack formats and styles,” says Electro-Mec managing director Ron Garwood.

“Its flexibility, particularly in terms of artwork to indicate varying time periods, is one of its greatest advantages. Nevertheless, as products have become increasingly sophisticated so the variety of blister pack layouts has continued to grow.

“The chevron-shaped blister packs, where 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 needs to be isolated and highlighted on the pack.

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

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

While products and pack layouts are continually developing, one pharmaceutical packaging requirement that has not changed is the need for accuracy.

Meeting these new challenges, while maintaining speed and efficiency and minimising rejects, have all but changed the face of blister packing and filling.

Increased speeds and throughput on the packing lines have necessitated the development of bulk feed systems to keep product moving through the feeders.

Dusty products have provided a new challenge with many tablets leaving a fine residue on the blister pack. This causes problems in sealing, presentation and the perceived quality of the product. A means of extracting the dust during the packing and filling process has had to be devised.

Large or awkward shaped capsules and caplets have been prone to stand upright rather than lie down in the blister form. A special caplet orientation unit that gently pushes each caplet into the forms solves this problem and can be used equally effectively with brush box feeding methods.

Machines are also 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 the market place and again this can often involve complicated or challenging packing requirements.

Clinical trials, for example, not only mean short packing runs but can very often involve 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 adjacent.

It may not always be possible, because of space restrictions, to dedicate an individual feeder to each product and so machines have to be adapted to handle more than one product at the same time.

In ever-developing markets, new blister packaging challenges will constantly emerge. The packaging industry has proved itself very capable of responding in the past and doubtless will continue to work with customers to devise appropriate solutions in the future.