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Child Safe Packaging Group


Developments Towards Child Resistant Flexible Packs

Date of page: Thu 22 May 2003 at 10:49am

Child Resistant Packaging ??? Safety for Children, Openability for Adults and Developments Towards Child Resistant Flexible Packs

By Stephen Wilkins

Clinical Trials 2003, 21st ??? 22nd May, Madrid

The Background

Initially I would like to discuss the background to child resistant packaging, the development of standards throughout the European Union, their harmony and lack of harmony in some cases.

The last eighteen months has seen the publication of two new standards; in the UK BS 8404 covering flexible child resistant packaging for pharmaceuticals and Internationally ISO 8317 2nd Edition (April 2003) dealing with child resistant reclosable packaging but incorporating a number of important developments.

Finally, I shall look at some of the ways that the packaging industry has reacted to these changes and show some recent developments and ideas.

Firstly though the background.

Child resistant (CR) packaging emerged in the early 1970???s in the United Kingdom, and slightly later throughout other European Union Countries. Initially testing, using panels of children, was undertaken only for reclosable systems; the familiar bottle and child resistant closure. It was considered then and it continued to be believed until recently that flexible, or non-reclosable packs; the familiar blister or strip, were inherently child resistant.

The standards to which reclosables needed to comply have, during the past 27years, undergone change and modernisation to conform to the changing characteristics and needs of the population. In the UK the standards were BS 5321 (1975), BS 6652 (1985), BS EN 28317 then ISO 8317 and finally 8317 second edition April 2003.

Non-reclosables enjoyed the ascription of ???inherent child resistance??? until December 21st last year, through compliance with BS 7236 (1989), which did not specify child panel testing or testing by adult panels, merely materials, seal strength, seal integrity, freedom from rattle and resistance to bending. It was set out in the introduction to BS 7236 that if compliance was achieved the pack would ?????..(be) comparable to reclosable child resistant packaging in terms of child safety.???

It was easy to see that compliance with BS 7236 granted an element of protection in the event of prosecution for breach of consumer protection legislation or the EU directive on general product safety and would provide a suitable defence in the event of any civil action. Similarly it enabled lip service to be paid to the Royal Pharmaceutical Society???s practice direction that ???..prescription medicines should be packed in child resistant containers.???

In 1997 BS EN 862 was published, this standard was subsequently updated in 2001, it is entitled ??? Packaging ??? Child Resistant Packaging ??? Requirements and Testing Procedures for Non-Reclosable Packages for Non Pharmaceutical Products.

The major sea change in the standards to which flexible packaging need to comply arose though in December 2001 with the publication of BS 8404 (2001) entitled ??? Packaging ??? Child Resistant Packaging ??? Requirements and Testing Procedures for Non-Reclosable Packages for Pharmaceutical Products.

A child resistant non-reclosable packaging standard for medicinal products has been in existence in Germany since October 1980. Its reference number is DIN 55 559 and it was up-dated in October 1998.

All four standards are intended for type approval, in other words to certify products as child resistant when formed from a specified set of materials, and clearly they are not designed for QC procedures

A Discussion Concerning the Standards

The three standards dealing with non-reclosables and the standard dealing with reclosables differ in a number of respects and it is worth setting down the major areas of difference to enable us to gain an understanding of the environment of the regulatory structure. If desired a more detailed comparison can be provided or dealt with during discussion.

The Child Test

In the case of all standards the child sample consists of a maximum of 200 children aged 42 to 51 months, equal in distribution between boys and girls.

In all standards sequential testing is used for the child test, which by measuring trends enables a success to be ascertained after testing a minimum of 29 individuals, and a failure after only 5. This is achieved by plotting results as they occur, either above the previous result or immediately to the right of it, and when the resulting curve passes into either an acceptance or a rejection zone the pack will pass or fail.
If the total sample is used, in all cases, a pack will be considered child resistant if at least 85% of the children in the test panel shall be unable to open the package without a demonstration or at least 80% of the children in the test panel shall be unable to open the package after a demonstration.

The Definition of an Opening

BS EN 862 ??? simply that the pack be opened.

DIN 55 559 ??? ???..a child is able to gain access to sufficient unit doses to cause severe injury or damage or to remove more than eight units.???

BS 84 04 ??? ?????the children are able to access more than eight units.???

ISO 8317 ??? A simple opening.

The Test Period

In the case of BS 8404, DIN 55 559 and ISO 8317 the test period is 5 minutes prior to a silent demonstration and 5 minutes after. In the case of BS EN 862 (2001) the period is 3 minutes prior to demonstration and 3 minutes after.

There is no satisfactory reason for the different test period, 3 minutes or 5 minutes, and clearly there is no satisfactory reason for the difference in the definition of an opening, viz. ??? ?????.more than 8 units??? (BS 8404) or ?????.sufficient unit doses to cause severe injury or damage.??? (DIN 55 559).

Brand owners, packer/fillers and licence holders will obviously wish to act prudently in this regard.

The Adult Test

Child resistant packaging remains the only system of packaging that needs to pass a panel test for openability by adults.

In the case of BS 8404 the adult test group consists of 100 literate participants, selected randomly, between the ages of 50 and 70; 25% 50 to 54, 25% 55 to 59 and 50% 60 to 70, skewed 70% female.

In the case of BS EN 862 the adult test ??? which is optional, utilises a panel of 100, again 70% shall be female, 80% must be between 18 and 60 years of age and 20% between 61 and 65 years of age.

In the case of DIN 55 559 the adult test uses a group of 100 persons between 18 and 45 years of age, and 70 persons between 61 and 65 years of age. Again skewed 70% female to 30% male.

In the case of ISO 8317 (2nd Edition) the test panel consists of 100 adults between the ages of 50 and 70 configured identically to BS 8404 namely 25% 50 to 54, 25% 55 to 59, 50% 60 to 70 and skewed 70% female.

Passing the adult test is achieved in the following fashion.

BS 8404 ??? after a period of familiarisation 90% of the sample must be able to extract 1 unit dose within 1 minute without a demonstration.

For BS EN 862 optional adult test shall be deemed to have failed if the package cannot be opened within 5 minutes by 90% of the sample, or as specified in the sequential procedure; no demonstration is allowed.

In the case of DIN 55 559 the period for opening is 5 minutes and the failure threshold is 15%.

In the case of ISO 8317 the pack must be opened and reclosed within 1 minute without demonstration.

There are however major areas of concern within BS8404 and these indicate that only lip service is being paid to the needs of the elderly.

Firstly at BS 8404 section ??? Composition of the Adult test group ??? the standard states ???Persons with obvious physical disabilities that might affect manual dexterity shall not be approached and those unable to understand the written opening instructions discounted.???

Clearly to discount those who suffer a physical disability is to create a sample that does not reflect the universe and thus immediately to introduce statistical bias.

But here is the major area of concern. At section headed ???Test Procedure??? where a period of five minutes familiarisation is being allowed, the standard states ???Those participants who successfully open the test package within the five minute period shall be given a new identical package and shall be requested to open this one as quickly as possible. A one-minute test period shall be allowed for the participant to open the new packaging.??? Remember, 90% of the panel must now open and extract one tablet for the pack to pass.

It goes on to say ???Those participants unable to open the test package within the five minute test period shall be discounted from the test and their places taken by new panellists.??? (My emphasis)

Now statistically this is an indefensible piece of methodology, it is effectively a case of ???keep interfering with the sample until we find one that suits us.???

In the second edition of the reclosable standard ISO 8317 a refinement has been incorporated. In section 5.5.3 it states ???If during the five-minute familiarisation period any panellist is unable to open the package he/she will be given a screening test. This screening test shall consist of asking the panellist to open and reclose two conventional non-child resistant closures in one minute each being -

A. A 28mm diameter continuous screw thread closure applied at 1.1N.m torque onto a 25ml to 50ml cylindrical plastic container.
B. A 28mm diameter snap on closure applied to a 25ml - 50ml round plastic container.

Panellists unable to open and reclose both of these packages in the one minute screening test are to be discounted from the adult panel test ??? in other words their inability to open a child resistant closure is explained by the fact that they cannot open any closure at all.

The revision to the standard goes on to say that panellists who are able to open both these packages in the screening test but not the CRC are counted as a failure in the overall result.

The disparity of standards is due to the haphazard nature of the timing of their introduction but the glaring bias in BS 8404 indicates that the standard will not produce packaging systems that are truly senior friendly, namely openable by 90% of the elderly population or universe. This in turn may encourage elderly users to decant medicines or have medicines decanted from their CR blister packs and the danger to children will be correspondingly increased.

However, in an article I published in Manufacturing Chemist in the UK in February of last year I said ???The UK pharmaceutical industry and all the other organisations involved in the preparation of BS 8404 are to be congratulated on achieving a workable standard that advances child safety in pharmaceutical packaging and certainly does not pay lip service to existing rules, procedures and practices. Indeed, many in the pharmaceutical industry had overcome long held beliefs even to be a party to BS 8404.???

BS 8404 is therefore a start, it is a standard with which the industry can work but which can be improved upon.

Making Blister Packs and other Non-Reclosables Child Resistant

In the United States where blister packs are less popular than in the European Union child resistance is generally achieved using a peel back and push mechanism instead of the simple push through that is the preferred European non child resistant design.

Peel back and push has a number of inherent problems when considered alongside the limitations of elderly users. According to the UK charity Age Concern, which has undertaken a programme to assist designers in assimilating the modalities of old age; it is possible to test the finger tip friction by coating the fingertips in talcum powder, this, according to Age Concern, replicates the lack of grip experienced by those between 60 and 70.

It is for this reason that blister packs using the traditional peel back and push, or merely peel back system, have not achieved popularity in the United States where the system originated and has been used since the late 1970???s.

Our organisation, the Child-Safe Packaging Group, has investigated a number of alternative designs to achieve both child resistance and senior friendliness and, at the same time, be easily manufacturable by brand owners and packer/fillers.

One of the first solutions that we considered was to utilise a label solution by adhering over the foil a security strip, which we termed ???unburstable.??? In fact it exhibited high burst but low tear strength. This was a patent originated by Doctor James Robertson, a Paediatrician and Consultant to the Child-Safe Packaging Group. Development work was undertaken by Pago Limited, the label print and label print machinery manufacturers.

The security strip system was subjected to child testing in a number of configurations using ever more aggressive adhesives. Unfortunately it did not work. The worst case scenario being generated by the security strip giving greater integrity to the foil, which instead of breaking at the first blister, was torn off in its entirety thus enabling all the contents to be extracted.

We have toyed with ideas using peel back and push with a channel along the centre of a blister enabling a thumb nail to be inserted thus assisting the peel back. This is satisfactory for all those who have thumb nails!

Dr Robertson, to whom I have already referred has most recently taken out a patent, which by design of the blister cavities and channels alongside them, creates thumbnail breaks for adults to pierce a high burst but low tear strength backing material. Dr Robertson???s invention is based upon the fact that children???s finger and thumbnails are soft and those of adults are hard. Indeed the older the adult the harder the finer and thumbnails.

A number of solutions have been observed that are presently being developed and these revolve around an integral box, which is itself child resistant. However, it is questionable as to whether the blisters contained within the box are child resistant and, according to BS 8404, ???..the packages should be presented to the children without the outer retail package, giving them access to the individual blister units.???

There has been discussion as to whether the child resistant outer box constitutes an integral part of the blister pack or an outer retail unit. However, the form of words, ???..access to the individual units??? is totally unequivocal, therefore an outer box that is child resistant may well qualify under ISO 8317 as a child resistant reclosable but does not qualify under BS 8404 as a non-reclosable package for pharmaceutical products.

Whilst the concept of making the blister packs box child resistant will not comply with BS 8404, creation of a box to contain blister packs could comply with ISO 8317. Dragon Plastics, a member of the Child-Safe Packaging Group, has produced BlisterloK, now at the development stage. A single piece injection moulding, where child resistance is achieved through the necessity of simultaneously pressing two points on either side of the flip top and at the same time raising that top with the fingers of the other hand.

This, as well as creating child resistance for a single or number of blister packs, has the benefit of added value because it substitutes a degradable cardboard container for a durable injection moulded plastic one.

Continuing on the theme of added value, Pago, to whom I have already referred, remain committed to a mid-line label solution. But their research indicates that the necessary adhesion can only be achieved in the case of a substantial increase in size of the blister pack and a concomitant increase in size of the box, with the obvious cost increase - probably up to 50%.

Pago???s view is that if a significant piece of added value can be incorporated then this additional cost will be not only acceptable but almost welcome. The additional added value that they have considered takes the form of a magnetic strip, an integral part of the child resistant label, which will contain product, batch and other data to make product tracing easy.

But more than anything else to assist in hospital dispensing and prevent circumstances where incorrect drug dosages are given to hospital patients. The system would work because a magnetic strip reader would verify the prescription and the patient at the point of dispensing.

Another, and apparently workable, child resistant flexible pack has been developed by the UK company Pill Protect.

Pill Protect, which passed BS 8404 and received a compliance certificate in March 2003, is a flexible mid-line solution and allows existing blister packing equipment to run at optimum speeds. The system has been used in Europe and the United States for clinical trials and is now available to the wider market.

The system comprises a combination of permanent and peelable adhesive labels, diecut and applied in registration to the foil-backed blister. Opening is straight forward, firstly a safety strip is removed and this exposes each cavity label but importantly exposes a tab which enables easy peeling and clearly has allowed the system to pass the adult testing ??? BS 8404.

The major advantage of Pill Protect is that it provides child resistance with existing systems and at existing speeds. However, it is still, I believe, subject to ongoing type approval.

The Concept of Child Resistance

Child resistance is achieved by creating a barrier of either dexterity or cognisance. Examples of barriers of dexterity are generally the necessity to undertake two opposing actions simultaneously, hence push down & turn the most popular child resistant closure system and squeeze & turn ??? less popular particularly with the elderly constituency.

Amongst reclosables an example of a barrier of cognisance is a ???line up the arrows??? solution, and amongst non-reclosables barriers of cognisance are achieved through an instruction ??? for example ???fold a 45?? and reveal a hidden tear start.??? Peel back and push is also a barrier of cognisance as generally a graphic or written instruction is required.

Whilst mid or end line manufacturing systems for child resistance, for example label solutions, are desirable from a cost point of view, it is debatable as to whether these will find acceptance in use by the elderly constituency.

And my belief is that the European packaging supply industry can distinguish itself by developing a cognitive system of child resistance, which will defeat the attempts of children to open a package but present no difficulty for adults to of all ages to use properly.

Designing the Cognitive Solution

Our organisation the Child-Safe Packaging Group has considered a number of designs that we have either sponsored or sponsored and developed, which will create a barrier of cognisance. I am including in this section other designs, which bear upon cognisance but rely upon physical attributes.

Firstly let us consider a system not originated by us but in use by Glaxo SmithKline. This is a laminate obscuring the blister but indicating the location of them. Never designed to be child resistant this system could be made so, if suitable integrity is given to the PVC and the outer foil.

Reverting briefly to a physical/cognisant barrier, we assisted in the concept of a system where a double blister pack was used but the push out portion of the blister was only exposed when compressed with an adult sized hand. Male or female, old or young the hand needed to be adult sized and a child???s hand would simply not accomplish the task. That claimed cognisance on the basis that the system was sufficiently complex as to require a written or graphic guide.

I believe that the best route forward though lies along the lines of one of our developments whereby in unit dose medicines each unit is housed within a child proof, indeed adult proof or impregnable chamber, and for extraction it needs to be encouraged along a channel into an expulsion chamber. The Child-Safe Packaging Group has sponsored a number of ideas utilising this system. It is this sort of barrier of cognisance that I believe will constitute the best route forward.

I was led recently by a colleague ??? Dr Belinda Winder of Sheffield University in the direction of false affordances. In other words what signs are given in this slide (33) ??? which door is push, which is pull. The door on the left is a true affordance but the door on the right is not.

Now could it be that a system can utilise affordances that are false to children but true to adults. Clearly this is an area for discussion and for research.

The tabs on the liners in this slide indicate an affordance, is it true, is it false. Clearly it is necessary to fold back and pull ??? but in which direction. Research here is ongoing but the time-honoured paradigm of child resistance, the reclosable push down and turn has always succeeded by adopting an opening procedure that is impossible for children but possible for adults. Namely two opposing actions simultaneously.

That of itself gives the child a false affordance, namely ???do we unscrew ??? of course we unscrew.??? It never occurs to the child to push down first.

If a series of opening signs can be devised based upon this paradigm then I believe the most workable child resistant flexible pack will have been created.

Brand owners and packer/fillers though could look again at tried and tested systems and certainly for many prescription drugs and over the counter analgesics used by the ???walking wounded???, namely those people who though sick continue with their daily lives, the bottle and CRC may well be the best solution.

Unit dose packaging is unique, it protects the product not merely from the environment but from contact with other products. But where such sophisticated packaging is not required, consideration should well given to reclosable systems.

A final word, as we speak the Comit?? Europ??en de Normalisation ??? CEN is debating a new standard ??? EN 14375, presently CEN is prepared to adopt BS 8404 almost unchanged. Pressure though is being brought by ANEC (The European Association for Consumer Participation in Standardisation.)

ANEC is demanding that levels of toxicity be incorporated into the new European Standard.

After the great steps forward over the past seven years catalysed by our organisation my suggestion now is that toxicity be incorporated. This will bring the European Union into line with the USA and, at the same time, the standards that I have referred to herein be harmonised.

Stephen Wilkins
Madrid 22nd May 2003
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